Patent Application
20230031554
None.
Energy storage systems like batteries are required for a range of applications like grid-based, electric vehicles, solar storage, uninterruptible power sources, etc. Lithium-ion and lead acid batteries currently dominate the market; however, they are expensive, flammable and contain toxic elements. Aqueous based metal anode systems like zinc (Zn)-anode batteries can compete with lithium and lead on volumetric and gravimetric energy densities. These are usually available in the market as primary batteries as they can be only used once because of the irreversibility of its active materials after a full discharge.
In some embodiments, a dual electrolyte battery comprises a cathode, an anode, a catholyte in contact with the cathode, and an anolyte in contact with the anode. The catholyte comprises a first gelled electrolyte solution, and the anolyte comprises a second gelled electrolyte solution. A concentration of an electrolyte in the anolyte is higher than a concentration of the electrolyte in the catholyte.
In some embodiments, a dual electrolyte battery comprises a cathode, an anode, a catholyte in contact with the cathode, and an anolyte in contact with the anode. The catholyte comprises a first gelled electrolyte solution, and the anolyte comprises a second gelled electrolyte solution. The first gelled electrolyte solution and the second gelled electrolyte solution comprise a hydroxide, and a concentration of the hydroxide in the anolyte is higher than a concentration of the hydroxide in the catholyte.
In some embodiments, a method of forming dual electrolyte battery comprises disposing a catholyte in contact with a cathode, disposing an anolyte in contact with an anode, and disposing at least one of a separator or a buffer layer between the anolyte and the catholyte. The catholyte comprises a first gelled electrolyte solution, and anolyte comprises a second gelled electrolyte solution. A concentration of the hydroxide in the anolyte is higher than a concentration of the hydroxide in the catholyte.
These and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying claims.
For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.
In this disclosure, the terms “negative electrode” and “anode” are both used to mean “negative electrode.” Likewise, the terms “positive electrode” and “cathode” are both used to mean “positive electrode.” Reference to an “electrode” alone can refer to the anode, cathode, or both. Reference to the term “primary battery” (e.g., “primary battery,” “primary electrochemical cell,” or “primary cell”), refers to a cell or battery that after a single discharge is disposed of and replaced. Reference to the term “secondary battery” (e.g., “secondary battery,” “secondary electrochemical cell,” or “secondary cell”), refers to a cell or battery that can be recharged one or more times and reused. As used herein, a “catholyte” refers to an electrolyte solution in contact with the cathode without being in direct contact with the anode, and an “anolyte” refers to an electrolyte solution in contact with the anode without being in direct contact with the cathode. The term electrolyte alone can refer to the catholyte, the anolyte, or an electrolyte in direct contact with both the anode and the cathode.
Energy storage systems like batteries are required for a range of applications like grid-based, electric vehicles, solar storage, uninterruptible power sources, etc. Lithium-ion and lead acid batteries currently dominate the market; however, they are expensive, flammable and contain toxic elements. Aqueous based metal anode systems like zinc (Zn)-anode batteries can compete with lithium and lead on volumetric and gravimetric energy densities when paired with a cheap and abundant material cathode like manganese dioxide (MnO2). These batteries can deliver >400 Wh/L in aqueous alkaline electrolyte. The high energy density is possible because of the high theoretical capacity of MnO2 and Zn which is around 617 mAh/g and 820 mAh/g based on the first and second electron reactions, respectively.
The irreversibility arises when maximum utilization is tried to be attained which leads to problems like volume expansion, breakdown of crystal structure to form spinels, redistribution of active material, zinc poisoning of the cathode, passivation of the metallic anode and dendritic shorts. The electrolyte, potassium hydroxide (KOH), is the source of some of the problems mentioned. During discharge the 4+ state of Mn reduces to the 3+ state which leads to an increase in its solubility in high KOH concentration at high capacity utilization. The loss of active Mn+ ions is the cause of capacity loss in the battery. Also, the dissolved Mn+ ions can also dissociate to form Mn4+ and Mn2+ ions which can lead to the formation of lower oxides like spinels Mn3O4 and pyrochroite [Mn(OH)2]. The reactions get complicated further as Zn delivers its capacity through a dissolution reaction where it forms dissolved zincate ions [Zn(OH)42−]. These dissolved zincate ions also react with the dissolved Mn ions to form inactive Zn spinels like ZnMn2O4. The Zn anodes can also form dendrites during charge which can penetrate the separator to short the battery.
Another problem of the Zn anodes is the active redistribution of the active materials during the dissolution reaction, which leads to a loss of active ions from the current collector and thus, loss in capacity. The cathode also undergoes large volume expansion during its discharge reaction as the protons from the electrolyte intercalate into the crystal structure and this leads to the active material denuding from the current collector and thus, loss in capacity again.
In this disclosure, we disclose a method and procedure to make polymer gelled electrolytes (PGE's) with KOH in the framework tailored in terms of concentration, viscosity, ionic conductivity, etc. for the respective electrodes. The fabrication of PGE's allows for the use of two electrolyte concentrations in a single battery where they are tuned to obtain improved or optimum performance out of the cathode and anode, respectively.
More specifically, the cells and methods as disclosed herein can use a polymer gelled electrolyte (PGE) with differing concentrations for the cathode and anode side, respectively, where the PGE's are tailored in their properties to achieve improved utilization out of the respective electrodes. The MnO2 cathode is preferably gelled in low KOH concentrations to limit the solubility of Mn+ ions, while the Zn anode is preferably gelled in high KOH concentrations to increase the solubility of Zn ions as the capacity utilization is depended on the dissolution of Zn. Other additives like carbon, Teflon, cellulose fibers can also be added to the PGE's to enhance capacity utilization of the electrodes and limit gas entrapment in the gels. Further, the viscosity of the PGE for the anode may be lower than that of the cathode. This can allow for any evolved gases at the anode to migrate out of the anode, while the higher viscosity in the cathode can limit the migration of any manganese ions out of the cathode and any zincate ions into the cathode.
In some embodiment, a cell having a first PGE of concentration A applied on the cathode and a second PGE of concentration B applied on the anode side is disclosed. A separator or a buffering layer can exist between the PGE's to prevent mixing. The PGE of concentration A can be lower on the cathode side, while that of concentration B can be higher on the anode side. In some aspects the PGE of concentration A can have a higher viscosity that the PGE of concentration B on the anode side.
The reason for designing this dual electrolyte type cell is explained with reference to
Another advantage of having a dual electrolyte cell with lower alkaline concentration of PGE on the cathode side and higher alkaline concentration on the anode side is the increase in cell potential as shown in
Referring to
In some embodiments, the battery 10 can comprise one or more cathodes 12 and one or more anodes 13, which can be present in any configuration or form factor. When a plurality of anodes 13 and/or a plurality of cathodes 12 are present, the electrodes can be configured in a layered configuration such that the electrodes alternate (e.g., anode, cathode, anode, etc.). Any number of anodes 13 and/or cathodes 12 can be present to provide a desired capacity and/or output voltage. In the jellyroll configuration (e.g., as shown in
In an embodiment, housing 7 comprises a molded box or container that is generally non-reactive with respect to the electrolyte solutions in the battery 10, including the electrolyte. In an embodiment, the housing 7 comprises a polymer (e.g., a polypropylene molded box, an acrylic polymer molded box, etc.), a coated metal, or the like.
The cathode 12 can comprise a mixture of components including an electrochemically active material. Additional components such as a binder, a conductive material, and/or one or more additional components can also be optionally included that can serve to improve the lifespan, rechargeability, and electrochemical properties of the cathode 12. The cathode 12 can comprise a cathode material 2 (e.g., an electroactive material, additives, etc.). The cathode can comprise between about 1 wt. % and about 95 wt. % active material. Suitable cathode materials 2 can include, but are not limited to, manganese dioxide, copper manganese oxide, hausmannite, manganese oxide, copper intercalated bismuth birnessite, birnessite, todokorite, ramsdellite, pyrolusite, pyrochroite, silver oxide, silver dioxide, silver, nickel oxyhydroxide, nickel hydroxide, nickel, lead oxide, copper oxide, copper dioxide, lead, lead dioxide (α and β), potassium persulfate, sodium persulfate, ammonium persulfate, potassium permanganate, calcium permanganate, barium permanganate, silver permanganate, ammonium permanganate, peroxide, gold, perchlorate, cobalt oxide (CoO, CoO2, Co3O4), lithium cobalt oxide, sodium cobalt oxide, perchlorate, nickel oxide, bromine, mercury, vanadium oxide, bismuth vanadium oxide, hydroquinone, calix[4]quinone, tetrachlorobenzoquinone, 1,4-naphthoquinone, 9,10-anthraquinone, 1,2-napthaquinone, 9,10-phenanthrenequinone, nitroxide-oxammonium cation redox pair like 2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO), carbon, 2,3-dicyano-5,6-dichlorodicyanoquinone, tetracyanoethylene, sulfur trioxide, ozone, oxygen, air, lithium nickel manganese cobalt oxide, sulfur, lithium iron phosphate, lithium copper oxide, lithium copper oxyphosphate, or any combination thereof. In some embodiments, the cathode can comprise an air electrode.
In some embodiments, the cathode material 2 can be based on one or many polymorphs of MnO2, including electrolytic (EMD), α-MnO2, β-MnO2, γ-MnO2, δ-MnO2, ε-MnO2, or λ-MnO2. Other forms of MnO2 can also be present such as hydrated MnO2, pyrolusite, birnessite, ramsdellite, hollandite, romanechite, todorkite, lithiophorite, chalcophanite, sodium or potassium rich birnessite, cryptomelane, buserite, manganese oxyhydroxide (MnOOH), α-MnOOH, γ-MnOOH, β-MnOOH, manganese hydroxide [Mn(OH)2], partially or fully protonated manganese dioxide, Mn3O4, Mn2O3, bixbyite, MnO, lithiated manganese dioxide (LiMn2O4, Li2MnO3), CuMn2O4, aluminum manganese oxide, zinc manganese dioxide, bismuth manganese oxide, copper intercalated birnessite, copper intercalated bismuth birnessite, tin doped manganese oxide, magnesium manganese oxide, or any combination thereof. In general, the cycled form of manganese dioxide in the cathode can have a layered configuration, which in some embodiment can comprise δ-MnO2 that is interchangeably referred to as birnessite. If non-birnessite polymorphic forms of manganese dioxide are used, these can be converted to birnessite in-situ by one or more conditioning cycles as described in more details below. For example, a full or partial discharge to the end of the MnO2 second electron stage (e.g., between about 20% to about 100% of the 2nd electron capacity of the cathode) may be performed and subsequently recharging back to its Mn4+ state, resulting in birnessite-phase manganese dioxide.
The addition of a conductive additive such as conductive carbon enables high loadings of an electroactive material in the cathode material, resulting in high volumetric and gravimetric energy density. In some embodiments, the conductive additive can comprise graphite, carbon fiber, carbon black, acetylene black, single walled carbon nanotubes, multi-walled carbon nanotubes, nickel or copper coated carbon nanotubes, dispersions of single walled carbon nanotubes, dispersions of multi-walled carbon nanotubes, graphene, graphyne, graphene oxide, or a combination thereof. Higher loadings of the electroactive material in the cathode are, in some embodiments, desirable to increase the energy density. Other examples of conductive carbon include TIMREX Primary Synthetic Graphite (all types), TIMREX Natural Flake Graphite (all types), TIMREX MB, MK, MX, KC, B, LB Grades(examples, KS15, KS44, KC44, MB15, MB25, MK15, MK25, MK44, MX15, MX25, BNB90, LB family) TIMREX Dispersions; ENASCO 150G, 210G, 250G, 260G, 350G, 150P, 250P; SUPER P, SUPER P Li, carbon black (examples include Ketjenblack EC-300J, Ketjenblack EC-600JD, Ketjenblack EC-600JD powder), acetylene black, carbon nanotubes (single or multi-walled), Zenyatta graphite, and/or combinations thereof.
In some embodiments, the conductive additive can have a particle size range from about 1 to about 50 microns, or between about 2 and about 30 microns, or between about 5 and about 15 microns. The total conductive additive mass percentage in the cathode material 2 can range from about 5% to about 99% or between about 10% to about 80%. In some embodiments, the electroactive component in the cathode material 2 can be between 1 and 99 wt. % of the weight of the cathode material 2, and the conductive additive can be between 1 and 99 wt. %.
The cathode material 2 can also comprise a conductive component. The addition of a conductive component such as metal additives to the cathode material 2 may be accomplished by addition of one or more metal powders such as nickel powder to the cathode material 2. The conductive metal component can be present in a concentration of between about 0-30 wt. % in the cathode material 2. The conductive metal component may be, for example, nickel, copper, silver, gold, tin, cobalt, antimony, brass, bronze, aluminum, calcium, iron, or platinum. In one embodiment, the conductive metal component is a powder. In some embodiments, the conductive component can be added as an oxide and/or salt. For example, the conductive component can be cobalt oxide, cobalt hydroxide, lead oxide, lead hydroxide, or a combination thereof. In some embodiments, a second conductive metal component is added to act as a supportive conductive backbone for the first and second electron reactions to take place. The second electron reaction has a dissolution-precipitation reaction where Mn+ ions become soluble in the electrolyte and precipitate out on the materials such as graphite resulting in an electrochemical reaction and the formation of manganese hydroxide [Mn(OH)2] which is non-conductive. This ultimately results in a capacity fade in subsequent cycles. Suitable conductive components that can help to reduce the solubility of the manganese ions include transition metals like Ni, Co, Fe, Ti and metals like Ag, Au, Al, Ca. Oxides and salts of such metals are also suitable. Transition metals like Co can also help in reducing the solubility of Mn+ ions. Such conductive metal components may be incorporated into the electrode by chemical means or by physical means (e.g. ball milling, mortar/pestle, spex mixture). An example of such an electrode comprises 5-95% birnessite, 5-95% conductive carbon, 0-50% conductive component (e.g., a conductive metal), and 1-10% binder.
In some embodiments, a binder can be used with the cathode material 2. The binder can be present in a concentration of between about 0-10 wt. %, or alternatively between about 1-5 wt. % by weight of the cathode material. In some embodiments, the binder comprises water-soluble cellulose-based hydrogels, which can be used as thickeners and strong binders, and have been cross-linked with good mechanical strength and with conductive polymers. The binder may also be a cellulose film sold as cellophane. The binders can be made by physically cross-linking the water-soluble cellulose-based hydrogels with a polymer through repeated cooling and thawing cycles. In some embodiments, the binder can comprise a 0-10 wt. % carboxymethyl cellulose (CMC) solution cross-linked with 0-10 wt. % polyvinyl alcohol (PVA) on an equal volume basis. The binder, compared to the traditionally-used PTFE (polytetrafluoroethylene), shows superior performance. PTFE is a very resistive material, but its use in the industry has been widespread due to its good rollable properties. This, however, does not rule out using PTFE as a binder. Mixtures of PTFE with the aqueous binder and some conductive carbon can be used to create rollable binders. Using the aqueous-based binder can help in achieving a significant fraction of the two-electron capacity with minimal capacity loss over many cycles. In some embodiments, the binder can be water-based, have superior water retention capabilities, adhesion properties, and help to maintain the conductivity relative to an identical cathode using a PTFE binder instead. Examples of suitable water-based hydrogels can include, but are not limited to, methyl cellulose (MC), carboxymethyl cellulose (CMC), hydroypropyl cellulose (HPH), hydroypropylmethyl cellulose (HPMC), hydroxethylmethyl cellulose (HEMC), carboxymethylhydroxyethyl cellulose, hydroxyethyl cellulose (HEC), and combinations thereof. Examples of crosslinking polymers include polyvinyl alcohol, polyvinylacetate, polyaniline, polyvinylpyrrolidone, polyvinylidene fluoride, polypyrrole, and combinations thereof. In some embodiments, a 0-10 wt. % solution of water-cased cellulose hydrogen can be cross linked with a 0-10 wt. % solution of crosslinking polymers by, for example, repeated freeze/thaw cycles, radiation treatment, and/or chemical agents (e.g. epichlorohydrin). The aqueous binder may be mixed with 0-5% PTFE to improve manufacturability.
The cathode material 2 can also comprise additional elements. The additional elements can be included in the cathode material including a bismuth compound and/or copper/copper compounds, which together allow improved galvanostatic battery cycling of the cathode. When present as birnessite, the copper and/or bismuth can be incorporated into the layered nanostructure of the birnessite. The resulting birnessite cathode material can exhibit improved cycling and long-term performance with the copper and bismuth incorporated into the crystal and nanostructure of the birnessite.
The bismuth compound can be incorporated into the cathode 12 as an inorganic or organic salt of bismuth (oxidation states 5, 4, 3, 2, or 1), as a bismuth oxide, or as bismuth metal (i.e. elemental bismuth). The bismuth compound can be present in the cathode material at a concentration between about 1-20 wt. % of the weight of the cathode material 2. Examples of bismuth compounds include bismuth chloride, bismuth bromide, bismuth fluoride, bismuth iodide, bismuth sulfate, bismuth nitrate, bismuth trichloride, bismuth citrate, bismuth telluride, bismuth selenide, bismuth subsalicylate, bismuth neodecanoate, bismuth carbonate, bismuth subgallate, bismuth strontium calcium copper oxide, bismuth acetate, bismuth trifluoromethanesulfonate, bismuth nitrate oxide, bismuth gallate hydrate, bismuth phosphate, bismuth cobalt zinc oxide, bismuth sulphite agar, bismuth oxychloride, bismuth aluminate hydrate, bismuth tungsten oxide, bismuth lead strontium calcium copper oxide, bismuth antimonide, bismuth antimony telluride, bismuth oxide yittia stabilized, bismuth-lead alloy, ammonium bismuth citrate, 2-napthol bismuth salt, duchloritri(o-tolyl)bismuth, dichlordiphenyl(p-tolyl)bismuth, triphenylbismuth, and/or combinations thereof.
The copper compound can be incorporated into the cathode 12 as an organic or inorganic salt of copper (oxidation states 1, 2, 3, or 4), as a copper oxide, or as copper metal (i.e., elemental copper). The copper compound can be present in a concentration between about 1-70 wt. % of the weight of the cathode material 2. In some embodiments, the copper compound is present in a concentration between about 5-50 wt. % of the weight of the cathode material 2. In other embodiments, the copper compound is present in a concentration between about 10-50 wt. % of the weight of the cathode material 2. In yet other embodiments, the copper compound is present in a concentration between about 5-20 wt. % of the weight of the cathode material 2. Examples of copper compounds include copper and copper salts such as copper aluminum oxide, copper (I) oxide, copper (II) oxide and/or copper salts in a +1, +2, +3, or +4 oxidation state including, but not limited to, copper nitrate, copper sulfate, copper chloride, etc. The effect of copper is to alter the oxidation and reduction voltages of bismuth. This results in a cathode with full reversibility during galvanostatic cycling, as compared to a bismuth-modified MnO2 which cannot withstand galvanostatic cycling as well.
The cathodes 12 can be produced using methods implementable in large-scale manufacturing. For a MnO2 cathode, the cathode 12 can be capable of delivering the full second electron capacity of the MnO2. In some embodiments, the cathode material 2 can comprises 2-30 wt. % conductive carbon, 0-30% conductive metal additive, 1-70 wt. % copper compound, 1-20 wt. % bismuth compound, 0-10 wt. % binder and birnessite or EMD. In another embodiment the cathode material comprises 2-30 wt. % conductive carbon, 0-30% conductive metal additive, 1-20% wt. bismuth compound, 0-10 wt. % binder and birnessite or EMD. In one embodiment, the cathode material consists essentially of 2-30 wt. % conductive carbon, 0-30% conductive metal additive, 1-70 wt. % copper compound, 1-20 wt. % bismuth compound, 0-10 wt. % binder and the balance birnessite or EMD. In another embodiment the cathode material consists essentially of 2-30 wt. % conductive carbon, 0-30% conductive metal additive, 1-20 wt. % bismuth compound, 0-10 wt. % binder and the balance birnessite or EMD.
The resulting cathode may have a porosity in the range of 20%-85% as determined by mercury infiltration porosimetry. The porosity can be measured according to ASTM D4284-12 “Standard Test Method for Determining Pore Volume Distribution of Catalysts and Catalyst Carriers by Mercury Intrusion Porosimetry” using the version as of the date of the filing of this application.
The cathode material 2 can be formed on a cathode current collector 1 formed from a conductive material that serves as an electrical connection between the cathode material and an external electrical connection or connections. In some embodiments, the cathode current collector 1 can be, for example, carbon, lead, nickel, steel (e.g., stainless steel, etc.), nickel-coated steel, nickel plated copper, tin-coated steel, copper plated nickel, silver coated copper, copper, magnesium, aluminum, tin, iron, platinum, silver, gold, titanium, bismuth, titanium, half nickel and half copper, or any combination thereof. In some embodiments, the current collector 1 can comprise a carbon felt or conductive polymer mesh. The cathode current collector may be formed into a mesh (e.g., an expanded mesh, woven mesh, etc.), perforated metal, foam, foil, felt, fibrous architecture, porous block architecture, perforated foil, wire screen, a wrapped assembly, or any combination thereof. In some embodiments, the current collector can be formed into or form a part of a pocket assembly, where the pocket can hold the cathode material 2 within the current collector 1. A tab (e.g., a portion of the cathode current collector 1 extending outside of the cathode material 2 as shown at the top of the cathode 12 in
The cathode material 2 can be pressed onto the cathode current collector 1 to form the cathode 12. For example, the cathode material 2 can be adhered to the cathode current collector 1 by pressing at, for example, a pressure between 1,000 psi and 20,000 psi (between 6.9×106 and 1.4×108 Pascals). The cathode material 2 may be adhered to the cathode current collector 1 as a paste. The resulting cathode 12 can have a thickness of between about 0.1 mm to about 5 mm.
The use of the electrolytes having different properties as described herein can allow for a variety of anode materials to be used. In some embodiments, the anode can comprise lithium, zinc, aluminum, magnesium, iron, calcium, strontium, lanthanum, potassium, sodium, zirconium, titanium, titanium oxide, indium, indium oxide, indium hydroxide, zinc oxide, Mn3O4, hetaerolite (ZnMn2O4), vanadium, tin, tin oxide, barium hydroxide, barium, cesium, aluminum hydroxide, copper, bismuth, silicon, carbon and a mixture of any of these materials. The cells as described herein can be formed by pairing of any of the cathode materials described herein and any of the anode materials as described to the extent that the materials mentioned above to generate a voltage in the presence of suitable electrolytes (e.g., a suitable anolyte and catholyte, etc.).
In some embodiments, the anode material 5 can comprise zinc, which can be present as elemental zinc and/or zine oxide. In some embodiments, the Zn anode mixture comprises Zn, zinc oxide (ZnO), an electronically conductive material, and a binder. The Zn may be present in the anode material 5 in an amount of from about 50 wt. % to about 90 wt. %, alternatively from about 60 wt. % to about 80 wt. %, or alternatively from about 65 wt. % to about 75 wt. %, based on the total weight of the anode material. Additional elements that can be in the anode in addition to the zinc or in place of the zinc include, but are not limited to, lithium, aluminum, magnesium, iron, cadmium and a combination thereof, where each element can be present in amounts that are the same or similar to that of the zinc described herein.
In some embodiments, the anode material 5 can comprise zinc oxide (ZnO), which may be present in an amount of from about 5 wt. % to about 20 wt. %, alternatively from about 5 wt. % to about 15 wt. %, or alternatively from about 5 wt. % to about 10 wt. %, based on the total weight of anode material. As will be appreciated by one of skill in the art, and with the help of this disclosure, the purpose of the ZnO in the anode mixture is to provide a source of Zn during the recharging steps, and the zinc present can be converted between zinc and zinc oxide during charging and discharging phases.
In an embodiment, an electrically conductive material may be optionally present in the anode material in an amount of from about 5 wt. % to about 20 wt. %, alternatively from about 5 wt. % to about 15 wt. %, or alternatively from about 5 wt. % to about 10 wt. %, based on the total weight of the anode material. As will be appreciated by one of skill in the art, and with the help of this disclosure, the electrically conductive material can be used in the anode mixture as a conducting agent, e.g., to enhance the overall electric conductivity of the anode mixture. Non-limiting examples of electrically conductive material suitable for use can include any of the conductive carbons described herein such as carbon, graphite, graphite powder, graphite powder flakes, graphite powder spheroids, carbon black, activated carbon, conductive carbon, amorphous carbon, glassy carbon, and the like, or combinations thereof. The conductive material can also comprise any of the conductive carbon materials described with respect to the cathode material including, but not limited to, acetylene black, single walled carbon nanotubes, multi-walled carbon nanotubes, graphene, graphyne, or any combinations thereof.
The anode material 5 may also comprise a binder. Generally, a binder functions to hold the electroactive material particles together and in contact with the current collector. The binder can be present in a concentration of 0-10 wt. %. The binders may comprise water-soluble cellulose-based hydrogels like methyl cellulose (MC), carboxymethyl cellulose (CMC), hydroypropyl cellulose (HPH), hydroypropylmethyl cellulose (HPMC), hydroxethylmethyl cellulose (HEMC), carboxymethylhydroxyethyl cellulose and hydroxyethyl cellulose (HEC), which were used as thickeners and strong binders, and have been cross-linked with good mechanical strength and with conductive polymers like polyvinyl alcohol, polyvinylacetate, polyaniline, polyvinylpyrrolidone, polyvinylidene fluoride and polypyrrole. The binder may also be a cellulose film sold as cellophane. The binder may also be PTFE, which is a very resistive material, but its use in the industry has been widespread due to its good rollable properties. In some embodiments, the binder may be present in anode material in an amount of from about 2 wt. % to about 10 wt. %, alternatively from about 2 wt. % to about 7 wt. %, or alternatively from about 4 wt. % to about 6 wt. %, based on the total weight of the anode material.
In some embodiments, the anode material 5 can be used by itself without a separate anode current collector 4, though a tab or other electrical connection can still be provided to the anode material 5. In this embodiment, the anode material may have the form or architecture of a foil, a mesh, a perforated layer, a foam, a felt, or a powder. For example, the anode can comprise a metal foil electrode, a mesh electrode, or a perforated metal foil electrode.
In some embodiments, the anode 13 can comprise an optional anode current collector 4. The anode current collector 4 can be used with an anode 13, including any of those described with respect to the cathode 12. The anode material 5 can be pressed onto the anode current collector 4 to form the anode 13. For example, the anode material 5 can be adhered to the anode current collector 4 by pressing at, for example, a pressure between 1,000 psi and 20,000 psi (between 6.9×106 and 1.4×108 Pascals). The anode material 5 may be adhered to the anode current collector 4 as a paste. A tab of the anode current collector 4, when present, can extend outside of the device to form the current collector tab. The resulting anode 13 can have a thickness of between about 0.1 mm to about 5 mm.
As shown in
In some embodiments as shown in
The separator 9 may comprise one or more layers. For example, when the separator is used, between 1 to 5 layers of the separator can be applied between adjacent electrodes. The separator can be formed from a suitable material such as nylon, polyester, polyethylene, polypropylene, poly(tetrafluoroethylene) (PTFE), poly(vinyl chloride) (PVC), polyvinyl alcohol, cellulose, or any combination thereof. Suitable layers and separator forms can include, but are not limited to, a polymeric separator layer such as a sintered polymer film membrane, polyolefin membrane, a polyolefin nonwoven membrane, a cellulose membrane, a cellophane, a battery-grade cellophane, a hydrophilically modified polyolefin membrane, and the like, or combinations thereof. As used herein, the phrase “hydrophilically modified” refers to a material whose contact angle with water is less than 45°. In another embodiment, the contact angle with water is less than 30°. In yet another embodiment, the contact angle with water is less than 20°. The polyolefin may be modified by, for example, the addition of TRITON X100™ or oxygen plasma treatment. In some embodiments, the separator 9 can comprise a CELGARD® brand microporous separator. In an embodiment, the separator 9 can comprise a FS 2192 SG membrane, which is a polyolefin nonwoven membrane commercially available from Freudenberg, Germany. In some embodiments, the separator can comprise a lithium super ionic conductor (LISICON®), sodium super ionic conductions (NASICON), NAFION®, a bipolar membrane, water electrolysis membrane, a composite of polyvinyl alcohol and graphene oxide, polyvinyl alcohol, crosslinked polyvinyl alcohol, or a combination thereof.
While the separator 9 can comprise a variety of materials, the use of a PGE for the electrolyte can allow for a relatively inexpensive separator 9 to be used when one or more separators are present. For example, the separator 9 can comprise CELLOPHANE®, polyvinyl alcohol, CELGARD®, a composite of polyvinyl alcohol and graphene oxide, crosslinked polyvinyl alcohol, PELLON®, and/or a composite of carbon-polyvinyl alcohol. Use of the separator 9 may help in improving the cycle life of the battery 20, but is not necessary in all embodiments.
When a buffer layer 21 is used, the buffer layer 21 can be used alone or in combination with a separator 9. The buffer layer 21 can comprise a gelled solution that can comprise the same electrolyte formulation as the anolyte and/or the catholyte. For example, the buffer layer 21 can be a PGE as described herein. One or more additives can also be present in the buffer layer 21 such as calcium hydroxide, layered double hydroxides like hydrotalcites, quintinite, fougerite, magnesium hydroxide, or combinations thereof. For example, when the anolyte and catholyte have the same formulation, only with different compositions and/or viscosities, the buffer layer can have a concentration of the electrolyte that is the same as the anolyte or catholyte, or have a concentration that is between that of the anolyte and the catholyte. The buffer layer can have a viscosity greater than that of either the anolyte or catholyte to help prevent mixing between the anolyte and catholyte as well as limiting the migration of ions between the anolyte and catholyte.
As shown in
The catholyte 3 can be an acidic or neutral solution, and the pH of the catholyte can be between −1.2 and 7. The catholyte 3 can be used in conditions having temperatures ranging between 0 and 200° C. In some embodiments, the catholyte can comprise an acid such as a mineral acid (e.g., hydrochloric acid, nitric acid, sulfuric acid, etc.). For acid catholyte compositions, the acid concentration can be between about 0 M and about 16 M. In some embodiments, the catholyte solution can comprise a solution comprising potassium permanganate, sodium permanganate, lithium permanganate, calcium permanganate, manganese sulfate, manganese chloride, manganese nitrate, manganese perchlorate, manganese acetate, manganese bis(trifluoromethanesulfonate), manganese triflate, manganese carbonate, manganese oxalate, manganese fluorosilicate, manganese ferrocyanide, manganese bromide, magnesium sulfate, ammonium chloride, ammonium sulfate, ammonium hydroxide, zinc sulfate, zinc triflate, zinc acetate, zinc nitrate, bismuth chloride, bismuth nitrate, nitric acid, sulfuric acid, hydrochloric acid, sodium sulfate, potassium sulfate, cobalt sulfate, lead sulfate, sodium hydroxide, potassium hydroxide, titanium sulfate, titanium chloride, lithium nitrate, lithium chloride, lithium bromide, lithium bicarbonate, lithium acetate, lithium sulfate, lithium nitrate, lithium nitrite, lithium hydroxide, lithium perchlorate, lithium oxalate, lithium fluoride, lithium carbonate, lithium sulfate, lithium bromate, polyvinyl alchohol, carboxymethyl cellulose, xanthum gum, carrageenan, acrylamide, potassium persulfate, sodium persulfate, ammonium persulfate, N,N′-Methylenebisacrylamide, or any combination thereof. For example, the catholyte solution can comprise manganese sulfate mixed with sulfuric acid or potassium permanganate mixed with sulfuric acid. Other dopants to this solution can be zinc sulfate, lead sulfate, titanium disulfide, titanium sulfate hydrate, silver sulfate, cobalt sulfate, and nickel sulfate. In some embodiments, the catholyte solution can comprise manganese sulfate, ammonium chloride, ammonium sulfate, manganese acetate, potassium permanganate, and/or a salt of permanganate, where the additives can have a concentration between 0 and 10M. Depending on the type of manganese salts used voltage of the battery system can be different. For example, in manganese sulfate electrolyte the voltage of the SS-HiVAB is around 2.45-2.5V, while in potassium permanganate electrolyte the voltage of the SS-HiVAB is around 2.8-2.9V.
In some embodiments, the catholyte can comprise a permanganate. Permanganates have a high positive potential. This can allow the overall cell potential to be increased within the battery 10. When present, the permanganate can be present in a molar ratio of an acid (e.g., a mineral acid such a hydrochloric acid, sulfuric acid, etc.) to permanganate of between about 5:1 to about 1:5, or about 1:1 to about 1:6, or between about 1:2 to about 1:4, or about 1:3, though the exact amount can vary based on the expected operation conditions of the battery 10. The concentration of the permanganate (e.g., potassium permanganate or a salt of permanganate, etc.) can be greater than 0 and less than or equal to 5 M. In some embodiments, the catholyte solution comprises sulfuric acid, hydrochloric acid or nitric acid at a concentration greater than 0 and less than or equal to 16M. The use of a permanganate can be advantageous for creating a high voltage battery such that when the use of a catholyte with permanganates is combined with a very negative anode potential, the resulting batter can have a voltage of approximately 2.8V when the cathode and anode are MnO2|Zn and a voltage of approximately 4V when the cathode and anode are MnO2|Al. When the catholyte comprises a permanganate, suitable permanganates can include, but are not limited to, potassium permanganate, sodium permanganate, lithium permanganate, calcium permanganate, and combinations thereof.
In some embodiments, the anolyte can be an alkaline electrolyte, while the catholyte can be an acidic or neutral solution. The alkaline electrolyte in the anolyte can be a hydroxide such as potassium hydroxide, sodium hydroxide, lithium hydroxide, ammonium hydroxide, cesium hydroxide, or any combination thereof. The resulting anolyte can have a pH greater than 7. In some embodiments, the pH of the anolyte can be greater than or equal to 10 and less than or equal to about 15.13. As described herein, the anolyte can be polymerized or gelled. The resulting anolyte can be in a semi-solid state that resists flowing within the battery. This can serve to limit or prevent any mixing between the anolyte and the catholyte. The anolyte can be polymerized using any suitable techniques, including any of those described herein. Usually a higher concentration of alkaline electrolyte is used to increase the solubility of any metals in the gelled state. For example, the higher concentration can be between 25-70 wt. % of the anolyte.
In addition to a hydroxide, the anolyte 6 can comprise additional components. In some embodiments, the alkaline electrolyte can have zinc oxide, potassium carbonate, potassium iodide and potassium fluoride as additives. When zinc compounds are present in the anolyte, the anolyte can comprise zinc sulfate, zinc chloride, zinc acetate, zinc carbonate, zinc chlorate, zinc fluoride, zinc formate, zinc nitrate, zinc oxalate, zinc sulfite, zinc tartrate, zinc cyanide, zinc oxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, potassium chloride, sodium chloride, potassium fluoride, lithium nitrate, lithium chloride, lithium bromide, lithium bicarbonate, lithium acetate, lithium sulfate, lithium permanganate, lithium nitrate, lithium nitrite, lithium perchlorate, lithium oxalate, lithium fluoride, lithium carbonate, lithium bromate, acrylic acid, N,N′-Methylenebisacrylamide, potassium persulfate, ammonium persulfate, sodium persulfate, or a combination thereof.
In some embodiments, an organic solvent containing a suitable salt can be used as an electrolyte. Examples of suitable organic solvents include, but are not limited to, cyclic carbonates, linear carbonates, dialkyl carbonates, aliphatic carboxylate esters, γ-lactones, linear ethers, cyclic ethers, aprotic organic solvents, fluorinated carboxylate esters, and combinations thereof. Any suitable additives including salts as described herein can be used with the organic solvents to form an organic electrolyte for the anolyte and/or catholyte.
In some embodiments, an ionic liquid can be used to form a gelled electrolyte (e.g., a gelled anolyte, a gelled catholyte, etc.). The ionic liquids can comprise 1-ethyl-3-methylimidazolium chloride (EMImCl), 1-allyl-3-methylimidazolium bromixde, 1-allyl-3-methylimidazolium chloride, 1-butyl-2,3-dimethylimidazolium chloride, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium tetrachloroaluminate, lithium hexafluorophosphate (LiPF6), lithium perchlorate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(oxalato)borate, and combinations thereof. Other ionic liquids are known and can also be used. In some embodiments, EMImCl can be used as the ionic liquid and can be purified before mixing with an aluminum salt to form an aluminum-ion conducting electrolytes. The aluminum salt can be aluminum chloride, aluminum acetate, aluminum nitrate, aluminum bromide, and others. The mixture of EMImCl with aluminum chloride can be made by slowly adding a precise amount of aluminum chloride in an inert atmosphere. The mixing ratio of aluminum chloride with EMImCl can be between 5:1 to 1:1, or about 1.5:1.
In some embodiments, a water in salt electrolyte can be gelled and used as the catholyte and/or anolyte. A water in salt electrolyte can include an electrolyte in which the salt concentration is above the saturation point. The activity of water in an aqueous electrolyte can be further reduced by increasing the salt concentration above the saturation point in order to form a water in salt electrolyte. The ionic conductivity of such electrolytes can be higher than those in a regular aqueous electrolyte. A water in salt electrolyte can comprise water along with a suitable salt above its saturation point, including any of the salts and additives described herein with regard to the aqueous anolyte and/or catholyte.
In some embodiments, the compounds within the electrolyte of the anolyte and the catholyte can be the same, but the concentration can vary between the anolyte and the catholyte. In these embodiments, the catholyte and anolyte can comprise any of the compounds listed above for the anolyte and/or catholyte. For example, the anolyte and catholyte can comprise a hydroxide such as potassium hydroxide. The concentration of the hydroxide in contact with the anolyte can be higher than the concentration of the hydroxide in the catholyte. When gelled, the viscosity of the anolyte and the catholyte can be different. In some embodiments, the viscosity of the catholyte may be higher (e.g., resulting in a thicker gel) than the viscosity of the anolyte.
One or both of the anolyte and the catholyte can be gelled in the battery. The polymerization process can be performed with any electrolyte, including any of those described herein (e.g., organic, aqueous, ionic liquid, water in salt, etc.). A number of polymerization techniques can be used to form the gelled/solid electrolyte—for example, step-growth, chain-growth, emulsion polymerization, solution polymerization, suspension polymerization, precipitation polymerization, photopolymerization and others. Once the gelled/solid electrolytes are formed through the polymerization step, they can be combined in a single battery housing as described herein. The battery can use separators or be membrane-less or separator-less.
As described herein, the electrolyte can be polymerized or gelled to form a polymer gel electrolyte (PGE) for the catholyte and/or the anolyte. The resulting PGE can be in a semi-solid state that resists flowing within the battery. For example, the PGE can comprise an inert hydrophilic polymer matrix impregnated with aqueous electrolyte. The electrolyte can be polymerized using any suitable techniques. In an embodiment, a method of forming a PGE can begin with selecting a monomer material for the PGE. The monomer can be polar vinyl monomer selected from the group consisting of acrylic acid, vinyl acetate, acrylate esters, vinyl isocyanate, acrylonitrile, or any combinations thereof. The aqueous electrolyte component can then be selected, and can include any of the components described above with respect to the electrolyte. An initiator can be added to start the polymerization process. In some embodiments, a cross-linker can be used in the electrolyte composition to further cross-link the polymer matrix in order to form the PGE. The monomer in the composition (e.g., a polar vinyl monomer) can be present in an amount of between about 5% to about 50% by weight, the initiator can be present in an amount of between about 0.001 wt. % to about 0.1 wt. %, and the cross-linker can be present in an amount of between 0 to 5 wt. %.
In some embodiments, the PGE can be formed in-situ, which refers to the introduction of the electrolyte as a liquid into the housing followed by subsequent polymerization to form the PGE within the housing. This method can allow the electrolyte composition to soak into the void spaces, the anode, and/or the cathode prior to fully polymerizing to form the PGE. In some embodiments, a vacuum (e.g., a pressure less than atmospheric pressure) can be created within the housing 7 upon introduction of the electrolyte into the corresponding compartment. The vacuum can serve to remove air and allow the electrolyte to penetrate the anode 13, the cathode 12, and/or the various void spaces within the battery 10. In some embodiments, the vacuum can be between about 10 and 29.9 inches of mercury or between about 20 and about 29.9 inches of mercury vacuum. The use of the vacuum can help to avoid the presence of air pockets within the battery 10 prior to the full polymerization of the electrolyte. In some embodiments, the electrodes can be soaked in the electrolyte solution for between 1-120 minutes at a temperature of between 0° C. to 30° C. prior to full polymerization of the electrolyte to allow the electrolyte to impregnate the electrodes. Once the electrolyte is polymerized, the battery can be allowed to rest prior to use. In some embodiments, the battery can be allowed to rest for between 5 minutes and 24 hours.
In order to help impregnate the electrodes with the electrolyte, the electrodes can be pre-soaked with the selected electrolyte solution prior to polymerizing the electrolyte. This can be performed by soaking the electrodes in the electrolyte (e.g., in a catholyte or anolyte separately) outside of the battery or housing, and then placing the pre-soaked electrodes into the housing to construct the battery. In some embodiments, an electrolyte that does not contain a polymer or gelling agent can be introduced into the battery to soak the electrodes in-situ. This can include the use of a vacuum to assist in impregnating the electrodes. The electrodes can be soaked for between about 1 minute and 24 hours. In some embodiments, the soaking can be carried out over a plurality of cycles in which the battery is filled with the electrolyte and allowed to soak, drained, refilled and allowed to soak, followed by draining a desired number of times. Once the electrodes are soaked and impregnated with the electrolyte, the electrolyte containing the polymer and polymerization agents (e.g., an initiator, cross-linking agent, etc.) can be introduced into the housing and allowed to polymerize to form the final battery.
The composition of the electrolyte, the monomer material, the initiator, and the conditions of the formation (e.g., temperature, etc.) can be selected to provide a desired polymerization time to allow the electrolyte composition to properly soak the components of the batter to absorb and penetrate into the electrodes. The temperature can be controlled to control the polymerization process, where colder temperatures can inhibit or slow the polymerization, and warmer temperatures can decrease the polymerization time or accelerate the polymerization process. In addition, an increase in an alkaline electrolyte component (e.g., a hydroxide) can decrease the polymerization time, and an increase in the initiator concentration will decrease the polymerization time. Suitable polymerization times can be between 1 minute and 24 hours, based on the composition of the electrolyte solution and the temperature of the reaction.
As an example of a polymerization process, a mixture of acrylic acid, N,N′-methylenebisacrylamide, and alkaline solution can be created at a temperature of around 0° C. Any additives can then be added to the solution (e.g., gassing inhibitors, additional additives as described herein, etc.). For example, zinc oxide, when used in the electrolyte, can be dissolved in the alkaline solution after mixing the precursor components, where the zinc oxide can beneficial during the electrochemical cycling of the anode. To polymerize the resulting mixture an initiator such as potassium persulfate can be added to initiate the polymerization process and form a solid or semi-solid polymerized electrolyte (e.g., a PGE). The resulting polymerized electrolyte can be stable over time once the polymerization process has occurred.
As an example, a PGE described herein can be made through a free radical polymerization process. In an embodiment, acrylic acid (AA) can be used as a monomer with N,N′-methylenebisacrylamide (MBA) as the cross-linker and potassium persulfate (K2S2O8) as the initiator. An alkaline electrolyte such as KOH can be added to this process, which can be embedded in the framework. The addition of alkaline electrolyte to AA results in neutralization, which reduces the concentration of the alkaline electrolyte in the polymeric gel. Theoretical and experimental values after neutralization of AA in KOH is reported in
The polymerization process can occur prior to the construction of the battery 10 or after the cell is constructed. In some embodiments, the electrolyte can be polymerized and placed into a tray to form a sheet. Once polymerized, the sheet can be cut into a suitable size and shape and one or more layers can be used to form the electrolyte 15 in contact with the anode 13. When a pre-formed PGE is used, additional liquid electrolyte can be introduced into the battery and/or the electrodes can be pre-soaked with the electrolyte prior to constructing the battery.
In some embodiments, the PGE can be formed using an aqueous electrolyte, organic electrolyte, ionic liquid, water in salt electrolyte, and the like. In some embodiments, an aqueous electrolyte can be used for the catholyte and/or anolyte and gelled to form an aquous hydrogel as the PGE. In some embodiments, aqueous hydrogels can be made through a free radical polymerization process. For example, acrylic acid (AA) can be selected as the monomer with N,N′-methylenebisacrylamide (MBA) as the cross-linker and potassium persulfate as the initiator. In aqueous alkaline batteries, a suitable hydroxide (e.g., potassium hydroxide (KOH), sodium hydroxide, lithium hydroxide, etc.) can be used to form the electrolyte. The hydroxide can be encapsulated in a hydrogel network by neutralizing the hydroxide with the AA. To create a hydrogel, the monomer can be combined with any cross-linker until the cross-linker is dissolved. Separately, an amount of the hydroxide can be cooled to slow the reaction. In some embodiments in which the electrolyte is an aqueous electrolyte, the hydroxide can be cooled to a temperature below about 10° C., below about 5° C. or below about 0° C. The mixed solution of the monomer and any cross-linker can then be added drop-wise to the chilled solution of the hydroxide as the neutralization reaction releases heat. To gel the resulting mixture of the hydroxide, monomer, and cross-linker, an initiator such as potassium persulfate can be added. The mixture can then be allowed to form a PGE. The amounts and concentrations of the ingredients can be varied to obtain varying mechanical strengths of the hydrogels.
Electrolytes comprising ionic liquids can also be used to form PGEs, including any of the ionic liquid described herein. To form a PGE using an ionic liquid, a solution of any additives, which can be in a suitable solvent, can be prepared and a monomer can be added. The monomer can be any suitable monomer. For example, acrylamide can be used as a polymerization agent for ionic liquids. To this solution, the ionic liquid along with the additive solution can be mixed along with an initiator. Any suitable initiator for use with the polymerization agent can be used. For example, azobisisobutyronitrile can be used with acrylamide. The initiator can be added in a suitable amount such about 1 wt. % of the polymerization agent. This final solution can then be heated heated to form a polymerized gel.
Organic electrolytes comprising a salt dissolved in an organic solvent can also be gelled to form an anolyte and/or catholyte. As an example, lithium-ion conducting electrolytes can be gelled using a number of polymerization techniques such as ring-opening polymerization, photo-initiated radical polymerization, UV-initiated radical polymerization, thermal-initiated polymerization, in-situ polymerization, UV-irridiation, electrospinning, and others. The lithium electrolyte can comprise lithium hexafluorophosphate (LiPF6), lithium perchlorate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(oxalato)borate, and combinations thereof in an organic solvent such as ethylene carbonate, dimethyl carbonate, propylene carbonate, diethyl carbonate, ethyl methyl carbonate, and combinations thereof. An exemplary mixture can include 1M LiPF6 mixed in a solvent mixture of ethylene carbonate and dimethyl carbonate. Other solvents also exist that can be used as a mixture to reduce the flammability of the organic electrolyte.
The organic electrolyte can be gelled by mixing the selected salts with the organic solvent. A gelling agent can then be added along with an initiator. The gelling agent can be added in an amount between about 0.1 to about 5 wt. % of the mixture, and the initiator can be added in an amount of between about 0.01 to about 1 wt % of the mixture. In some embodiments, a suitable gelling agent for an organic electrolyte can comprise pentaerythritol tetraacrylate and the initiator can comprise azodiisobutyronitrile. The resulting mixture can be gelled (e.g., polymerized) by heating the mixture to about 50-90° C., or to about 70° C. and holding for 1-24 hours.
For an aqueous electrolyte which is acidic or neutral in nature, the polymerization can be carried out using a number of processes. In an embodiment, a method for making a solid state gelled aqueous acid or neutral electrolyte can comprise the addition of acrylamide to a solution comprising manganese sulfate, H2SO4, ammonium sulfate, potassium permanganate, and/or sulfuric acid. A gelling agent comprising acrylamide can be added to the solution and mixed at a temperature between about 70-90° C. for at least an hour until the solution is homogenous. After the solution is mixed well then a cross-linker and initiator can be added to the solution and mixed between 2-48 hours until the solution gels.
The final cell or battery design would have a cathode with a lower PGE alkaline concentration and an anode with a higher PGE alkaline concentration with a separator or buffering layer that prevents the intermixing of the two PGE's. This final battery with dual electrolytes allows for high reversibility and improved or maximum utilization of the electrodes and thus, a higher energy density.
The embodiments having been generally described, the following examples are given as particular embodiments of the disclosure and to demonstrate the practice and advantages thereof. It is understood that the examples are given by way of illustration and are not intended to limit the specification or the claims in any manner.
The performance of a MnO2 cathode was tested in aqueous low KOH concentration of 10 wt. %. The cathode comprised of 80 wt. % MnO2 (EMD), 15 wt. % graphite and 5 wt. % Teflon pressed onto a nickel current collector. The counter electrode in the experiment was sintered nickel. Zn was avoided as the anode in this experiment to remove any deleterious effect of Zn on the MnO2 performance in aqueous KOH. Cellophane was used as the separator. The cell potential was monitored against a mercury/mercury oxide (Hg/HgO) reference electrode. The cathode was cycled at 40% utilization of the theoretical one electron capacity (308 mAh/g).
The performance of this cell is shown in
The cycling performance of a Zn mesh anode in high concentration PGE was tested. The PGE was made from 45 wt. % KOH, where after gelation process it would be around 30 wt. % as indicated in
The full discharge performance of a complete MnO2|Zn cell was tested in a dual electrolyte design. The cathode comprised of 80 wt. % MnO2 (EMD), 15 wt. % graphite and 5 wt. % Teflon pressed onto a nickel current collector. The MnO2 cathode was covered with a PGE made from low KOH concentration (20 wt. %), while the Zn mesh anode was covered with a PGE made from high KOH concentration (50 wt. %). Polyvinyl alcohol (PVA) was used as the separator. The cell was cycled to obtain the maximum discharge performance. The performance is shown in
The cyclability of a complete MnO2|Zn cell was tested in a dual electrolyte design. The cathode comprised of 80 wt. % MnO2 (EMD), 15 wt. % graphite and 5 wt. % Teflon pressed onto a nickel current collector. The anode comprised of 95 wt. % Zn powder (doped with bismuth and indium) and 5 wt. % Teflon. The MnO2 cathode was covered with a PGE made from low KOH concentration (25 wt. %), while the Zn mesh anode was covered with a PGE made from high KOH concentration (45 wt. %). Polyvinyl alcohol (PVA) was used as the separator. The cycling performance of this cell is shown in
The cyclability of a complete MnO2|Zn cell was tested in a dual electrolyte design, where the cathode PGE had expanded carbon embedded within its framework to boost MnO2 performance. The cathode comprised of 80 wt. % MnO2 (EMD), 15 wt. % graphite and 5 wt. % Teflon pressed onto a nickel current collector. The anode comprised of Zn mesh. The MnO2 cathode was covered with a PGE made from low KOH concentration (25 wt. %) with expanded graphite (BNB-90) embedded within its framework during the gelation process, while the Zn mesh anode was covered with a PGE made from high KOH concentration (54 wt. %). Polyvinyl alcohol (PVA) was used as the separator. The cycling performance of this cell is shown in
The cyclability of a complete MnO2|Zn cell was tested in a dual electrolyte design, where the cathode was densified. The cathode comprised of 80 wt. % MnO2 (EMD), 15 wt. % graphite and 5 wt. % Teflon pressed onto a nickel current collector. The anode comprised of Zn mesh. The MnO2 cathode was covered with a PGE made from low KOH concentration (20 wt. %), while the Zn mesh anode was covered with a PGE made from high KOH concentration (50 wt. %). Polyvinyl alcohol (PVA) was used as the separator. The cycling performance of this cell is shown in
Having described various batteries, systems, and methods, specific aspects can include, but are not limited to:
In a first aspect, a dual electrolyte battery comprises a cathode; an anode; a catholyte in contact with the cathode, wherein the catholyte comprises a first gelled electrolyte solution; and an anolyte in contact with the anode, wherein the anolyte comprises a second gelled electrolyte solution, wherein a concentration of an electrolyte in the anolyte is higher than a concentration of the electrolyte in the catholyte.
A second aspect can include the battery of the first aspect, further comprising: a separator disposed between the anolyte and the catholyte.
A third aspect can include the battery of the first aspect, further comprising: a buffer layer disposed between the anolyte and the catholyte, wherein the buffer layer comprises a third gelled electrolyte solution.
A fourth aspect can include the battery of any one of the first to third aspects, wherein a viscosity of the first gelled electrolyte solution is higher than a viscosity of the second gelled electrolyte solution.
A fifth aspect can include the battery of any one of the first to fourth aspects, wherein the cathode comprises an active material, and wherein the active material comprises at least one of manganese oxide, lithium manganese oxide, aluminum manganese oxide, zinc manganese oxide, copper manganese oxide, bismuth manganese oxide, copper intercalated birnessite, copper intercalated bismuth birnessite, tin doped manganese oxide, magnesium manganese oxide, silver oxide, silver dioxide, silver, nickel oxyhydroxide, nickel hydroxide, nickel, lead oxide, copper oxide, copper dioxide, lead, lead dioxide, potassium persulfate, sodium persulfate, ammonium persulfate, potassium permanganate, calcium permanganate, barium permanganate, silver permanganate, ammonium permanganate, peroxide, gold, perchlorate, cobalt oxide, lithium cobalt oxide, sodium cobalt oxide, perchlorate, nickel oxide, bromine, mercury, vanadium oxide, bismuth vanadium oxide, hydroquinone, calix[4]quinone, tetrachlorobenzoquinone, 1,4-naphthoquinone, 9,10-anthraquinone, 1,2-napthaquinone, 9,10-phenanthrenequinone, nitroxide-oxammonium cation redox pair like 2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO), carbon, 2,3-dicyano-5,6-dichlorodicyanoquinone, tetracyanoethylene, sulfur trioxide, ozone, oxygen, air, lithium nickel manganese cobalt oxide, sulfur, lithium iron phosphate, lithium copper oxide, lithium copper oxyphosphate, and any mixture thereof.
A sixth aspect can include the battery of any one of the first to fifth aspects, wherein the cathode comprises a conductive carbon, and wherein the conductive carbon comprises graphite, carbon fiber, carbon black, acetylene black, single walled carbon nanotubes, multi-walled carbon nanotubes, nickel or copper coated carbon nanotubes, dispersions of single walled carbon nanotubes, dispersions of multi-walled carbon nanotubes, graphene, graphyne, graphene oxide, and combinations thereof.
A seventh aspect can include the battery of any one of the first to sixth aspects, wherein the cathode comprises a binder, and wherein the binder comprises polytetrafluoroethylene, carboxymethyl cellulose, polyvinyl alcohol or a combination thereof.
An eighth aspect can include the battery of any one of the first to seventh aspects, wherein the cathode comprises 1-95 wt. % of an active material, 4-98 wt. % of a conductive carbon, and 1-5 wt. % of a binder.
A ninth aspect can include the battery of any one of the first to eighth aspects, wherein the cathode comprises a pressed cathode material on a current collector, wherein the current collector comprises carbon, lead, zinc, stainless steel, copper, nickel, silver, bismuth, titanium, magnesium, aluminum, indium, tin, gold, polypropylene, or a combination thereof.
A tenth aspect can include the battery of the ninth aspect, wherein the current collector is a mesh, foil, foam, felt, fibrous, a porous block architecture, or a combination thereof.
An eleventh aspect can include the battery of any one of the first to tenth aspects, wherein the anode comprises an anode active material, and wherein the anode active material comprises zinc, aluminum, iron, copper, bismuth, tin, lithium, magnesium, calcium, titanium, or a combination thereof.
A twelfth aspect can include the battery of any one of the first to eleventh aspects, wherein the anode comprises 90-100% of an active material and 0-10% of a binder.
A thirteenth aspect can include the battery of any one of the first to twelfth aspects, wherein the anode comprises a binder, and wherein the binder comprises polytetrafluoroethylene, carboxymethyl cellulose, polyvinyl alcohol, or a combination thereof.
A fourteenth aspect can include the battery of any one of the first to thirteenth aspects, wherein the first gelled electrolyte solution comprises an alkaline solution embedded within a gel, and wherein the alkaline solution has a concentration ranging from 1-25 wt. %.
A fifteenth aspect can include the battery of any one of the first to fourteenth aspects, wherein the second gelled electrolyte solution comprises an alkaline solution embedded within a gel, and wherein the alkaline solution has a concentration ranging from 20-55 wt. %.
A sixteenth aspect can include the battery of any one of the first to fifteenth aspects, wherein the alkaline solution comprises potassium hydroxide, sodium hydroxide, lithium hydroxide, cesium hydroxide, or a combination thereof.
A seventeenth aspect can include the battery of any one of the first to sixteenth aspects, wherein anolyte, catholyte, or both comprise one or more electrolyte additives, wherein the electrolyte additives comprise expanded graphite, carbon nanotube, carbon black, graphene oxide, graphene, potassium carbonate, potassium fluoride, barium hydroxide, polytetrafluoroethylene, indium hydroxide, bismuth oxide, titanium oxide, cellulose fibers, or combinations thereof.
An eighteenth aspect can include the battery of any one of the first to seventeenth aspects, further comprising at least one of a separator or buffer layer disposed between the anolyte and catholyte, and wherein the at least one of the separator or buffer layer comprises cellophane, Celgard, polyvinyl alcohol, cross-linked polyvinyl alcohol, calcium hydroxide, polymer gelled electrolyte, layered double hydroxide, NASICON, LISICON, or combinations thereof.
In a nineteenth aspect, a dual electrolyte battery comprises: a cathode; an anode; a catholyte in contact with the cathode, wherein the catholyte comprises a first gelled electrolyte solution; and an anolyte in contact with the anode, wherein the anolyte comprises a second gelled electrolyte solution, wherein the first gelled electrolyte solution and the second gelled electrolyte solution comprise a hydroxide, and wherein a concentration of the hydroxide in the anolyte is higher than a concentration of the hydroxide in the catholyte.
A twentieth aspect can include the battery of the nineteenth aspect, further comprising: a separator disposed between the anolyte and the catholyte.
A twenty first aspect can include the battery of the nineteenth or twentieth aspect, further comprising: a buffer layer disposed between the anolyte and the catholyte, wherein the buffer layer comprises a third gelled electrolyte solution.
A twenty second aspect can include the battery of any one of the nineteenth to twenty first aspects, wherein a viscosity of the first gelled electrolyte solution is higher than a viscosity of the second gelled electrolyte solution.
A twenty third aspect can include the battery of any one of the nineteenth to twenty second aspects, wherein a concentration of the hydroxide in the first gelled electrolyte solution is in a range of from 1-25 wt. %.
A twenty fourth aspect can include the battery of any one of the nineteenth to twenty third aspects, wherein a concentration of the hydroxide in the second gelled electrolyte solution is in a range of from 20-55 wt. %.
A twenty fifth aspect can include the battery of any one of the nineteenth to twenty first fourth aspects, wherein the hydroxide comprises potassium hydroxide, sodium hydroxide, lithium hydroxide, cesium hydroxide, or a combination thereof.
In a twenty sixth aspect, a method of forming dual electrolyte battery comprises disposing a catholyte in contact with a cathode, wherein the catholyte comprises a first gelled electrolyte solution; disposing an anolyte in contact with an anode, wherein the anolyte comprises a second gelled electrolyte solution, wherein a concentration of the hydroxide in the anolyte is higher than a concentration of the hydroxide in the catholyte; and disposing at least one of a separator or a buffer layer between the anolyte and the catholyte.
A twenty seventh aspect can include the method of the twenty sixth aspect, further comprising: disposing the catholyte, anolyte, anode, and cathode in a housing to form a battery.
A twenty eighth aspect can include the method of the twenty sixth or twenty seventh aspect, wherein the buffer layer comprises a third gelled electrolyte solution.
A twenty ninth aspect can include the method of any one of the twenty sixth to twenty eighth aspects, wherein a viscosity of the first gelled electrolyte solution is higher than a viscosity of the second gelled electrolyte solution.
A thirtieth aspect can include the method of any one of the twenty sixth to twenty ninth aspects, wherein a concentration of the hydroxide in the first gelled electrolyte solution is in a range of from 1-25 wt. %.
A thirty first aspect can include the method of any one of the twenty sixth to thirtieth aspects, wherein a concentration of the hydroxide in the second gelled electrolyte solution is in a range of from 20-55 wt. %.
A thirty second aspect can include the method of any one of the twenty sixth to thirty first aspects, wherein the hydroxide comprises potassium hydroxide, sodium hydroxide, lithium hydroxide, cesium hydroxide, or a combination thereof.
Embodiments are discussed herein with reference to the Figures. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes as the systems and methods extend beyond these limited embodiments. For example, it should be appreciated that those skilled in the art will, in light of the teachings of the present description, recognize a multiplicity of alternate and suitable approaches, depending upon the needs of the particular application, to implement the functionality of any given detail described herein, beyond the particular implementation choices in the following embodiments described and shown. That is, there are numerous modifications and variations that are too numerous to be listed but that all fit within the scope of the present description. Also, singular words should be read as plural and vice versa and masculine as feminine and vice versa, where appropriate, and alternative embodiments do not necessarily imply that the two are mutually exclusive.
It is to be further understood that the present description is not limited to the particular methodology, compounds, materials, manufacturing techniques, uses, and applications, described herein, as these may vary. It is also to be understood that the terminology used herein is used for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present systems and methods. It must be noted that as used herein and in the appended claims (in this application, or any derived applications thereof), the singular forms “a,” “an,” and “the” include the plural reference unless the context clearly dictates otherwise. Thus, for example, a reference to “an element” is a reference to one or more elements and includes equivalents thereof known to those skilled in the art. All conjunctions used are to be understood in the most inclusive sense possible. Thus, the word “or” should be understood as having the definition of a logical “or” rather than that of a logical “exclusive or” unless the context clearly necessitates otherwise. Structures described herein are to be understood also to refer to functional equivalents of such structures. Language that may be construed to express approximation should be so understood unless the context clearly dictates otherwise.
Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this description belongs. Preferred methods, techniques, devices, and materials are described, although any methods, techniques, devices, or materials similar or equivalent to those described herein may be used in the practice or testing of the present systems and methods. Structures described herein are to be understood also to refer to functional equivalents of such structures. The present systems and methods will now be described in detail with reference to embodiments thereof as illustrated in the accompanying drawings.
From reading the present disclosure, other variations and modifications will be apparent to persons skilled in the art. Such variations and modifications may involve equivalent and other features which are already known in the art, and which may be used instead of or in addition to features already described herein.
Although Claims may be formulated in this Application or of any further Application derived therefrom, to particular combinations of features, it should be understood that the scope of the disclosure also includes any novel feature or any novel combination of features disclosed herein either explicitly or implicitly or any generalization thereof, whether or not it relates to the same systems or methods as presently claimed in any Claim and whether or not it mitigates any or all of the same technical problems as do the present systems and methods.
Features which are described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. The Applicants hereby give notice that new claims may be formulated to such features and/or combinations of such features during the prosecution of the present Application or of any further Application derived therefrom.
This application claims the benefit of U.S. Provisional Application No. 62/953,674 filed on Dec. 26, 2019 and entitled, “DUAL ELECTROLYTE APPROACH TO INCREASE ENERGY DENSITY OF AQUEOUS METAL-BASED BATTERIES,” which is incorporated herein by reference in its entirety for all purposes.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2020/066814 | 12/23/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62953674 | Dec 2019 | US |
