Pre-lithiation of all-solid-state batteries

Abstract

Systems, methods, and apparatus for producing pre-lithiated all-solid-state battery cells are described. The method includes obtaining a pre-lithiated negative electrode slurry, applying the pre-lithiated slurry on a current collector, evaporating a solvent of the pre-lithiated negative electrode slurry to produce an intermediate assembly including the current collector, calendering the negative electrode by applying pressure to the intermediate assembly to produce a calendered negative electrode assembly, and drying the calendered negative electrode assembly. And assembling the all-solid-state battery cell including the rolled negative electrode assembly therein. The pre-lithiated anode slurry includes a lithium salt configured to activate an interfacial lithiation reaction with the electroactive material and a non-aqueous solvent configured to maintain the lithium salt in solution. The pre-lithiated anode slurry may be coated on a lithium foil laminated current collector, or may be mixed with a solid lithium material before being coated on the current collector. The pre-lithiated all-solid-state battery cell may include lithium metal between the negative electrode layer and the negative electrode current collector.

Description

Technical Field

[0001] This disclosure relates to the field of all-solid-state batteries, and more specifically, to systems and methods for pre-lithiating all-solid-state batteries via lithium conduction processing. Background Technology

[0002] High-energy-density electrochemical batteries, such as lithium-ion batteries, are used in a variety of consumer products and vehicles. These include hybrid electric vehicles (HEVs) and electric vehicles (EVs). However, the use of electroactive materials with high specific capacity and energy density is limited by irreversible capacity loss and reduced cycle stability of these materials.

[0003] All-solid-state batteries (“ASSB”), such as sulfide-based ASSB (S-ASSB), offer advantages over similar liquid electrolyte batteries or gel electrolyte batteries, such as higher theoretical energy density and enhanced thermal stability when using lithium metal as foil.

[0004] Silicon-based anodes, such as pure silicon anodes, have low lithiation potentials, high volumetric capacity, little to no dendrite growth, and reduce or avoid continuous solid-electrolyte interface growth (e.g., during cycling). However, SiS-ASSB exhibits a decrease in active lithium in the early stages of cycling.

[0005] Pre-lithiation is used to improve the initial coulombic efficiency of SiS-ASSB. Pre-lithiation involves lithiating the negative and / or positive electrodes with additional lithium material to compensate for the loss of active lithium that occurs during the initial cycling of the battery. Insufficient lithium in pre-lithiation leaves residual lithium-ion trapping sites, thereby reducing the initial coulombic efficiency of the battery cell. Furthermore, excess lithium in pre-lithiation may inhibit performance due to electrode inhomogeneities caused by the presence of lithium metal or unwanted lithium compounds.

[0006] Lithium foil can be used for pre-lithiation. However, the use of lithium foil is limited by the need for strict humidity control (e.g., -50°C dew point), the varying uniformity of the resulting batteries, and the long processing time required to suppress interfacial incompatibility with sulfides.

[0007] Before battery assembly, lithium foil is used by placing it on opposite sides of a rolled electrode (such as a rolled silicon anode), using a high-pressure compression assembly, and waiting for the reaction to proceed before assembling the battery. However, the solid-solid reaction process is characterized by poor uniformity and slow kinetics, resulting in long processing times.

[0008] Alternatively, lithium foil can be included in the battery assembly by placing the foil between the negative electrode layer and the solid electrolyte layer. The foil layer is then at least partially consumed during cell fabrication and initial cycling. However, this results in poor uniformity, potentially leading to unconsumed lithium metal within the cell and causing side reactions at the lithium / sulfide interface, which may reduce or eliminate the ability to use certain sulfides.

[0009] Therefore, pre-lithiated ASSB is needed in the field to overcome these challenges. Summary of the Invention

[0010] The systems, methods, and apparatus disclosed herein provide pre-lithiation for optimizing cell performance and producing all-solid-state batteries.

[0011] Advantageously, the all-solid-state battery disclosed herein overcomes the drawbacks associated with unreacted lithium present in the negative electrode. Furthermore, the battery also optimizes coulombic efficiency, capacity, open-circuit voltage, and cycle stability.

[0012] Furthermore, the method disclosed in this paper optimizes the production of all-solid-state batteries. Pre-lithiation completion, electrode uniformity, and consistency between battery cells can all be optimized. Further, the negative electrode can be incorporated into the all-solid-state battery cell or directly tested immediately after production. Even further, the moisture resistance of the battery assembly and precursors during processing is optimized. Still further, reaction kinetics can be optimized by reducing or eliminating dependence on solid-solid reaction kinetics.

[0013] Furthermore, the method disclosed in this paper can increase tolerance to lower-grade lithium materials.

[0014] According to various aspects of this disclosure, a method for producing a pre-lithiated anode includes: obtaining a pre-lithiated anode slurry; coating the pre-lithiated anode slurry onto a current collector; evaporating a solvent from the pre-lithiated anode slurry to produce an intermediate component including the current collector; rolling the anode by applying pressure to the intermediate component to produce a rolled anode component; and assembling an all-solid-state battery cell including the rolled anode component. The pre-lithiated anode slurry is configured to form an anode and comprises an anode electroactive material, a filler, a binder, a sulfide, a lithium salt, and a non-aqueous solvent. The anode electroactive material comprises an unlithiated anode electroactive material. The filler is configured to enhance the conductivity of the anode. The binder is configured to suspend the anode electroactive material and the conductive filler in a dispersed state within the anode. The sulfide is configured to supplement or provide ionic conductivity through the anode. The lithium salt is configured to activate an interfacial lithiation reaction with the anode electroactive material. The non-aqueous solvent is configured to maintain the lithium salt in solution. The pre-lithiated anode slurry is evaporated by heating.

[0015] According to other aspects of this disclosure, the pre-lithiated anode is formed by coating a pre-lithiated anode slurry onto a lithium foil laminate current collector, wherein the anode electroactive material is an unlithiated form of silicon material, silicon oxide material, silicon / carbon composite material, silicon / metal alloy material, graphite material, tin oxide material, or a combination thereof.

[0016] According to other aspects of this disclosure, the lithium foil is consumed by the negative electrode electroactive material, so that the rolled negative electrode assembly does not contain lithium foil.

[0017] According to other aspects of this disclosure, the intermediate components include each of a current collector and a pre-lithiated negative electrode slurry having an interface with the lithium foil.

[0018] According to other aspects of this disclosure, assembling an all-solid-state battery cell also includes applying a voltage to the all-solid-state battery cell to charge the battery cell while a lithium foil is present between the negative electrode and the current collector.

[0019] According to other aspects of this disclosure, the thickness of the lithium foil is from 10 μm to 50 μm.

[0020] According to other aspects of this disclosure, the lithium salt is selected from the group consisting of lithium halides, 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 other aspects of this disclosure, the concentration of the lithium salt is from 0.01 mol to 0.5 mol of lithium per liter of solvent.

[0022] According to other aspects of this disclosure, the pre-lithiated negative electrode slurry is mixed with solid lithium material in a slurry tank before being coated onto the current collector, wherein the negative electrode electroactive material is unlithiated silicon material, silicon oxide material, silicon / carbon composite material, silicon / metal alloy material, graphite material, tin oxide material, or a combination thereof.

[0023] According to other aspects of this disclosure, the scheduled time periods are mixed, ranging from 6 hours to 24 hours.

[0024] According to other aspects of this disclosure, the solid lithium material is held in place relative to the slurry tank.

[0025] According to various aspects of this disclosure, an all-solid-state battery cell includes a rolled negative electrode assembly, which is formed by the following steps: obtaining a pre-lithiated negative electrode slurry; coating the pre-lithiated negative electrode slurry onto a current collector; evaporating the solvent of the pre-lithiated negative electrode slurry to produce an intermediate assembly including a current collector; and rolling the negative electrode by applying pressure to the intermediate assembly to produce a rolled negative electrode assembly. The pre-lithiated negative electrode slurry is configured to form a negative electrode and consists of an unlithiated negative electrode active material, a filler, a binder, a sulfide, a lithium salt, and a non-aqueous solvent. The unlithiated negative electrode active material may be a pure unlithiated negative electrode active material. The filler is configured to enhance the conductivity of the negative electrode. The binder is configured to suspend the negative electrode active material and the conductive filler in a dispersed state within the negative electrode. The sulfide is configured to supplement or provide ionic conductivity through the negative electrode. The lithium salt is configured to activate the interfacial lithiation reaction with the negative electrode active material. The non-aqueous solvent is configured to maintain the lithium salt in solution. The pre-lithiated anode slurry is evaporated by heating.

[0026] According to other aspects of this disclosure, the pre-lithiated anode is formed by coating a pre-lithiated anode slurry onto a lithium foil laminate current collector, wherein the anode electroactive material is an unlithiated form of silicon material, silicon oxide material, silicon / carbon composite material, silicon / metal alloy material, graphite material, tin oxide material, or a combination thereof.

[0027] According to other aspects of this disclosure, the lithium foil is consumed by the negative electrode electroactive material, so that the rolled negative electrode assembly does not contain lithium foil.

[0028] According to other aspects of this disclosure, the intermediate components include each of a current collector and a pre-lithiated negative electrode slurry having an interface with the lithium foil.

[0029] According to other aspects of this disclosure, assembling an all-solid-state battery cell also includes applying a voltage to the all-solid-state battery cell to charge the battery cell while a lithium foil is present between the negative electrode and the current collector.

[0030] According to other aspects of this disclosure, the thickness of the lithium foil is from 10 μm to 50 μm.

[0031] According to other aspects of this disclosure, the lithium salt is selected from the group consisting of lithium halides, 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 other aspects of this disclosure, the concentration of the lithium salt is from 0.01 mol to 0.5 mol of lithium per liter of solvent.

[0033] According to a further aspect of this disclosure, the pre-lithiated negative electrode slurry is mixed with solid lithium material in a slurry tank before being coated onto the current collector, wherein the negative electrode electroactive material is unlithiated silicon material, silicon oxide material, silicon / carbon composite material, silicon / metal alloy material, graphite material, tin oxide material, or a combination thereof.

[0034] According to other aspects of this disclosure, the scheduled time periods are mixed, ranging from 6 hours to 24 hours.

[0035] According to other aspects of this disclosure, the solid lithium material is held in place relative to the slurry tank.

[0036] The foregoing features and advantages, as well as other features and advantages, of this disclosure will become apparent from the following detailed description of the best mode for carrying out this disclosure, taken in conjunction with the accompanying drawings. Attached Figure Description

[0037] The accompanying drawings are illustrative and not intended to limit the scope of the claims. Exemplary aspects are discussed in the following detailed description and illustrated in the drawings, wherein:

[0038] Figure 1 This is a schematic diagram of a sulfide-based all-solid-state battery according to aspects of this disclosure;

[0039] Figure 2A Based on the aspects of this disclosure Figure 1 A flowchart of a method for producing sulfide-based all-solid-state batteries;

[0040] Figure 2B -D is Figure 2A A schematic diagram of the intermediate electrode assembly of the method;

[0041] Figure 3 This is a flowchart of a method for producing a sulfide-based all-solid-state battery according to aspects of this disclosure;

[0042] Figure 3B -D is Figure 3 A schematic diagram of the intermediate electrode assembly of the method;

[0043] Figure 4 Use based on aspects of this disclosure Figure 3 A schematic diagram of the second sulfide-based all-solid-state battery produced by the method;

[0044] Figure 5 This is a schematic diagram of a slurry tank for producing negative electrode slurry according to aspects of this disclosure;

[0045] Figure 6 This is a schematic diagram of a second slurry tank for producing negative electrode slurry according to aspects of this disclosure;

[0046] Figure 7It is a graph showing the initial coulombic efficiency curves of an exemplary battery compared to a reference battery; and

[0047] Figure 8 This is a graph showing the cycle capacity of an exemplary battery compared to a reference battery. Detailed Implementation

[0048] The following description is merely exemplary in nature and is not intended to limit this disclosure, its application, or its uses. Furthermore, it is not intended to be bound by the express or implied theories presented in the foregoing description of the technical field, background art, invention summary, or accompanying drawings, or the following detailed description.

[0049] Figure 1 A schematic all-solid-state battery 10 according to aspects of this disclosure is shown. The all-solid-state battery has a three-layer structure having two all-solid-state battery cells 12. Each all-solid-state battery cell 12 includes a pair of electrodes (negative electrode 14 and positive electrode 16) separated by a solid electrolyte layer 18. The negative electrode 14 is disposed on a negative electrode current collector 20, and each positive electrode 16 is disposed on a positive electrode current collector 22, with each corresponding current collector configured to be opposite to the solid electrolyte layer 18.

[0050] The negative electrode 14 is configured to insert ions via the negative electrode active material during charging of the all-solid-state battery cell 12, and to deintercalate ions during discharging of the all-solid-state battery cell 12. The negative electrode active 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, or combinations thereof. In some aspects, the lithiated material is a lithiated silicon-rich oxide, where x is less than 1. In the illustrated embodiment, the lithiated material is lithiated silicon, with the general formula Li. x Si y Where x is between 0 and 1 and y is between 0 and 1. In some respects, lithiated materials are lithium-ion silicon oxide materials, 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 material is a silicon / transition metal alloy material. In some preferred aspects, the transition metal can be selected from the group consisting of iron, tin, silver, manganese, cobalt, and combinations thereof. The negative electrode electroactive material can have a suitable morphology selected from the group consisting of nanoparticles, nanofibers, nanotubes, micron particles, and combinations thereof.

[0051] The negative electrode 14 can be loaded to optimize the operating characteristics of the all-solid-state battery cell 12. In some aspects, the negative electrode active material accounts for 50% to 92% by weight of the negative electrode 14. In some preferred aspects, the negative electrode active material accounts for 70% to 90% by weight of the negative electrode. The negative electrode active material can be pre-lithiated with pure lithium or lithium-containing materials. The pre-lithiated material can provide 10% to 140% of the capacity of the negative electrode 14 material. In some aspects, the pre-lithiated material provides 20% to 50% of the capacity of the negative electrode material. In some preferred aspects, the pre-lithiated material provides 50% to 140% of the capacity of the negative electrode material. In other preferred aspects, the pre-lithiated material provides 80% to 120% of the capacity of the negative electrode material. In other preferred aspects, the pre-lithiated material provides 90% to 110% of the capacity of the negative electrode material. In other preferred aspects, the pre-lithiated material provides 95% to 100% of the capacity of the negative electrode material. Alternatively, in some preferred aspects, pre-lithiated materials provide more than 100% of the capacity of the anode material.

[0052] The negative electrode 14 may also include carbon materials to enhance its properties. For example, carbon materials can be selected to optimize the conductivity of the negative electrode 14, promote specific morphologies of the electroactive material, enhance ion intercalation and deintercalation, optimize the mechanical properties of the negative electrode 14, or combinations thereof. The carbon materials can be selected from the group consisting of graphite, carbon nanotubes, hard carbon, or soft carbon.

[0053] The positive electrode 16 is configured to insert ions received from the negative electrode 14 via the positive electrode active material during the discharge of the all-solid-state battery cell 12 and to deintercalate ions to the negative electrode 14 during the charging of the all-solid-state battery cell 12. The positive electrode active material cooperates with the negative electrode active material to promote ion and electron flow between the negative electrode 14 and the positive electrode 16. The positive electrode active material may be a transition metal active material, such as a transition metal-rich active material. In some aspects, the positive electrode active material is selected from lithium-rich and manganese-rich (“LMR”) materials, nickel-manganese-cobalt (“NCM” ​​or “NMC”) materials, lithium nickel-cobalt-aluminum (“NCA”) materials, lithium nickel-cobalt-manganese-aluminum (“NCMA”) materials, lithium iron phosphate (“LFP”) materials, lithium iron-manganese phosphate (“LMFP”) materials, lithium nickel oxide (“LNO”) materials, and combinations thereof.

[0054] LMR materials can be LMR oxides or LMR layered oxides represented by the formula xLi₂MnO₃(1-x)LiMO₂, where M is one or more transition metals. In some respects, M is selected from the group consisting of manganese, nickel, cobalt, iron, and combinations thereof. NCM materials can be represented by the formula Li[Ni 1-x-y Co x Mn y [O2] represents NCA material, which can be expressed as Li[Ni] 1-x-y Cox Al y O2 represents NCMA material, which can be produced by the formula Li[Ni]. 1-x-y Co x Mn y Al z O2 represents LFP materials. LFP materials can be represented by the formula LiFePO4. LMFP materials can be represented by the formula LiMn. x Fe 1-y PO4 is used to represent LNO materials, which can be represented by the formula LiNiO2. In some aspects, the positive electrode active material is selected from the group consisting of NCM, NCMA, and combinations thereof. In some preferred aspects, the positive electrode active material is NCM.

[0055] The solid electrolyte layer 18 is configured to electronically isolate the negative electrode 14 and the positive electrode 16 and provide ion conduction through it. The solid electrolyte layer 18 may be selected from the group consisting of quasi-binary sulfides, quasi-ternary sulfides, quasi-quaternary sulfides, halide solid electrolytes and hydride solid electrolytes and combinations thereof.

[0056] The negative current collector 20 is configured to collect free electrons from the adjacent negative electrode 14 and distribute them to the adjacent negative electrode 14, and the positive current collector 22 is configured to collect free electrons from the adjacent positive electrode 16 and distribute them to the adjacent positive electrode 16. Free electrons move between the negative current collector 20 and the positive current collector 22 via an external device 24 through an external circuit 26. The external device 24 can be a load that consumes power from the all-solid-state battery cell 12 and / or a power source that supplies power to the all-solid-state battery cell 12.

[0057] Figure 2A This is a flowchart of a method 200 for producing a sulfide-based all-solid-state battery 10 according to aspects of this disclosure. Figure 2B -D indicates the intermediate electrode assembly of method 200.

[0058] At frame 202, negative electrode slurry 14a is obtained. The negative electrode slurry comprises a negative electrode electroactive material, a sulfide, a binder, a filler, and a suspension of one or more lithium salts dissolved in a solvent.

[0059] The sulfide is configured to supplement or provide ionic conductivity through the electrode. Sulfides can be selected to produce sulfide-based solid-state electrodes in glass, ceramic, or glass-ceramic form. The sulfide can be one or more thiophosphates. In some aspects, one or more thiophosphates are selected from the group consisting of lithium thiophosphate (“LPS”), lithium thiophosphate carbide (“LPSCX”), lithium thiophosphate germanium (“LGPS”), lithium thiophosphate chloride (“LPSCl”), lithium thiophosphate silicon chloride (“LSiPSCl”), and combinations thereof. LPS can be, for example, Li₂P₂S₆. In some aspects, the halide (X) of LPCSX is selected from the group consisting of fluorine, chlorine, bromine, and combinations thereof. LPSCl can be, for example, Li₆PS₅Cl. LGPS can be, for example, Li 10 GeP2S 12 LSiPSCl can be, for example, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Based on the weight of the negative electrode, sulfides can be present in an amount ranging from 5% to 40% by weight. In some cases, the solid content is 10% to 30% by weight, based on the weight of the negative electrode.

[0060] The adhesive is configured to suspend the negative electrode electroactive material and conductive filler in a dispersed state within the negative electrode. The adhesive may be further configured to facilitate electrode layer formation, promote particle dispersion within the electrode, provide mechanical stability, and / or enhance adhesion to adjacent layers. In some aspects, the adhesive is selected from the group consisting of nitrile butadiene rubber (“NBR”), hydrogenated NBR (“HNBR”), styrene-butadiene-styrene (“SBS”), styrene-ethylene-butene-styrene (“SEBS”), styrene thermoplastic elastomer (“STPE”), poly(vinylidene fluoride-co-hexafluoropropylene”) (“PVDF-HFP”), and combinations thereof. STPE may be a hydrogenated styrene block copolymer, such as SEPTON. TM SEPTON TM The adhesive may 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 adhesive may be present in an amount of 3% to 10% by weight, based on the weight of the negative electrode. In some aspects, the adhesive is present in an amount of 5% to 8% by weight, based on the weight of the negative electrode.

[0061] The filler is configured to enhance the conductivity of the electrode layer. The filler can be, for example, a carbon material. In some aspects, the carbon material is selected from the group consisting of carbon nanotubes, graphene, and carbon black powder. A certain amount of filler is added to supplement or provide conductivity through the negative electrode by increasing the connectivity of the layer above the permeation threshold. In some aspects, the filler material can be excluded from the composition because other materials for the negative electrode slurry can be selected to exceed the permeation threshold without additional filler material.

[0062] The lithium salt is configured to activate the interfacial lithiation reaction. In some aspects, the lithium salt is selected from the group consisting of lithium halides (“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 salt is from 0.01 mol to 0.5 mol of lithium per liter of solvent.

[0063] The solvent is a non-aqueous solvent of moderate to low polarity, configured to maintain 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, p-xylene, acetonitrile (“ACN” or “MeCN”), toluene, heptane, ethyl acetate (“EA”), and combinations thereof. Based on the weight of the solution, the solvent may be present in an amount such that the solid content is from 15% by weight to 60% by weight. In some aspects, based on the weight of the solution, the solid content is from 30% by weight to 45% by weight.

[0064] At frame 204, negative electrode paste 14a is coated onto lithium foil 14b with a substantially uniform thickness to produce first assembly 214. In some respects, lithium foil 14b is part of lithium foil laminated current collector.

[0065] The lithium foil 14b is metallic lithium, and its thickness is chosen such that the lithium foil is consumed before the all-solid-state battery cell 12 is assembled. In some aspects, the thickness of the lithium foil 14b is 10 μm to 50 μm. In some preferred aspects, the thickness of the lithium foil 14b is 20 μm to 35 μm. Alternatively, in some aspects, the lithium foil is configured to provide 50% to 100% of the capacity of the negative electrode material.

[0066] At frame 206, lithiation of the negative electrode electroactive material within the negative electrode slurry 14a is activated to produce a second intermediate component 216. In the illustrated embodiment, the second intermediate component 216 is formed by sandwiching a first current collector 20 between two lithium foils 14b of the first components 214. The lithium salts of the negative electrode slurry 14a and the lithium foils 14b synergistically promote the reaction of lithium and silicon, thereby forming Li between the negative electrode slurry 14a and the lithium foils 14b. x Si y Alloy. Promotes the reaction to form a conductive layer 14c grown from the interface between lithium foil 14b and negative electrode paste 14a.

[0067] At frame 208, the second intermediate component is heated to evaporate the solvent of the negative electrode slurry 14a. Advantageously, heating can be selected to increase the reaction rate of lithium and silicon. In some aspects, heating is performed at a temperature of 60°C to 200°C. In some preferred aspects, heating is performed at a temperature of 80°C to 170°C.

[0068] At frame 210, pressure is applied to the opposite side of the second intermediate component 216 to produce a third intermediate component 218 (e.g., a rolled negative electrode component). Advantageously, the pressure can be selected to further increase the reaction rate of lithium and silicon. After pressure is applied, the rolled negative electrode component includes a first current collector 20 sandwiched between two conductive layers 14c. Advantageously, the outer surface of each conductive layer 14c has a substantially uniform surface that is free of unreacted negative electrode paste and lithium metal.

[0069] At frame 212, the rolled negative electrode is incorporated into the all-solid-state battery assembly. Advantageously, the rolled negative electrode produced by method 300 can be incorporated into the all-solid-state battery cell or directly tested immediately after the production of the rolled negative electrode assembly 218. Further, method 300 provides a rolled negative electrode with a uniform thickness to optimize the interfacial performance between the rolled negative electrode and adjacent layers of the all-solid-state battery assembly, such as the solid electrolyte layer 18. Further still, method 300 provides more robust moisture resistance during processing, for example, by coating lithium metal with a non-aqueous negative electrode slurry 14a. Furthermore, any remaining trace amounts of lithium metal are disposed between the negative electrode and the first current collector 20, wherein they do not negatively interact with the electrochemistry of the compounds in the all-solid-state battery cell 12 or the solid electrolyte 18.

[0070] Figure 3 This is a flowchart of a method 300 for producing a sulfide-based all-solid-state battery 10' according to aspects of this disclosure. Figure 3B -D indicates the intermediate electrode assembly of method 300.

[0071] At frame 302, an unlithiated negative electrode slurry 14a is obtained. The negative electrode slurry 14a comprises a negative electrode electroactive material, a sulfide, a binder, a filler, and a suspension of one or more lithium salts dissolved in a solvent.

[0072] The sulfide is configured to supplement or provide ionic conductivity through the electrode. Sulfides can be selected to produce sulfide-based solid-state electrodes in glass, ceramic, or glass-ceramic form. The sulfide can be one or more thiophosphates. In some aspects, one or more thiophosphates are selected from the group consisting of lithium thiophosphate (“LPS”), lithium thiophosphate carbide (“LPSCX”), lithium thiophosphate germanium (“LGPS”), lithium thiophosphate chloride (“LPSCl”), lithium thiophosphate silicon chloride (“LSiPSCl”), and combinations thereof. LPS can be, for example, Li₂P₂S₆. In some aspects, the halide (X) of LPCSX is selected from the group consisting of fluorine, chlorine, bromine, and combinations thereof. LPSCl can be, for example, Li₆PS₅Cl. LGPS can be, for example, Li 10 GeP2S 12 LSiPSCl can be, for example, Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Based on the weight of the negative electrode, sulfides can be present in an amount ranging from 5% to 40% by weight. In some cases, the solid content is 10% to 30% by weight, based on the weight of the negative electrode.

[0073] The adhesive is configured to suspend the negative electrode electroactive material and conductive filler in a dispersed state within the negative electrode. The adhesive may be further configured to facilitate electrode layer formation, promote particle dispersion within the electrode, provide mechanical stability, and / or enhance adhesion to adjacent layers. In some aspects, the adhesive is selected from the group consisting of nitrile butadiene rubber (“NBR”), hydrogenated NBR (“HNBR”), styrene-butadiene-styrene (“SBS”), styrene-ethylene-butene-styrene (“SEBS”), styrene thermoplastic elastomer (“STPE”), poly(vinylidene fluoride-co-hexafluoropropylene”) (“PVDF-HFP”), and combinations thereof. STPE may be a hydrogenated styrene block copolymer, such as SEPTON. TM SEPTON TM The adhesive may 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 adhesive may be present in an amount of 3% to 10% by weight, based on the weight of the negative electrode. In some aspects, the adhesive is present in an amount of 5% to 8% by weight, based on the weight of the negative electrode.

[0074] The filler is configured to enhance the conductivity of the electrode layer. The filler can be, for example, a carbon material. In some aspects, the carbon material is selected from the group consisting of carbon nanotubes, graphene, and carbon black powder. A certain amount of filler is added to supplement or provide conductivity through the negative electrode by increasing the connectivity of the layer above the permeation threshold. In some aspects, the filler material can be excluded from the composition because other materials for the negative electrode slurry can be selected to exceed the permeation threshold without additional filler material.

[0075] The lithium salt is configured to activate the interfacial lithiation reaction. In some aspects, the lithium salt is selected from the group consisting of lithium halides (“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 salt is from 0.01 mol to 0.5 mol of lithium per liter of solvent.

[0076] The solvent is a non-aqueous solvent of moderate to low polarity, configured to maintain 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, p-xylene, acetonitrile (“ACN” or “MeCN”), toluene, heptane, ethyl acetate (“EA”), and combinations thereof. Based on the weight of the solution, the solvent may be present in an amount such that the solid content is from 15% by weight to 60% by weight. In some aspects, based on the weight of the solution, the solid content is from 30% by weight to 45% by weight.

[0077] At frame 304, negative electrode paste 14a is coated onto lithium foil 14b with a substantially uniform thickness to produce first assembly 314. In some respects, lithium foil 14b is part of lithium foil laminated current collector.

[0078] The lithium foil 14b is metallic lithium, and its thickness is selected such that the lithium foil is consumed before the all-solid-state battery cell 12' is assembled. In some aspects, the thickness of the lithium foil 14b is 10 μm to 50 μm. In some preferred aspects, the thickness of the lithium foil 14b is 20 μm to 35 μm. Alternatively, in some aspects, the lithium foil is configured to provide 101% to 140% of the capacity of the negative electrode material.

[0079] At frame 306, lithiation of the negative electrode electroactive material within the negative electrode slurry 14a is activated to produce a second intermediate component 316. In the illustrated embodiment, the second intermediate component 316 is formed by sandwiching a first current collector 20 between two lithium foils 14b of the first components 314. The lithium salts of the negative electrode slurry 14a and the lithium foils 14b synergistically promote the reaction of lithium and silicon, thereby forming Li between the negative electrode slurry 14a and the lithium foils 14b. x Si y Alloy. Promotes the reaction to form a conductive layer 14c grown from the interface between lithium foil 14b and negative electrode paste 14a.

[0080] At frame 308, the second intermediate component is heated to evaporate the solvent of the negative electrode slurry 14a. Advantageously, heating can be selected to increase the reaction rate of lithium and silicon. In some aspects, heating is performed at a temperature of 60°C to 300°C. In some preferred aspects, heating is performed at a temperature of 80°C to 170°C.

[0081] At frame 310, pressure is applied to the opposite side of the second intermediate component 316 to produce a third intermediate component 318 (e.g., a rolled negative electrode component). Advantageously, the pressure can be selected to further increase the reaction rate of lithium and silicon. After pressure is applied, the third intermediate component 318 includes a first current collector 20 sandwiched between two lithium foils 14b sandwiched between two conductive layers 14c. Advantageously, the outer surface of each conductive layer 14c has a substantially uniform surface.

[0082] At frame 312, the rolled negative electrode is incorporated into the all-solid-state battery assembly. Advantageously, the rolled negative electrode produced by method 300 can be incorporated into the all-solid-state battery cell or directly tested immediately after the production of the rolled negative electrode assembly 318. Further, method 300 provides a rolled negative electrode with a uniform thickness to optimize the interfacial performance between the rolled negative electrode and adjacent layers of the all-solid-state battery assembly, such as the solid electrolyte layer 18. Further still, method 300 provides more robust moisture resistance during processing, for example, by coating lithium metal with a non-aqueous negative electrode slurry 14a. Still further, method 300 optimizes the complete lithiation of the negative electrode while reducing or eliminating the drawbacks associated with unreacted lithium foil. Furthermore, any remaining trace amounts of lithium metal are disposed between the negative electrode and the first current collector 20, wherein they do not negatively interact with the electrochemistry of the compounds in the all-solid-state battery cell 12' or the solid electrolyte 18.

[0083] Figure 4This is a schematic diagram of a sulfide-based all-solid-state battery 10' produced using method 300. The all-solid-state battery 10' has a three-layer structure comprising two all-solid-state battery cells 12'. Each all-solid-state battery cell 12' includes a pair of electrodes (anode 14 and cathode 16) separated by a solid electrolyte layer 18. Each cathode 14 is disposed on a lithium foil 402, and the lithium foil 402 is disposed on a cathode current collector 20. Each cathode 16 is disposed on a cathode current collector 22, and each corresponding current collector is configured to be opposite to the solid electrolyte layer 18. Advantageously, the illustrated all-solid-state battery 10' overcomes the disadvantages associated with unreacted lithium foil present in the cathode.

[0084] Figure 5 This is a schematic diagram of a system 500 for producing pre-lithiated anode slurry. System 500 includes a slurry tank 502 containing unlithiated anode slurry 504. Unlithiated anode slurry 504 includes a suspension of anode electroactive material 506, sulfide 508, solid lithium material 510, binder (not shown), filler (not shown), and lithium salt dissolved in a solvent.

[0085] The negative electrode slurry 504 is pre-lithiated by maintaining it in a well-mixed state for a predetermined period of time using, for example, a high-intensity mixer. The predetermined period of time can be, for example, from about 4 hours to about 48 hours. More preferably, the predetermined period of time can be from about 6 hours to about 24 hours. The solid lithium material 510 can be in a suitable form, such as foil or granules.

[0086] Solid lithium material 510 is at least partially consumed during the pre-lithiation of the negative electrode active material 506. Advantageously, the remaining solid lithium material 510 can be removed from the pre-lithiated negative electrode slurry before the pre-lithiated negative electrode slurry is applied to the current collector. Furthermore, in removing the solid lithium material 510, the pre-lithiation of the negative electrode slurry allows for the use of lower-grade lithium materials, such as lithium materials containing contaminants, having non-uniform morphology, having non-uniform size, etc. In some aspects, the solid lithium material 510 is one or more industrial waste lithium materials.

[0087] Pre-lithiation can be optimized because the slurry tank 502 provides a lithium content calculation based on non-local measurements (such as stoichiometry or gravimetric analysis), and the well-mixed solution provides a homogeneous mixture of bulk electroactive material and solid lithium material rather than relying on the average thickness of the lithium foil for design calculations. For example, deviations in lithium foil thickness and / or negative electrode slurry thickness can lead to over- and / or under-lithiation at points in the negative electrode because reaction kinetics are influenced by the local environment along the negative electrode. Furthermore, pre-lithiation can be optimized because the reaction kinetics within the slurry tank 502 are much faster than solid-solid reaction kinetics. Additionally, pre-lithiation in the slurry tank 502 and in a non-aqueous solvent reduces or eliminates the need for humidity control during the pre-lithiation process. The pre-lithiated negative electrode slurry can be applied as a uniform layer to the first current collector 20 to produce, for example, a third intermediate component 218 (e.g., a rolled negative electrode component).

[0088] In some aspects, sulfide 508, binder, and filler are added after the negative electrode active material has undergone partial pre-lithiation. Advantageously, although sulfide 508, binder, and filler do not produce side reactions with lithium metal, excluding one or more of these during pre-lithiation can improve the reaction rate by avoiding physical interference during lithium and silicon mixing.

[0089] Figure 6 This is a schematic diagram of a system 600 for producing pre-lithiated anode slurry. System 600 includes a slurry tank 502 containing unlithiated anode slurry 504. The unlithiated anode slurry includes a suspension of anode electroactive material 506, sulfide 508, binder (not shown), filler (not shown), and lithium salt dissolved in a solvent.

[0090] The negative electrode slurry 504 is pre-lithiated by maintaining it in a well-mixed state for a predetermined period of time using, for example, a high-intensity mixer. The predetermined period of time can be, for example, from about 4 hours to about 48 hours. More preferably, the predetermined period of time can be from about 6 hours to about 24 hours.

[0091] Solid lithium material 610 is maintained in a fixed position relative to slurry tank 502. Solid lithium material 610 can be in a suitable form, such as foil or granules. In the illustrated embodiment, solid lithium material 610 is attached to the wall of slurry tank 502. Solid lithium material 610 is at least partially consumed during the pre-lithiation of the negative electrode active material 506. Advantageously, unreacted solid lithium material 610 remains in slurry tank 502 when the pre-lithiated negative electrode slurry is removed. Further, the pre-lithiation of the negative electrode slurry allows for the use of lower-grade lithium materials, such as lithium materials containing contaminants, having an inhomogeneous morphology, having inhomogeneous dimensions, etc., during the removal of solid lithium material 610. In some aspects, solid lithium material 610 is one or more industrial waste lithium materials.

[0092] Pre-lithiation can be optimized because the slurry tank 502 provides a homogeneous mixture of bulk electroactive material and solid lithium material based on non-local measurements (e.g., stoichiometry or gravimetric analysis) and the well-mixed solution provides a homogeneous mixture of bulk electroactive material and solid lithium material, rather than relying on the average thickness of the lithium foil for design calculations. For example, deviations in lithium foil thickness and / or negative electrode slurry thickness can lead to over- and / or under-lithiation at points in the negative electrode because reaction kinetics are influenced by the local environment along the negative electrode. Furthermore, pre-lithiation can be optimized because the reaction kinetics within the slurry tank 502 are much faster than solid-solid reaction kinetics. Additionally, pre-lithiation in the slurry tank 502 and in a non-aqueous solvent reduces or eliminates the need for humidity control during the pre-lithiation process. The pre-lithiated negative electrode slurry can be applied as a uniform layer to the first current collector 20 to produce, for example, a third intermediate component 218 (e.g., a rolled negative electrode component).

[0093] In some aspects, sulfide 508, binder, and filler are added after the negative electrode active material has undergone partial pre-lithiation. Advantageously, although sulfide 508, binder, and filler do not produce side reactions with lithium metal, excluding one or more of these during pre-lithiation can improve the reaction rate by avoiding physical interference during lithium and silicon mixing.

[0094] As will be understood by those skilled in the art, this disclosure is readily adaptable to various modifications and alternatives, and some representative embodiments have been illustrated in the accompanying drawings and described in detail above. However, it should be understood that the novel aspects of this disclosure are not limited to the specific forms shown in the drawings. Rather, this disclosure covers modifications, equivalents, combinations, sub-combinations, arrangements, groupings, and substitutions that fall within the scope and spirit of this disclosure and are defined by the appended claims.

[0095] As used herein, unless the context clearly indicates otherwise: the words “and” and “or” should be both conjunctions and antonyms, unless the context clearly indicates otherwise; the word “all” means “any and all”; the word “any” means “any and all”; the word “including” means “including but not limited to”; the singular forms “a”, “an”, and “the” include the plural referent and vice versa.

[0096] The numerical values ​​of parameters (e.g., quantities or conditions) in this specification, unless otherwise expressly or clearly indicated by the context (including the appended claims), shall be understood to be modified by the term “about,” regardless of whether “about” actually precedes the numerical value. The numerical parameters set forth herein and in the appended claims are approximate values ​​that may vary depending on the desired characteristics sought to be obtained by this disclosure. At least, and without attempting to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be interpreted at least based on the number of significant figures reported and by applying ordinary rounding techniques.

[0097] For example, words like “approximately,” “about,” and “basically” can be used in this text to mean “within, close to, or almost within,” “within 0-10% of,” or “within acceptable manufacturing tolerances,” or logical combinations thereof.

[0098] While the scope and limits of the term "about" are readily understood by those skilled in the art, the term "about" implies that the numerical value or property is permissible without precision. If the imprecision provided by "about" is not understood in this ordinary sense in the art, then "about" at least indicates a variation that may be caused by common methods of measuring and using such parameters. For example, unless otherwise understood in the art, the term "about" refers to within 10% (e.g., ±10%) of the value.

[0099] While the scope and limits of the term "substantially" are readily understood by one of ordinary skill in the art, the term "substantially" implies that some imprecision is permissible in the stated numerical value or property. If the imprecision provided by "substantially" is not understood in that ordinary sense in the art, then "substantially" at least indicates variations that may be caused by manufacturing processes and the measurement of such parameters. For example, unless otherwise understood in the art, the term "substantially" means within 5% (e.g., ±5%) of the stated value.

[0100] While the scope and limits of the term "essentially" are readily understood by those skilled in the art, the term "essentially" implies that the numerical value or property allows for some slight inaccuracy. If the inaccuracy provided by "essentially" is not understood in this ordinary sense in the art, then "essentially" indicates at least negligible variation in the expected parameter that may be difficult to overcome. For example, unless otherwise understood in the art, the term "essentially" means within 1% (e.g., ±1%) of the value.

[0101] While the scope and limits of the term "pure" are readily understood by those skilled in the art, the term "pure" means that a compound may include very small amounts of other materials. If the imprecision provided by "pure" is not understood in this ordinary sense in the art, then "pure" at least indicates variations that may be caused by separation processes and measurements of such parameters. For example, unless otherwise understood in the art, the term "pure" refers to said material at a purity greater than 99.9%.

[0102] It should be understood that the scope provided herein includes the scope, sub-scopes within the scope, and each value within the scope.

[0103] While the best mode for carrying out this disclosure has been described in detail, those skilled in the art to which this disclosure pertains will recognize various alternative designs and implementations for practicing this disclosure within the scope of the appended claims.

[0104] Example

[0105] Two types of exemplary and reference batteries were prepared for comparison.

[0106] The first type of exemplary battery is prepared from a negative electrode slurry containing 5% by weight of SEEPS binder and THF solvent. The solids content of the negative electrode slurry is 33.89% by weight. The negative electrode slurry is coated onto a lithium foil with a thickness of 20 μm to pre-lithiate the negative electrode material.

[0107] The resulting negative electrode composition is: 68.14 wt% Si, 4.87 wt% SEEPS, 24.33 wt% LPSCl, and 2.66 wt% LiFSI. The positive electrode composition is: 70 wt% NCM721 and 30 wt% LPSCl.

[0108] The reference cell was prepared from a negative electrode slurry containing 5% by weight of SEEPS binder and THF solvent. The solids content of the negative electrode slurry was 33.89% by weight. The resulting negative electrode composition was: 68.14% by weight of Si, 4.87% by weight of SEEPS, 24.33% by weight of LPSCl, and 2.66% by weight of LiFSI. The positive electrode composition was: 70% by weight of NCM721 and 30% by weight of LPSCl.

[0109] Figure 7 This is a graph showing the initial charge and discharge curves of an exemplary battery (line 702) compared to a reference battery (line 704) at a C rating of C / 10. It can be seen that the exemplary battery has an initial coulombic efficiency of 86.58%, while the reference battery has 61.50%.

[0110] Figure 8 This is a graph showing the cycle capacity of the exemplary battery (line 802) compared to a reference battery (line 804). Capacity measurements are in mAh / g. The initial charge / discharge cycles were performed at a C rating of C / 10. The third cycle was performed at a C rating of C / 5. The fifth cycle was performed at a C rating of C / 3. It can be seen that the exemplary battery not only has a higher capacity but also a higher capacity retention rate across different cycles.

[0111] The second type of exemplary battery is prepared from a pre-lithiation slurry comprising 5% by weight of SEEPS binder and THF solvent. The negative electrode slurry has a solids content of 33.89% by weight. The pre-lithiation slurry of the first of the second exemplary batteries is mixed for 6 hours, and the pre-lithiation slurry of the second of the second exemplary batteries is mixed for 24 hours.

[0112] The resulting anode composition was: 68.14 wt% Si, 4.87 wt% SEEPS, 24.33 wt% LPSCl, and 2.66 wt% LiFSI. The lithium anode loading was 0.322 g, and the silicon anode loading was 3.5 g. The cathode composition was: 70 wt% NCM721 and 30 wt% LPSCl.

[0113] After cycling at C / 10, the capacity and coulombic efficiency of the second exemplary battery and the reference battery were compared. The reference battery had a capacity of 96.08 mAh / g, a coulombic efficiency of 61.50%, and an open-circuit voltage of approximately 0.6V.

[0114] The second exemplary battery prepared after a six-hour mixing time had 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 exemplary battery prepared after a twenty-four-hour mixing time had a capacity of 121.29 mAh / g, a coulombic efficiency of 70.05%, and an open-circuit voltage of approximately 1.7 V. It is worth noting that while increasing the mixing time improves the initial electrical performance, mixing times exceeding 48 hours lead to negative electrode stratification.

Claims

1. A method for producing a pre-lithiated anode, comprising: A pre-lithiated negative electrode slurry is obtained and configured to form a negative electrode, the pre-lithiated negative electrode slurry comprising the following: A negative electrode active material, wherein the negative electrode active material is composed of an unlithiated negative electrode active material. The filler is configured to enhance the conductivity of the negative electrode. An adhesive, configured to suspend the negative electrode electroactive material and the filler in a dispersed state within the negative electrode. Sulfides, which are configured to supplement or provide ionic conductivity through the negative electrode, Lithium salt, wherein the lithium salt is configured to activate the interfacial lithiation reaction with the negative electrode electroactive material, and A non-aqueous solvent, wherein the non-aqueous solvent is configured to maintain the lithium salt in solution; The pre-lithiated negative electrode slurry is coated onto the current collector; The non-aqueous solvent of the pre-lithiated anode slurry is evaporated by heating to produce an intermediate component including the current collector; the anode is rolled by applying pressure to the intermediate component to produce a rolled anode component; and Assemble an all-solid-state battery cell, including the rolled negative electrode assembly.

2. The method according to claim 1, wherein, The pre-lithiated negative electrode is formed by coating the pre-lithiated negative electrode slurry onto the lithium foil of a lithium foil laminated current collector, wherein the negative electrode electroactive material is an unlithiated form of silicon material, silicon oxide material, silicon / carbon composite material, silicon / metal alloy material, graphite material, tin oxide material, or a combination thereof.

3. The method according to claim 2, wherein, The lithium foil is consumed by the negative electrode electroactive material, so that the rolled negative electrode assembly does not contain the lithium foil.

4. The method according to claim 2, wherein, The intermediate components include each of the current collector and the pre-lithiated negative electrode slurry having an interface with the lithium foil.

5. The method according to claim 2, wherein, The thickness of the lithium foil is 10 μm to 50 μm.

6. The method according to claim 1, wherein, The lithium salt is selected from the group consisting of lithium halides, 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. The method according to claim 6, wherein, The concentration of the lithium salt is from 0.01 mol to 0.5 mol of lithium per liter of solvent.

8. The method according to claim 1, wherein, The pre-lithiated negative electrode slurry is mixed with solid lithium material in a slurry tank before being coated onto the current collector, wherein the negative electrode electroactive material is unlithiated silicon material, silicon oxide material, silicon / carbon composite material, silicon / metal alloy material, graphite material, tin oxide material, or a combination thereof.

9. The method according to claim 8, wherein, The mixture is carried out over a predetermined period of 6 to 24 hours.

10. The method according to claim 8, wherein, The solid lithium material remains in place relative to the slurry tank.

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