Patent Application
20240047734
The invention is directed to the field of solid state rechargeable batteries.
Dendrite formation (e.g.,: Li or Na dendrite formation ) is a major cause of battery failure and shortening of battery life in solid state batteries with electrodes containing lithium or sodium metal. Dendrite formation diminishes the capacity of batteries and eventually causes total failure by shorting when dendrites meet each other or the opposite electrode. Previous attempts to solve this problem have focused on improving the stability of the solid state electrolyte and modifications to the interfaces between electrodes and the solid state electrolyte, e.g., adding barrier layers. Such remediations have Met with limited success.
Thus, there is a need for improved solid state batteries incorporating solid state electrolytes.
The invention provides rechargeable solid state batteries with multilayers of solid state electrolytes. The rechargeable solid state batteries disclosed herein are advantageous as they represent an advance in battery cycling performance combined with excellent power and energy density.
In one aspect, the invention provides a rechargeable battery including a) an anode and a cathode and b) a solid state electrolyte multilayer disposed between the anode and the cathode including: i) a first solid state electrolyte and ii) a second solid state electrolyte. The second solid state electrolyte is separated from the anode by the first solid state electrolyte, i.e., the multilayer includes at least two layers, e.g., at least three.
In certain embodiments, the second solid state electrolyte is less stable to the anode metal, e.g., lithium or sodium, than the first solid state electrolyte. In some embodiments, the first solid state electrolyte has a first decomposition energy (Ehull), a first local effective modulus, e.g., when being made into solid state batteries, and a first critical modulus (K*), where the first critical modulus is lower than the first local effective modulus thereby causing the first decomposition energy to have a positive value. In some embodiments, the second solid state electrolyte has a second decomposition energy (Ehull), a second local effective modulus, e.g., when being made into solid state batteries, and a second critical modulus (K*); where the second decomposition energy is more negative than the first decomposition energy, and local decomposition of the second solid state electrolyte raises the second local effective modulus to locally above the second critical modulus.
In some embodiments, the solid state electrolyte multilayer is under mechanical constriction. In particular embodiments, the mechanical constrictions generates a local stress of about 0.1 GPa to about 250 GPa on the multilayer. In certain embodiments, the battery is under external pressure of about 0.1 MPa to about 1000 MPa. Pressure can vary, or be varied, periodically during battery cycling, e.g., by a passive response system, e.g., springs, e.g., with spring constants determined to apply a particular pressure, or, e.g., an active response system, e.g., configured to adjust pressure in real-time, e.g., as monitored by pressure sensors. In some embodiments, the mechanical constriction is produced by warm isotropic pressing (WIP), cold isotropic pressing (CIP), hydraulic cold pressing, or external pressure applied to the battery during assembly, e.g., a formation pressure from cold and/or hot and/or warm isotropic and/or anisotropic press and/or rolling with the external pressure of about 0.1 MPa to 1000 MPa and temperature at about 25° C.-1000° C.
In some embodiments, the porosity of the anode, cathode, and/or multilayer is 0%-25%. In some embodiments, the external pressure is provided by mechanical stress from a battery case or a pouch cell and/or from a hydraulic press made by a gel or liquid sealed in an environment within a case, cell, or press. In some embodiments, the battery case or pouch cell includes steel, aluminum, a polymer, a spring system, an electronic pressurization system with pressure sensors, and/or a combination thereof.
In some embodiments, the anode includes Li or Na metal. In some embodiments, the anode further includes a protective layer, e.g., including silicon, silicon dioxide, Li4Ti5O12, Li3V2O5, carbon (e.g., amorphous carbon, carbon nanotube, graphene, carbon nanofiber, fullerenes (e.g., C60 fullerene), hard carbon, or graphite), Au, Ag, Sn, SnO2, or a combination thereof. The particle size of the protection materials can be 1 nm to 100 μm. The protection layer can be mixed with the Li metal and/or polymer with a thickness of 0 μm-500 μm. In some embodiments, the anode further includes Li, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, In, Sn, Sb, Bi, Cs, Te, or a combination thereof (e.g., as an alloy). In some embodiments, the anode includes Li, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, In, Sn, Sb, Bi, Cs, Te, or a combination thereof in a protective layer. The lithium metal can also mix or alloy with these elements to form one single layer. The mixture of Li and other metal can form a 2D parallel layer or a 3D structure. The loading of the Li or Na in the anode can be 0-50 mg/cm2. The thickness of the Li or Na in the anode can be 0 μm-1000 μm. 0 μmeans the battery can be made with an anode-free design, where Li or Na source is from the cathode material.
In certain embodiments, the cathode includes LiNi0.8Mn0.1Co0.1O2 (NMC811), LiNi0.33Mn0.33Co0.33O2 (NMC111), LiNi0.5Mn0.3Co0.3O2 (NMC532), LiNi0.6Mn0.2Co0.2O2 (NMC622), LiNi0.9Mn0.05Co0.05O2 (NMC955), LiNixMnyCo(1−x−y)O2 (0≤x,y≤1), LiNixCoyAl(1−x−y)O2 (0≤x,y≤1), LiMn2O4, LiMnO2, LiNiO2, Li1+zNixMnyCo(1−x−y)O2 (0≤x,y≤1), Li1+zNixMnyCowAl(1−x−y−z−s)O2 (0≤x,y,z,s≤1), Li1+zNixMnyCosW(1−x−y−z−s)O2 (0≤x,y,z,w≤1), V2O5, selenium, sulfur, selenium-sulfur compound, LiCoO2 (LCO), LiFePO4, LiNi0.5Mn1.5O4, Li2CoPO4F, LiNiPO4, Li2Ni(PO4)F, LiMnF4, LiFeF4, or LiCo0.05Mn1.5O4. The cathode can be coated with LiNbO3, LiTaO3 Li2ZrO3, LiNbxTa1−xO3 (0≤x≤1), yLi2ZrO3-(1-y)LiNbxTa1−xO3 (0≤x, y≤1), Al2O3, TiO2, ZrO2AlF3, MgF2, SiO2, ZrS, ZnO, Li4SiO4 Li3PO4, Li3InCl6, Li1+xAlxTi2−x(PO4)3(0<x<2), LiMn2O4, LiInO2—LiI, Li6PS5Cl, LiAlO2, a polymer, or carbon. In some embodiments, the cathode includes a polymer and/or carbon black, or the first and/or second solid electrolytes include a polymer.
In certain embodiments, the first solid state electrolytes is selected from Table 1, or the solid electrolytes of Table 1 with one or more elements replaced by a homogeneous element:
xLi3PS4—(1 − x)LiI
The second solid state electrolyte may be selected from Table 2, or the solid electrolytes of Table 1 with one or more elements replaced by a homogeneous element:
nLiX—xACl3-(1 − x)GaF3
nLiCl—LiOH—GaF3 (n = 2, 3, 4)
nLiX—GaF3 (X = Cl, Br, n = 2, 3, 4)
where 0≤a, h, d, p, q , w, x, y, z, u, v, and w≤1 unless otherwise specified, where C is the critical doping content, above which the electrolyte become less stable, and where C can be varied for u, v, and w; 0≤C≤1.
In some embodiments, the anode includes Na metal. in some embodiments, the first solid state electrolyte is selected from Table 3, or the solid electrolytes of Table 3 with one or more elements replaced by a homogeneous element:
and/or the second solid state electrolyte is selected from Table 4, or the solid electrolytes of Table 4 with one or more elements replaced by a homogeneous element:
Sb1−v−i)2±p
indicates data missing or illegible when filed
where 0≤p, q, w, x, y, z, u, v, and w≤1 unless otherwise specified, where C is the critical doping content above which the electrolyte become less stable, and where C can be varied for u, v, and w; 0≤C≤1.
In some embodiments, the anode includes Na; where the anode further includes a protective layer including graphite, silicon, silicon dioxide, Na4Ti5O12, Na3V2O5, Au, Ag, Sn, SnO2, or carbon, or a combination thereof; and/or where the protective layer includes Na metal or a mixture of Na metal and/or polymer with a thickness of 0 μm-500 μm. The particle size of the protection materials can be 1 nm to 100 μm, e.g., about 1-100 nm (e.g., about 1-10 nm, 1-25 nm, 10-20 nm, 20-30 nm, 25-50 nm, 30-40 nm, 40-50 nm, 50-60 nm, 50-75 nm, 60-70 nm, 70-80 nm, 75-100 nm, 80-90 nm, or 90-100 nm, e.g., about 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm), e.g., about 100-1000 nm (e.g., about 100-110 nm, 100-125 nm, 100-200 nm, 200-300 nm, 250-500 nm, 300-400 nm, 400-500 nm, 500-600 nm, 500-750 nm, 600-700 nm, 700-800 nm, 750-1000 nm, 800-900 nm, or 900-1000 nm, e.g., about 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, or 1000 nm), e.g., about 1-10 μm (e.g., about 1-2 μm, 1-5 nm, 2-3 μm, 3-4 μm, 4-5 μm, 5-10 μm, 5-6 μm, 6-7 μm, 7-8 μm, 8-9 μm, or 9-10 μm, e.g., about 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm), or, e.g., about 10-100 μm (e.g., about 10-20 μm, 10-25 μm, 10-50 μm, 20-30 μm, 25-50 μm, 30-40 μm, 40-50 μm, 50-60 μm, 50-75 μm, 60-70 μm, 75-100 μm, 70-80 μm, 80-90 μm, or 90-100 μm, e.g., about 10 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm). In some embodiments, the carbon includes hard carbon, amorphous carbon, carbon nanotube, graphene, carbon nanofiber, or a fullerene (e.g., C60). In some embodiments, the sodium metal in the protection layer is mixed or alloyed with Li, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, In, Sn, Sb, Bi, Cs, Te, or a combination thereof. In some embodiments, the cathode includes NawMnO2, NawCoO2, NawNiO2, NawTiO2, NawVO2, NawCrO2, NawFeO2, Naw(MnxFeyCozNi1−x−y−z)O2 (0≤x,y,z≤1), Naw(M)PO4, Naw(M)P2O7, Naw(M)O2, NaxMy(XO4)2; where M is a metal element or a combination of metal elements, e.g., transition metal elements; where X is B, S, P, Si, As, Mo, W, or a combination thereof; where 0≤x,y,z≤3; 0<w≤1; and where O can be partially replaced by F, Cl, Br, or I. In some embodiments, the cathode includes a coating of NaNbO3, NaTaO3, Na2ZrO3, NaNbxTa1−xO3 (0≤x≤1), yNa2ZrO3-(1−y)NaNbxTa1−xO3 (0≤x, y≤1), Al2O3, TiO2, ZrO2, AlF3, MgF2, SiO2, ZnS, ZnO, Na4SiO4, Na3PO4, Na3InCl6, Na1+xAlxTi2−x(PO4)3(0<x<2), NaMn2O4, NaInO2—NaI, Na6PS5Cl, NaAlO2, or carbon.
In some embodiments, the battery can cycle at a current density from 0.001 mA/cm2 to 100 mA/cm2. In some embodiments the battery retains at least 80% of capacity after at least 10,000 charge-discharge cycles from 20 C-rate to 100 C-rate, e.g., 2 mA/cm2 cathode loading, with an initial capacity higher than 80 mAh/g and a current density higher than 8 mA/cm2. In particular embodiments, the solid state electrolyte multilayer includes at least two different first solid state electrolytes. In some embodiments, the battery cathode material has a power density of at least 10 kW/kg. In some embodiments, the battery cathode material has an energy density of at least 600 Wh/kg.
In some embodiments, the first and/or second solid state electrolyte has a core-shell particle structure. In certain embodiments, the core-shell particles have a core conductivity and a shell conductivity that are different. In some embodiments, the core conductivity is higher than the shell conductivity. In some embodiments, the core-shell particles have a core composition and a shell composition, and the core composition is different from the shell composition, e.g., having different non-stoichiometric weightings of, e.g., Li or Na. The different core and shell compositions can provide different properties, e.g., K*, Ehull, conductivity, etc., e.g., the shell composition may have a smaller K* or a more negative Ehull than the core, or, e.g., the core conductivity may be higher than the shell conductivity, or any combination thereof.
In some embodiments, the first solid state electrolyte includes a material selected from Table 5 or Table 6, or a material having a formula of a material selected from Table 5 or Table 6 with one or more elements replaced with an element of equal group number:
Additionally or alternatively, the second solid state electrolyte includes a material selected from Table 7 or Table 8, or a material having a formula of a material selected from Table 5 or Table 6 with one or more elements replaced with an element of equal group number:
In Tables 5-8‘_{#}’ and ‘_{#±x, y, z, w, I, or m}’ represent non stoichiornetric weightings of an element immediately to the left of ‘_{#}’ or ‘_{#±x, y, z, w, I, or m}’ in a chemical formula of the material, where # can be in the range of #±n, wherein 0≤n≤0.5, where 0≤x, y, z, w, I, and m≤#, and where # can be ±n, 0≤n ≤0.5.
In some embodiments, the first solid state electrolyte includes a material selected from Table 9 or Table 10, or a material having a formula of a material selected from Table 9 or Table 10 with one or more elements replaced with an element of equal group number:
Additionally or alternatively, the second solid state electrolyte includes a material selected from Table 11 or Table 12, or a material having a formula of a material selected from Table 11 or Table 12 with one or more elements replaced with an element of equal group number:
In Tables 9-12‘_{#}’ and ‘_{#±x, y, z, w, I, or m}’ represent non stoichiornetric weightings of an element immediately to the left of ‘_{#}’ or ‘_{#±x, y, z, w, I, or m}’ in a chemical formula of the material, where # can be in the range of #±n, wherein 0≤n≤0.5, where 0≤x, y, z, w, I, and m≤#, and where # can be ±n, 0≤n ≤0.5.
In certain embodiments, the first or second solid state electrolyte has a core-shell particle structure, and the material of Table 6, Table 8, Table 10, or Table 12 is in the shell.
In some embodiments, the cathode is mixed with a solid state electrolyte including a material selected from Table 13 or Table 14:
In Tables 13 and 14, ‘_{#}’ and ‘_{#±x, y, z, w, I, or m}’ represent non stoichiornetric weightings of an element immediately to the left of ‘_{#}’ or ‘_{#±x, y, z, w, I, or m}’ in a chemical formula of the material, where # can be in the range of #±n, wherein 0≤n≤0.5, where 0≤x, y, z, w, I, and m≤#, and where # can be ±n, 0≤n≤0.5.
In certain embodiments, the solid-state electrolyte mixed with the cathode includes any one of materials 32-40 from Table 13 or any one of materials 37-45 from Table 14.
In some embodiments, the solid state electrolyte mixed with the cathode has a core-shell particle structure.
In another aspect, the invention provides a method of storing energy including applying a voltage across the anode and cathode and charging any rechargeable battery disclosed herein. In another aspect, the invention provides a method of providing energy including connecting a load to the anode and cathode and discharging any rechargeable battery disclosed herein.
The term “about,” as used herein, refers to ±10% of a recited value.
The term “stability,” as used herein with respect to solid-state electrolytes, refers to the stability of the material to decomposition via reaction with a metal in the anode, e.g., lithium or sodium. Stability of solid electrolytes can be determined experimentally.
The invention provides rechargeable batteries including a solid state electrolyte (SSE) multilayer containing three or more layers and two or more solid state electrolytes with different stabilities. The solid state electrolytes may be arranged such that the less stable electrolyte is sandwiched between more stable electrolyte(s). Localized decomposition of the less stable electrolyte can block the formation or progression of cracks in the multilayer and arrest dendrite progress.
Solid-state electrolyte with high mechanical strength is expected to solve the issue of lithium or sodium dendrites and enable Li or Na anodes. However, in practice it remains a challenge, as it is found that lithium can still penetrate most solid electrolytes even at a very low current density. This invention provides solid-state batteries using a multilayer design of solid electrolytes with a hierarchy of interface stabilities to achieve an ultra-high current density with no dendrite penetration. The more stable electrolyte ensures the interface stabilities with both high voltage cathodes and Li or Na metal anodes, while the less stable electrolyte responds to any dendrite growth with localized decompositions, to effectively inhibit the further growth of the dendrite by local mechanical constriction induced kinetic stability. Micron or submicron sized cracks in ceramic pellets are inevitable in any battery assembly over long-time cycling. The solid state electrolyte multilayers of the invention dynamically generate self-decomposed and well-constrained “cement” or “concrete” to fill in these cracks, no matter which pathway the dendrite chooses, thereby preserving battery performance. We emphasize that these comparisons and analyses about electrochemical stabilities at the various interfaces are made possible because the problem of Li metal dendrite induced capacity fading and internal short have been largely prevented through the designed functional decompositions of the invention. The invention provides new design principles for electrolytes, interfaces and devices within the framework of the mechanical constriction theory to enable solid state batteries with high capacity, stable cycling, high-rate, and high current density capabilities.
The cycling performance of Li metal anode paired with LiNi0.8Mn0.1Co0.1O2 cathode is demonstrated to be very stable, with 82% capacity retention after 10,000 cycles at 20 C (70% capacity retention after 9,300 cycles at 15 C). The average Coulombic efficiency is 99.96% at 20 C and 100.0009% at 15 C among all the thousands of cycles, with the highest power density reaching 11.9 kW/kg and the energy density up to 631 Wh/kg at the cathode active material level. LiNi0.8Mn0.1Co0.1O2 (NMC811) is regarded as one of the most important cathode materials with high capacity, energy density, and also cost effectiveness due to the decreased composition of the expensive Co element, while Li metal is considered as the holy grail of the anode for Li-ion batteries due to the high capacity and energy density. The stable cycling of NMC811 lithium metal battery is of great significance to the industry of electrical vehicle batteries. However, the stability of such a battery with most electrolytes, either liquid or solid, is poor. It is known that Li10±xM1±yP2±pS12±q (M=Ge, Si) is not stable with lithium metal.1 Protection layers such as graphite2 or indium metal3 are usually applied to insulate the contact between solid electrolytes and the lithium metal. While Li-argyrodites Li6−yPS5−yCl1+y is much more stable with lithium metal than LGPS.4-6 The invention thus provides a highly stable battery that can employ high capacity anodes and cathodes and has a broad space to provide batteries with an energy density and a power density greater than other batteries.
Rechargeable batteries of the invention typically include an anode, a cathode, and a solid state electrolyte multilayer disposed between the anode and the cathode. The solid state multilayer includes a first solid state electrolytes (erg., LPSCl) and a second solid state electrolyte (e.g., LGPS). The multilayer includes at least one layer of a first solid state electrolyte, which is more stable with lithium or sodium metal than the second solid state electrolyte. The second solid state electrolyte is separated from the anode by the first solid state electrolyte. The multilayer may contain ‘n’ layers of the second solid state electrolyte and ‘n’ layers of the one or more first solid state electrolytes (where n=e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.).
The solid state multilayer may alternatively be arranged in, e.g., a “sandwich” structure, e.g., with one layer of the second solid state electrolyte between two layers of the one or more first solid state electrolytes (e.g., LPSCl-LGPS or LPSCl-LGPS-LPSCl). Alternatively, the multilayer may contain ‘n’ layers of the second solid state electrolyte and ‘n’ or ‘n+1’ layers of the one or more first solid state electrolytes (where n=e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.).
The second solid state electrolyte is less stable with lithium or sodium metal than the one or more first solid state electrolytes. Such an arrangement allows the first solid state electrolyte to protect the second solid state electrolyte from, e.g., large-scale decomposition, while confined localized decomposition of the second solid state electrolyte arrests the progression of metal dendrites (see, e.g.,
The multilayer design is not limited to any specific materials. The versatility of the multilayer design is demonstrated in
Following this design principle, a broad range of solid state electrolytes can be included as the one or more first solid state electrolytes or the second electrolyte, as long as they are appropriately placed relative to each other in the multilayer design according to their relative stabilities, e.g., polymers, gels, or sulfides, halides, oxides, phosphates and nitrates, as listed in Tables 1 to 4.
A very promising aspect of the invention is that the stability of the multilayer structure takes advantage of relative chemical and/or electrochemical stabilities, which are not sensitive to the thickness or the micron crack density of the electrolyte layers. This new strategy of incorporating instability by design is different from the conventional wisdom in the field to improve battery stability using solid state electrolytes to mechanically block the Li (or Na) dendrite penetration, which naturally requires a thick and crack-free electrolyte layer. The flexibility and versatility inherent in the multilayer batteries of the invention make them readily compatible with mass production procedures in battery industry, where the thickness and mechanical flexibility of the electrolyte layer can be further optimized in the future without sacrificing the safety and performance.
To quantify the electrochemical stability of solid electrolytes and their interfaces in such a solid state battery (SSB), a constrained ensemble description has been developed, where decompositions with a positive reaction strain can in principle be suppressed through a metastability if the local effective modulus (e.g., from being made into solid state batteries), Keff, is sufficient. Keff in the unit of GPa reflects the complicated coupling of microstructures, the mechanical strength of materials, and the stack pressure of battery devices.
We have found that when Keff is larger than a critical threshold modulus, K*, the Gibbs energy of the decomposition reaction, Ehull goes from negative to positive so that the decomposition can be suppressed through a metastability. Since most sulfide electrolytes are unstable at 0 V with Li metal, it is thus attractive to have a low K* interface between solid electrolyte and Li metal, so that interface reactions can be more easily stabilized through mechanical constriction. Importantly, since a stress field surrounding the decomposition front is inevitable in practice, a lower K* likely also causes a smaller decomposition-induced local volume expansion and a weaker stress field before it is fully inhibited by the metastability. Meanwhile, decompositions with sufficient Ehull at Keff=0 GPa can serve as an effective supply of “concrete” to heal any microcracks, which may preexist in battery assembly or be generated by various stress fields during cycling, including the field induced by the local decomposition itself. Thus, an interface reaction with low K* and sufficient Ehull may effectively prevent the fracture and dendrite propagations. The continuous local stress field surrounding the decomposition front without cracks or with cracks immediately healed by electrochemical decompositions thus can provide the kinetic stability that further strengthens the metastability.
The invention provides the first quantification of the above picture to design functional decompositions by using high-throughput ab initio computations to evaluate the K* and Ehull of over 120,000 materials, and further use machine learning to extract the information to suggest solid electrolyte compositions that are likely to show small K* and sufficient Ehull at the interface to Li metal (See Methods in Example 4). The suggested composition change can be implemented in through a core-shell strategy, where the shell composition can be modified from the core, advantageously, also according to the predicted composition for a low K*. For example, the core conductivity may be higher than the shell conductivity. Alternatively or in addition, the shell composition may have a smaller K* or a more negative Ehull than the core. The design principles identified herein also apply to SSBs having other anode metals, e.g., Na.
In some embodiments, the solid state electrolyte multilayer is under mechanical constriction. Mechanical constriction of the solid state electrolyte can limit the extent of chemical or electrochemical decomposition of solid state electrolyte materials by volumetric constraint, as detailed. Local stress on the order of a few GPa up to the mechanical modulus of solid electrolyte (e.g., around 20 GPa for sulfide solid electrolytes), may be generated from mechanical constriction. The mechanical constriction can be implemented by an external pressure applied to the battery cell of at least 0.1 MPa up to several hundred MPa. The level of external pressure needed for a battery is determined by the battery material, material processing, and battery assembly methods. Mechanical constriction may be provided by a formation pressure from cold and/or hot and/or warm isotropic and/or anisotropic press and/or rolling with the external pressure on the order of 0.1 MPa to 1000 MPa and temperature at 25° C.-500° C. Examples of suitable assembly methods include, but are not limited to, warm isotropic pressing (WIP), cold isotropic pressing (CIP), and hydraulic cold pressing of the battery cell or pouch. The mechanical constriction may result from an applied pressure of at least 0.1 MPa, e.g., at least 20 MPa, or about 0.1 MPa to about 40 MPa, e.g., about 0.1 MPa to about 1 MPa, about 0.1 MPa to about 10 MPa, about 1 MPa to about 30 MPa, about 20 MPa to about 40 MPa, about 30 MPa to about 50 MPa, about 40 MPa to about 60 MPa, about 50 MPa to about 70 MPa, about 60 MPa to about 80 MPa, about 70 MPa to about 90 MPa, or about 80 MPa to about 100 MPa, about 100 MPa to about 200 MPa, about 200 MPa to about 400 MPa, about 300 MPa to about 500 MPa, about 400 MPa to about 600 MPa, about 500 MPa to about 700 MPa, about 600 MPa to about 800 MPa, about 700 MPa to about 900 MPa, or about 800 MPa to about 1,000 MPa, e.g., about 70 MPa, about 75 MPa, about 80 MPa, about 85 MPa, about 90 MPa, about 95 MPa, about 100 MPa, about 150 MPa, about 200 MPa, about 250 MPa, about 300 MPa, about 350 MPa, about 400 MPa, about 450 MPa, about 500 MPa, about 550 MPa, about 600 MPa, about 650 MPa, about 700 MPa, about 750 MPa, about 800 MPa about 850 MPa, about 900 MPa, about 950 MPa, or about 1,000 MPa. Greater mechanical constriction may be applied during battery fabrication. After providing the formation pressure, the porosity of the anode, cathode, and/or multilayer may be 0% -15%. In some embodiments, the mechanical constriction is sufficient to raise the local effective modulus above K*, thereby preventing decomposition, or such that a local stress field caused by decomposition of the solid state electrolyte raises Keff above K* thereby arresting decomposition.
When the battery is operating, the local stress can be maintained by applying an operational stack pressure an the order of 0.1 MPa to 1000 MPa. The operational stack pressure can be applied by the mechanical stress from battery case or pouch cell made of steel, aluminum, plastic, polymer, as well as their 3D structures, and/or from a hydraulic press made by gel or any liquid sealed in an environment surrounding the pouch cell. The external pressure may also change periodically during battery cycling, e.g., through a passive response system, e.g., springs, or, e.g., an active response system, e.g., controlled by pressure sensors and programmed elect of devices.
The one or more first solid state electrolytes may be selected from Table 1, Table 3, Table 5, Table 6, Table 9, or Table 10.14, 17-18, 20-21, 26-38 The second solid state electrolyte may be selected from Table 2, Table 4, Table 7, Table 8, Table 11, or Table 12.15-16, 19, 20, 22, 24-25 Solid state electrolytes advantageous for mixing with a cathode material are described in Tables 13 and 14. Other solid state electrolyte materials that may be suitable include sulfide solid electrolytes, e.g., SixPySz, e.g., SiP2S12, or β/γ-PS4. Other solid state electrolytes include, but are not limited to, germanium solid electrolytes, e.g., GeaPbSc, e.g., GeP2S12, tin solid electrolytes, e.g., SndPeSf, e.g., SnP2S12, iodine solid electrolytes, e.g., P2S8I crystals, glass electrolytes, alkali metal-sulfide-P2S5 electrolytes or alkali metal-sulfide-P2S5-alkali metal-halide electrolytes, or glass-ceramic electrolytes, e.g., alkali metal-PgSh-i electrolytes. Other solid state electrolyte materials are known in the art. The solid state electrolyte material may be in various forms, such as a powder, particle, clay, or solid sheet. An exemplary form is a powder. Advantageously, the solid state electrolyte may adopt a core-shell particle structure. In particular, methods of the invention (see, e.g., Example 4) may be used to produce core-shell LPSCl—X (where X is a halide) solid state electrolytes having properties suited for use as first or second solid state electrolytes. LGPS (Li10GeP2S12) may also adopt a core-shell particle structure. Solid state electrolyte particles, e.g., core-shell particles, may have a cross sectional dimension, e.g., diameter, of between about 1 nm and about 30 μm, e.g., about 1-100 nm (e.g., about 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm), e.g., about 100-1000 nm (e.g., about 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, or 1000 nm), e.g., about 1-10 μm (e.g., about 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm), or, e.g., about 10-30 μm(e.g., about 10 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, or 30 μm). In core-shell particles, the shell may make up from about 0.1% to about 99.9% of the particle, e.g., about 1-10%, about 10-20%, about 20-30%, about 25-50%, about 40-60%, about 50-75%, about 60-80%, about 75-90%, or about 80-99% of the particle, by, e.g., volume or mass.
Stability may be determined experimentally. For example, if a lithium metal symmetric battery made with a solid electrolyte (Li-solid electrolyte-Li) can run for 10 or more cycles at a current density <0.5 mA/cm2 without clear voltage ramp-up, the electrolyte can be classified as stable for the application as the first solid state electrolyte. For a less stable electrolyte (the second solid electrolyte), such a symmetric battery would show clear voltage ramp-up within just a few, e.g., 1-3, cycles. A less stable solid state electrolyte also shows clear composition and structure change after contacting or cycling with a lithium metal anode. In some embodiments, the second solid state electrolyte has a good response to mechanical constriction, reflected as the straining of the solid-state electrolyte in X-ray diffraction measurement after being the central layer of the multilayer solid-state battery during cycling, which is due to the positive reaction strain of the constricted local decompositions.
Electrode materials can be chosen to have optimum properties for ion transport. For example, may be preferred LiNi0.8Mn0.1Co0.1O2 (NMC811) due to its high capacity, energy density, and also cost effectiveness due to the decreased composition of the expensive Co element. As another example, Li metal has high capacity and energy density. Electrodes for use in a solid state electrolyte battery can include metals, e.g., transition metals, e.g., Au, alkali metals, e.g., Li or Na, or crystalline compounds, e.g., lithium titanate, or an alloy thereof. Other materials for use as electrodes in solid state electrolyte batteries are known in the art.
The electrodes may be a solid piece of the material, or alternatively, may be deposited on an appropriate substrate, e.g., a fluoropolymer or carbon. For example, liquefied polytetrafluoroethylene (PTFE) has been used as the binder when making solutions of electrode materials for deposition onto a substrate. Other binders are known in the art. The electrode material can be used without any additives. Alternatively, the electrode material may have additives to enhance its physical and/or ion conducting properties. For example, the electrode materials may have an additive that modifies the surface area exposed to the solid electrolyte, such as carbon. Other additives are known in the art. In particular embodiments, the anode includes Li, e.g., Li metal. The lithium metal can also mix or alloy with Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, In, Sn, Sb, Bi, Cs, Te, or a combination thereof to form one single layer. The mixture of Li and other metal can form a 2D parallel layer or a 3D structure. The loading of the Li in the anode can be 0-50 mg/cm2. The thickness of the Li in the anode can be 0 μm- 1000 μm. A thickness of 0 μm means the battery can be made with an anode-free design, where Li source is from the cathode material.
In some embodiments, the cathode can include, e.g., LiNi0.8Mn0.1Co0.1O2 (NMC811), LiNi0.33Mn0.33Co0.33O2 (NMC111), LiNi0.5Mn0.3Co0.3O2 (NMC532), LiNi0.6Mn0.2Co0.2O2 (NMC622), LiNi0.9Mn0.05Co0.05O2 (NMC955), LiNixMnyCo(1−x−y)O2 (0≤x,y≤1), LiNixCoyAl(1−x−y)O2 (0≤x,y≤1), LiMn2O4, LiMnO2, LiNiO2, Li1+zNixMnyCo(1−x−y)O2 (0≤x,y≤1), Li1+zNixMnyCowAl(1−x−y−z−s)O2 (0≤x,y,z,s≤1), Li1+zNixMnyCosW(1−x−y−z−s)O2 (0≤x,y,z,w≤1), V2O5, selenium, sulfur, selenium-sulfur compound, LiCoO2 (LCO), LiFePO4, LiNi0.5Mn1.5O4, Li2CoPO4F, LiNiPO4, Li2Ni(PO4)F, LiMnF4, LiFeF4, or LiCo0.05Mn1.5O4.
The cathode can be mixed with polymer and/or carbon. Examples of polymers may include polyethylene oxide, polyvinylidene fluoride, poly(vinylidene fluoride-co-hexafluoropropylene), poly(ethyl methacrylate), or poly(vinylidene fluoride-co-trifluoroethylene). The particle size of cathode materials can be 1 nm-30 μm, The loading of the cathode can be 0.1-100 mg/cm2. The thickness of the cathode can be 5 μm- 2000 μm. The cathode may be mixed with solid state electrolyte materials, e.g., those described in Table 13 and Table 14, e.g., to provide increased cathode capacity.
Where the anode includes Na metal, the sodium metal can be mixed or alloyed with one or more metals of Li, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, In, Sn, Sb, Bi, Cs, or Te. The mixtures of Na and other metal can form a 2D parallel layer or a 3D structure. The loading of the Na in the anode can be 0-50 mg/cm2. The thickness of the Na in the anode can be 0 μm-1000 μm. 0 μm means the battery can be made with an anode-free design, where Na source is from the cathode material.
Na cathode materials can be NawMnO2, NawCoO2, NawNiO2, NawTiO2, NawVO2, NawCrO2, NawFeO2, Naw(MnxFeyCozNi1−x−y−z)O2 (0≤x,y,z≤1), Naw(M)PO4, Naw(M)P2O7, Naw(M)O2, NaxMy(XO4)2 (M represents metal elements, e.g., including but not limited to transition metals, it can be one metal element or combination of metal elements; X represents B, S, P, Si, As, Mo, W; 0≤x,y,z≤3; 0<w≤1; O can be partially replaced by F, Cl, Br, I).
Other cathode materials such as selenium or sulfur that exhibit promising high capacity and energy density also shows much better cycling performance in our multilayer design than the single layer design.
In certain embodiments, cathode can be mixed with polymer and carbon black, solid electrolytes can be mixed with polymer. Examples of polymers may include polyethylene oxide, polyvinylidene fluoride, poly(vinylidene fluoride-co-hexafluoropropylene), poly(ethyl methacrylate), or poly(vinylidene fluoride-co -trifluoroethylene). The thickness of the solid electrolyte layer is 5-1000 μm. The thickness of the cathode can be 5-2000 μm. The anode, cathode, and solid electrolytes can use bipolar or parallel stacking to form a battery module. The area of each layer can be 0.1 cm2-1 m2.
In some cases, the electrode materials may further include a coating on their surface to act as an interfacial layer between the base electrode material and the solid state electrolyte. In particular, the coatings are configured to improve the interface stability between the electrode, e.g., the cathode, and the solid electrolyte for superior cycling performance. For example, coating materials for electrodes of the invention include, but are not limited LiNbO3, LiTaO3 Li2ZrO3, LiNbxTa1−xO3 (0≤x≤1), yLi2ZrO3-(1−y)LiNbxTa1−xO3 (0≤x,y≤1), Al2O3, TiO2, ZrO2AlF3, MgF2, SiO2, ZrS, ZnO, Li4SiO4 Li3PO4, Li3InCl6, Li1+xAlxTi2−x(PO4)3(0<x<2), LiMn2O4, LiInO2—LiI, Li6PS5Cl, LiAlO2, and carbon, in particular LiNbO3.
An anode including Li may include a protection layer including silicon, silicon dioxide, Li4Ti5O12, Li3V2O5, Au, Ag, Sn, SnO2, carbon (e.g., amorphous carbon, carbon nanotube, graphene, carbon nanofiber, a fullerene. (e.g., C60), hard carbon, or graphite), or a combination thereof. The particle size of the protection materials can be 1 nm to 100 μm, e.g., about 1-100 nm (e.g., about 1-10 nm, 1-25 nm, 10-20 nm, 20-30 nm, 25-50 nm, 30-40 nm, 40-50 nm, 50-60 nm, 50-75 nm, 60-70 nm, 70-80 nm, 75-100 nm, 80-90 nm, or 90-100 nm, e.g., about 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm), e.g., about 100-1000 nm (e.g., about 100-110 nm, 100-125 nm, 100-200 nm, 200-300 nm, 250-500 nm, 300-400 nm, 400-500 nm, 500-600 nm, 500-750 nm, 600-700 nm, 700-800 nm, 750-1000 nm, 800-900 nm, or 900-1000 nm, e.g., about 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, or 1000 nm), e.g., about 1-10 μm (e.g., about 1-2 μm, 1-5 nm, 2-3 μm, 3-4 μm, 4-5 μm, 5-10 μm, 5-6 μm, 6-7 μm, 7-8 μm, 8-9 μm, or 9-10 μm, e.g., about 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm), or, e.g., about 10-100 μm (e.g., about 10-20 μm, 10-25 μm, 10-50 μm, 20-30 μm, 25-50 μm, 30-40 μm, 40-50 μm, 50-60 μm, 50-75 μm, 60-70 μm, 75-100 μm, 70-80 μm, 80-90 μm, or 90-100 μm, e.g., about 10 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm). The protection layer can be mixed with the Li metal and/or polymer with a thickness of 0 μm-500 μm. The lithium metal layer can be protected by a layer formed by one or more elements of Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, In, Sn, Sb, Bi, Cs, or Te. The lithium metal layer can be alloyed with one or more elements of Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, In, Sn, Sb, Bi, Cs, or Te.
In particular embodiments, the solid state electrolyte multilayer is separated from the anode and/or the cathode by a protection layer including silicon, Li4Ti5O12, Li3V2O5, silicon dioxide, carbon (e.g., amorphous carbon, carbon nanotube, graphene, carbon nanofiber, fullerene (e.g., C60), hard carbon, or graphite, e.g., as a graphite coating on the electrodes), Au, Ag, Sn, SnO2 or a combination thereof. The particle size of the protection materials can be 1 nm to 100 μm, e.g., about 1-100 nm (e.g., about 1-10 nm, 1-25 nm, 10-20 nm, 20-30 nm, 25-50 nm, 30-40 nm, 40-50 nm, 50-60 nm, 50-75 nm, 60-70 nm, 70-80 nm, 75-100 nm, 80-90 nm, or 90-100 nm, e.g., about 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm), e.g., about 100-1000 nm (e.g., about 100-110 nm, 100-125 nm, 100-200 nm, 200-300 nm, 250-500 nm, 300-400 nm, 400-500 nm, 500-600 nm, 500-750 nm, 600-700 nm, 700-800 nm, 750-1000 nm, 800-900 nm, or 900-1000 nm, e.g., about 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, or 1000 nm), e.g., about 1-10 μm (e.g., about 1-2 μm, 1-5 nm, 2-3 μm, 3-4 μm, 4-5 μm, 5-10 μm, 5-6 μm, 6-7 μm, 7-8 μm, 8-9 μm, or 9-10 μm, e.g., about 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6, μm, 7 μm, 8 μm, 9 μm, or 10 μm), or, e.g., about 10-100 μm (e.g., about 10-20 μm, 10-25 μm, 10-50 μm, 20-30 μm, 25-50 μm, 30-40 μm, 40-50 μm, 50-60 μm, 50-75 μm, 60-70 μm, 75-100 μm, 70-80 μm, 80-90 μm, or 90-100 μm, e.g., about 10 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm).
For batteries using Na, Na metal may include a protection layer including silicon, silicon dioxide, Na4Ti5O12, Na3V2O5, carbon (hard carbon, amorphous carbon, carbon nanotube, graphene, carbon nanofiber, fullerene (e.g., C60), hard carbon, or graphite), Au, Ag, Cn, SnO2 or a combination thereof. The particle size of the protection materials can be 1 nm to 100 μm, e.g., about 1-100 nm (e.g., about 1-10 nm, 1-25 nm, 10-20 nm, 20-30 nm, 25-50 nm, 30-40 nm, 40-50 nm, 50-60 nm, 50-75 nm, 60-70 nm, 70-80 nm, 75-100 nm, 80-90 nm, or 90-100 nm, e.g., about 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm), e.g., about 100-1000 nm (e.g., about 100-110 nm, 100-125 nm, 100-200 nm, 200-300 nm, 250-500 nm, 300-400 nm, 400-500 nm, 500-600 nm, 500-750 nm, 600-700 nm, 700-800 nm, 750-1000 nm, 800-900 nm, or 900-1000 nm, e.g., about 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, or 1000 nm), e.g., about 1-10 μm (e.g., about 1-2 μm, 1-5 nm, 2-3 μm, 3-4 μm, 4-5 μm, 5-10 μm, 5-6 μm, 6-7 μm, 7-8 μm, 8-9 μm, or 9-10 μm, e.g., about 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm), or, e.g., about 10-100 μm (e.g., about 10-20 μm, 10-25 μm, 10-50 μm, 20-30 μm, 25-50 μm, 30-40 μm, 40-50 μm, 50-60 μm, 50-75 μm, 60-70 μm, 75-100 μm, 70-80 μm, 80-90 μm, or 90-100 μm, e.g., about 10 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm). The protection layer can be mixed with Na metal and/or polymer with a thickness of 0 μm-500 μm. The sodium metal layer can be protected by a layer formed by one or more elements of Li, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, In, Cn, Sb, Bi, Cs, or Te. The protection layer can include sodium metal alloyed with one or more elements of Li, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, In, Sn, Sb, Bi, Cs, or Te.
An Na cathode can be coated with NaNbO3, NaTaO3, Na2ZrO3, NaNbxTa1−xO3 (0≤x≤1), yNa2ZrO3-(1−y)NaNbxTa1−xO3 (0≤x, y≤1), Al2O3, TiO2, ZrO2, AlF3, MgF2, SiO2, ZnS, ZnO, Na4SiO4, Na3PO4, Na3InCl6, Na1+xAlxTi2−x(PO4)3(0<x<2), NaMn2O4, NaInO2—NaI, Na6PS5Cl, NaAlO2, and carbon.
Indium may also be used to coat the electrodes.
In some embodiments, electrode coatings may include polyethylene oxide, polyvinylidene fluoride, poly (vinylidene fluoride-co-hexafluoropropylene), poly(ethyl methacrylate), or poly(vinylidene fluoride-co -trifluaroethylene).
In some embodiments, the battery retains at least 80% of capacity after at least 10,000 charge-discharge cycles from 20 C to 100 C-rate, e.g., at 2 mg/cm2 cathode loading, with an initial capacity higher than 80 mAh/g and a current density higher than 8 mA/cm2. In some embodiments, the battery can cycle at a current density from 0.001 mA/cm2 to 100 mA/cm2 In some embodiments, the battery cathode material has a power density of at least 10 kW/kg. In some embodiments, the battery cathode material has an energy density of at least 600 Wh/kg (e.g., 631 Wh/kg). Batteries of the invention may have average Coulombic efficiency of 99.96% or higher at 20 C and 100.00% at 15 C across all the thousands of cycles, with the highest power density reaching 11.9 kW/kg and the energy density up to 631 Wh/kg at the cathode active material level. Batteries of the invention may have low Coulombic inefficiency, e.g., on the order of 10−4 to 10−3.
Li5.5PS4.5Cl1.5 (LPSCl) was prepared by high energy ball milling, followed by a post annealing treatment. Stoichiometric amounts of powders of Li2S ((>99.9% purity, Alfa Aesar)), P2S5 (S>99% purity, Sigma Aldrich) and LiCl (>99% purity, Alfa Aesar) were milled for 16 hours in a planetary mill PM200 (Retsch GmbH, Germany) under a protective Argon atmosphere. Subsequently, the ball milled powder was transferred to quartz tubes and heated at 500° C. for 1 hour, using heating and cooling rates of 5 and 1° C. min−1, respectively.
Li9.54Si1.74(P0.9Sb0.1)1.44S11.7Cl0.3 (LSPS) was prepared using the same method. Li2S (>99.9% purity, Alfa Aesar), SiS2 (>99% purity, American Elements), P2S5 (>99% purity, Sigma Aldrich), Sb2S5 (Sigma Aldrich), and LiCl (>99% purity, Alfa Aesar) 40 hours (LSPS). A spinning rate of 375 rpm was employed. The powder was heated at 460° C. for 8 hours, using heating and cooling rates of 5 and naturally cooling down. All heating treatments were under Ar gas flow protection.
The ¼″ diameter Li foil with the thickness of 25 μm was covered by a ⅜″ diameter graphite film with a weight ratio of graphite (BTR, China) and PTFE as 95:5. The capacity ratio of Li and graphite is 2.5:1. The cathode layer was made by mixing 30 wt % solid electrolyte and 70 wt % LiCoO2 (Sigma Aldrich) or LiNi0.8Mn0.1Co0.1O2 (XTC, China) with a loading of 2 mg/cm2. 140 mg Li10Ge1P2S12 (MSE Supplies LLC) or LPSCl was employed as electrolyte. For the combined electrolyte, 30 mg LPSCl and 110 mg LGPS (or LSPS) were used. Anode-solid electrolyte-cathode for half battery or anode-electrolyte-anode for symmetric battery were pressed together in a homemade pressurized cell at 467 MPa and kept at 250 MPa during testing. All batteries were assembled in an argon atmosphere glovebox and the galvanostatic battery cycling test was performed on an ArbinBT2000 workstation.
The symmetric battery using pure lithium metal as electrodes and Li10Ge1P2S12 (LGPS) as electrolyte can fail quickly with a voltage spark, as shown in
To focus on the most notable difference of the two electrolytes about the stability against lithium metal. lithium was discharged on to LGPS or LPSCl in asymmetric batteries (see, e.g.,
On the other hand, as shown in
Previously, it was predicted that Li—Ge alloys should be the standard decomposition products on the interface between LGPS and Li metal at no mechanical constrictions, e.g., such interface immersed in a liquid electrolyte cell environment.2 However, under the testing condition of sufficient local mechanical constriction in our all-solid-state battery design, the suppression of Ge reduction was predicted in computation and observed in XPS, making the decomposition electronically insulating.2 Recently, it was found that such mechanical constriction can further provide kinetic stability to effectively inhibit the propagation of LGPS decomposition through ionic passivation, when going far beyond the voltage (meta)stability window, and stabilize LGPS up to 10V.9 Here, mechanical constriction is likely to inhibit further propagation of the decomposition interface between LGPS and Li dendrite at 0 V by such Ionic and electronic passivations. Therefore, this well-constrained decomposition serves as a self-decomposed “cement” or “concrete” to fill all the micron or submicron sized cracks that either preexisted during battery assembly or emerged during battery cycling, enabling a high current density cycling without the short-circuit induced by the Li dendrite penetration.
In order to demonstrate the uniqueness and practical application of the multilayer design, batteries of the single layer electrolyte design with lithium metal anode and high voltage cathode of NMC811 are made using various electrolytes. The solid-state battery configuration with the multilayer design shows significantly improved battery performances for NMC811 cathode paired with Li metal anode (
At elevated temperature (55° C.) and low cycling rate, the solid-state battery shows a 155.7 mAh/g capacity at 1.5 C. After 600 cycles, the battery shows almost no degradation with 97.7% capacity retention (
To further demonstrate the stability of the multilayer batteries of the invention against Li dendrite under extreme cycling conditions, a graphite covered Li—LiNi0.8Mn0.1Co0.1O2 (Li/G-NMC811) batteries with Li5.5PS4.5Cl1.5 Li9.54Si1.74(P0.9Sb0.1)1.44S11.7Cl0.3 (LPSCl-LSPS-LPSCl) as the electrolyte was cycled at 15 and 20 C up to 10,000 cycles. The battery shows a capacity retention of 90% after 3,000 cycles and 70% after 9,300 cycles at 15 C (
On the contrary, and consistent with the results from the symmetric battery tests, the irreversible capacity in the first cycle is small in the Li-LPSCl-LCO battery (see
The solid-state electrolyte design strategy of the invention was demonstrated experimentally by doping the original electrolyte material of Li argyrodite electrolyte Li5.5PS45.Cl1.5(LPSCl). Both LPSCl and doped LPSCl—X, e.g., Li5.5PS4.5Cl1.5 −yXy (X=F, Br or I; y 0.4 for F, 0.15 for Br and I), were synthesized by solid-state reactions, followed by SSB assembly using graphite protected Li metal as the anode and NMC811 (LiNi0.83Mn0.06Co0.11O2 in this Example) single crystal particles as the cathode, with a multilayer electrolyte configuration following our recent approach (See Methods). By replacing the central layer of LPSCl with LPSCl—X with the compositional modification guided by our computational design, batteries of the invention demonstrate a super long cycling performance of over 25,000 cycles at a high current density of 8.6 mA/cm2 (or 20 C-rate). Moreover, high capacities of SSBs with various interfaces between cathode and electrolyte particles, and between multiple electrolyte layers have been demonstrated for NMC811, reaching 197 mAh/g at 0.5 C-rate, around 180 mAh/g at 1.5 C-rate. Such batteries of the invention can also show very different capacities at 20 C-rate, i.e., an impressive 120 mAh/g v.s. a good 90 mAh/g (1 C=150 mAh/g or 0.43 mA/cm2).
Core-shell LPSCl—X electrolytes were synthesized by solid state reactions (see Methods, below), whose x-ray diffraction (XRD), optical photographs and scanning electron microscopy (SEM) images can be found in
Note that our EDX and XPS analyses of the original LPSCl without Br doping also show a core-shell structure with a shell region of Li and Cl rich, and S deficient compositions (
To test these different stabilities predicted above for the original LPSCl and the doped LPSCl—X, we deposited Li metal to the electrolyte through discharge in an asymmetric battery assembly with the multilayer configuration of Li metal, then graphite (G), then LPSCl, then LGPS, then an electrolyte of interest here (LPSCl or LPSCl—X), i.e., Li-G|LPSCl|LGPS|electrolyte. The thin graphite layer added between Li metal and LPSCl is for an improved interface stability at the initial battery assembly.
We further made a SSB assembly of Li-G|LPSCl|LNO@NMC811 with LiNbO3 (LNO) coated single crystal particles of NMC811 or simply 811, embedded in LPSCl. The battery shows a high discharge capacity of 191 mAh/g at 0.5 C-rate, which, however, decays quickly with the high-rate cycling (
The initial 0.5 C capacity for LPSCl—F and LPSCl—Br batteries are 148 mAh/g and 136 mAh/g respectively, while that of LPSCl—I is 178 mAh/g. At 20 C, the LPSCl—F battery shows an 88 mAh/g initial discharge capacity, which quickly peaked at 95 mAh/g at 750 cycles, and then shows a large retention of 93% to 81.5 mAh/g after 10,000 cycles, and 83% to 73.2 mAh/g after 20,000 cycles. These numbers for the LPSCl—Br battery are 89 mAh/g (initial), 93 mAh/g (peak at 7th cycle), 78% (69 mAh/g) retention after 10,000 cycles and 77% after 16,000 cycles; and those for the LPSCl—I battery are 124 mAh/g (initial), 128 mAh/g (peak at 3rd cycle) and 79% (98.2 mAh/g) retention after 10,000 cycles. The performance of the multilayer electrolyte batteries shows a substantial improvement compared with the battery with the single electrolyte layer of LPSCl (
We further introduce LGPS to the battery multilayer configurations. We first assemble three batteries of Li-G|LPSCl|LPSCl—I|LGPS|811, called the LPSCl—I|LGPS|1811 battery; Li-G|LPSCl|LGPS|811, called the LGPS|811 battery: and Li-G|LPSCl|LGPS|LNO@811, called the LGPS|LNO@811 battery.
We note that the LGPS|811 and LPSCl—I|LGPS|811 batteries with uncoated bare NMC811 show different behaviors from the LGPS|LNO@811 battery with the LNO coated NMC811 when ramping up the rate. At 20 C-rate, the LGPS|LNO@811 battery shows only 90 mAh/g capacity while the LGPS|811 battery reaches 120 mAh/g and stabilizes at 111 mAh/g after 400 cycles. The LPSCl—I|LGPS1811 battery reaches the highest 128 mAh/g, and after the 2500th cycle at 20 C-rate, the battery is cycled at slower rates back to 0.5 C-rate with capacity of 198 mAh/g for 50 cycles. Note also that all three batteries recovered their low-rate capacities after the high-rate cycling.
Bare 811 batteries, however, show a larger capacity drop at the beginning of high-rate cycling tests, which is followed by a slow increase of capacity until it is stabilized. Such a phenomenon largely disappears for LNO coated 811. Therefore, the interface between LNO@811 and LGPS plays an important role in their high-rate behavior. Further development of a coating material or an electrolyte matrix for in situ coating through interface decompositions during the battery cycling is critical for SSBs to show both the flat cyclability and the >120 mAh/g high-rate capacity.
We further tested SSBs with different multilayer combinations, with their initial discharge capacities and average voltages shown in
At 20 C-rate, bare 811-LGPS ({circle around (1)}{circle around (3)}{circle around (4)}) and bare 811-LPSCl ({circle around (6)}) batteries can all reach capacities higher than 100 mAh/g, suggesting interfaces between bare 811 and sulfide electrolytes may be in general good for high-rate capacity. The LNO@811-LPSCl ({circle around (5)}{circle around (7)}) batteries are higher than 100 mAh/g, while the LNO@811-LGPS ({circle around (2)}) battery shows a lower capacity of 90 mAh/g, suggesting that the LNO coating for 811 might be more compatible to LPSCl than LGPS at high rates. Another type of bare 811 with larger tap density and particle size shows lower high-rate capacities with LGPS ({circle around (4)}) and LPSCl ({circle around (8)}) as the cathode matrix than the counterparts with smaller 811 particles ({circle around (1)} and {circle around (6)}), respectively), which suggests that Li diffusion kinetics in 811 becomes a prominent factor to limit the capacity at 20 C-rate. However, these SSBs all show much better high-rate performance than the liquid electrolyte LNO@811 batteries (
At extremely high rates higher than 20 C-rate, bare 811-LGPS-LPSCl—I ({circle around (3)}) battery shows high capacities from 50 mAh/g (100 C-rate, 43 mA/cm2 current density) to 120 mAh/g (40 C-rate, 17.2 mA/cm2) in
The cycling performance of solid-state batteries with the multilayer design (Li/Si-G|LPSCl-LGPS-LPSCl|NMC811) is shown in
The results of XPS measurements of cycled battery pellet cross sections with ion milling results for a cycled LPSCl in Li-G|LPSCl|811 battery run at 8.6 mA/cm2 are shown in
DPT binary computation: The unconstrained (Keff0 GPa) Ehull (or decomposition energies) for a pseudo phase AxB1−x is GRXN(x, 0 GPa), which is calculated by constructing phase diagram using the Python Materials Genomics library. All GRXN(x, 0 GPa) are used as Ehull the input in machine learning. At different x compositions, both the volume (V) of the pseudo phase and the reaction strain (ε) are different, and GRXN(x, Keff) can be calculated by
The K* is the critical Keff when ail x composition pseudo phases have the zero decomposition energy:
If ε(x)≤0, ε(x) will be defined to be 0 and K* will become infinite. For the situation that the material is intrinsically stable with Li, both Ehull and K* are 0 by definition. The new method here is built upon our computational platform, and together with the new machine learning model expands the ability of the Constrained ensemble prediction to the design of material (in)stabilities.
Machine learning: Compositions, energies, and volumes of 124,497 materials are queried from Materials Project for high throughput calculations of null energies (Ehull) and K* values for the interfaces between materials and Li metal. Machine learning is applied to model the relation between macroscopic properties (composition, energy, volume) and target values (Ehull, K* ). Machine learning models in this work are based on decision trees. A decision tree consists of hierarchical computation (decision) nodes. The input data to the decision trees is in the form (x, y)=({x1, x2, . . . , xn}, y) where xi are the features and y is a target value. The decision tree can perform both the regression and classification tasks, depending on whether the nature of target variable y being continuous or a finite number of classes. Starting with the input features, each node of the tree applies a conditional statement on the value of a feature, then moves to a subsequent node based on the truth of that statement. The optimization of the tree includes choosing both the feature and threshold for the criteria for each node that overall best splits the set of items. Instead of measuring the error, better metrics such as the cross entropy and the Gini index are generally used to measure the goodness of the choice of criteria and data split. Our input features X consist of the 104-dimensional composition vectors. Specifically, for K* at 0V, we also include the x from 0 to 0.9 in our input for a better learning result. The target v are chosen as the K*, and decomposition energy at different situations. For K* at 0V, the target y is the K* at the corresponding x. We use an ensemble model of individual decision trees, the Extremely Randomized Tree model. In such models, a number of N trees are initialized simultaneously (N=30 in our setting). Each tree in the ensemble is fed with training data sampled from the training set. A random subset of candidate features is used, from which thresholds are drawn at random for each candidate feature, and the best of these randomly generated thresholds is picked as the splitting rule. Using the trained models with target property y, we, obtain the composition with optimal y using the grid search. Optimization with fixed F/Br/I in
Materials synthesis: Li5.5PS4.5Cl1.5, Li5.5PS4.5Cl1.1F0.4 , Li5.5PS4.5Cl1.45Br0.15, and Li5.5PS4.5Cl1.45I0.15 were prepared by ball milling and solid state reactions. Stoichiometric amounts of Li2S (99.9% purity, Alfa Aesar), P2S5 (99% purity. Sigma Aldrich), LiF (>99% purity, Sigma Aldrich) ; LiBr (99% purity, Sigma Aldrich), LiI(>99.9% purity, Sigma Aldrich), and LiCl (>99% purity, Alfa Aesar) were weighted and milled for 16 hours under argon protection. The precursor was transferred into a quartz tube and annealed at 550° C. for 1 hour with a temperature increasing rate of 5° C./min and a cooling rate of 1° C./min, in an argon flow.
LGPS (325 mesh) was purchased from MSE.
Scanning electron microscopy—focused ion beam—energy dispersive spectroscopy (SEM-FIB-EDX): The SEM-FIB-EDX was conducted on a FEI Helios 660. Solid state electrolyte powder was dispersed on to a carbon tape and attached to a SEM stub. The sample was sealed in a plastic box in the glovebox with O2 and H2O<0.1%. The sample was quickly transferred into the SEM in ˜15 s to avoid the air exposure. The high voltage is 10 kV and the magnification is 10,000×. The solid electrolyte particle was etched by the focused ion beam and the EDX line scan was conducted on the cross-section of the particle after the etching.
X-ray photoelectron spectroscopy (XPS): XPS was performed using a Thermo Scientific K-Alpha+ with a beam size of 400 um. Samples were mounted onto a standard XPS sample holder and sealed with plastic bags. Samples were then transferred into a vacuum environment with about 15 seconds air exposure. Some other samples were mounted onto a sample holder with vacuum transfer module to completely avoid the air exposure. Ar+ ion milling was performed with 1000 eV ion energy and monatomic mode, which is estimated to mill Ta2O5 with ˜140 GPa bulk modulus at 0.26 nm/s. Survey spectrum is used for quantification. All XPS results were fitted through peak differentiating and imitating via Avantage.
X-ray diffraction (XRD): XRD data were obtained using a Rigaku Miniflex 6G. Powder samples are sealed with Kapton film in an argon-filled glovebox to prevent the air contamination.
Electrochemistry: A lithium metal solid state battery was made with the structure of Li/graphite-LPSCl-central layer-(separating layer)-cathode matrix. A 25 um lithium metal was covered by a graphite thin film to act as the anode. The graphite layer was made by mixing 95 wt % graphite (BTR, China) with 5 wt % PTFE, and the capacity ratio of lithium to graphite is 2.5:1. 40 mg LPSCl and 100 mg central layer powders were applied as the electrolyte. A 60 mg separating layer of the same electrolyte powder in the cathode matrix is added when the central layer is different from that in the cathode matrix. The LiNbO3 is coated on NMC611 (MSE Supplies) by 1.9 wt % following previous report(17). The larger particle size NMC811 is obtained from XTC, China. 70 wt % (LNO@)811 was mixed with 30 wt % LPSCl to serve as the cathode with an additional 3% PTFE to make a cathode film. The loading of the cathode is 2 mg/cm2. The battery was initially pressed at 460 MPa and a stack pressure of 250 MPa was maintained by a pressurized cell. The battery was either cycled on an Arbin battery testing station (data log rate: 10 points/sec) at 55° C. in an environmental chamber with the humidity controlled <10% inside Memmert hpp110, on a Solartron 1400 cell test system (data log rate: 10 points/sec) or an LANHE battery test system (data log rate: 1 point/sec) at 55° C. as listed.
In
The liquid cells were assembled using Li metal as the anode, glass fiber as the separator and 1 M LiPF6 in EC/DMC, (v:v=1:1) as the electrolyte. A cathode film with the same active material loading of 2 mA/cm2 was applied, with the of NMC811:Carbon:PTFE=85:10:5.
Other embodiments are in the claims.
| Number | Date | Country | |
|---|---|---|---|
| 63212407 | Jun 2021 | US | |
| 63179011 | Apr 2021 | US | |
| 63108075 | Oct 2020 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US21/57591 | Nov 2021 | US |
| Child | 18141740 | US |
