PRELITHIATION OF SOLID-BODY BATTERIES

Abstract

Systems, methods, and apparatus for the fabrication of a pre-lithiated solid-state battery cell are described. This includes obtaining an anode slurry intended for pre-lithiation, applying the slurry intended for pre-lithiation to a current collector, evaporating the solvent of the anode slurry intended for pre-lithiation to create an intermediate assembly comprising the current collector, calendering an anode by applying pressure to the intermediate assembly to create a calendered anode assembly, and assembling a solid-state battery cell comprising the calendered anode assembly. The anode slurry intended for pre-lithiation comprises a lithium salt designed to initiate an interfacial lithiation reaction with the electroactive material and a non-aqueous solvent designed to keep the lithium salt in solution.The anode slurry intended for pre-lithiation can be applied to a current collector laminated with lithium foil or further mixed with solid lithium materials before application to the current collector. The pre-lithiated solid-state battery cell may include lithium metal between the anode layer and the anode current collector.

Description

INTRODUCTION

[0001] The disclosure relates to the field of solid-state batteries and in particular to systems and methods for pre-lithiation of solid-state batteries by lithium-conductive processing.

[0002] Electrochemical cells with high energy density, such as lithium-ion batteries, can be used in a wide variety of consumer goods and vehicles. These include hybrid electric vehicles (HEVs) and electric vehicles (EVs). However, the use of electroactive materials with high specific capacities and energy densities is hampered by the irreversible capacity loss and reduced cycle stability of these materials.

[0003] Solid-state batteries (all-solid-state batteries, "ASSBs"), such as sulfide-based ASSBs (S-ASSBs), provide advantages over similar liquid or gel electrolyte batteries, such as a higher theoretical energy density when using Li-metal as a foil and better thermal stability.

[0004] Silicon-based anodes, such as pure silicon anodes, exhibit a low lithiation potential, high capacity density, little to no dendritic growth, and a reduction or prevention of the continuous growth of the solid electrolyte intermediate phase (e.g., during cycling). However, Si-S-ASSBs experience a decrease in active lithium during the first few cycles.

[0005] Pre-lithiation is used to increase the initial coulombic efficiency of Si-S ASSBs. During pre-lithiation, the anode and / or cathode are lithiated with additional lithium material to compensate for the loss of active lithium that occurs during the cell's initial cycles. Insufficient lithium content during pre-lithiation leaves lithium-ion trapping sites, reducing the battery cell's initial coulombic efficiency. Conversely, an excess of lithium during pre-lithiation can impair performance, as the electrodes may be uneven due to the presence of lithium metal or unwanted lithium compounds.

[0006] Lithium foils can be used for pre-lithiation. However, their use is hampered by the need for strict humidity controls (e.g., a dew point of -50 °C), varying uniformity of the resulting cells, and long processing times to prevent interface incompatibility with the sulfides.

[0007] The lithium foils can be used prior to cell assembly by placing them on opposite sides of a calendered electrode, such as a calendered silicon anode, compressing the assembly under high pressure, and allowing the reaction to occur before assembling the cells. However, the described solid-solid reaction process exhibits poor uniformity and slow kinetics, contributing to long processing times.

[0008] Alternatively, the lithium foils can be integrated into the cell assembly by placing them between the anode layer and the solid electrolyte layer. The foil layers are then at least partially consumed during manufacturing and the first cycling of the battery cell. However, this results in poor uniformity, can lead to unused lithium metal remaining in the battery cell, and allows for side reactions at the lithium-sulfide interfaces, which may limit or preclude the use of certain sulfides.

[0009] Therefore, there is a need in engineering for a pre-lithiation of ASSBs that overcomes these problems. SUMMARY

[0010] Systems, methods and devices according to the present disclosure provide the prelithiation of solid-state batteries, which optimizes the performance and production of battery cells.

[0011] Advantageously, the solid-state batteries disclosed herein overcome the disadvantages associated with the presence of unreacted lithium in the anode. Furthermore, the batteries exhibit optimized coulombic efficiencies, capacity, open-circuit voltage, and cycle stability.

[0012] In addition, the methods disclosed herein optimize the production of solid-state batteries. The completeness of the prelithiation, the uniformity of the electrodes, and the consistency between the battery cells can all be optimized. Furthermore, the anodes can be integrated into a solid-state battery cell or subjected to direct testing immediately after fabrication. Again, the moisture resistance of the cell components and precursors during processing is optimized. Finally, the reaction kinetics can be optimized by reducing or eliminating the dependence on solid-solid reaction kinetics.

[0013] Furthermore, the methods disclosed herein can provide increased tolerance to inferior lithium materials.

[0014] According to some aspects of the present disclosure, a method for producing a pre-lithiated anode comprises obtaining an anode slurry intended for pre-lithiation, applying the anode slurry intended for pre-lithiation to a current collector, evaporating the solvent of the anode slurry intended for pre-lithiation to produce an intermediate assembly comprising the current collector, calendering an anode by applying pressure to the intermediate assembly to produce a calendered anode assembly, and assembling a solid-state battery cell comprising the calendered anode assembly contained therein. The anode slurry intended for pre-lithiation is designed to form the anode and consists of an anode electroactive material, a filler, a binder, sulfides, a lithium salt, and a non-aqueous solvent.The anode electroactive material consists of a non-lithiated anode electroactive material. The filler is designed to increase the electrical conductivity of the anode. The binder is designed to suspend the anode electroactive material and the electrically conductive filler in a dispersed state within the anode. The sulfides are designed to supplement or provide ionic conductivity through the anode. The lithium salt is designed to initiate an interfacial lithiation reaction with the anode electroactive material. The non-aqueous solvent is designed to keep the lithium salt in solution. Evaporation is achieved by applying heat to the anode slurry intended for pre-lithiation.

[0015] According to further aspects of the present disclosure, the pre-lithiated anode is formed by applying the anode slurry intended for pre-lithiation to a current collector laminated with lithium foil, wherein the anode electroactive material is a non-lithiated form of a silicon material, a silicon oxide material, a silicon-carbon composite material, a silicon metal alloy material, a graphite material, a tin oxide material or a combination thereof.

[0016] According to further aspects of the present disclosure, the lithium foil is consumed by the anode electroactive material in such a way that the calendered anode arrangement is free of the lithium foil.

[0017] According to further aspects of the present disclosure, the intermediate arrangement comprises both the current collector and the anode slurry intended for pre-lithiation, which has an interface with the lithium foil.

[0018] According to further aspects of the present disclosure, assembling the solid-state battery cell further includes applying a voltage to the solid-state battery cell to charge the battery cell while the lithium foil is located between the anode and the current collector.

[0019] According to further aspects of the present disclosure, the lithium foil has a thickness of 10 µm to 50 µm.

[0020] According to further aspects of the present disclosure, the lithium salt is selected from the group consisting of lithium halide, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(oxalate)borate, lithium tetrafluoroborate, lithium difluoro(oxalate)borate, lithium hexafluorophosphate, lithium perchlorate, lithium nitrate and combinations thereof.

[0021] According to further aspects of the present disclosure, the concentration of the lithium salts is in the range of 0.01 mol to 0.5 mol of lithium per liter of solvent.

[0022] According to further aspects of the present disclosure, the anode slurry intended for pre-lithiation is further mixed with a solid lithium material in a slurry tank before being applied to the current collector, wherein the anode electroactive material is a non-lithiated form of a silicon material, a silicon oxide material, a silicon-carbon composite material, a silicon metal alloy material, a graphite material, a tin oxide material or a combination thereof.

[0023] According to further aspects of the present disclosure, the mixing is carried out over a predetermined period of 6 hours to 24 hours.

[0024] According to further aspects of the present disclosure, the solid lithium material is held in place in relation to the slurry tank.

[0025] According to some aspects of the present disclosure, a solid-state battery cell comprises a calendered anode assembly formed by obtaining an anode slurry intended for prelithiation, applying the anode slurry intended for prelithiation to a current collector, evaporating the solvent of the anode slurry intended for prelithiation to create an intermediate assembly comprising the current collector, and calendering an anode by applying pressure to the intermediate assembly to produce the calendered anode assembly. The anode slurry intended for prelithiation is designed to form the anode and consists of a non-lithiated anode electroactive material, a filler, a binder, sulfides, a lithium salt, and a non-aqueous solvent. The non-lithiated anode electroactive material may be a pure non-lithiated anode electroactive material.The filler is designed to increase the electrical conductivity of the anode. The binder is designed to suspend the anode electroactive material and the electrically conductive filler in a dispersed state within the anode. The sulfides are designed to supplement or provide ionic conductivity through the anode. The lithium salt is designed to initiate an interfacial lithiation reaction with the anode electroactive material. The non-aqueous solvent is designed to keep the lithium salt in solution. Evaporation is achieved by applying heat to the anode slurry intended for pre-lithiation.

[0026] According to further aspects of the present disclosure, the pre-lithiated anode is formed by applying the anode slurry intended for pre-lithiation to a current collector laminated with lithium foil, wherein the anode electroactive material is a non-lithiated form of a silicon material, a silicon oxide material, a silicon-carbon composite material, a silicon metal alloy material, a graphite material, a tin oxide material or a combination thereof.

[0027] According to further aspects of the present disclosure, the lithium foil is consumed by the anode electroactive material in such a way that the calendered anode arrangement is free of the lithium foil.

[0028] According to further aspects of the present disclosure, the intermediate arrangement comprises both the current collector and the anode slurry intended for pre-lithiation, which has an interface with the lithium foil.

[0029] According to further aspects of the present disclosure, assembling the solid-state battery cell further includes applying a voltage to the solid-state battery cell to charge the battery cell while the lithium foil is located between the anode and the current collector.

[0030] According to further aspects of the present disclosure, the lithium foil has a thickness of 10 µm to 50 µm.

[0031] According to further aspects of the present disclosure, the lithium salt is selected from the group consisting of lithium halide, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(oxalate)borate, lithium tetrafluoroborate, lithium difluoro(oxalate)borate, lithium hexafluorophosphate, lithium perchlorate, lithium nitrate and combinations thereof.

[0032] According to further aspects of the present disclosure, the concentration of the lithium salts is in the range of 0.01 to 0.5 mol of lithium per liter of solvent.

[0033] According to further aspects of the present disclosure, the anode slurry intended for pre-lithiation is further mixed with a solid lithium material in a slurry tank before being applied to the current collector, wherein the anode electroactive material is a non-lithiated form of a silicon material, a silicon oxide material, a silicon-carbon composite material, a silicon metal alloy material, a graphite material, a tin oxide material or a combination thereof.

[0034] According to further aspects of the present disclosure, the mixing is carried out over a predetermined period of 6 hours to 24 hours.

[0035] According to further aspects of the present disclosure, the solid lithium material is held in place in relation to the slurry tank.

[0036] The above features and advantages, as well as further features and advantages of the present disclosure, are readily apparent from the following detailed description of the best ways of carrying out the present disclosure when considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings are for illustrative purposes only and are not intended to limit the subject matter defined by the claims. Exemplary aspects are discussed in the following detailed description and shown in the accompanying drawings, which: Fig. 1 a sulfide-based solid-state battery according to the aspects of the present disclosure shown in a schematic illustration, Fig. 2A a method for manufacturing the sulfide-based solid-state battery of Fig. 1 according to the aspects of the present revelation shown in a flowchart, Fig. 2B-D electrode intermediates of the method of Fig. 2A in schematic illustrations show, Fig. 3A shows a process for manufacturing a sulfide-based solid-state battery according to the aspects of the present disclosure in a flowchart, Fig. 3B-D electrode intermediates of the method of Fig. 3A in schematic illustrations show, Fig. 4 a second sulfide-based solid-state battery, which is produced using the method of Fig. 3 was produced, according to the aspects of the present revelation shown in a schematic illustration, Fig. 5 shows a slurry tank for producing an anode slurry according to some aspects of the present disclosure in a schematic illustration, Fig. 6 shows a second slurry tank for producing the anode slurry according to some aspects of the present disclosure in a schematic illustration, Fig. Figure 7 shows a diagram illustrating a curve of the initial Coulomb efficiency of an example cell compared to a reference cell, and Fig. Figure 8 shows a diagram illustrating the cycling capacity of the example cell compared to the reference cell. DETAILED DESCRIPTION

[0038] The following detailed description is merely exemplary and is not intended to limit the application or possible uses. Furthermore, there is no intention to be bound by any express or implied theory presented in the preceding introduction, the summary or brief description of the drawings, or the following detailed description.

[0039] Fig. Figure 1 illustrates a schematic solid-state battery 10 according to some aspects of the present disclosure. The solid-state battery has a three-layer structure with two solid-state battery cells 12. Each solid-state battery cell 12 comprises a pair of electrodes (anode 14 and cathode 16) separated by a solid electrolyte layer 18. The anodes 14 are arranged on an anode current collector 20, and each cathode 16 is arranged on a cathode current collector 22, with the respective current collector facing the solid electrolyte layer 18.

[0040] The anode 14 is designed to store ions via the anode electroactive material while the solid-state battery cell 12 charges, and to release ions while the solid-state battery cell 12 discharges. The anode electroactive material can be, for example, a lithiated material, a silicon material, a silicon oxide material, a silicon-carbon composite material, a silicon-metal alloy material, a graphite material, a tin oxide material, combinations thereof, or the like. In some aspects, the lithiated material is a lithiated silicon-rich oxide where x is less than 1. In the illustrated example, the lithiated material is lithiated silicon with the general formula Li x Si y, where x and y are between 0 and 1. In some aspects, the lithiated material is a lithiated silicon dioxide material with the general formula Li y SiO x , where y is between 0 and 1 and x is between 0 and 2. In some aspects, the silicon metal alloy is a silicon transition metal alloy. In some preferred aspects, the transition metal may be selected from the group consisting of iron, tin, silver, manganese, cobalt, combinations thereof, and the like. The anode electroactive material may have a suitable morphology selected from the group consisting of nanoparticles, nanofibers, nanotubes, microparticles, combinations thereof, and the like.

[0041] The anode 14 can be charged to optimize the operating characteristics of the solid-state battery cell 12. In some aspects, the anode electroactive material comprises 50 wt.% to 92 wt.% of the anode 14. In some preferred aspects, the anode electroactive material comprises 70 wt.% to 90 wt.% of the anode. The anode electroactive material can be pre-lithiated with pure lithium or a lithium-containing material. The pre-lithiation material can provide 10% to 140% of the capacity of the anode 14 material. In some aspects, the pre-lithiation material provides 20% to 50% of the capacity of the anode materials. In some preferred aspects, the pre-lithiation material provides 50% to 140% of the capacity of the anode materials. In further preferred aspects, the pre-lithiation material provides 80% to 120% of the capacity of the anode materials.In further preferred aspects, the prelithiation material provides 90% to 110% of the capacity of the anode materials. In yet more preferred aspects, the prelithiation material provides 95% to 100% of the capacity of the anode materials. Additionally or alternatively, in some preferred aspects, the prelithiation material provides more than 100% of the capacity of the anode materials.

[0042] The anode 14 may further comprise a carbon material to enhance its properties. For example, the carbon material may be selected to optimize the electrical conductivity of the anode 14, promote a specific morphology of the anode electroactive material, improve ion insertion and removal, optimize the mechanical properties of the anode 14, or combinations thereof. The carbon material may be selected from the group consisting of graphite, carbon nanotubes, hard carbon, or soft carbon.

[0043] The cathode 16 is designed to store ions received from the anode 14 via the cathode electroactive material when the solid-state battery cell 12 discharges, and to release the ions for transport to the anode 14 while the solid-state battery cell 12 charges. The cathode electroactive material interacts with the anode electroactive material to facilitate the flow of ions and electrons between the anode 14 and the cathode 16. The cathode electroactive material can be a transition metal electroactive material, e.g., an electroactive material rich in transition metals.In some aspects, the cathode electroactive material is selected from the group consisting of a lithium and manganese rich material (“LMR” material), a nickel manganese cobalt material (“NCM” ​​or “NMC” material), a lithium nickel cobalt aluminum material (“NCA” material), a lithium nickel cobalt manganese aluminum material (“NCMA” material), a lithium iron phosphate material (“LFP” material), a lithium manganese iron phosphate material (“LMFP” material), a lithium nickel oxide material (“LNO” material) and combinations thereof.

[0044] The LMR material can be an LMR oxide or an LMR layered oxide with the formula Li₂MnO₃(1-x)₂.iMO₂, where M represents one or more transition metals. In certain aspects, M is selected from the group consisting of manganese, nickel, cobalt, iron, and combinations thereof. The NCM material can have the formula Li[Ni₂]₂. 1-x-y Co x Mn yexhibit ]O2. The NCA material can have the formula Li[Ni 1-x-y CO x Al y exhibit ]O2. The NCMA material can have the formula Li[Ni 1-x-y CO x Mn y Al z The LFP material can have the formula LiFePO4. The LMFP material can have the formula LiMn. x Fe 1-y The material may contain PO4. The LNO material may have the formula LiNiO2. In some aspects, the cathode electroactive material is selected from the group consisting of NCM, NCMA, and combinations thereof. In some preferred aspects, the cathode electroactive material is NCM.

[0045] The solid electrolyte layer 18 is designed to electronically insulate the anode 14 and the cathode 16 and to provide ionic conduction through them. The solid electrolyte layer 18 can be selected from a group consisting of a pseudobinary sulfide, a pseudoternary sulfide, a pseudoquaternary sulfide, a halide solid electrolyte, and a hydride solid electrolyte, as well as combinations thereof.

[0046] The anode current collector 20 is designed to collect free electrons from the adjacent anode 14 and distribute them to it, and the cathode current collector 22 is designed to collect free electrons from the adjacent cathode 16 and distribute them to it. The free electrons are moved between the anode current collector 20 and the cathode current collectors 22 by an external device 24 via an external circuit 26. The external device 24 can be a load that consumes electrical energy from the solid-state battery cell 12 and / or a power source that supplies the solid-state battery cell 12 with electrical energy.

[0047] Fig. 2A shows a process 200 for manufacturing a sulfide-based solid-state battery 10 according to some aspects of the present disclosure in a flowchart. Fig. Figures 2B-D illustrate electrode intermediate arrangements of method 200.

[0048] In block 202, an anode slurry 14a is obtained. The anode slurry comprises a suspension of the anode electroactive material, sulfides, a binder, a filler, and one or more lithium salts dissolved in a solvent.

[0049] The sulfides are designed to supplement or provide ionic conductivity through the electrode. The sulfides can be selected to create a glassy, ​​ceramic, or glass-ceramic form of the sulfide-based solid-state electrode. The sulfides can be one or more thiophosphates. In some aspects, the one or more thiophosphates are selected from the group consisting of lithium thiophosphate (“LPS”), lithium thiophosphate carbon halide (“LPSCX”), lithium germanium thiophosphate (“LGPS”), lithium thiophosphate chloride (“LPSCl”), lithium silicon thiophosphate chloride (“LSiPSCl”), and combinations thereof. For example, the LPS can be Li₂P₂S₆. In some aspects, the halide (X) of the LPSCX is selected from the group consisting of fluorine, chlorine, bromine, and combinations thereof. For example, the LPS can be Li₆PS₅Cl. The LGPS can be Li₆PS₅Cl. B. around Li 10 GeP2S 12This could be, for example, Li. 9,54 S 1,74 P 1,44 S 11,7 Cl 0,3 The sulfides can be present in amounts ranging from 5 wt% to 40 wt%, based on the weight of the anode. In some cases, the solids content ranges from 10 wt% to 30 wt%, based on the weight of the anode.

[0050] The binder is designed to suspend the anode electroactive material and the electrically conductive filler in a dispersed state within the anode. The binder may also be designed to support electrode layer formation, promote particle discretization within the electrode, provide mechanical stability, and / or enhance adhesion to adjacent layers. For some aspects, the binder is selected from the group consisting of nitrile butadiene rubber (“NBR”), hydrogenated NBR (“HNBR”), styrene butadiene styrene (“SBS”), styrene ethylene butylene styrene (“SEBS”), styrene thermoplastic elastomer (“STPE”), polyvinylidene fluoride co-hexafluoropropylene (“PVDF-HFP”), and combinations thereof. The STPE may be a hydrogenated styrene block copolymer, such as SEPTON™.SEPTON™ can be selected from the group consisting of styrene-ethylene-ethylene-propylene-styrene (“SEEPS”), styrene-ethylene-propylene-styrene (“SEPS”), styrene-ethylene-propylene (“SEP”), and combinations thereof. The binder may be present in a quantity of 3% to 10% by weight of the anode. In some aspects, the binder is present in a quantity of 5% to 8% by weight of the anode.

[0051] The filler is designed to increase the electrical conductivity of the electrode layer. The filler can be, for example, a carbon material. In some cases, the carbon material is selected from the group consisting of carbon nanotubes, graphene, and carbon black powder. The filler is added in an amount that supplements or provides the electrical conductivity through the anode by increasing the layer's connectivity beyond the percolation threshold. In some cases, the filler material can be omitted from the composition because the other materials in the anode slurry can be selected to exceed the percolation threshold without additional filler material.

[0052] The lithium salts are designed to initiate an interfacial lithiation reaction. In some aspects, the lithium salts are selected from the group consisting of lithium halide (“LiX”), lithium bis(fluorosulfonyl)imide (“LiFSI”), lithium bis(trifluoromethanesulfonyl)imide (“LiTFSI”), lithium bis(oxalate)borate (“LiBOB”), lithium tetrafluoroborate (“LiBF4”), lithium difluoro(oxalate)borate (“LiDFOB”), lithium hexafluorophosphate (“LiPF6”), lithium perchlorate (“LiClO4”), lithium nitrate (“LiNO3”), and combinations thereof. In some aspects, the halogen of the lithium halide is selected from the group consisting of fluorine, chlorine, bromine, iodine, and combinations thereof. In some aspects, the concentration of the lithium salts is in the range of 0.01 mol to 0.5 mol of lithium per liter of solvent.

[0053] The solvent is a non-aqueous solvent of medium to low polarity, designed to keep one or more lithium salts in solution. The solvent may be selected from the group consisting of tetrahydrofuran (“THF”), methyltetrahydrofuran (“MeTHF”), dimethyl ether (“DME”), anisole, para-xylene, acetonitrile (“ACN” or “MeCN”), toluene, heptane, ethyl acetate (“EA”), and combinations thereof. The solvent may be present in such a quantity that the solids content ranges from 15% to 60% by weight of the solution. In some cases, the solids content ranges from 30% to 45% by weight of the solution.

[0054] In block 204, the anode slurry 14a is applied to a lithium foil 14b of a generally uniform thickness to produce a first arrangement 214. In some aspects, the lithium foil 14b is part of a current collector laminated with lithium foils.

[0055] The lithium foil 14b is metallic lithium with a thickness chosen such that the lithium foil is consumed before the assembly of the solid-state battery cell 12. In some aspects, the thickness of the lithium foil 14b is in the range of 10 µm to 50 µm. In some preferred aspects, the thickness of the lithium foil 14b is in the range of 20 µm to 35 µm. Additionally or alternatively, in some aspects, the lithium foil is designed to provide 50% to 100% of the capacity of the anode materials.

[0056] In block 206, the lithiation of the anode electroactive material in the anode slurry 14a is activated to generate a second intermediate assembly 216. In the illustrated example, the second intermediate assembly 216 is formed by placing the first current collector 20 between the lithium foils 14b of two first assemblies 214. The lithium salts of the anode slurry 14a and the lithium foil 14b act together to promote the reactions of lithium and silicon and form a Li x Si y - an alloy is formed between the anode slurry 14a and the lithium foil 14b. The promoted reactions form a conductive layer 14c that grows at the interface between the lithium foil 14b and the anode slurry 14a.

[0057] In block 208, heat is supplied to the second intermediate assembly to evaporate the solvent of the anode slurry 14a. Advantageously, the heat can be selected to increase the reaction rate of lithium and silicon. In some aspects, the heat is supplied at a temperature of 60 °C to 200 °C. In some preferred aspects, the heat is supplied at a temperature of 80 °C to 170 °C.

[0058] In block 210, pressure is applied to opposite sides of the second intermediate assembly 216 to create a third intermediate assembly 218 (e.g., a calendered anode assembly). Advantageously, the pressure can be selected to further increase the reaction rate of lithium and silicon. After pressurization, the calendered anode assembly comprises the first current collector 20, which is sandwiched between two conductive layers 14c. Advantageously, the outer surface of each conductive layer 14c has a generally uniform surface that is free of unreacted anode slurry and lithium metal.

[0059] In block 212, the calendered anode is incorporated into a solid-state battery assembly. Advantageously, the calendered anode produced according to method 300 can be incorporated into a solid-state battery cell or subjected to direct testing immediately after the fabrication of the calendered anode assembly 218. Furthermore, method 300 provides a uniform thickness for the calendered anode to optimize the interfacial properties between the calendered anode and the adjacent layers of the solid-state battery assembly, such as the solid electrolyte layer 18. Additionally, method 300 provides more robust resistance to moisture during processing, for example, by coating the lithium metal with a non-aqueous anode slurry 14a.Furthermore, remaining traces of lithium metal are arranged between the anode and the first current collector 20, where they do not interact negatively with the electrochemistry of the solid-state battery cell 12 or the compounds of the solid-state electrolyte 18.

[0060] Fig. 3A shows a process 300 for manufacturing a sulfide-based solid-state battery 10' according to some aspects of the present disclosure in a flowchart. Fig. Figures 3B-D illustrate electrode intermediate arrangements of method 300.

[0061] In block 302, a non-lithiated anode slurry 14a is obtained. The anode slurry 14a comprises a suspension of the anode electroactive material, sulfides, a binder, a filler, and one or more lithium salts dissolved in a solvent.

[0062] The sulfides are designed to supplement or provide ionic conductivity through the electrode. The sulfides can be selected to create a glassy, ​​ceramic, or glass-ceramic form of the sulfide-based solid-state electrode. The sulfides can be one or more thiophosphates. In some aspects, the one or more thiophosphates are selected from the group consisting of lithium thiophosphate (“LPS”), lithium thiophosphate carbon halide (“LPSCX”), lithium germanium thiophosphate (“LGPS”), lithium thiophosphate chloride (“LPSCl”), lithium silicon thiophosphate chloride (“LSiPSCl”), and combinations thereof. For example, the LPS can be Li₂P₂S₆. In some aspects, the halide (X) of the LPSCX is selected from the group consisting of fluorine, chlorine, bromine, and combinations thereof. For example, the LPS can be Li₆PS₅Cl. The LGPS can be Li₆PS₅Cl. B. around Li 10 GeP2S 12This could be, for example, Li. 9,54 S 11,74 P 1,44 S 11,7 Cl 0,3 The sulfides can be present in amounts ranging from 5 wt% to 40 wt%, based on the weight of the anode. In some cases, the solids content ranges from 10 wt% to 30 wt%, based on the weight of the anode.

[0063] The binder is designed to suspend the anode electroactive material and the electrically conductive filler in a dispersed state within the anode. The binder may also be designed to support electrode layer formation, promote particle discretization within the electrode, provide mechanical stability, and / or enhance adhesion to adjacent layers. For some aspects, the binder is selected from the group consisting of nitrile butadiene rubber (“NBR”), hydrogenated NBR (“HNBR”), styrene butadiene styrene (“SBS”), styrene ethylene butylene styrene (“SEBS”), styrene thermoplastic elastomer (“STPE”), polyvinylidene fluoride co-hexafluoropropylene (“PVDF-HFP”), and combinations thereof. The STPE may be a hydrogenated styrene block copolymer, such as SEPTON™.SEPTON™ can be selected from the group consisting of styrene-ethylene-ethylene-propylene-styrene (“SEEPS”), styrene-ethylene-propylene-styrene (“SEPS”), styrene-ethylene-propylene (“SEP”), and combinations thereof. The binder may be present in a quantity of 3% to 10% by weight of the anode. In some aspects, the binder is present in a quantity of 5% to 8% by weight of the anode.

[0064] The filler is designed to increase the electrical conductivity of the electrode layer. The filler can be, for example, a carbon material. In some cases, the carbon material is selected from the group consisting of carbon nanotubes, graphene, and carbon black powder. The filler is added in an amount that supplements or provides the electrical conductivity through the anode by increasing the layer's connectivity beyond the percolation threshold. In some cases, the filler material can be omitted from the composition because the other materials in the anode slurry can be selected to exceed the percolation threshold without additional filler material.

[0065] The lithium salts are designed to initiate an interfacial lithiation reaction. In some aspects, the lithium salts are selected from the group consisting of lithium halide (“LiX”), lithium bis(fluorosulfonyl)imide (“LiFSI”), lithium bis(trifluoromethanesulfonyl)imide (“LiTFSI”), lithium bis(oxalate)borate (“LiBOB”), lithium tetrafluoroborate (“LiBF4”), lithium difluoro(oxalate)borate (“LiDFOB”), lithium hexafluorophosphate (“LiPF6”), lithium perchlorate (“LiClO4”), lithium nitrate (“LiNO3”), and combinations thereof. In some aspects, the halogen of the lithium halide is selected from the group consisting of fluorine, chlorine, bromine, iodine, and combinations thereof. In some aspects, the concentration of the lithium salts is in the range of 0.01 mol to 0.5 mol of lithium per liter of solvent.

[0066] The solvent is a non-aqueous solvent of medium to low polarity, designed to keep one or more lithium salts in solution. The solvent may be selected from the group consisting of tetrahydrofuran (“THF”), methyltetrahydrofuran (“MeTHF”), dimethyl ether (“DME”), anisole, para-xylene, acetonitrile (“ACN” or “MeCN”), toluene, heptane, ethyl acetate (“EA”), and combinations thereof. The solvent may be present in such a quantity that the solids content ranges from 15% to 60% by weight of the solution. In some cases, the solids content ranges from 30% to 45% by weight of the solution.

[0067] In block 304, the anode slurry 14a is applied to a lithium foil 14b of a generally uniform thickness to produce a first arrangement 314. In some aspects, the lithium foil 14b is part of a current collector laminated with lithium foils.

[0068] The lithium foil 14b is metallic lithium with a thickness chosen such that the lithium foil is consumed before the assembly of the solid-state battery cell 12'. In some aspects, the thickness of the lithium foil 14b is in the range of 10 µm to 50 µm. In some preferred aspects, the thickness of the lithium foil 14b is in the range of 20 µm to 35 µm. Additionally or alternatively, in some aspects, the lithium foil is designed to provide 101% to 140% of the capacity of the anode materials.

[0069] In block 306, the lithiation of the anode electroactive material in the anode slurry 14a is activated to generate a second intermediate assembly 316. In the illustrated example, the second intermediate assembly 316 is formed by placing the first current collector 20 between the lithium foils 14b of two first assemblies 314. The lithium salts of the anode slurry 14a and the lithium foil 14b act together to promote the reactions of lithium and silicon and form a Li x Si y - an alloy is formed between the anode slurry 14a and the lithium foil 14b. The promoted reactions form a conductive layer 14c that grows at the interface between the lithium foil 14b and the anode slurry 14a.

[0070] In block 308, heat is supplied to the second intermediate assembly to evaporate the solvent of the anode slurry 14a. Advantageously, the heat can be selected to increase the reaction rate of lithium and silicon. In some aspects, the heat is supplied at a temperature of 60 °C to 300 °C. In some preferred aspects, the heat is supplied at a temperature of 80 °C to 170 °C.

[0071] In block 310, pressure is applied to opposite sides of the second intermediate assembly 316 to create a third intermediate assembly 318 (e.g., a calendered anode assembly). Advantageously, the pressure can be selected to further increase the reaction rate of lithium and silicon. After pressure is applied, the third intermediate assembly 318 comprises the first current collector 20, which is sandwiched between two layers of lithium foil 14b, which in turn are sandwiched between two conductive layers 14c. Advantageously, the outer surface of each conductive layer 14c has a generally uniform surface.

[0072] In block 312, the calendered anode is incorporated into a solid-state battery assembly. Advantageously, the calendered anode produced by process 300 can be incorporated into a solid-state battery cell or subjected to direct testing immediately after the fabrication of the calendered anode assembly 318. Furthermore, process 300 provides a uniform thickness for the calendered anode to optimize the interfacial properties between the calendered anode and the adjacent layers of the solid-state battery assembly, such as the solid electrolyte layer 18. Additionally, process 300 provides more robust resistance to moisture during processing, for example, by coating the lithium metal with a non-aqueous anode slurry 14a.Furthermore, the process 300 optimizes the complete lithiation of the anode and simultaneously reduces or eliminates the disadvantages associated with unreacted lithium foils. In addition, residual traces of lithium metal are positioned between the anode and the first current collector 20, where they do not interact negatively with the electrochemistry of the solid-state battery cell 12' or the compounds of the solid-state electrolyte 18.

[0073] Fig. Figure 4 shows a schematic illustration of the sulfide-based solid-state battery 10', which was fabricated using method 300. The solid-state battery 10' has a three-layer structure with two solid-state battery cells 12'. Each solid-state battery cell 12' comprises a pair of electrodes (anode 14 and cathode 16) separated by a solid electrolyte layer 18. Each anode 14 is arranged on a lithium foil 402, and the lithium foils 402 are arranged on an anode current collector 20. Each cathode 16 is arranged on a cathode current collector 22, with the respective current collector facing the solid electrolyte layer 18. Advantageously, the illustrated solid-state battery 10' overcomes the disadvantages associated with the presence of unreacted lithium foil in the anode.

[0074] Fig. Figure 5 shows a schematic illustration of the system 500 for producing an anode slurry intended for pre-lithiation. The system 500 comprises a slurry tank 502 containing a non-lithiated anode slurry 504. The non-lithiated anode slurry 504 comprises a suspension of the anode electroactive material 506, sulfides 508, a solid lithium material 510, a binder (not shown), a filler (not shown), and lithium salts dissolved in a solvent.

[0075] The anode slurry 504 is pre-lithiated by maintaining it in a well-mixed state for a predetermined period, e.g., using a high-performance mixer. The predetermined period can be, for example, approximately 4 hours to approximately 48 hours. Preferably, the predetermined period can be approximately 6 hours to approximately 24 hours. The solid lithium material 510 can be in a suitable form, e.g., foils or pellets.

[0076] The solid lithium material 510 is at least partially consumed during the pre-lithiation of the anode electroactive material 506. Advantageously, the remaining solid lithium material 510 can be removed from the anode slurry intended for pre-lithiation before the anode slurry is applied to a current collector. Furthermore, pre-lithiation of the anode slurry not only allows for the simultaneous removal of the solid lithium material 510 but also enables the use of lower-grade lithium materials—for example, lithium materials containing impurities, exhibiting non-uniform morphology, being of uneven size, and the like. In some aspects, the solid lithium material 510 consists of one or more lithium materials derived from industrial waste.

[0077] Pre-lithiation can be optimized because the slurry tank 502 allows the calculation of the lithium content based on non-local measurements such as stoichiometry or weight. This is because the well-mixed solution provides a homogeneous mixture of the bulk electroactive materials and the solid lithium material, rather than relying on the average thickness of the lithium foil for the calculations. For example, variations in the thickness of the lithium foil and / or the thickness of the anode slurry can lead to over- and / or under-lithiation at certain locations on the anode, as the reaction kinetics are influenced by the local environment along the anode. Furthermore, pre-lithiation can be optimized because the reaction kinetics in the slurry tank 502 proceed much faster than the solid-solid reaction kinetics.Furthermore, by performing the prelithiation in the slurry tank 502 and in the non-aqueous solvent, the need for moisture control during the prelithiation process is reduced or eliminated. The anode slurry intended for prelithiation can be applied in a uniform layer to the first current collector 20 to produce, for example, the third intermediate arrangement 218 (e.g., a calendered anode arrangement).

[0078] In some cases, the sulfides 508, the binder, and the filler are added after the anode electroactive material has been partially pre-lithiated. While the sulfides 508, the binder, and the filler do not cause side reactions with the lithium metal, excluding one or more of these substances during pre-lithiation can advantageously increase the reaction rate by avoiding physical interference during the mixing of the lithium and silicon.

[0079] Fig. Figure 6 shows a schematic illustration of the system 600 for producing an anode slurry intended for pre-lithiation. The system 600 comprises a slurry tank 502 containing a non-lithiated anode slurry 504. The non-lithiated anode slurry comprises a suspension of the anode electroactive material 506, sulfides 508, a binder (not shown), a filler (not shown), and lithium salts dissolved in a solvent.

[0080] The anode slurry 504 is pre-lithiated by maintaining it in a well-mixed state for a predetermined period, e.g., using a high-performance mixer. The predetermined period can be, for example, approximately 4 hours to approximately 48 hours. Preferably, the predetermined period can be approximately 6 hours to approximately 24 hours.

[0081] The solid lithium material 610 is held in a fixed position relative to the slurry tank 502. The solid lithium material 610 can be in a suitable form, e.g., foils or pellets. In the illustrated example, the solid lithium material 610 is attached to the walls of the slurry tank 502. The solid lithium material 610 is at least partially consumed during the pre-lithiation of the anode electroactive material 506. Advantageously, unreacted solid lithium material 610 remains in the slurry tank 502 when the anode slurry intended for pre-lithiation is removed from the slurry tank 502. Furthermore, pre-lithiation of the anode slurry not only allows for the simultaneous removal of the solid lithium material 610 but also enables the use of lower-grade lithium materials—e.g.,Lithium materials containing impurities, exhibiting uneven morphology, varying sizes, and the like. In some aspects, the solid lithium material 610 consists of one or more lithium materials derived from industrial waste.

[0082] Pre-lithiation can be optimized because the slurry tank 502 allows the calculation of the lithium content based on non-local measurements such as stoichiometry or weight. This is because the well-mixed solution provides a homogeneous mixture of the bulk electroactive materials and the solid lithium material, rather than relying on the average thickness of the lithium foil for the calculations. For example, variations in the thickness of the lithium foil and / or the thickness of the anode slurry can lead to over- and / or under-lithiation at certain locations on the anode, as the reaction kinetics are influenced by the local environment along the anode. Furthermore, pre-lithiation can be optimized because the reaction kinetics in the slurry tank 502 proceed much faster than the solid-solid reaction kinetics.Furthermore, by performing the prelithiation in the slurry tank 502 and in the non-aqueous solvent, the need for moisture control during the prelithiation process is reduced or eliminated. The anode slurry intended for prelithiation can be applied in a uniform layer to the first current collector 20 to produce, for example, the third intermediate arrangement 218 (e.g., a calendered anode arrangement).

[0083] In some cases, the sulfides 508, the binder, and the filler are added after the anode electroactive material has been partially pre-lithiated. While the sulfides 508, the binder, and the filler do not cause side reactions with the lithium metal, excluding one or more of these substances during pre-lithiation can advantageously increase the reaction rate by avoiding physical interference during the mixing of the lithium and silicon.

[0084] As the person skilled in the art understands, the present disclosure is open to various modifications and alternative forms, representative embodiments being shown by way of example in the drawings and described in detail above. It is understood, however, that the novel aspects of this disclosure are not limited to the particular forms illustrated in the accompanying drawings. Rather, the disclosure is intended to cover modifications, equivalents, combinations, sub-combinations, transformations, groupings, and alternatives that fall within the scope and spirit of the disclosure and are defined by the attached claims.

[0085] As used herein, unless the context clearly indicates otherwise, the words "and" and "or" function as both conjunction and disjunction; unless the context clearly indicates otherwise, the word "all" means "any and all", the word "any" means "any and all", the word "comprehensive" means "comprehensive without restriction", and the singular forms "a", "an", as well as "the", "a" and "a" include the plural forms and vice versa.

[0086] Unless expressly stated otherwise, or in light of the context, including the appended claims, numerical values ​​of parameters (e.g., of quantities or conditions) in this description are to be understood as being modified by the term "approximately," regardless of whether "approximately" actually precedes the numerical value. The numerical parameters specified herein and in the appended claims are approximate values ​​that may vary depending on the desired properties to be achieved by the present disclosure. At a minimum—and not as an attempt to limit the application of the equivalence doctrine to the scope of the claims—each numerical parameter should be interpreted at least with respect to the number of significant figures specified and using standard rounding methods.

[0087] Approximate words such as "approximately", "about", "essentially" and the like may be used herein to mean "at, close or almost at", "within 0-10% of" or "within acceptable manufacturing tolerances" or, for example, a logical combination thereof.

[0088] While the measure and limits of the term "approximately" are readily understood by the average person with expertise in the field, the term "approximately" indicates that the stated numerical value or property permits inaccuracies. Unless otherwise understood in engineering, the inaccuracy implied by "approximately" is understood in this ordinary sense, then "approximately" at least indicates variations that may arise from ordinary methods of measurement and use of such parameters. Unless otherwise understood in engineering, the term "approximately" means, for example, within 10% (e.g., ±10%) of the stated value.

[0089] While the measure and limits of the term "essentially" are readily understood by an average person with expertise in the field, the term "essentially" indicates that the stated numerical value or characteristic allows for a certain degree of inaccuracy. Unless otherwise understood in engineering, the inaccuracy implied by "essentially" is understood in this ordinary sense, then "essentially" at least indicates variations that may arise from manufacturing processes and the measurement of such parameters. Unless otherwise understood in engineering, the term "essentially" means, for example, within 5% (e.g., ±5%) of the stated value.

[0090] While the measure and limits of the term "generally" are readily understood by an average expert, the term "generally" indicates that the stated numerical value or property allows for a slight degree of inaccuracy. Unless otherwise understood in engineering, the inaccuracy implied by "generally" is understood by this common meaning, then "generally" at least indicates negligible variations in the desired parameters that may be insurmountable. Unless otherwise understood in engineering, the term "generally" means, for example, within 1% (e.g., ±1%) of the stated value.

[0091] While the measure and limits of the term "pure" are readily understood by the average expert, the term "pure" indicates that the compound may contain very small traces of other substances. If the imprecision implied by "pure" is not understood differently in engineering with this common meaning, then "pure" at least indicates variations that can arise from separation processes and the measurement of such parameters. If it is not understood differently in engineering, the term "pure" means, for example, over 99.9% of the stated value.

[0092] It is understood that the ranges provided herein include the specified range, subranges within the specified range, and each value within the specified range.

[0093] While the best ways of carrying out the disclosure have been described in detail, experts familiar with the field to which this disclosure relates will recognize various alternative configurations and embodiments for carrying out the disclosure within the scope of the attached claims. Examples

[0094] For comparison, two types of example cells and one reference cell are produced.

[0095] The first type of sample cell is prepared from an anode slurry comprising a SEEPS binder at 5 wt% and a THF solvent. The solids content of the anode slurry is 33.89 wt%. The anode slurry is applied to a 20 µm thick lithium foil to pre-lithiate the anode material.

[0096] The resulting anode composition comprises Si at 68.14 wt%, SEEPS at 4.87 wt%, LPSCI at 24.33 wt%, and LiFSI at 2.66 wt%. The cathode composition comprises NCM721 at 70 wt% and LPSCI at 30 wt%.

[0097] The reference cell is prepared from an anode slurry comprising a SEEPS binder at 5 wt% and a THF solvent. The solids content of the anode slurry is 33.89 wt%. The composition of the resulting anode includes Si at 68.14 wt%, SEEPS at 4.87 wt%, LPSCI at 24.33 wt%, and LiFSI at 2.66 wt%. The composition of the cathode includes NCM721 at 70 wt% and LPSCI at 30 wt%.

[0098] Fig. Figure 7 shows a diagram illustrating the initial charging and discharging curve of the example cell (line 702) compared to the reference cell (line 704) at a C-value of C / 10. As can be seen, the initial coulombic efficiency of the example cell is 86.58% and that of the reference cell is 61.50%.

[0099] Fig. Figure 8 shows a diagram illustrating the cycle capacities of the example cell (line 802) compared to the reference cell (line 804). The measured capacities are given in mAh / g. The first charge / discharge cycles are performed at a C-value of C / 10. In cycle 3, the cycles are performed at a C-value of C / 5. In cycle 5, the cycles are performed at a C-value of C / 3. As can be seen, the example cell not only exhibits a higher capacity but also a higher capacity retention over different cycles.

[0100] The second type of sample cells is prepared from a pre-lithiation slurry comprising a SEEPS binder at 5 wt% and a THF solvent. The solids content of the anode slurry is 33.89 wt%. The pre-lithiation slurry for the first of the second sample cells is mixed for 6 hours, and the pre-lithiation slurry for the second of the second sample cells is mixed for 24 hours.

[0101] The resulting anode composition comprises Si at 68.14 wt%, SEEPS at 4.87 wt%, LPSCI at 24.33 wt%, and LiFSI at 2.66 wt%. The anode charge is 0.322 g lithium and 3.5 g silicon. The cathode composition comprises NCM721 at 70 wt% and LPSCI at 30 wt%.

[0102] The capacities and coulombic efficiencies of the second example cells and the reference cell are compared after one C / 10 formation cycle. The reference cell exhibited a capacity of 96.08 mAh / g, a coulombic efficiency of 61.50%, and an open-circuit voltage of approximately 0.6 V.

[0103] The second sample cell, produced after a six-hour mixing time, exhibits a capacity of 113.98 mAh / g, a coulombic efficiency of 67.00%, and an open-circuit voltage of approximately 1.4 V. The second sample cell, produced after a twenty-four-hour mixing time, exhibits a capacity of 121.29 mAh / g, a coulombic efficiency of 70.05%, and an open-circuit voltage of approximately 1.7 V. It should be noted that while increasing the mixing times improves the initial electrical performance, mixing times exceeding 48 hours lead to anode delamination.

Claims

[1] Method for producing a pre-lithiated anode, comprising: Obtaining an anode slurry intended for pre-lithiation, designed to form an anode, wherein the anode slurry intended for pre-lithiation is composed of: an anode electroactive material consisting of a non-lithiated anode electroactive material, a filler designed to improve the electrical conductivity of the anode, a binder designed to suspend the anode electroactive material and the filler in a dispersed state within the anode, Sulfides designed to supplement or provide ionic conductivity through the anode, lithium salt designed to trigger an interfacial lithiation reaction with the anode electroactive material, and a non-aqueous solvent designed to keep the lithium salt in solution, Application of the anode slurry intended for pre-lithiation onto a current collector, Evaporation of the non-aqueous solvent of the anode slurry intended for pre-lithiation by the application of heat to create an intermediate arrangement comprising the current collector, Calendering the anode by applying pressure to the intermediate arrangement to create a calendered anode arrangement, and Assembling a solid-state battery cell that includes the calendered anode assembly contained therein. [2] Method according to claim 1, wherein the pre-lithiated anode is formed by applying the anode slurry intended for pre-lithiation to the lithium foil of a current collector laminated with lithium foil, wherein the anode electroactive material is a non-lithiated form of a silicon material, a silicon oxide material, a silicon-carbon composite material, a silicon metal alloy material, a graphite material, a tin oxide material or a combination thereof. [3] Method according to claim 2, wherein the lithium foil is consumed by the anode electroactive material in such a way that the calendered anode arrangement is free of the lithium foil. [4] Method according to claim 2, wherein the intermediate arrangement comprises both the current collector and the anode slurry intended for prelithiation, which has an interface with the lithium foil. [5] Method according to claim 2, wherein the lithium foil has a thickness of 10 µm to 50 µm. [6] Method according to claim 1, wherein the lithium salt is selected from the group consisting of lithium halide, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(oxalate)borate, lithium tetrafluoroborate, lithium difluoro(oxalate)borate, lithium hexafluorophosphate, lithium perchlorate, lithium nitrate and combinations thereof. [7] Method according to claim 6, wherein the concentration of the lithium salts is in the range of 0.01 mol to 0.5 mol lithium per liter of solvent. [8] Method according to claim 1, wherein the anode slurry intended for pre-lithiation is further mixed in a slurry tank with a solid lithium material before being applied to the current collector, wherein the anode electroactive material is a non-lithiated form of a silicon material, a silicon oxide material, a silicon-carbon composite material, a silicon metal alloy material, a graphite material, a tin oxide material or a combination thereof. [9] Method according to claim 8, wherein the mixing is carried out over a predetermined period of 6 hours to 24 hours. [10] Method according to claim 8, wherein the solid lithium material is held in place with respect to the slurry tank.

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