Patent Application
20240291100
Drivers of battery electric vehicles (BEVs) are pressing automakers to re-design their powertrains to enable recharge to 80% state-of-charge (SOC) in 15 min (fast-charge)—and more preferably in 5 min (ultra-fast-charge). In doing so, recharging BEVs would be competitive with the refueling of vehicles powered by internal combustion engines. This remains a significant challenge in that further engineering the battery pack, while useful for thermal management, does not address the underlying problems of ion transport and interfacial charge-transfer resistance responsible for high overpotentials encountered while charging cells at high current densities.
Ion-transport bottlenecks have their origins in solvation, speciation, and electrode-electrolyte interactions, where maximizing ion flux in the cell requires electrolytes with concomitantly high ionic charge carrier mobility and concentration. Dilute electrolytes (DEs) are often limited by low ionic charge carrier concentration, despite high ionic charge carrier mobility. Super-concentrated electrolytes (SCEs), on the other hand, grant access to electrolytes with higher charge carrier concentration, yet suffer from low carrier mobility due to their higher viscosity. Additional considerations arise at electrified interfaces, where ion flux is influenced by additional factors—e.g., the energetics of ion solvation and desolvation—and where interphases that form from electrolyte decomposition at anode and cathode play important roles.
Provided herein are electrochemical cell comprising (i) an anode or a current collector, (ii) a first electrolyte, (iii) a polymer membrane separator (including separators comprising microporous polymers), (iv) a second electrolyte, and (v) a cathode, wherein:
In some embodiments, at least one electrolyte comprises a locally concentrated electrolyte comprising one or more alkali metal salts (e.g., lithium bis(fluorosulfonyl)imide), a solvent (e.g., 1,2-dimethoxyethane), and a diluent (e.g., tetrafluoroethyl-2,2,2,3-tetrafluoropropyl ether). In some embodiments, the electrolyte contains one or more additional alkali metal salts such as lithium difluoro(oxalate)borate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, lithium hexafluorophosphate, or lithium bis(trifluoromethanesulfonyl)imide.
Also provided herein are microporous polymer according to the formula:
-[A-AB-B]n-,
Also provided berein are electrochemical cells comprising microporous polymers as set forth above, as well as methods for charging and recharging electrochemical cells under fast- and ultrafast-charging conditions.
employing locally concentrated electrolyte A and a microporous polymer separator is greater than or equal to 1 mAh cm−2 and less than or equal to 15 mAh cm−2. A 1.0 mA cm−2 charge/discharge protocol was used.
High power batteries require embodied materials that minimize charge transfer resistance at electrode-electrolyte interfaces and avoid excessive polarization, which depends both on the cell and electrode architectures as well as the ionic charge transport properties of the electrolyte. The present disclosure addresses each of these challenges directly with advanced electrolytes and interlayers in high energy density lithium metal batteries.
The need for low charge transfer resistance at the anode-electrolyte interface is addressed by using a microporous polymer film which becomes in-filled with specific components of a multicomponent electrolyte through selective partitioning, which is controlled both by the chemical structure of the polymer as well as the selection of components in the electrolyte. Judicious pairing of polymers and electrolytes provides synergistic effects—the selective partitioning afforded by the polymer provides for formation of a hybrid interphase which could not be formed without both polymer and electrolyte present.
The need for low charge transfer resistance at the cathode-electrolyte interface is addressed through the choice of cathode materials as well as the components in the electrolyte. Finally, the need for high conductivity electrolytes and low overall cell resistance is addressed through the choice of specific electrolyte components as well as the cell architecture. In doing so, the power rating of lithium metal cells can be increased by at least a factor of 4, with specific combinations accessing greater than 850 W/kg. In contrast, conventional cells would access ˜200 W/kg. The cycle life of these high power high energy density cells is long, due to the passivation of the lithium anode, which slows down considerably the rate of lithium consumption due to parasitic side reactions with other cell components. Determinations of lithium half cell and full cell Coulombic efficiencies under high rate cycling show 99.5%, consistent with a low capacity fade rate where 80% capacity is retained across hundreds of cycles.
Battery assemblies provided herein are useful in electric vehicles, seacraft, aircraft, and drones, the like. Advantages of the assemblies include, but are not limited to, power delivered as well as the cycle life of the high energy density cells. High power is desirable, e.g., for vertical takeoff and landing (eVTOL) in electric aircraft as well as in medium and long-baul trucking when bringing to speed large payloads. Rechargeable lithium metal batteries according to the present disclosure, delivering high power with long cycle life, can be used in applications where conventional lithium-ion batteries cannot.
As used herein, the term “locally concentrated electrolyte” refers to an electrolyte comprising one or more solvents, one or more diluents, and/or one or more alkali metal salts. The total molar concentration of the alkali metal salt(s) in the electrolytes typically ranges from about 0.5 M to about 7.5 M.
As used herein in the context of electrochemical cells, the term “solvent” refers to an electrolyte component which dissolves alkali metal salts in an electrolyte. Examples of solvents include, but are not limited to, ethers, orthoesters, carbonates, lactones, sulfoxides, sulfones, sultones, sulfonamides, amides, carbamates, and combinations thereof.
As used herein, the term “diluent” refers to an electrolyte component comprising a fluorinated ether, a fluorinated orthoester, a fluorinated carbonate, a fluorinated lactone, a fluorinated sulfoxide, a fluorinated sulfone, a fluorinated sultone, a fluorinated sulfonamide, a fluorinated amide, a fluorinated carbamate, a fluorinated urea, or any combination thereof.
As used herein, the term “alkali metal salt” refers to an electrolyte component
comprising at least one alkali metal cation and a counter anion. Examples of alkali metal salts contain anions such as chlorate, perchlorate, nitrate, phosphate, hexafluorophosphate, borate, tetrafluoroborate, difluoro(oxalate)borate, bis(oxalate)borate, bis(fluorosulfonyl)imide, bis(trifluoromethane)sulfonimide, closo-dodecaborates, halogenated closo-dodecaborates. closo-carboranes, halogenated closo-carboranes, and combinations thereof. In some embodiments, the alkali metal salt is a sodium salt. In some embodiments, the alkali metal salt is a lithium salt.
As used herein, the term “polymer” refers to a molecule composed of repeating structural units, referred to herein as monomers or repeat units, connected by covalent chemical bonds. Polymers are generally characterized by a high molecular weight, such as a molecular weight greater than 100 atomic mass units (amu), greater than 500 amu, greater than 1000 amu, greater than 10000 amu or greater than 100000 amu. In some embodiments, a polymer may be characterized by a molecular weight provided in g/mol or kg/mol, such as a molecular weight of about 200 kg/mol or about 80 kg/mol. The term polymer includes homopolymers, or polymers consisting essentially of a single repeating monomer subunit.
The term polymer also includes copolymers, which are formed when two or more different types of monomers are linked in the same polymer. Copolymers may comprise two or more monomer subunits, and may include random, block, alternating, segmented, grafted, tapered and other copolymers. Useful polymers include organic polymers that may be in amorphous, semi-amorphous, crystalline or partially crystalline states.
As used herein, the term “repeat unit” refers to a part of a polymer that represents a repetitive structure of the polymer chain, the repetition of which would make up the complete polymer chain with the exception of end groups corresponding to terminal ends of the polymer chain. A repeat unit may also be referred to herein as a monomer. Repeat units may be identified in a polymer structure by brackets or parentheses and include a subscript n, which represents the degree of polymerization. In some embodiments, values for subscript n include integers selected from, for example, 10 to 1000, 50 to 900, 100 to 800, or 200 to 500. In some embodiments, subscript n is an integer more than 1000. It will be appreciated that a value for subscript n in a polymer may not be explicitly provided, consistent with use by skilled artisans in the field of polymer chemistry.
As used herein, the term “microporosity” refers to a characteristic of a material describing the inclusion of voids, channels, openings, recessed regions, etc., also referred to herein as micropores, in the body of material. In some embodiments, the micropores have a cross sectional dimension of about 2 nm or less. Micropores may have, for example, a cross sectional dimension of about 1.7 nm or less, 1.5 nm or less, 1.2 nm or less, 1 nm or less. or 0.8 nm or less. Optionally, micropores may have cross sectional dimensions selected from the range of 0.5 nm to 2 nm, selected from the range of 0.5 nm to 1.2 nm, or selected from the range of 1.2 nm to 1.7 nm. The inclusion of micropores in a material may allow for other materials, such as gases, liquids, ions, etc., to pass through the micropores.
As used herein, the term “intrinsic microporosity” refers to a continuous network of interconnected voids in a material formed as a direct consequence of the shape and rigidity of the components of the material. Intrinsic microporosity is achieved in some polymers by the polymers possessing individual structural units that are rigid and that may be oriented relative to one another in such a way that the structural units align to form an opening or pore. Additionally or alternatively, a polymer possessing intrinsic microporosity may have a structure that exhibits frustrated packing. Frustrated packing of a polymer may occur when a polymer molecule contacts itself or other like polymer molecules and the rigidity of the molecule(s) causes the molecule(s) to lie in a configuration where spaces between the molecule(s) are created. Such spaces may correspond to micropores in a film or membrane made of the polymer molecules, for example.
As used herein, the terms “polymer of intrinsic microporosity” and “microporous polymer” are used as synonyms to refer to a polymer that exhibits microporosity due to the shape and rigidity of the molecular structure of the repeat units within the polymer, where the repeat units may align relative to one another such that spaces or openings are generated along the polymer chain. Additionally or alternatively, the repeat units may align in an aggregate of the polymer in a way that frustrates packing of the polymer molecules in the aggregate such that spaces or openings are generated between different polymer molecules and/or between segments of the same polymer molecule. These spaces within the aggregated polymer may, at least in part, provide the microporosity to such a polymer. Due to the inclusion of the micropores, some polymers of intrinsic microporosity may exhibit high surface areas, such as a surface area selected from the range of 300 m2 g−1 to 1500 m2 g−1. Example polymers of intrinsic microporosity include, but are not limited to, those described in US 2017/0346104, U.S. Pat. Nos. 10,710,065, 7,690,514, 8,056,732, WO 2005/012397, and WO 2005/113121, each of which is incorporated herein by reference, as well as those described by Mckeown (ISRN Materials Science, Volume 2012, Article ID 513986), which is incorporated herein by reference.
As used herein, the term “electrochemical cell” refers to a device that produces electrical energy through chemical reactions. Example electrochemical cells include batteries and fuel cells. Batteries may include solid-state batteries, semi-solid batteries, wet cell batteries, dry cell batteries, flow batteries, solar flow batteries, primary batteries, secondary batteries, etc. A battery may refer to an assembly of a plurality of individual electrochemical cells, such as arranged in a series configuration. Example electrochemical cells include an anode, a cathode, a separator between the anode and the cathode, and an electrolyte. Electrochemical cells may further include a current collector in electrical contact with an electrode and/or an electrolyte and may be used, in part, to provide a conductive path between the electrode and a load.
As used herein, the term “anode” refers to an electrode in an electrochemical cell where oxidation occurs during discharge of the electrochemical cell. In some embodiments, an anode is identified in an electrochemical cell as the negative electrode, where electrons are emitted during discharge for use by a load. In some embodiments, an anode oxidizes material and releases positive ions to an electrolyte during discharge.
As used herein, the term “cathode” refers to an electrode in an electrochemical cell where reduction occurs during discharge of the electrochemical cell. In some embodiments, a cathode is identified in an electrochemical cell as the positive electrode, where electrons are received during discharge after use by a load. In some embodiments, a cathode reduces positive ions received from an electrolyte during discharge.
As used herein, the term “current collector” refers to any conductive substrate which is capable of carrying a current to and from the electroactive species in an electrochemical cell. In the context of anode-free electrochemical cells, ions extracted from a cathode (e.g., lithium ions) are electrodeposited at the current collector. The plated metal is then re-dissolved and deposited at the cathode during discharging of the cell. Examples of current collectors include metallized plastic films, metal foils, metal grids, expanded metal grids, metal mesh, metal wool, woven carbon fabric, woven carbon mesh, non-woven carbon mesh, and carbon felt.
As used herein, the term “separator” refers to an ion conductive barrier used to separate an anode (or current collector) and a cathode in an electrochemical cell. In some embodiments, a separator is a porous or semi-permeable membrane that restricts the passage of certain materials across the membrane. In some embodiments, a separator provides a physical spacing between the anode and the cathode in an electrochemical cell. In some embodiments, a separator is not electrically conductive and provides a gap in electrical conductivity between the anode and the cathode in an electrochemical cell.
As used herein, the term “electrolyte” refers to an ionically conductive substance or composition and may include solvents, ionic liquids, metal salts, ions such as metal ions or inorganic ions, polymers, ceramics, and other components.
As used herein, the term “anode electrolyte” refers to an electrolyte in an electrochemical cell in contact with an anode (or current collector). An anode electrolyte may further be in contact with a separator in an electrochemical cell.
As used herein, the term “cathode electrolyte” refers to an electrolyte in an electrochemical cell in contact with a cathode. A cathode electrolyte may further be in contact with a separator in an electrochemical cell.
As used herein, the term “membrane” refers to a web of material that extends in lateral dimensions, which may be orthogonal to a thickness dimension of the membrane. In some embodiments, the term “membrane” may be used interchangeably herein with the term “film” or “interlayer.” Optionally, a membrane separates two regions in space by the physical materials that make up the membrane. A membrane may be used as a support or template for other materials in order to provide structure and/or stability to the other material, for example. The other material may be attached to one side of the membrane, and or may encapsulate all or portions of the membrane.
As used herein, the term “support membrane” refers to a structural film that may provide mechanical stability to another material coated onto or otherwise attached to the film. In some embodiments, a support membrane may be porous or otherwise allow materials, such as ions, gases, or liquids, to pass through the support membrane, though any coated or otherwise supported material may restrict, at least in part, the passage of the ions, gases, or liquids.
As used herein, the term “alkyl,” by itself or as part of another substituent, refers to a straight or branched, saturated, aliphatic radical having the number of carbon atoms indicated. Alkyl can include any number of carbons, such as C1-2, C1-3, C1-4, C1-5, C1-6, C1-7, C1-8, C1-9, C1-10, C2-3, C2-4, C2-5, C2-6, C3-4, C3-5, C3-6, C4-5, C4-6 and C5-6. For example, C1-6 alkyl includes, but is not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, scc-butyl, tert-butyl, pentyl, isopentyl, hexyl, etc. Alkyl can also refer to alkyl groups having up to 20 carbons atoms, such as, but not limited to heptyl, octyl, nonyl, decyl, etc. Alkyl groups can be substituted or unsubstituted. For example, “substituted alkyl” groups can be substituted with one or more groups selected from halo, hydroxy, amino, alkylamino, amido, acyl, nitro, cyano, and alkoxy.
As used herein, the term “alkenyl” refers to an alkyl group, as defined herein, having one or more carbon-carbon double bonds.
As used herein, the term “alkynyl” refers to an alkyl group, as defined herein, having one or more carbon-carbon triple bonds.
As used herein, the term “heteroalkyl” refers to an alkyl group, as defined herein, containing one or more heteroatoms selected from N, O, S, B, Al, Si, and P. Typically, heteroatoms in a heteroalkyl group are non-adjacent heteroatoms.
As used herein, the term “cycloalkyl,” by itself or as part of another substituent, refers to a saturated or partially unsaturated, monocyclic, fused bicyclic or bridged polycyclic ring assembly containing from 3 to 12 ring atoms, or the number of atoms indicated. Cycloalkyl can include any number of carbons, such as C3-6, C4-6, C5-6, C3-8, C4-8, C5-8, C6-8, C3-9, C3-10, C3-11, and C3-12. Saturated monocyclic cycloalkyl rings include, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cyclooctyl. Saturated bicyclic and polycyclic cycloalkyl rings include, for example, norbornane, [2.2.2] bicyclooctane, decahydronaphthalene and adamantane. Cycloalkyl groups can also be partially unsaturated, having one or more double or triple bonds in the ring. Representative cycloalkyl groups that are partially unsaturated include, but are not limited to, cyclobutene, cyclopentene, cyclohexene, cyclohexadiene (1,3- and 1,4-isomers), cycloheptene, cycloheptadiene, cyclooctene. cyclooctadiene (1,3-, 1,4- and 1,5-isomers), norbornene, and norbomadiene. When cycloalkyl is a saturated monocyclic C3-8 cycloalkyl, exemplary groups include, but are not limited to cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl. When cycloalkyl is a saturated monocyclic C3-6 cycloalkyl, exemplary groups include, but are not limited to cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. Cycloalkyl groups can be substituted or unsubstituted. For example, “substituted cycloalkyl” groups can be substituted with one or more groups selected from halo, hydroxy, amino, alkylamino, amido, acyl, nitro, cyano, and alkoxy.
As used herein, the term “chalcogenide” refers to an atom selected from oxygen, sulfur, selenium, tellurium, and polonium. In certain embodiments, monomers and polymers of the present disclosure contain chalcogenides selected from oxygen and sulfur.
As used herein, the term “pnictide” refers to an atom selected from nitrogen, phosphorus, arsenic, antimony, and bismuth. In certain embodiments, monomers and polymers of the present disclosure contain pnictides selected from nitrogen and phosphorus.
As used herein, the terms “halo” and “halogen,” by themselves or as part of another substituent, refer to a fluorine, chlorine, bromine, or iodine atom.
As used herein, the term “aryl,” by itself or as part of another substituent, refers to an aromatic ring system having any suitable number of carbon ring atoms and any suitable number of rings. Aryl groups can include any suitable number of carbon ring atoms, such as C6, C7, C8, C9, C10, C11, 12, C13, C14, C15 or C16, as well as C6-10, C6-12, or C6-14. Aryl groups can be monocyclic, fused to form bicyclic (e.g., benzocyclohexyl) or tricyclic groups, or linked by a bond to form a biaryl group. Representative aryl groups include phenyl, naphthyl and biphenyl. Other aryl groups include benzyl, having a methylene linking group. Some aryl groups have from 6 to 12 ring members, such as phenyl, naphthyl or biphenyl. Other aryl groups have from 6 to 10 ring members, such as phenyl or naphthyl. Some other aryl groups have 6 ring members, such as phenyl. Aryl groups can be substituted or unsubstituted. For example, “substituted aryl” groups can be substituted with one or more groups selected from halo, hydroxy, amino, alkylamino, amido, acyl, nitro, cyano, and alkoxy.
As used herein, the term “heteroaryl,” by itself or as part of another substituent, refers to a monocyclic or fused bicyclic or tricyclic aromatic ring assembly containing 5 to 16 ring atoms, where from 1 to 5 of the ring atoms are a heteroatom such as N, O or S. Additional heteroatoms can also be useful, including, but not limited to, B, Al, Si and P. The heteroatoms can be oxidized to form moieties such as, but not limited to, —S(O)— and —S(O)2—. Heteroaryl groups can include any number of ring atoms, such as C5-6, C3-8, C4-8, C5-8, C6-8, C3-9, C3-10, C3-11, or C3-12, wherein at least one of the carbon atoms is replaced by a heteroatom. Any suitable number of heteroatoms can be included in the heteroaryl groups, such as 1, 2, 3, 4; or 5, or 1 to 2, 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, 2 to 5, 3 to 4, or 3 to 5. For example, heteroaryl groups can be C5-8 heteroaryl, wherein 1 to 4 carbon ring atoms arc replaced with heteroatoms: or C5-6 heteroaryl, wherein 1 to 3 carbon ring atoms are replaced with heteroatoms: or C5-6 heteroaryl, wherein 1 to 4 carbon ring atoms are replaced with heteroatoms; or C5-6 heteroaryl, wherein 1 to 3 carbon ring atoms are replaced with heteroatoms. The heteroaryl group can include groups such as pyrrole, pyridine, imidazole, pyrazole, triazole, tetrazole, pyrazine, pyrimidine, pyridazine, triazine (1,2,3-, 1,2,4- and 1,3,5-isomers), thiophene, furan, thiazole, isothiazole, oxazole, and isoxazole. The heteroaryl groups can also be fused to aromatic ring systems, such as a phenyl ring, to form members including, but not limited to, benzopyrroles such as indole and isoindole, benzopyridines such as quinoline and isoquinoline, benzopyrazine (quinoxaline), benzopyrimidine (quinazoline), benzopyridazines such as phthalazine and cinnoline, benzothiophene, and benzofuran. Other heteroaryl groups include heteroaryl rings linked by a bond, such as bipyridine. Heteroaryl groups can be substituted or unsubstituted. For example, “substituted heteroaryl” groups can be substituted with one or more groups selected from halo, hydroxy, amino, alkylamino, amido, acyl, nitro, cyano, and alkoxy.
The heteroaryl groups can be linked via any position on the ring. For example, pyrrole includes 1-, 2- and 3-pyrrole, pyridine includes 2 -, 3- and 4-pyridine, imidazole includes 1-, 2 -, 4- and 5-imidazole, pyrazole includes 1-, 3 -, 4- and 5-pyrazole, triazole includes 1-, 4- and 5-triazole, tetrazole includes 1- and 5-tetrazole, pyrimidine includes 2-, 4-, 5- and 6- pyrimidine, pyridazine includes 3- and 4-pyridazine, 1,2,3-triazine includes 4- and 5-triazine, 1,2,4-triazine includes 3-, 5- and 6-triazine, 1,3,5-triazine includes 2-triazine, thiophene includes 2- and 3-thiophene, furan includes 2- and 3-furan, thiazole includes 2-, 4- and S-thiazole, isothiazole includes 3 -, 4- and 5-isothiazole, oxazole includes 2-, 4- and 5-oxazole, isoxazole includes 3 -, 4- and 5-isoxazole, indole includes 1 -, 2- and 3-indole, isoindole includes 1- and 2-isoindole, quinoline includes 2-, 3- and 4-quinoline, isoquinoline includes 1 -, 3- and 4-isoquinoline, quinazoline includes 2- and 4-quinazoline, cinnoline includes 3- and 4-cinnoline, benzothiophene includes 2- and 3-benzothiophene, and benzofuran includes 2- and 3-benzofuran.
As used herein, the term “heterocyclyl,” by itself or as part of another substituent, refers to a saturated ring system having from 3 to 12 ring members and from 1 to 4 heteroatoms of N, O and S. Additional heteroatoms can also be useful, including, but not limited to, B, Al, Si and P. The heteroatoms can be oxidized to form moieties such as, but not limited to, —S(O)— and —S(O)2—. Heterocyclyl groups can include any number of ring atoms, such as, C3-6, C4-6, C5-6, C3-8, C4-8, C5-8, C6-8, C3-9, C3-10, C3-11, or C3-12, wherein at least one of the carbon atoms is replaced by a heteroatom. Any suitable number of carbon ring atoms can be replaced with heteroatoms in the heterocyclyl groups, such as 1, 2, 3, or 4, or 1 to 2, 1 to 3, 1 to 4, 2 to 3, 2 to 4, or 3 to 4. The heterocyclyl group can include groups such as aziridine, azetidine, pyrrolidine, piperidine, azepane, azocane, quinuclidine, pyrazolidine, imidazolidine, piperazine (1,2-, 1,3- and 1,4-isomers), oxirane, oxctane, tetrahydrofuran, oxane (tetrahydropyran), oxepane, thiirane, thietane, thiolane (tetrahydrothiophene), thiane (tetrahydrothiopyran), oxazolidine, isoxazolidine, thiazolidine, isothiazolidine, dioxolane, dithiolane, morpholine, thiomorpholine, dioxane, or dithiane. The heterocyclyl groups can also be fused to aromatic or non-aromatic ring systems to form members including, but not limited to, indoline. Heterocyclyl groups can be unsubstituted or substituted. For example, “substituted heterocyclyl” groups can be substituted with one or more groups selected from halo, hydroxy, amino, oxo, alkylamino, amido, acyl, nitro, cyano, and alkoxy.
The heterocyclyl groups can be linked via any position on the ring. For example, aziridine can be 1- or 2-aziridine, azetidine can be 1- or 2- azetidine, pyrrolidine can be 1-, 2- or 3-pyrrolidine, piperidine can be 1-, 2-, 3- or 4-piperidine, pyrazolidine can be 1-, 2-, 3 -, or 4-pyrazolidine, imidazolidine can be 1-, 2-, 3- or 4-imidazolidine, piperazine can be 1-, 2-, 3- or 4-piperazine, tetrahydrofuran can be 1- or 2-tetrahydrofuran, oxazolidine can be 2-, 3-, 4- or 5-oxazolidine, isoxazolidine can be 2 -, 3-, 4- or 5-isoxazolidine, thiazolidine can be 2-, 3- 4- or 5-thiazolidine, isothiazolidine can be 2-, 3-, 4- or 5- isothiazolidine, and morpholine can be 2-, 3- or 4-morpholine.
As used herein, the term “amino” refers to a moiety —NR2, wherein each R group is H or alkyl. An amino moiety can be ionized to form the corresponding ammonium cation. “Dialkylamino” refers to an amino moiety wherein cach R group is alkyl.
As used herein, the term “sulfonyl” refers to a moiety —SO2R, wherein the R group is alkyl, baloalkyl, or aryl. An amino moiety can be ionized to form the corresponding ammonium cation.
As used herein, the term “haloalkyl,” by itself or as part of another substituent, refers to an alkyl group where some or all of the hydrogen atoms are replaced with halogen atoms. As for alkyl groups, haloalkyl groups can have any suitable number of carbon atoms, such as C1-6. For example, haloalkyl includes trifluoromethyl, fluoromethyl, etc. In some instances, the term “perfluoro” can be used to define a compound or radical where all the hydrogens are replaced with fluorine. For example, perfluoromethyl refers to 1,1,1-trifluoromethyl.
As used herein, the term “hydroxy” refers to the moiety —OH.
As used herein, the term “cyano” refers to a carbon atom triple-bonded to a nitrogen atom (i.e., the moiety —C≡N).
As used herein, the term “carboxy” refers to the moiety —C(O)OH. A carboxy moiety can be ionized to form the corresponding carboxylate anion.
As used herein, the term “amido” refers to a moicty —NRC(O)R or —C(O)NR3, wherein each R group is H or alkyl.
As used herein, the term “acyl” refers to a moiety —C(O)R, wherein R is alkyl.
As used herein, the term “nitro” refers to the moiety —NO2.
As used herein, the term “oxo” refers to an oxygen atom that is double-bonded to a compound (i.e., O═).
The term “salt,” in reference to a monomer or polymer as described herein, refers to an acid salt or base salt of the monomer or polymer. A monomer or polymer may have one or more salt moieties. Illustrative examples of salts are mineral acid salts (e.g., salts formed with hydrochloric acid, hydrobromic acid, phosphoric acid, or the like), organic acid salts (e.g., salts formed with acetic acid, propionic acid, glutamic acid, citric acid and the like), quaternary ammonium salts (e.g., salts formed with methyl iodide, ethyl iodide, or the like). Salts of basic monomers and/or polymers, e.g., those having amine groups, can be formed with acids such as of mineral acids, organic carboxylic acids, and organic sulfonic acids, e.g., hydrochloric acid, methanesulfonic acid, maleic acid, and the like. Salts of acidic monomers and/or polymers can be formed with bases including cationic salts such as alkali and alkaline earth metal salts, such as sodium, lithium, potassium, calcium, magnesium salts, as well as ammonium salts, such as ammonium, trimethyl-ammonium, diethylammonium, and tris-(hydroxymethyl)-methyl-ammonium salts. The neutral form of a monomer or polymer can be regenerated by contacting the salt with a base or acid and optionally isolating the parent compound. Counterions (e.g., anions in a polycationic polymer) may be exchanged as described herein.
The terms “about” or “approximate” and the like are synonymous and are used to indicate that the value modified by the term has an understood range associated with it, where the range can be ±20%, ±15%, ±10%, ±5%, or ±1%. The term “substantially” is used to indicate that a value is close to a targeted value, where close can mean, for example, the value is within 80% of the targeted value, within 85% of the targeted value, within 90% of the targeted value, within 95% of the targeted value, or within 99% of the targeted value.
Provided herein are monomer compounds according to Formula I, II, III, IV, V, VI, VII, or VIII:
Compounds according to Formula I, II, III, IV, V, VI, VII, and VIII can be used as monomers for the synthesis of microporous polymers as described herein.
In some embodiments, each R1 in compounds according to Formula I, II, III, IV, V, VI, VII, and VIII is independently selected from the group consisting of:
wherein X1, X2, X3, X4, and X3 are independently selected from O, S, Se, NR, and PR, wherein R is (C1-20)alkyl or (C6-10)aryl. In some embodiments, X1, X2, X3, X4, and X5 are independently selected from O, S, and Se. In some embodiments, X1, X2, X3, X4, and X5 are O.
In some embodiments, each R1 in compounds according to Formula I, II, III, IV, V, VI, VII, and VIII is independently selected from the group consisting of:
wherein X1 and X2 are independently selected from O, S, Se, NR, and PR, wherein R is (C1-20)alkyl or (C6-10)aryl. In some embodiments, X1 and X2 are independently selected from O, S, and Se. In some embodiments, X1 and X2 are O.
In some embodiments, R4 and R5 can also be bonded together to form a 4, 5, 6, 7, or 8 membered cycloalkyl, heterocyclyl, aryl, or heteroaryl. In some embodiments, R4 and R5 can also be bonded together with a linker X2 to form a 6, 7, or 8 membered cycloalkyl, aryl, or heterocyclyl.
The amine-containing R1 moieties may be introduced according to the methods provided herein, employing a formaldehyde source and an appropriate amine. Numerous suitable amines are commercially available or can be prepared according to known methods, including those described in Fiesers' Reagents for Organic Synthesis Volumes 1-28 (John Wiley & Sons, 2016), by March (Advanced Organic Chemistry 6th Ed. John Wiley & Sons, 2007), and by Larock (Comprehensive Organic Transformations 3rd Ed. John Wiley & Sons, 2018).
Also provided herein are methods for preparing compounds according to Formula I, II, III, IV, V, VI, VII, and VIII. The methods include:
Starting materials according to Formula (Ia), (IIa), (IIIa), (IVa), (Va), (VIa), (VIIa), or (VIIIa) may be obtained from commercial sources or synthesized according to the methods described herein or according to other known methods. See, e.g., Chemical Reviews 2018, 118(12), 5871-5911; Advanced Materials 2018, 30, 1704953; Science China: Chemistry 2017, 60(8), 1023-1032; Progress in Polymer Science 2015, 43, 1-32; Encyclopedia of Membrane Science and Technology 2013, 2, 781-797; Polymer 2013, 54(18), 4729-4761; Macromolecules 2010, 43(12), 5163-5176; Polymer Chemistry 2010, 1(1), 63-68; Chemical Society Reviews 2006, 35(8), 675-683; Chemistry—A European Journal 2005, 11(9), 2610-2620; and references cited therein. Amine precursors used for installation of RI moieties in the methods may have any combination X1-X5 set forth above. Formaldehyde, as well as formaldehyde-generating compounds such as paraformaldehyde or 1,3,5-trioxane, may be employed. Typically, the amine precursor and the formaldehyde/formaldehyde-generating compound will be used in excess with respect to the starting material. For example, 2-250 molar equivalents of the amine precursor and the formaldehyde/formaldehyde-generating compound with respect to the starting material may be used. In some embodiments, 25-75 molar equivalents of an amine precursor and a formaldehyde-generating compound (e.g., paraformaldehyde) with respect to the starting material (e.g., a compound of Formula (Ia) or a compound of Formula (VIa)) are used to form the monomer product. Reactions are typically conducted at temperatures ranging from around −10° C. to about 150° C.for a period of time sufficient to form the monomer product (e.g., from about 1 hour to about 18 hours), depending on factors such as the particular starting material or amine precursor used in the reaction. In some embodiments, the reaction is conducted at ambient temperature (e.g., about 20° C., or about 25° C.). Elevated temperatures may be achieved through conventional heating or through microwave-assisted heating. Reaction mixtures may contain a solvent or mixture of solvents including, but not limited to, further comprises a solvent or mixture of solvents. The solvent may be, but it not limited to, methanol, ethanol, benzene, p-cresol, toluene, xylene, diethyl ether, glycol, diethyl ether, petroleum ether, hexane, cyclohexane, pentane, methylene chloride, chloroform, carbon tetrachloride, dioxanc, tetrahydrofuran (THF), dimethyl sulfoxide, dimethylformamide, hexamethyl-phosphoric triamide, ethyl acetate, pyridine, triethylamine, picoline, and the like, or a mixture thereof. Ethers, orthoesters, carbonates, lactones, sulfoxides, sulfones, sultones, sulfonamides, amides, carbamates, may also be used as solvents for synthesis of monomer compounds.
Microporous polymers of the present disclosure can include chelator-functionalized microporous polymers. In some embodiments, the present disclosure provides a microporous polymer according to the formula:
-[A-AB-B]n-,
In general, no specification of the chain ends is assumed for polymers of the formula -[A-AB-B]n-. That is, either chain end can contain a monomer segment A-A or a monomer segment B-B, independent of the other chain end. At the chain ends, however, moieties represented as
for example, in any of the monomer segments depicted herein will be present as catechols:
In the structures above, the dashed bonds represent the connection to the remainder of the polymer chain, and R1 can include any of the moieties and combinations thereof as set forth herein.
In some embodiments, each monomer segment A-A is independently a monomer segment according to Formula A, B, C, D, E, F, G, or H. Such segments may contain any combination of R1, R2, R3, R4, X1, X2, X3, X4, X5 groups set forth above for monomer compounds according to Formula I-VIII.
In some embodiments, polymers of intrinsic microporosity may be characterized by a surface area. In some embodiments, polymers of intrinsic microporosity may be characterized by gas adsorption/desorption amount and rates, such as for N2 adsorption/desorption, which may allow for determination of their surface area, for example. Adsorption isotherms may be determined to allow for determination of a Brunauer, Emmett, and Teller (BET) surface area. BET surface areas may allow for comparison of microporosity characters, for example, between different polymers of intrinsic microporosity. For example, a first polymer of intrinsic microporosity that exhibits a smaller BET surface area than a second polymer of intrinsic microporosity may be characterized as having less microporosity than the second polymer of intrinsic microporosity. Useful unmodified and modified polymers of intrinsic microporosity include, but are not limited to, those exhibiting a surface area of at least 50 m2/g, such as a surface area of 50 m2 g−1 to 2000 m2 g−1, or 200 m2/g to 1000 m2/g, or 250 m2/g to 800 m2/g. In some embodiments, the microporous polymer has a surface area ranging from about 50 m2 g−1 to about 2000 m2 g−1.
Microporosity and pore sizes of polymers of intrinsic microporosity may be characterized by determining the effective rate of diffusion of one or more gases across a film of the polymer having a known thickness. Microporosity and pore size characteristics of polymers of intrinsic microporosity may also be probed using positron annihilation lifetime spectroscopy.
In some embodiments, polymers of intrinsic microporosity may be characterized by their solubility in organic solvents, such as tetrahydrofuran or chloroform. In some embodiments, polymers of intrinsic microporosity may exhibit high solubility in organic solvents, while other polymers may exhibit low or no solubility in organic solvents.
In some embodiments, polymers of intrinsic microporosity may be characterized by their molecular weights. Optionally, size exclusion chromatography may be useful for determining molecular weights of polymers of intrinsic microporosity. Optionally, gel permeation chromatography may be useful for determining molecular weights of polymers of intrinsic microporosity. Molecular weight determination may, in turn, allow for determination of a degree of polymerization of a polymer of intrinsic microporosity. Example polymers of intrinsic microporosity include, but are not limited to, those exhibiting molecular weights of at least 50 kg/mol, at least 100 kg/mol, at least 200 kg/mol, or at least 300 kg/mol. In some embodiments, polymers of intrinsic microporosity exhibit molecular weights selected from the range of about 50 kg/mol to about 250 kg/mol, or from the range of about 80 kg/mol to about 200 kg/mol. Example polymers of intrinsic microporosity include, but are not limited to, those exhibiting degrees of polymerization selected from the range of 100 to 1000, from the range of 200 to 900, from the range of 300 to 800, from the range of 400 to 700, or from the range of 500 to 600.
Chemical structure characterization of polymers of intrinsic microporosity may be accomplished using a variety of techniques. Such characterizations may also allow for determination of modifications and degrees of modifications to polymers of intrinsic microporosity. For example, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy may be useful. In some embodiments, infrared spectroscopy may also be useful. Additionally or alternatively, ionization mass spectrometry, such as electrospray ionization mass spectrometry, may also be useful for identifying structural moieties within a polymer of intrinsic microporosity. Other characterization techniques known to the skilled artisan may be useful for characterizing unmodified polymers of intrinsic microporosity and modified polymers of intrinsic microporosity. For example, in some embodiments, polymers of intrinsic microporosity may be characterized by their ultraviolet and/or visible absorption spectra.
In some embodiments, the microporous polymers have any one or more of the following properties: a surface area of ranging from about 50 m2 g−1 to about 2000 m2 g−1; pore sizes ranging from about 0.4 nm to about 2 nm; and a porosity ranging from about 5% to about 40%. Percent porosity φ may be defined as φ=VV/VT×100%, wherein VV is the void volume and VT is the total volume. The void volume of a particular material can be determined based on pore size characterization as described herein. In some embodiments, the microporous polymer has pore sizes ranging from about 0.4 nm to about 2 nm. In some embodiments, the microporous polymer has a porosity ranging from about 5% to about 40%.
Microporous polymers according to the present disclosure may have varying proportions of spirocyclic biscatechol monomer segments (e.g., A-A monomer segments according to Formula (A), Formula (B), Formula (C), and/or Formula (E)) and bridged bicyclic monomer segments (e.g., A-A monomer segments according to Formula (F) and/or Formula (G)). In some embodiments, for example, a polymer may contain spirocyclic biscatechol monomer segments A-A (A-A-1), bridged bicyclic monomer segments A-A (A-A-2), and monomer segments B-B, wherein the molar ratio [A-A-1]:[A-A-2]:[B-B] is in the range of [1-10]:[0-10]:[1-10]. In some embodiments, the molar ratio [A-A-1]:[A-A-2]:[B-B] is in the range of [0-10]:[1-10]:[1-10]. In some embodiments, the molar ratio [A-A-1]:[A-A-2]:[B-B] is in the range of [1-5]:[0-5]:[1-3]. In some embodiments, the molar ratio [A-A-1]:[A-A-2]:[B-B] is in the range of [0-5]:[1-5]:[1-3]. In some embodiments, the molar ratio [A-A-1]:[A-A-2]:[B-B] is in the range of [1-3]:[0-1]:[2]. In any of these embodiments, the ratio {[A-A-1]+[A-A-2]}:[B-B] may be approximately 1:1. In any of these embodiments, the microporous polymer may have the structure:
wherein the sum of subscripts a1, a2, and b ranges from 10-10,000. In some embodiments, the sum of subscripts a1, a2, and b ranges from 10-10,000, and the sum {a1+a2} is equal to the sum {b+b}. Such polymers may contain any combination of the R1 and R2 groups set forth herein.
Also provided herein are methods for preparing microporous polymers. The methods include:
Any suitable organic base or an inorganic base may be utilized. Examples of
suitable bases include potassium carbonate, sodium carbonate, sodium acetate, Huenig's base (i.e., N,N-diisopropylethylamine), lutidines including 2,6-lutidine (i.e., 2,6-dimethylpyridine), triethylamine, tributylamine, pyridine, 2,6-di-tert-butylpyridine, 1,8-diazabicycloundec-7-ene (DBU), quinuclidine, and the collidines. Combinations of two or more bases can be used. In some embodiments, the polymerization mixture further comprises solid grinding media, liquid grinding media, or a combination thereof. In some embodiments, the methods further include shaking or rotating the polymerization mixture, e.g., in a shaking or rotating container, also called a ball mill.
Microporous polymers according to the present disclosure may be used for preparation of membranes, e.g., for use as separators in electrochemical cells. Typically, thickness of the membranes will range from about 0.1 micrometers (μm) to about 5000 μm. Membrane thickness may range, for example, from about 0.1 μm to about 1000 μm, or from about 25 μm to about 500 μm, or from about 50 μm to about 150 μm. In some embodiments, the membranes have a thickness ranging from 0.1 micrometer to 1000 micrometers.
In some embodiments, the membrane is in contact with a support material. The support material may contain one or more components including, but not limited to, a poly(arylether), a poly(arylether) copolymer, a poly(arylether sulfone) copolymer, a poly(arylether ketone), a poly(arylether ketone) copolymer, polyethylene, a polyethylene copolymer, polypropylene, a polypropylene copolymer, a polycycloolefin, a cycloolefin copolymer, polyacrylonitrile, a polyacrylonitrile copolymer, poly(vinylidene fluoride), a poly(vinylidene fluoride) copolymer, poly(tetrafluoroethylene), a poly(tetrafluoroethylene) copolymer, poly(hexafluoropropylene), a poly(hexafluoropropylene) copolymer, poly(vinyl chloride), a poly(vinyl chloride) copolymer, a polyamide, a polyamide copolymer, polyaramide, a polyaramide copolymer, polyurethane, a polyurethane copolymer, a polyurea, a polyurea copolymer, a porous metal, a porous alloyed metal, a porous metal oxide, and a porous metal sulfide.
Membranes may be prepared by suitable method. In some embodiments, the method of preparing the membrane includes casting at least one microporous polymer as described above from a solution or a dispersion of the polymer in a solvent or mixture of solvents. which are then substantially removed by evaporation to produce the membrane. In some embodiments, the method further includes the evaporation of solvent from the microporous polymer on a support to yield a supported membrane.
In some embodiments, the polymer membrane separator comprises one or more microporous polymers. In some embodiments, the polymer membrane includes one or more chelator-functionalized or amine-functionalized microporous polymers. In some embodiments, the polymer membrane includes an amine-functionalized microporous polymer. In some embodiments, the polymer membrane separator comprises one or more microporous polymers according to the formula:
-[A-AB-B]n-,
In some embodiments, the microporous polymer has the structure:
Also provided herein are electrochemical cells, including rechargeable electrochemical cells comprising a separator containing a membrane as described above. Examples of electrochemical cells in which microporous polymers according to the present disclosure can be employed include, but are not limited to, those described in U.S. Pat. Nos. 11,318,455; 10,727,488; and 10,710,065. Microporous polymers according to the presence disclosure can be applied in conjunction with aqueous cell chemistries currently under investigation for redox-flow batteries, hybrid redox-flow batteries, redox-targeting batteries, and solar flow batteries, including metal coordination complexes, organometallics, polyoxometalates, redox-active organic molecules, and redoxmers. The separator containing the microporous polymers allows the working ion(s) of the electrochemical cell to be passed through it, shuttling the ions between the anode and the cathode while preventing the transfer of electrons. The separator may optionally contain one or more support materials as described herein. In some embodiments, the area-specific impedance of the separator is less than or equal to 20 Ohm*cm2. In some embodiments, the separator is stable up to an operating potential of at least 3.7 V vs. Li/Li+.
In some embodiments, the electrochemical cell comprises a polymer membrane separator containing a microporous polymer as described above. The electrochemical cell further comprises an anode, an anode electrolyte, a cathode electrolyte, and a cathode, wherein:
In some embodiments, an electrochemical cell comprises (i) an anode, (ii) a first electrolyte, (iii) a polymer membrane separator, (iv) a second electrolyte, and (v) a cathode, wherein:
In some embodiments, the electrochemical cell comprises a polymer membrane separator containing one or more microporous polymers, e.g., as described in WO 2020/037246. The electrochemical cell further comprises an anode, an anode electrolyte, a cathode electrolyte, and a cathode, wherein:
In some embodiments, an electrochemical cell comprises (i) an anode, (ii) a first electrolyte, (iii) a polymer membrane separator comprising a microporous polymer, (iv) a second electrolyte, and (v) a cathode, wherein:
In some embodiments, the electrochemical cell comprises an anode. The anode in the electrochemical cells can contain any suitable material. The anode, for example, may include or consist of zinc or lithium. In some embodiments, the anode comprises graphite. In some embodiments, the anode comprises lithium metal, sodium metal, or potassium metal. In some embodiments, the anode comprises one or more of magnesium, calcium, aluminum, and/or zinc metal. In some embodiments, the anode comprises one or more of boron, silicon, germanium, arsenic, antimony, tellurium, and/or polonium semimetal. In some embodiments, the anode comprises a composite of metals, semimetals, and/or alloys thereof with a binder and/or one or more conductive additives such as C60, carbon black, acetylene black, SuperP, KetjenBlack, graphene, multi-layer graphene, single-wall carbon nanotubes, multi-wall carbon nanotubes, carbon nanofibers, carbon fiber, MXenes, metal oxides, and/or black phosphorous.
The cathode in the electrochemical cells can contain any suitable material. The cathode, for example, may contain an active material such as sodium (2,2,6,6-tetramethylpiperidin-1-yl)oxyl-4-sulfate, a metal or metal oxide (e.g., a layered transition metal oxide such as LiNixMnyCo2O2, referred to as NMC), and/or an electrolyte. In some embodiments, the cathode comprises a metal oxide, a polyanion oxide, a cation-disordered rocksalt, a metal sulfide, a metal fluoride, CFx, sulfur, oxygen, or combinations thereof. In some embodiments, the metal oxide is LiNixMnyCozO2.
Also provided herein are rechargeable anode-free electrochemical cells containing microporous polymers, locally concentrated electrolytes, or a combination thereof. In some embodiments, the anode-free electrochemical cells contain a current collector, a current collector electrolyte, a polymer membrane separator, a cathode, and a cathode electrolyte, wherein:
Also provided herein are electrochemical cells comprising a current collector, a current collector electrolyte, a polymer membrane separator, a cathode, and a cathode electrolyte, wherein:
In some embodiments, an electrochemical cell comprises (i) a current collector, (ii) a first electrolyte, (iii) a polymer membrane separator, (iv) a second electrolyte, and (v) a cathode, wherein:
In some embodiments, an electrochemical cell comprises (i) a current collector, (ii) a first electrolyte, (iii) a polymer membrane separator comprising a microporous polymer, (iv) a second electrolyte, and (v) a cathode, wherein:
In some embodiments, the electrochemical cell comprises the current collector. In some embodiments, the current collector comprises copper metal. In some embodiments, the current collector comprises a lithium alloy, a sodium alloy, or a potassium alloy. In some embodiments, the lithium alloy is selected from the group consisting of Li—Zn, Li—Al, Li—B, Li—Cd, Li—Ag, Li—Si, Li—Pb, Li—Sn, and Li—Mg.
In some embodiments, the first electrolyte and the second electrolyte are the same. In some embodiments, the first electrolyte and the second electrolyte are different.
The electrolytes provided herein were developed, in part, to address problematic bulk and interfacial behaviors associated with dilute electrolytes (DEs) and super-concentrated electrolytes (SCEs). Without being bound to any particular theory, it was hypothesized that the use of locally super-concentrated electrolytes (LSCEs), which employ a non-coordinating diluent, may reduce the viscosity of SCEs and provide concomitantly high carrier mobility and concentration. As described in detail below, it has now been discovered that LSCEs can stabilize electrochemical cells under conditions of ultra-fast-charge where decomposition of dilute electrolytes is observed.
Locally concentrated electrolytes used in the electrochemical cells of the present disclosure generally include one or more solvents, one or more diluents, and/or one or more alkali metal salts. In some embodiments, the electrolytes comprise one or more alkali metal salts, a solvent, and a diluent. The total molar concentration of the alkali metal salt(s) in the electrolytes typically ranges from about 0.5 M to about 7.5 M (e.g., 0.5-6 M, or 1-5 M, or 1-1.5 M, or 2-3M, or 3.5-4 M). In some embodiments, the electrolyte comprises 0.1 to 10 molar equivalents of the alkali metal salts with respect to the solvents. In some embodiments, the electrolyte comprises 0.1 to 10 molar equivalents of the alkali metal salts with respect to the solvents and 0.1 to 10 molar equivalents of the alkali metal salts with respect to the diluent.
In some embodiments, the solvent is a non-fluorinated solvent. In some embodiments, the solvent is an ether, an orthoester, a carbonate, a lactone, a sulfoxide, a sulfone, a sultone, a sulfonamide, an amide, a carbamate, or any combination thereof. Examples of such solvents include, but are not limited to, 1,2-dimethoxyethane (DME), 1,3-dioxolane (DOL), 1,4-dioxane, tetrahydrofuran (THF), allyl ether, diethylene glycol dimethyl ether (or “diglyme”), triethylene glycol dimethyl ether (or “triglyme”), tetraethylene glycol dimethyl ether (or “tetraglyme”), butyl diglyme, dimethyl ether, diethyl ether, polyethylene glycol. acetonitrile, dimethyl sulfoxide, sulfolane, trimethyl phosphate (TMPa), tricthyl phosphate (TEPa), dimethyl methylphosphonate (DMMP), hexamethyldisiloxane, hexamethylcyclotrisiloxane, silanes, methanol, ethanol, benzene, p-cresol, toluene, xylene, hexane, cyclohexane, pentane, methylene chloride, chloroform, carbon tetrachloride, dimethylformamide, hexamethyl-phosphoric triamide, ethyl acetate, pyridine, tricethylamine, picoline, and the like, and mixtures thereof. In some embodiments, each solvent is independently selected from the group consisting of 1,2-dimethoxyethane (DME), 1,3-dioxolane, 1,4-dioxane, tetrahydrofuran, allyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, butyl diglyme, dimethyl ether, diethyl ether, polyethylene glycol, and combinations thereof. In some embodiments, the solvent comprises 1,2-dimethoxyethane (DME).
In some embodiments, the diluent is a fluorinated diluent. In some embodiments, the diluent is a fluorinated ether, a fluorinated orthoester, a fluorinated carbonate, a fluorinated lactone, a fluorinated sulfoxide, a fluorinated sulfone, a fluorinated sultone, a fluorinated sulfonamide, a fluorinated amide, a fluorinated carbamate, a fluorinated urea, or any combination thereof. Examples of such diluents include, but are not limited to, 1,1,2,2-tetrafluoroethyl-2,2,2,3-tetrafluoropropyl ether (TTE), bis(2,2,2-trifluoroethyl) ether (BTFE), 1,1,2,2,-tetrafluorocthyl-2,2,2-trifluoroethyl ether (TFTFE), methoxynonafluorobutane (MOFB), ethoxynonafluorobutane (EOFB), methyl 2,2,2-trifluoroethyl carbonate (MTFEC), di(2,2,2-trifluoroethyl) carbonate (DTFEC), tris(2,2,2-trifluorethyl)orthoformate, tris(hexafluoro-isopropyl)orthoformate, tris(2,2,2-difluoroethyl)orthoformate, bis(2,2,2-trifluoroethyl) methyl orthoformate, tris(2,2,3,3,3-pentafluoropropyl)orthoformate, and tris(2,2,3,3-tetrafluoropropyl)orthoformate. In some embodiments, each diluent is independently selected from the group consisting of 1,1,2,2-tetrafluoroethyl-2,2,2,3-tetrafluoropropyl ether (TTE), bis(2,2,2-trifluoroethyl) ether (BTFE), 1,1,2,2,-tetrafluoroethyl-2,2,2-trifluoroethyl ether (TFTFE), tris(2,2,2-trifluoroethyl)orthoformate (TFEO), methoxynonafluorobutane (MOFB), ethoxynonafluorobutane (EOFB), di(2,2,2-trifluoroethyl) carbonate (DTFEC), and combinations thereof. In some embodiments, the diluent comprises 1,1,2,2-tetrafluoroethyl-2,2,2,3-tetrafluoropropyl ether (TTE).
The alkali metal salts typically contain anions such as chlorate, perchlorate, nitrate, phosphate, hexafluorophosphate, borate, tetrafluoroborate, difluoro(oxalate)borate, bis(oxalate)borate, bis(fluorosulfonyl)imide, bis(trifluoromethane)sulfonimide, closo-dodecaborates, halogenated closo-dodecaborates. closo-carboranes, halogenated closo-carboranes, and combinations thereof. In some embodiments, the alkali metal salt is a sodium salt. In some embodiments, the alkali metal salt is a lithium salt. In some embodiments, the electrolyte contains two or more lithium salts. In some embodiments, each alkali metal salt is independently selected from the group consisting of sodium bis(fluorosulfonyl)imide (NaFSI), sodium bis(trifluoromethylsulfonyl)imide (NaTFSI), sodium bis(oxalato)borate (NaBOB), sodium difluoro oxalato borate anion (NaDFOB), NaPF6, NaAsF6, NaBFa, NaCF3SO3, NaClO4, NaI, NaBr, NaCl, NaSCN, NaNO3, and Na2SO4. In some embodiments, each alkali metal salt is independently selected from the group consisting of lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium bis(trifluoromethane-sulfonyl)imide (LiTFSI), lithium bis(oxalato)borate (LiBOB), lithium difluoro oxalato borate anion (LiDFOB), LiPF6, LiAsF6, LIBF4, LiCF3SO3, LiClO4, LiI, LiBr, LiCl, LiF, LiSCN, LiNO3, and Li2SO4. In some embodiments, the alkali metal salt comprises lithium bis(fluorosulfonyl)imide (LiFSI).
In some embodiments, the solvent is 1,2-dimethoxyethane (DME), the diluent is tetrafluoroethyl-2,2,2,3-tetrafluoropropyl ether (TTE), and wherein the electrolyte comprises a first alkali metal salt and one more additional alkali metal salts.
In some embodiments, the molar ratio of the alkali metal salts to the solvent ranges from about 1:1.75 to about 1:2.5. The molar ratio of the alkali metal salts to the solvent may range, for example, from about 1:1.8 to about 1:2.2, or from about 1:1.9 to about 1:2.1. In some embodiments, the molar ratio of alkali metal salts to the solvent is about 1:2.
In some embodiments, the molar ratio of the alkali metal salts to diluent ranges from about 1:0.25 to about 1:1.5. The molar ratio of the alkali metal salts to the diluent may range, for example, from about 1:1 to about 1:1.4, or from about 1:1.1 to about 1:1.3. In some embodiments, molar ratio of the alkali metal salts to the diluent is about 1:1.2.
In some embodiments, the molar ratio of the alkali metal salts to the solvent ranges from about 1:1.75 to about 1:2.5; and the molar ratio of the alkali metal salts to the diluent ranges from about 1:0.25 to about 1:1.5. In some embodiments, the molar ratio of the alkali metal salts to the solvent is about 1:2 and the molar ratio of the alkali metal salts to the diluent ranges from about 1:0.3 to about 1:1.3.
In some embodiments, the electrolytes comprise LiFSI, DME, and TTE in a molar ratio of about 1:x:y, wherein x ranges from about 1.9 to about 2.1 and y ranges from about 0.2 to about 3.8. In some embodiments, x is about 2 and y ranges from about 0.4 to about 1.5. In some embodiments, x is about 2 and y is about 1.2.
In some embodiments, the electrolytes contain a first alkali metal salt (e.g., LiFSI) and one more additional alkali metal salts (e.g., lithium difluoro(oxalate)borate, lithium perchlorate. lithium tetrafluoroborate, lithium trifluoromethanesulfonate, lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, or any combination thereof). In some embodiments, the first alkali metal salt is lithium bis(fluorosulfonyl)imide, and the additional alkaline metal salts are selected from the group consisting of lithium difluoro(oxalate)borate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, lithium hexafluorophosphate, and lithium bis(trifluoromethanesulfonyl)imide. In some embodiments, the electrolytes comprise the first alkali metal salt and a second alkali metal salt in a molar ratio ranging from about 75:25 to about 99:1. The molar ratio of the first and second alkali metal salts may range, for example, from about 80:20 to about 99:1, or from about 85:15 to about 95:5. In some embodiments, the molar ratio of the first and second alkali metal salts is about 90:10.
In some embodiments, the electrolytes comprise LiFSI, a second lithium metal salt, DME, and TTE in a molar ratio of about v:w:x:y, wherein v ranges from about 0.8 to about 0.99, w is equal to (1−v), x ranges from about 1.9 to about 2.1, and y ranges from about 0.2 to about 3.8. In some embodiments, v is about 0.9, w is about 0.1, x is about 2 and y ranges from about 0.4 to about 1.5. In some embodiments, x is about 2 and y is about 1.2.
In some embodiments, the electrochemical cell comprises:
In some embodiments, the electrochemical cell comprises:
In some embodiments, the electrochemical cell comprises:
In some embodiments, the electrochemical cell comprises:
In some embodiments, the electrochemical cell comprises:
In some embodiments, the ionic conductivity of the electrolyte is greater than or equal to 3 mS cm−1. In some embodiments, the viscosity of the electrolyte is less than or equal to 20 Pa*s at 20° C. The viscosity of the electrolyte may range, for example, from about 1 to 20 Pa*s at 20° C. In some embodiments, the electrolyte is stable up to an operating potential of at least 3.7 V vs. Li/Li+ (e.g., up to 4, 4.5, 5, 5.5, or 6 V). In some embodiments, the rechargeable electrochemical cell has an area capacity of greater than or equal to 1 mAh cm−2 and less than or equal to 15 mAh cm−2. In some embodiments, the rechargeable electrochemical cell has a cycle life of greater than or equal to 50 cycles (e.g., 50-10,000 cycles). In some embodiments, the cycle life is greater than or equal to 20 larger than the cycle life of an otherwise equivalent electrochemical cell with a conventional polyolefin separator and conventional liquid carbonate electrolyte. In some embodiments, the rechargeable electrochemical cell has a power rating of greater than or equal to 500 W kg−1 (e.g., 500-5000 W kg−1). In some embodiments, the rechargeable electrochemical cell has a power rating of greater than or equal to 2-fold higher than the power rating of an otherwise equivalent electrochemical cell with a conventional polyolefin separator and conventional liquid carbonate electrolyte.
During charge and discharge cycling of an electrochemical cell according to the present disclosure, cell voltages may be maintained (e.g., via a controller as described in U.S. Pat. No. 10,727,545) above a lower voltage limit, VLL, and below a normal operation charging voltage upper voltage limit, VUL. A constant charging current iNC may be maintained as the cell voltage increases. As cell voltage reaches the upper voltage limit, VUL, the charging current may be reduced and/or stopped after the cell voltage reaches VUL or after the cell is fully charged. VUL can vary according to the specific materials, performance requirements and application that the electrochemical cell is designed for. For example, VUL can be in the range of 2.5V to 5.5V. Electrochemical cells according to the present disclosure are particularly useful for fast- and ultrafast-charging methods. In some embodiments, charging an electrochemical cell includes increasing the state of charge (SOC) of the cell from a first value (e.g., 1%, 5%, 10%, 30%, 50% or more) to at least 80% in a period of time ranging from about 5 minutes to about 30 minutes (e.g., 5-15 minutes). In some embodiments, the C-rate during the charging ranges from 0.05C to 2C, or 0.1C to 2C.
A plurality of electrochemical cells may be connected in series and/or in parallel via electrode terminals for various applications. In some high-power applications such as electric vehicles. cells may be configured as one or more battery modules and/or packs. A battery module may be formed by electrically connecting a certain number of electrochemical cells and arranging them in a frame in order to protect the cells from external impact, heat, vibration, or the like. The battery pack may then be installed in the electric vehicle or other system. Many existing battery packs are made by assembling various control and protection systems such as battery management systems (e.g., as described in WO 2015/023820A2) and thermal management components on one or more battery modules.
Liquid electrolytes containing lithium bis(fluorosulfonyl)imide (LiFSI), 1,2-dimethoxyethane (DME), and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE) in molar ratios of 1.0:1.6:2.8, 1.0:1.6:2.4, 1.0:1.6:2.0, 1.0:2.0:2.8, and 1.0:2.4:2.0 (A, B, C, D, and E, respectively) were prepared by first adding lithium bis(fluorosulfonyl)imide in 1,2-dimethoxyethane and stirring for 10 minutes, or until fully dissolved. Then, 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether was added. The electrolyte ionic conductivity was then measured using a Mettler Toledo Seven2GoTM S3 conductivity meter at a temperature between 23° C. and 24° C.(
A 2032 coin cell was assembled with a lithium counter electrode, electrolyte, a polyolefin separator, and a stainless steel electrode with polymer coated at a thickness of 5 μm. This was done using the polymer shown below:
which was coated onto the stainless steel working electrode. The cell was constructed using electrolyte D from Example 1. Electrochemical impedance spectroscopy was performed using the same polymer membrane. Linear sweep voltammetry was conducted and the voltage stability of the cell exceeded 3.7 V vs. Li/Li+ at 25° C.
The polymer was coated onto lithium electrodes at a thickness of 5 μm and a 2032 coin cell was assembled using electrolyte D. A Nyquist plot was recorded (
A Li|NMC622 electrochemical cell was constructed using locally concentrated electrolyte A as described in Example 1 and the microporous polymer membrane described in Example 2, which was coated onto a polyolefin separator at a thickness of 1 μm. See,
A Cu|NMC622 electrochemical cell was constructed using locally concentrated electrolyte A as described in Example 1 and the microporous polymer described in Example 2. which was coated onto a polyolefin separator at a thickness of 1 μm. See,
Materials. Benzylamine, triethylene glycol, 4-toluenesulfonyl chloride, lithium bromide, paraformaldehyde, 10% palladium on carbon and potassium carbonate were obtained from Sigma Aldrich. 3,3,3′,3′-tetramethyl-1,1′-spirobisindane-5,5′,6,6′-tetraol and sodium hydroxide was obtained from Alfa Acsar. 1-aza-15-crown-5 and 1-aza-12-crown-4 were obtained from TCI. Tetrafluoroterephthalonitrile was obtained from Oakwood Chemical. N,N-dimethylacetamide was obtained from Acros Organics. Sodium hydroxide pellets were obtained from Alfa Acsar. Tetrahydrofuran, methylene dichloride, chloroform, N,N-dimethylformamide, methanol, and toluene were obtained from OmniSolv. Ethanol was obtained from Macron. CDCl3 was obtained from Cambridge Isotope Laboratories. Triethylene glycol ditosylate was synthesized in 96% yield according to the procedure of Du et al. (J. Am. Chem. Soc. 2019, 141 (17), 7163-7172).
1H and 13C Nuclear Magnetic Resonance (NMR) Spectroscopy. 1H and 13C NMR spectra were recorded on Bruker Avance II at 500 MHz and 125 MHz, respectively, and processed using Mestrenova 12.0.3 Software. Chemical shifts are reported in δ (ppm) relative to the residual solvent peak (CDCl3: 7.26 for 1H, 77.16 for 13C). Splitting patterns are designated as s (singlet), br s (broad singlet), d (doublet), t (triplet), q (quartet), and m (multiplet).
Electrospray lonization Mass Spectrometry (ESI-MS). Spectra were acquired on a Bruker MicroTOF spectrometer.
Size-Exclusion Chromatography (SEC). Molecular weights were determined using a Malvem Resolve/Reveal multi-detection SEC system using tetrahydrofuran as the eluent.
Column Chromatography. Column chromatography was carried out with a silica
or basic alumina stationary phase. Where noted, flash chromatography was carried out using a Biotage Isolera flash purification system, with Biotage SNAP KP-Sil columns.
Synthesis of N-benzyl 1-aza-9-crown-3:
An adaptation to the procedure of Sakamoto et al. (J. Org. Chem. 1986, 51 (25), 4974-4979) was used. To a round bottom flask (1000 mL) equipped with a magnetic stir bar was added N,N-dimethylacetamide (500 mL), lithium bromide (52.11 g, 600 mmol), potassium carbonate (41.46 g, 300 mmol), and triethylene glycol ditosylate (45.86 g, 100 mmol). Benzylamine (10.93 mL, 100 mmol) was then added while stirring. A reflux condenser was attached and the mixture heated to 130° C. for 96 h. The solvent was then removed under reduced pressure. Aqueous sodium hydroxide (1.0 M, 1000 mL) was added to the residue and the product was extracted 5 times with DCM (200 mL). The combined organic extracts were dried over sodium sulfate before solvent was removed under reduced pressure to yield the crude product as a red oil. This was purified using flash chromatography with a silica gel stationary phase and hexanes-ethyl acetate mobile phase. The solvent was removed under reduced pressure to yield the product as a yellow oil (5.53 g, 25% yield). 1H NMR and EI-MS spectra were in accordance with the literature procedure.
Synthesis of 1-aza-9-crown-3:
To a three-neck round bottom flask (1000 mL) equipped with a magnetic stir bar was added 10% Pd/C (0.60 g). The flask was evacuated and refilled with dinitrogen gas three times. In a separate round bottom flask, 500 mL of ethanol with 1-aza-9-crown-3 (5.30 g, 24 mmol) was sparged with dinitrogen gas to remove dissolved oxygen. The solution of the substrate in ethanol was then transferred to the evacuated reaction flask via cannula transfer. The flask was then evacuated and backfilled 3 times with dihydrogen gas. After stirring for 20 h, the reaction mixture was isolated by filtration through a Celite pad which was washed with ethanol. The solvent was then removed under reduced pressure to yield the product as a light yellow oil (2.19 g, 70% yield), then stored under dinitrogen gas at 4° C. 1H NMR and EI-MS spectra were in accordance with the literature procedure.
To a round bottom flask (250 mL) equipped with a magnetic stir bar was added toluene (80 mL), paraformaldehyde (0.24 g, 8.0 mmol), and 1-aza-9-crown-3 (1.05 g, 8.0 mmol). The reaction stirred for 10 min at reflux, at which point 3,3,3′,3′-tetramethyl-1,1′-spirobisindane-5,5′,6,6′-tetraol (1.36 g, 4.0 mmol) was added. A Dean-Stark apparatus was attached and the reaction was stirred at reflux for 96 h. The reaction was concentrated under reduced pressure, followed by purification by flash chromatography (methanol/methylene dichloride). The solvent was removed under reduced pressure to yield the product as a light orange powder (1.83 g. 68% yield). 1H NMR (CDCl3, 500 MHz): δ (ppm) 12.56 (br s, 2H), 6.66 (s, 2H), 5.65 (br s, 2H), 3.87-3.50 (br m, 16H), 3.45 (d, 2H, J=14.8 Hz), 3.04 (d, 2H, J=14.8 Hz), 3.00-2.46 (br m, 8H), 2.28 (d, 2H, J=13.4 Hz), 2.18 (d, 2H, J=13.4 Hz), 1.36 (s, 6H), 1.27 (s, 6H); 13C NMR (CDCl3, 125 MHz): δ (ppm) 145.2, 144.6. 142.0, 138.9, 115.9, 107.3, 74.0 (br), 72.8 (br), 72.2 (br), 70.7 (br), 57.9, 56.6, 55.2, 54.3 (br), 52.8 (br), 42.9, 33.0, 29.8; HR-MS (ESI) calc. for C35H51N2O830 627.3640; found 627.3758.
To a round bottom flask (250 mL) equipped with a magnetic stir bar was added toluene (70 mL), paraformaldehyde (0.21 g. 7.1 mmol), and 1-aza-12-crown-4 (1.24 g, 7.1 mmol). The reaction stirred for 10 min at reflux, at which point 3,3,3′,3′-tetramethyl-1,1′-spirobisindane-5,5,6,6′-tetraol (1.21 g, 3.5 mmol) was added. A Dean-Stark apparatus was attached and the reaction was stirred at reflux for 46 h. The reaction was concentrated under reduced pressure, followed by purification with silica gel chromatography (methanol-methylene dichloride). The solvent was removed under reduced pressure to yield the product as a light orange powder (0.55 g, 22% yield). 1H NMR (CDCl3, 500 MHz): δ (ppm) 11.83 (br s, 2H), 6.62 (s, 2H), 5.77 (br s, 2H), 3.76-3.37 (br m, 24H), 3.21-3.06 (m, 4H), 3.01-2.87 (br m, 2H), 2.68-2.56 (br m, 2H), 2.52-2.37 (br m, 2H), 2.25 (d, 2H, J=13.3 Hz), 2.16 (d, 2H, J=13.3 Hz), 2.13-2.03 (br m, 2H), 1.31 (s, 6H), 1.25 (s, 6H); 13C NMR (CDCl3, 125 MHZ): δ (ppm) 145.0, 144.8, 141.8, 138.8, 116.6, 107.1, 71.3, 71.0, 70.6, 70.0, 69.7, 68.3, 57.8, 56.7, 54.4, 54.2, 53.6, 42.8, 32.9, 30.0; HR-MS (ESI) calc. for C39H59N2O10+ 715.4164; found 715.4289.
To a round bottom flask (250 mL) equipped with a magnetic stir bar was added toluene (75 mL), paraformaldehyde (0.22 g, 7.4 mmol), and 1-aza-15-crown-5 (1.63 g, 7.4 mmol). The reaction stirred for 10 min at reflux, at which point 3,3,3′,3′-tetramethyl-1,1′-spirobisindane-5,5′,6,6′-tetraol (1.26 g, 3.7 mmol) was added. A Dean-Stark apparatus was attached and the reaction was stirred at reflux for 40 h. The reaction was concentrated under reduced pressure, followed by purification with silica gel chromatography (methanol-methylene dichloride). The solvent was removed under reduced pressure to vield the product as a beige powder (0.84 g, 28% yield). 1NMR (CDCl3, 500 MHz): δ (ppm) 11.84 (br s, 2H), 6.62 (s, 2H), 5.75 (br s, 2H), 3.78-3.42 (br m, 32H), 3.23 (d, 2H, J=14.7), 3.15 (d, 2H, J=14.7), 2.85-2.31 (br m, 8H), 2.24 (d, 2H, J=13.4 Hz), 2.15 (d, 2H, J=13.4 Hz), 1.32 (s, 6H), 1.25 (s, 6H); 13C NMR (CDCl3, 125 MHz): δ (ppm) 145.1, 144.7, 141.9, 138.7, 116.5, 107.0, 70.9, 70.4, 70.3, 69.0 (br s), 67.9 (br s), 57.8, 56.8, 54.1, 54.0-53.4 (br s), 42.8, 33.0, 30.0; HR-MS (ESI) calc. for C43H67N2O12+ 803.4689; found 803.4755.
To a round bottom flask (50 mL) equipped with a magnetic stir bar was added monomer 1a (0.72 g, 1.1 mmol), tetrafluoroterephthalonitrile (0.23 g, 1.1 mmol), anhydrous N,N-dimethylformamide (11 mL). After stirring at 65° C.for 5 min to dissolve the monomers, freshly ground potassium carbonate (0.63 g, 4.6 mmol) was then slowly added. A reflux condenser was attached and the mixture stirred for 8 h at 65° C. This was then added to water (100 mL) to precipitate the crude polymer as a yellow solid, which was then isolated by filtration and washed with an additional portion of water (100 mL). The crude polymer was dissolved in tetrahydrofuran (20 mL) at 50° C. and subsequently precipitated into methanol (200 mL) and isolated by filtration. After drying under reduced pressure at 65° C., polymer 2a was isolated as a brown solid (0.58 g) in 68% yield. 1H NMR (CDCl3, 500 MHz): δ (ppm) 6.70-6.91 (br s, 2H), 2.66-4.21 (br m, 22H), 0.91-2.59 (br m, 22H), SEC (THF): Mn=71.4 kg mol−1, Mw=119 kg mol−1, D=1.67.
To a round bottom flask (50 mL) equipped with a magnetic stir bar was added monomer 1b (0.54 g, 0.76 mmol), tetrafluoroterephthalonitrile (0.15 g, 0.76 mmol), anhydrous N,N-dimethylformamide (15 mL). After stirring at 65° C.for 5 min to dissolve the monomers, freshly ground potassium carbonate (0.42 g, 3.0 mmol) was then slowly added. A reflux condenser was attached and the mixture stirred for 12 h at 65° C. This was then added to water (200 mL) to precipitate the crude polymer as a yellow solid, which was then isolated by filtration and washed with an additional portion of water (200 mL). The crude polymer was dissolved in tetrahydrofuran (10 mL) at 50° C. and subsequently precipitated into methanol (100 mL) and isolated by filtration. After drying under reduced pressure at 65° C., polymer 2b was isolated as a yellow solid (0.50 g) in 79% yield. 1H NMR (CDCl3, 500 MHz): δ (ppm) 6.57-6.96 (br s, 2H), 3.30-3.90 (br m, 24H), 1.68-3.20 (br m, 16H) 0.92-1.51 (br m, 12H), SEC (THF): Mn=185 kg mol−1, Mw=273 kg mol−1, D=1.48.
To a round bottom flask (50 mL) equipped with a magnetic stir bar was added monomer 1c (0.84 g, 1.05 mmol), tetrafluoroterephthalonitrile (0.21 g, 1.05 mmol), anhydrous N,N-dimethylformamide (11 mL). After stirring at 65° C. for 5 min to dissolve the monomers, freshly ground potassium carbonate (0.58 g, 4.2 mmol) was then slowly added. A reflux condenser was attached and the mixture stirred for 24 h at 65° C. This was then added to water (100 mL) to precipitate the crude polymer as a yellow solid, which was then isolated by filtration and washed with an additional portion of water (100 mL). The crude polymer was dissolved in tetrahydrofuran (30 mL) at 50° C. and subsequently precipitated into methanol (300 mL) and isolated by filtration. The resulting solid was dissolved in chloroform (10 mL) at 50° C. and subsequently precipitated into methanol (100 mL) and isolated by filtration. After drying under reduced pressure at ambient temperature, polymer 2c was isolated as a yellow solid (0.61 g) in 63% yield. 1H NMR (CDCl3, 500 MHz): δ (ppm) 6.64-6.89 (br s, 2H), 2.59-3.98 (br m, 40H), 1.67-2.49 (br m, 8H) 0.89-1.58 (br m, 12H), SEC (THF): Mn=333 kg mol−1, Mw=424 kg mol−1, D=1.27.
Electrochemical impedance spectroscopy was conducted on Li|Li symmetric cells prepared using polymer-coated lithium electrodes and electrolyte D as described in Example 1. The resulting Nyquist plots are shown in
Li|NMC811 electrochemical cells were constructed using locally concentrated electrolyte D as described in Example 1 and microporous polymer membranes with aza-crown-ether pendants (“Aza-9-crown polymer” 2a: “Aza-12-crown polymer” 2b: and “Aza-15-crown polymer” 2c as described in Example 5), which were coated onto the Li metal anode. Cells were cycled using a 3.0 mA cm−2 charge/discharge protocol with a 4.2 V upper cutoff voltage and 3 V lower cutoff voltage. All cells cycled an areal capacity greater than 1.0 mA h cm−2, or nearly 1.0 mA h cm−2, through 100 cycles (
Cu|NMC622 electrochemical cells was constructed using locally concentrated electrolyte D as described in Example 1 and microporous polymer membranes with aza-crown-ether pendants (“Aza-9-crown polymer” 2a; “Aza-12-crown polymer” 2b; and “Aza-15-crown polymer” 2c as described in Example 5). Cells were cycled using a 1.0 mA cm−2 charge/3.0 mA cm−2 discharge protocol with a 4.3 V upper cutoff voltage and 3 V lower cutoff voltage. The cells containing the aza-9-crown polymer membrane or aza-12-crown polymer membrane reversibly cycled an arcal capacity greater than 1.0 mA h cm−2 for approximately 20 cycles (
Locally super concentrated electrolytes (LSCEs) 1-9, which feature a 1:2:x ratio of [LiFSI]:[DME]:[TTE] were prepared as summarized in the table below. The properties of this LSCE series were compared to a super-concentrated electrolyte (SCE) containing a 1:2 ratio of [LiFSI]:[DME] as a positive control, as well as to a commercially available dilute electrolyte (DE) containing 1 M LiPF6 in ethylene carbonate/dimethyl carbonate (1:1 by weight) as a negative control.
Dilute electrolytes rely on ion solvation with the maximum possible coordination number to facilitate ion-separation, which often ensures high mobility for ionic charge carriers. This is more challenging to realize with concentrated electrolytes, where mobility is compromised by changes to the mobile ion-solvation environment, including changes to the coordination number and speciation with respect to ion-pairing, clustering, and networking. Non-coordinating diluents can be useful in de-networking various ionic species into smaller clusters that exhibit higher mobility. This behavior is generally concurrent with substantial changes in viscosity due to the reduced prevalence of networking interactions. The degree to which a non-coordinating diluent triggers such changes in the electrolyte is therefore important.
These phenomena are evidenced in the magnitude of change in viscosity with increasing molar ratio relative to the SCE (
The ionic conductivity, i.e., the product of ionic charge carrier concentration and mobility, was measured for LSCEs 1-9 and both controls (
Following the initial characterization of bulk electrolyte properties described in Example 9, a screen for identifying promising electrolytes for fast-charge and ultrafast-charge applications was developed. Here, charging to 80% SOC in 15 min from a pre-determined SOC of Y % (Y=60, 50, 40, 30, 20, 10, 0) was attempted; the tests were repeated 5 times to discem variation between cycles, even if preliminary. The starting point for each of these tests was accessed at an EV-relevant discharge rate of C/3, corresponding to a current density of 0.5 mA cm−2. In this way, the charge current density necessarily scales with the imposed target for change in SOC (ΔSOC). For the NMC622 cathode employed in the screen, an 80% ΔSOC in 15 min would require a current density of 4.8 mA cm−2. To interpret the data, one then quantifies the degree to which Li|NMC622 cells assembled with certain electrolytes access the theoretical capacity before hitting the cutoff voltage, which in these screens was sct to 4.2 V vs. Li/Li+.
Li|NMC622 electrochemical cells were constructed using 1.5 mA h cm−2 NMC622 and electrolytes LSCE 1, LSCE 2, LSCE 3, LSCE 4, LSCE 5, LSCE 6, LSCE 7, LSCE 8, LSCE 9, SCE, or DE from Example 9. The charge current density was selected to pass the theoretical charge capacity (brown line) in 15 min, while the discharge current density was held at 0.5 mA cm−2 throughout the test (i.e., C/3). The theoretical charge capacities are also labeled with the expected percent change in state-of-charge (ΔSOC) after charging.
LSCE 7 (
Li|NMC622 electrochemical cells were constructed using 1.5 mA h cm−2 NMC622 and electrolytes LSCE 7, SCE, or DE from Example 9. Cells cycled with discharge current density of 0.5 mA cm−2 and a charge current density matched to deliver 80% ΔSOC in the allotted time. Cutoff voltages of 4.2 V/3.0 V were employed.
Data shown in
When targeting 80% ΔSOC in 10 min (
Having observed the effects of an LSCE on lowering the overpotential, which manifest in improved capacity retention during fast-charging and ultrafast-charging from deep discharge, the ability of the LSCE to extend cycle life when a smaller fraction of the cathode capacity is reversibly cycled with fast-charging was considered. Li|NMC622 coin cells were cycled, using a charge current density matched to charge to 80% SOC in 15 min from a pre-determined SOC of Z % (Y=60, 40, 20, 0), corresponding to 1.2, 2.4, 3.6 or 4.8 mA cm−2, respectively, while discharging at 0.5 mA cm−2. Data in
Li|Cu electrochemical cells were constructed using copper foil and electrolytes LSCE 7, SCE, or DE from Example 9. In
An investigation of potential mechanisms for capacity loss was conducted, focusing on capacity loss at the anode resulting from fast-charging. Without wishing to be bound by any particular theory, it is believed that fast Li plating could produce ramified deposits that can disconnect from the current collector at EV-relevant discharge rates or, alternatively, react with electrolyte. To investigate capacity fade originating from anode degradation, the Li consumption rate (LCR) was determined by repeatedly stripping and plating Li from a pre-defined reservoir. Inefficiencies in plating and stripping cause the reservoir to become depleted over time, which was evidenced by a voltage spike while stripping Li. This method accounted for Li consumption across a typical lifespan of a thin Li anode, which can reach hundreds of cycles and several hundred hours. Rates of Li loss could change at different stages of anode health, owing to changes in Li morphology upon repeated fast-charge cycling. This method contrasts more conventional determinations of Coulombic efficiency, which strip and plate Li from a reservoir 20 times or fewer before concluding the test. Such short term methods could generate artificially high efficiency values at early stages of cycle. Alternatively, longer measurements of Li consumption account for periods of accelerated rates of Li loss, so the average rate is reflective of the actual behavior and thereby a more reliable predictor of full cells cycled under same conditions.
To carry out these experiments, coin cells with a Li metal anode and bare Cu current collector were assembled. Li|Cu cells were first cycled 3 times, plating and stripping 1.2 mAh cm−2 of Li onto Cu to precondition the Cu surface, before depositing a 6 mAh cm−2 Li reservoir (
With a quantitative framework for gradual lithium consumption in symmetric cells in place, mechanisms of anode-driven capacity depletion were then considered so as to relate the calculated LCRs to Li|NMC full cell performance. Capacity drop in fast-charging lithium batteries can result from loss of anode material, loss of cathode material, resistance buildup on interphase(s), electrolyte depletion, or partial short-circuiting (“soft-shorts”), which can be considered loss of both anode and cathode material. While the LCR determination to quantitate anode material depletion under fast-charge conditions qualitatively agreed with the observed trend in Li|NMC full cell performance, back-calculations from the measured LCRs consistently overpredicted cycle life. suggesting that Li depletion is only partially responsible for battery failure. This could contribute to capacity fade through the proposed “dead Li” mechanism in which Li becomes disconnected from the current collector as a result of repeated of fast-charge cycling.
Briefly, Li plating at a high current density leads to the concentration of Li ions in solution (i.e., [Li+]) near the electrode to approach zero. Li electrodeposits grow fastest in regions with high [Lit], causing minor protrusions to seed ramified or mossy deposits. Upon subsequent stripping at low current density, Li protrusions have been shown to strip close to the protrusion site, leaving behind Li metal that is disconnected from the electrode. This Li is thought to be electrochemically inactive, or “dead”; although recent work has suggested it may be retrievable under certain circumstances (sec. e.g., Liu. et al. Nature 2021, 600, 659-663). Nevertheless, loss of the lithium inventory at the anode is likely to occur quickly when Li deposits as a mossy morphology. rather than dense or globular and will impact the capacity retention of the cell as more of it is lost.
While the dead Li mechanism for capacity loss is likely operative in the fast-charge and ultrafast-charge conditions tested, it may occur in tandem with resistance buildup in full cells. In particular. the Li|NMC full cell results with fast-, super-fast-, and ultra-fast-charge (
Instead, it is hypothesized here that electrolyte reactivity at Li could be responsible for generation of resistive interphases or depletion of electrolyte components, both of which could contribute to the total cell resistance and increase the fast charge overpotential. If this were the case. electrodeposits from LSCE 7 would have a low surface area and be globular, deposits from SCE would be similar in morphology with slightly higher surface area, and Li deposits from DE would be substantially higher in surface area.
Li|Li electrochemical cells were constructed using electrolytes LSCE 7, SCE, or DE from Example 9.
To understand differences in the plating morphology of Li metal, scanning electron microscopy (SEM) was employed (
Li|NMC811 electrochemical cells were constructed using locally concentrated electrolytes with one or two lithium salts, the components of which are summarized in the follow table.
Cells were cycled using a 1.0 mA cm−2/3.0 mA cm−2 charge/discharge protocol with a 4.2 V upper cutoff voltage and 3 V lower cutoff voltage (
Exemplary embodiments provided in accordance with the presently disclosed subject matter include, but are not limited to, the claims and the following embodiments:
-[A-AB-B]n-,
and
-[A-AB-B]n-,
[A-AB-B]n-,
Although the foregoing has been described in some detail by way of illustration and example for purposes of clarity and understanding, one of skill in the art will appreciate that certain changes and modifications can be practiced within the scope of the appended claims. In addition, each reference provided herein is incorporated by reference in its entirety to the same extent as if cach reference was individually incorporated by reference.
The present application claims priority to U.S. Provisional Pat. Appl. No. 63/184,759, filed on May 5, 2021, which application is incorporated herein by reference in its entirety.
This invention was made with government support under Contract No. DE-AC02-05CH11231 awarded by the U.S. Department of Energy and under Advanced Research Projects Agency-Energy (ARPA-E) Award No. DE-AR0000774. The government has certain rights in the invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2022/027867 | 5/5/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63184759 | May 2021 | US |
