Solid-state battery and method of manufacturing the same

Abstract

The application provides a solid-state battery, which comprises a shell, a positive electrode sheet, a separator and a negative electrode sheet arranged in the shell, solid-state electrolyte particles loaded on the positive electrode sheet and the negative electrode sheet, and an organic polymer filled in the shell; wherein the solid-state electrolyte particles comprise one or more of oxide solid-state electrolyte particles and sulfide solid-state electrolyte particles; at least part of the organic polymer is filled in the gap of the solid-state electrolyte particles; and the mass ratio of the total mass of the solid-state electrolyte particles on the positive electrode sheet and the negative electrode sheet to the mass of monomers of the organic polymer is 1:(0.1-0.6). The solid-state battery has the advantages of high ionic conductivity, low interface resistance, reduced growth of lithium dendrites and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a solid-state battery and a preparation method thereof. BACKGROUND

[0002] A solid-state battery is a battery using solid electrodes and solid electrolytes instead of liquid electrolytes. The solid-state electrolyte can provide lithium ions to establish an ion channel between the positive and negative electrodes of the battery, thereby conducting greater current and improving battery capacity. Compared with traditional lithium-ion batteries, solid-state batteries have the advantages of high energy density, small size, high safety, etc.

[0003] At present, the solid-state electrolytes commonly used to prepare solid-state batteries include polymer solid-state electrolytes, oxide solid-state electrolytes and sulfide solid-state electrolytes. The sulfide solid-state electrolyte and the oxide solid-state electrolyte have high electrical conductivity, with electrical conductivity of 10 -2 S / cm and 10 -3 S / cm, respectively; however, there are gaps between the oxide or sulfide solid-state electrolyte particles, which may cause lithium dendrite growth and bring safety hazards on the one hand, and lithium ions cannot pass through the gaps to cause high electrolyte interface resistance on the other hand; the interface resistance of the polymer solid-state electrolyte is low, but the solid-state battery prepared therefrom has the problem of low ion conductivity. SUMMARY

[0004] Therefore, it is necessary to provide a solid-state battery with high ion conductivity and low interface resistance and a preparation method thereof.

[0005] According to an aspect of the present application, a solid-state battery is provided, comprising a shell and a positive electrode sheet, a separator and a negative electrode sheet arranged in the shell, the positive electrode sheet and the negative electrode sheet being loaded with solid-state electrolyte particles, and the shell being filled with an organic polymer;

[0006] The solid-state electrolyte particles comprise one or more of oxide solid-state electrolyte particles and sulfide solid-state electrolyte particles; at least part of the organic polymer is filled in the gaps of the solid-state electrolyte particles; and the mass ratio of the total mass of the solid-state electrolyte particles on the positive electrode sheet and the negative electrode sheet to the monomer of the organic polymer is 1:(0.1-0.6).

[0007] In one embodiment, the mass ratio of the total mass of the solid-state electrolyte particles on the positive electrode sheet and the negative electrode sheet to the monomer of the organic polymer is 1:(0.2-0.5).

[0008] In one embodiment, the mass ratio of the total mass of the solid-state electrolyte particles on the positive electrode sheet and the negative electrode sheet to the monomer of the organic polymer is 1:(0.3-0.4).

[0009] In one of the embodiments, the organic polymer is obtained by in-situ polymerization of monomers filled in the shell by heating.

[0010] In one of the embodiments, the organic polymer comprises one or more of polyethylene oxide, polydioxolane.

[0011] In one of the embodiments, the monomers of the organic polymer comprise one or more of ethylene oxide, 1,3-dioxolane.

[0012] In one of the embodiments, the molecular weight of the organic polymer is 12000 g / mol to 35000 g / mol.

[0013] In one of the embodiments, the oxide solid-state electrolyte is selected from one or more of Li3Si 0.225 V 36 (PO4)3, Li 0.34 La 0.51 TiO 2.94 , Li7La3Zr2O 12 , Li 3.6 Ge 0.6 V 0.4 O4 and Li3Al 0.3 Ti7(PO4)3; and / or

[0014] The sulfide solid-state electrolyte is selected from one or more of Li2S-P2S5, Li2S-SiS2 and Li2S-B2S3.

[0015] In one of the embodiments, the positive electrode sheet comprises a positive current collector and a positive active material and solid-state electrolyte particles loaded on the positive current collector;

[0016] Optionally, the positive active material is selected from one or more of lithium cobaltate, lithium iron phosphate, nickel cobalt manganese ternary material and nickel cobalt aluminum ternary material;

[0017] Optionally, the mass ratio of the positive active material to the solid-state electrolyte particles in the positive electrode sheet is (85-95):(8-10).

[0018] The present application provides a preparation method of the solid-state battery as described above.

[0019] In one of the embodiments, the preparation method of the solid-state battery comprises the following steps:

[0020] Placing the positive electrode sheet, the separator and the negative electrode sheet in the shell;

[0021] Injecting the monomers of the organic polymer into the shell;

[0022] The shell is sealed, and the monomers of the organic polymer are polymerized in situ by heating.

[0023] In one embodiment, the heating temperature is 50-70℃, and the heating time is 20-30h.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] In the present application, the gap between the oxide and sulfide solid electrolyte particles is filled with an organic polymer, so that the battery has high ionic conductivity, and the lithium ions released by the oxide or sulfide solid electrolyte induce in-situ ring-opening polymerization of the polymer filler, forming a polymer solid electrolyte, eliminating the gap between the oxide solid electrolyte particles, reducing the interface resistance, and establishing a lithium ion channel between the positive and negative electrodes of the battery, so that the lithium ions can move freely. On the other hand, controlling the mass ratio of the oxide or sulfide solid electrolyte particles to the monomers of the organic polymer to be 1:(0.1-0.6) can effectively prevent the growth of lithium dendrites in the gap between the solid particles, and improve the performance and service life of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic view of the gap between the solid electrolyte particles;

[0027] Figure 2 is a schematic view of the gap between the solid electrolyte particles filled with an organic polymer in the present application;

[0028] Figure 3 is a schematic view of the preparation of the negative electrode sheet of the solid-state battery in the present application.

[0029] BRIEF DESCRIPTION OF DRAWINGS

[0030] 101, oxide and / or sulfide solid electrolyte particles; 102, gap between particles; 201, organic polymer; 301, negative current collector direction; 302, lithium metal target; 303, oxide solid electrolyte target; 304, lithium metal beam; 305, oxide solid electrolyte beam. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail. In the following description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the scope of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise specifically defined, all materials, reagents, instruments and equipment used in the present application are commercially available or are prepared by known methods.

[0033] Some embodiments of the present application provide a solid-state battery,

[0034] The shell and the positive electrode sheet, the separator and the negative electrode sheet arranged in the shell, the positive electrode sheet and the negative electrode sheet loaded with solid-state electrolyte particles, and the shell filled with organic polymers are provided.

[0035] The solid-state electrolyte particles include one or more of oxide solid-state electrolyte particles and sulfide solid-state electrolyte particles; at least part of the organic polymer is filled in the gap between the solid-state electrolyte particles; and the mass ratio of the total mass of the solid-state electrolyte particles on the positive electrode sheet and the negative electrode sheet to the monomer of the organic polymer is 1:(0.1-0.6).

[0036] It can be understood that the mass ratio of the total mass of the solid-state electrolyte particles on the positive electrode sheet and the negative electrode sheet to the monomer of the organic polymer can be, but is not limited to, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, etc.

[0037] Please refer to Figure 1 , there is a gap 102 between the oxide solid-state electrolyte particles and / or sulfide solid-state electrolyte particles 101, which may, on the one hand, cause lithium dendrite growth and pose a safety hazard, and on the other hand, lithium ions cannot pass through the gap, resulting in high electrolyte interface resistance. Please refer to Figure 2 , the organic polymer 201 is injected into the gap between the oxide solid-state electrolyte particles and / or sulfide solid-state electrolyte particles 101, and the lithium ions released by the oxide or sulfide solid-state electrolyte induce in-situ ring-opening polymerization of the polymer filler, forming a polymer solid-state electrolyte, eliminating the gap between the oxide solid-state electrolyte particles, reducing the interface resistance of the battery, and establishing a lithium ion channel between the positive and negative electrodes of the battery, allowing lithium ions to move freely.

[0038] The present application finds that filling a certain mass ratio of organic polymer 201 in the gap between the oxide or sulfide solid-state electrolyte particles can make the electrolyte have lower resistance and higher conductivity; at the same time, it prevents lithium dendrite growth between the gaps 102 between the solid-state electrolyte particles.

[0039] When the mass ratio of the solid-state electrolyte particles to the monomers of the organic polymer exceeds 1:0.6, the excess of the organic polymer reduces the overall ionic conductivity of the electrolyte.

[0040] In some embodiments, the mass ratio of the total mass of the solid-state electrolyte particles on the positive electrode sheet and the negative electrode sheet to the monomers of the organic polymer is 1:(0.2-0.5). Further controlling the mass ratio in the preferred range makes the performance of the solid-state battery more optimal.

[0041] In some embodiments, the mass ratio of the total mass of the solid-state electrolyte particles on the positive electrode sheet and the negative electrode sheet to the monomers of the organic polymer is 1:(0.3-0.4). Further controlling the mass ratio in the preferred range makes the performance of the solid-state battery more optimal.

[0042] In some embodiments, the organic polymer is obtained by in-situ polymerization of the organic polymer monomers filled in the shell by heating.

[0043] In some embodiments, the organic polymer comprises one or more of polyethylene oxide and polydioxolane.

[0044] It can be understood that the molecular formula of the polyethylene oxide is HO-(CH2CH2) n-OH, wherein n is an integer greater than or equal to 1. 20 ) n -H, and the molecular formula of the polydioxolane is HO-(CH2CH2) n-OH, wherein n is an integer greater than or equal to 1. 20 CH2CH 20 ) n -H.

[0045] In some embodiments, the monomers of the organic polymer comprise one or more of ethylene oxide and 1,3-dioxolane.

[0046] It can be understood that the lithium ions of the oxide or sulfide solid-state electrolyte can induce ring-opening of the monomers of the organic polymer, complete in-situ polymerization, generate the organic polymer, and realize solidification of the liquid-state electrolyte; at the same time, the organic polymer can realize free migration of lithium ions and eliminate the gaps between the oxide or sulfide solid-state electrolyte particles.

[0047] In some embodiments, the molecular weight of the organic polymer is 12000 g / mol-35000 g / mol.

[0048] It can be understood that the molecular weight of the organic polymer can be, but is not limited to, 12000 g / mol, 20000 g / mol, 30000 g / mol, 35000 g / mol, etc.

[0049] In some embodiments, the oxide solid-state electrolyte is selected from Li 1.3 Si 0.225 V 1.36(PO4)3, Li 1.3 Si 0.225 V 1.36 (PO4)3, Li0 .34 La 0.51 TiO 2.94 , Li7La3Zr2O 12 , Li 3.6 Ge 0.6 V 0.4 O4and Li 1.3 Al 0.3 Ti 1.7 (PO4)3; the sulfide solid-state electrolyte is selected from one or more of Li2S-P2S5, Li2S-SiS2, and Li2S-B2S3.

[0050] In some embodiments, the Li 1.3 Si 0.225 V 1.36 (PO4)3is prepared as follows: NH4H2PO4, V2O5, SiO2are ground and stirred in an elemental ratio to obtain a mixture, after heat treatment, a solid-state electrolyte precursor is obtained, which is then crushed into powder, mixed with Li2CO3, and after heat treatment, the oxide solid-state electrolyte particle Li 1.3 Si 0.225 V 1.36 (PO4)3.

[0051] In some embodiments, the positive electrode sheet comprises a positive electrode current collector and a positive electrode active material and solid-state electrolyte particles loaded on the positive electrode current collector;

[0052] In some specific examples, the positive electrode active material is selected from one or more of lithium cobaltate, lithium iron phosphate, nickel cobalt manganese ternary material, and nickel cobalt aluminum ternary material.

[0053] In some embodiments, the positive electrode current collector is further loaded with one or more of a conductive agent, a binder, and a solvent.

[0054] In some specific examples, the conductive agent is selected from one or more of graphene, conductive carbon black, and conductive graphite.

[0055] In some specific examples, the binder is selected from one or more of polytetrafluoroethylene (PVDF) and butadiene styrene rubber.

[0056] In some specific examples, the solvent is N-methyl pyrrolidone (NMP).

[0057] In some embodiments, the mass ratio of the positive electrode active material to the solid-state electrolyte particles, the conductive agent, the binder, and the solvent on the positive electrode sheet is (85-95):(8-10):(0.5-1.5):(1-3).

[0058] In some specific examples, the mass ratio of the positive active material, the solid-state electrolyte particles, the conductive agent, and the binder on the positive electrode sheet is 90:9:1:1.

[0059] In some embodiments, the negative electrode sheet includes a negative current collector and a negative active material and oxide solid-state electrolyte particles loaded on the negative current collector.

[0060] In some specific examples, the negative active material is selected from one or more of metal lithium, graphite, and silicon carbon.

[0061] The oxide and / or sulfide solid-state electrolyte included in the above solid-state battery makes the battery have high ionic conductivity; the interstitial space between the oxide or sulfide solid-state electrolyte particles is filled with an organic polymer, enabling lithium ions to migrate freely, eliminating the interstitial space between the oxide or sulfide solid-state electrolyte particles, reducing the interface resistance, and constructing a complete lithium ion channel in the entire battery system.

[0062] In addition, some embodiments of the present application also provide a preparation method of the above solid-state battery.

[0063] In some embodiments, the preparation method of the above solid-state battery includes steps S100, S300-S500.

[0064] Step S100: uniformly mixing a positive active material with oxide solid-state electrolyte particles, a conductive agent, and a binder, coating a positive current collector, and obtaining a positive electrode sheet.

[0065] In some specific examples, the positive current collector is an aluminum foil.

[0066] In some specific examples, step S100 includes steps S101-S103.

[0067] Step S101: uniformly mixing the positive active material, the oxide solid-state electrolyte particles, and the conductive agent, sintering at 890-910°C for 1.5-2.5h, sieving the sintered material, and obtaining D 50 The positive active material has a particle size of 8-12pm.

[0068] Step S102: uniformly mixing the positive active material obtained in step S101 with a binder and a solvent, and obtaining a slurry.

[0069] In some specific examples, the mass ratio of the positive active material, the oxide solid-state electrolyte particles, the conductive agent, and the binder is (85-95):(8-10):(0.5-1.5):(1-3).

[0070] In some specific examples, the solid content of the slurry in step S102 is 74% to 78%, and the viscosity is 7600 mPa·s to 8000 mPa·s.

[0071] Step S103: The slurry obtained in step S102 is uniformly coated on both sides of the positive current collector at a coating amount of 44 mg / cm 2 to 44.5 mg / cm 2 ; dried, rolled, and a positive electrode sheet with a thickness of 131 μm to 135 μm is obtained.

[0072] Step S300: A metal plating layer is formed on the surface of the negative current collector by magnetron sputtering of the negative electrode material; and an oxide solid electrolyte plating layer completely covering the metal plating layer is formed by magnetron sputtering of the oxide solid electrolyte onto the metal plating layer; and a negative electrode sheet is obtained.

[0073] In some specific examples, in step S300, referring to Figure 3 , the negative current collector is hung on a winding shaft, and the substrate moves along path 301 as shown in the figure; the lithium metal target 302 is excited to form a lithium metal beam 304, which is uniformly magnetron sputtered onto the first surface of the substrate to form a metal plating layer on the substrate; the oxide solid electrolyte target 303 is excited to form an oxide solid electrolyte beam 305, which is uniformly magnetron sputtered onto the metal plating layer to form an oxide solid electrolyte plating layer; the order of the plating layers on the second surface of the substrate is still the metal plating layer and the oxide solid electrolyte plating layer; and then the negative current collector is wound up.

[0074] In some specific examples, the negative current collector is a copper foil.

[0075] In some specific examples, in step S300, the single-sided thickness of the metal plating layer is 4.5 μm to 5.5 μm, and the single-sided thickness of the oxide solid electrolyte plating layer is 2.5 μm to 3.5 μm.

[0076] Step S400: The positive electrode sheet, the separator, and the negative electrode sheet are placed in a shell, and a monomer of an organic polymer is injected into the shell.

[0077] Step S500: The shell is sealed, and heated to complete in-situ polymerization of the monomer of the organic polymer.

[0078] In some specific examples, in step S500, the heating temperature is 50°C to 70°C, and the heating time is 20 h to 30 h.

[0079] In some embodiments, the method for preparing the solid-state battery described above comprises steps S200 to S500.

[0080] Step S200: mixing the positive electrode active material with the sulfide solid electrolyte, the conductive agent and the binder uniformly, spraying the positive electrode current collector to obtain a positive electrode sheet.

[0081] In some specific examples, step S200 comprises the following steps:

[0082] Step S201: mixing and grinding the positive electrode active material, the sulfide solid electrolyte, the conductive agent and the binder in an argon dry atmosphere to obtain a mixed powder.

[0083] In some specific examples, in step S201, the mass ratio of the positive electrode active material, the sulfide solid electrolyte, the conductive agent and the binder is (85-95):(8-10):(0.5-1.5):(1-3).

[0084] Step S202: spraying the mixed powder obtained in step S201 on both sides of the positive electrode current collector in an argon dry atmosphere.

[0085] In some specific examples, in step S202, the coating amount of spraying is 44 mg / cm 2 -44.5 mg / cm 2 .

[0086] Step S203: heating and softening the sprayed positive electrode current collector, and rolling to obtain a positive electrode sheet with a thickness of 130-135 pm.

[0087] Step S300: magnetron sputtering the negative electrode material onto the surface of the negative electrode current collector to form a metal plating layer; magnetron sputtering the oxide solid electrolyte onto the metal plating layer to form an oxide solid electrolyte plating layer completely covering the metal plating layer; and obtaining a negative electrode sheet.

[0088] In some specific examples, in step S300, the single-side thickness of the metal plating layer is 4.5-5.5 pm, and the single-side thickness of the oxide solid electrolyte plating layer is 2.5-3.5 pm.

[0089] Step S400: placing the positive electrode sheet, the separator and the negative electrode sheet in the shell, and injecting monomers of the organic polymer into the shell.

[0090] Step S500: sealing the shell, heating, and completing in-situ polymerization of the monomers of the organic polymer.

[0091] In some specific examples, in step S500, the heating temperature is 50-70°C, and the heating time is 20-30 h. Specific embodiments

[0093] The present invention will be further described below with reference to specific embodiments and comparative examples, but these should not be construed as limiting the scope of protection of the present invention.

[0094] Example 1

[0095] 1. Preparation of positive electrode sheet

[0096] (1) Preparation of cathode material: The cathode active material LiNi 0.8 Co 0.1 Mn 0.1 O2 and oxide solid electrolyte particles Li 1.3 Si 0.225 V 1.36 (PO4)3. The conductive agent was mixed at a mass ratio of 90:9:1 and sintered at 900℃ for 2 hours. The sintered material was then pulverized and sieved through a 200-mesh sieve to obtain D. 50 It is a cathode material with a diameter of 8μm to 12μm.

[0097] (2) Preparation of the positive electrode sheet: The above-mentioned positive electrode material, PVDF and NMP are mixed evenly to obtain a slurry, wherein the mass ratio of the positive electrode material to PVDF is 99:1; the solid content of the slurry is 76%, and the viscosity of the slurry is 7800 mPa·s; according to 44.2 mg / cm 2 The above-mentioned slurry was evenly coated on both sides of the aluminum foil, with an electrode area of ​​14.07 cm². 2 The oxide solid electrolyte particles weighed 0.055g, and after drying and rolling, a positive electrode sheet with a thickness of 133μm was obtained.

[0098] 2. Preparation of negative electrode sheet

[0099] like Figure 3 As shown, copper foil is used as the substrate and hung on an unwinding spool. First, lithium metal is used as the target material. After being excited, the lithium metal is uniformly magnetron sputtered onto the copper foil, forming a lithium metal beam that creates a lithium metal coating on the copper foil. The thickness of the lithium metal coating on one side is 5 μm. During the magnetron sputtering process, the magnetron sputtering power is 4.5 kW, and the magnetron sputtering vacuum degree is 5 × 10⁻⁶. -3 Pa, the distance between the target and the substrate is 40mm. Next, Li... 1.3 Si 0.225 V 1.36 (PO4)3 was used as the target material, Li 1.3 Si 0.225 V 1.36 (PO4)3, upon excitation, is uniformly magnetron sputtered onto the lithium metal coating, forming a solid electrolyte beam. An oxide solid electrolyte coating then forms on the lithium metal coating, completely covering it. The surface density of the oxide solid electrolyte coating on one side is 3.0 mg / cm³. 2; the vacuum degree of magnetron sputtering is 5*10 -3 Pa, the distance between the target material and the substrate is 40 mm, and the magnetron sputtering power is 4.5 kW; after the first surface of the copper foil substrate is plated, the second surface of the copper foil is plated, and the plating sequence is still lithium metal plating and solid oxide electrolyte layer. The thickness of the double-sided lithium metal plating layer is 10 μm, the thickness of the double-sided solid oxide electrolyte layer is 6 μm, the area of the pole piece is 15.44 cm 2 , and the weight of the solid electrolyte is 0.093 g. Finally, the negative pole piece with the completed plating is wound.

[0100] 3. The lithium metal negative pole piece, the separator, and the positive pole piece are wound to make a 1254 button cell, 1, 3-dioxolane is injected into the battery, and the mass ratio of the oxide solid electrolyte particles Li 1.3 Si 0.225 V 1.36 (PO4)3 to 1, 3-dioxolane is 1:0.1, the cell is sealed, the battery is statically placed at 45°C for 24 h, and then statically placed at 60°C for 24 h, and the in-situ polymerization of 1, 3-dioxolane is completed.

[0101] 4. Determination of the molecular weight of the gel polymer after in-situ polymerization: the battery is disassembled and heated to 150°C, the melting point of the substances in the battery except the gel polymer is much higher than 150°C, the collected liquid substances are the gel polymer, the gel permeation chromatography is used, and the molecular weight of the gel polymer is determined to be 24582 g / mol.

[0102] Example 2

[0103] The same as example 1, except that the mass ratio of the oxide solid electrolyte particles Li 1.3 Si 0.225 V 1.36 (PO4)3 to 1, 3-dioxolane is 1:0.2; and the molecular weight of the gel polymer is 25134 g / mol.

[0104] Example 3

[0105] The same as example 1, except that the mass ratio of the oxide solid electrolyte particles Li 1.3 Si 0.225 V 1.36 (PO4)3 to 1, 3-dioxolane is 1:0.3; and the molecular weight of the gel polymer is 25617 g / mol.

[0106] Example 4

[0107] The same as example 1, except that the mass ratio of the oxide solid electrolyte particles Li 1.3 Si 0.225 V 1.36The mass ratio of (PO4)3 to 1,3-dioxolane is 1:0.4; the molecular weight of the gel polymer is 24361 g / mol.

[0108] Example 5

[0109] The same as example 1, except that the oxide solid-state electrolyte particles Li 1.3 Si 0.225 V 1.36 The mass ratio of (PO4)3 to 1,3-dioxolane is 1:0.5; the molecular weight of the gel polymer is 25725 g / mol.

[0110] Example 6

[0111] The same as example 1, except that the oxide solid-state electrolyte particles Li 1.3 Si 0.225 V 1.36 The mass ratio of (PO4)3 to 1,3-dioxolane is 1:0.6; the molecular weight of the gel polymer is 25937 g / mol.

[0112] Example 7

[0113] 1. Preparation of the positive electrode sheet

[0114] In an argon dry atmosphere with a water content of less than 1 ppm and an oxygen content of less than 1 ppm, 35.2 g of positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O2, 3.2 g of sulfide solid-state electrolyte particles Li2S-P2S5, 0.4 g of graphene, 0.8 g of polytetrafluoroethylene, and 0.4 g of butadiene-styrene rubber were weighed and mixed into a ball mill tank to obtain a mixed powder. During the mixing and ball milling process, the mass ratio of the ball milling beads to the total mass of the mixture was 10:1, the mass ratio of large balls to small balls was 2:1, the rotation speed was set to 360 r / min, and the ball milling time was 60 min.

[0115] In an argon dry atmosphere with a water content of less than 1 ppm and an oxygen content of less than 1 ppm, aluminum foil was used as the positive electrode current collector and hung on the unwinding shaft, and the above-mentioned mixed powder was used as the target material. The powder was sprayed onto the surface of the aluminum foil by powder spraying. During the powder spraying process, the electrostatic voltage was 70 kV, the compressed argon gas pressure was 6.5 kg / cm 2, the electrostatic current is 15 μA, the powder flow rate pressure is 0.45 MPa, the atomization pressure is 0.40 MPa, and the distance between the spray gun nozzle and the aluminum foil is 40 mm. After completing the single-side spraying of the aluminum foil, the second side of the aluminum foil is sprayed, and the steps and parameter settings are the same as above, to obtain a double-side powder-sprayed positive electrode sheet. The coating surface density of the double-side powder-sprayed positive electrode sheet prepared is 44.2 g / cm 2 ; the electrode sheet area is 14.07 cm 2 ; and the sulfide solid-state electrolyte weight is 0.055 g.

[0116] The obtained powder-sprayed positive electrode sheet is placed in a high-temperature furnace for heating and softening. The heating temperature is set to 200 ℃, and the heating time is 5 min. Through high-temperature softening of polytetrafluoroethylene and butadiene-styrene rubber, LiNi 0.8 Co 0.1 Mn 0.1 O2, graphene, and Li2S-P2S5 solid-state electrolyte are adsorbed on the aluminum foil. After heating and softening of the powder-sprayed positive electrode sheet, a 133 μm positive electrode sheet is obtained through a rolling process. During the rolling process, the rolling pressure is 90 T, and the rolling speed is 50 m / min.

[0117] 2. The steps for preparing the negative electrode sheet are the same as in Example 1.

[0118] 3. The lithium metal negative electrode sheet, the separator, and the positive electrode sheet are wound to produce a 1254 button cell. 1,3-dioxolane is injected into the cell, and the mass ratio of the solid-state electrolyte particles (including oxide solid-state electrolyte particles and sulfide solid-state electrolyte particles) to 1,3-dioxolane is 1:0.4. The cell is sealed, and the battery is statically placed at 45 ℃ for 24 h and then at 60 ℃ for 24 h, to complete the in-situ polymerization of 1,3-dioxolane.

[0119] 4. Determination of the molecular weight of the gel polymer after in-situ polymerization: The cell is disassembled and heated to 150 ℃. The melting point of the substances in the cell, except for the gel polymer, is much higher than 150 ℃. The collected liquid substance is the gel polymer. The gel permeation chromatography method is used to determine that the molecular weight of the gel polymer is 34628 g / mol.

[0120] Example 8

[0121] The same as Example 7, except that the positive electrode active material is LiFePO4; the polymer monomer injected into the cell is oxirane; and the molecular weight of the gel polymer is 18526 g / mol.

[0122] Example 9

[0123] Example 4 except that: the positive active material was LiFePO4; the polymer monomer injected into the battery was ethylene oxide; and the molecular weight of the gel polymer was 13734 g / mol.

[0124] Example 10

[0125] Example 4 except that: the oxide solid-state electrolyte particles were Li7La3Zr2O11; and the molecular weight of the gel polymer was 24816 g / mol. 1.3 Al 0.3 Ti 1.7 (PO4)3; and the molecular weight of the gel polymer was 23674 g / mol.

[0126] Example 11

[0127] Example 4 except that: the oxide solid-state electrolyte particles were Li7La3Zr2O11; and the molecular weight of the gel polymer was 24816 g / mol. 3.6 Ge 0.6 V 0.4 O4; and the molecular weight of the gel polymer was 24671 g / mol.

[0128] Example 12

[0129] Example 4 except that: the oxide solid-state electrolyte particles were Li7La3Zr2O11; and the molecular weight of the gel polymer was 24816 g / mol. 0.34 La 0.51 TiO 2.94 ; and the molecular weight of the gel polymer was 24736 g / mol.

[0130] Example 13

[0131] Example 4 except that: the oxide solid-state electrolyte particles were Li7La3Zr2O11; and the molecular weight of the gel polymer was 24816 g / mol. 12 ; and the molecular weight of the gel polymer was 24816 g / mol.

[0132] Example 14

[0133] Example 7 except that: the sulfide solid-state electrolyte particles were Li2S-B2S3; and the molecular weight of the gel polymer was 32619 g / mol.

[0134] Example 15

[0135] Example 7 except that: the sulfide solid-state electrolyte particles were Li2S-SiS2; and the molecular weight of the gel polymer was 33284 g / mol.

[0136] Comparative Example 1

[0137] Example 1 except that: no 1,3-dioxolane was injected into the battery.

[0138] The preparation materials of the solid-state batteries of each embodiment and the comparative example are shown in Table 1.

[0139] Table 1 Preparation materials of solid-state batteries

[0140]

[0141]

[0142] Electrochemical performance test

[0143] The internal resistance of the button cell was tested by a battery internal resistance tester; the capacity of the button cell was tested under a current density of 0.5 C, and the specific capacity = the capacity of the button cell / the weight of the electrode material; the cycle performance of the button cell was tested by 50 cycles of charge and discharge under a current density of 0.5 C. The test results are shown in Table 2.

[0144] Table 2 Performance test results of solid-state batteries

[0145]

[0146]

[0147] Comparative Example 1 differs from Examples 1-7 in that no monomer of the organic polymer is added. The electrochemical performance test results show that the specific capacity of Comparative Example 1 is the lowest, and the internal resistance is the highest; the specific capacity retention rate after 50 cycles is lower than that of Examples 1-7, and the internal resistance growth rate is also higher than that of Examples 1-7. This shows that filling the organic polymer in the interstice of the oxide or sulfide can effectively improve the specific capacity of the solid-state battery and reduce the internal resistance of the battery; and a high specific capacity and a low internal resistance can also be maintained during use.

[0148] From Examples 1-4, when the mass ratio of the oxide and sulfide solid-state electrolyte particles to the monomer of the organic polymer is 1:(0.1-0.4), the specific capacity of the battery increases and the resistance decreases with the increase of the mass of the organic polymer; the reason is that the organic polymer gradually fills the pores between the solid-state electrolyte particles, and the interface resistance gradually disappears.

[0149] From Examples 5-6, when the mass ratio of the oxide and sulfide solid-state electrolyte particles to the monomer of the organic polymer reaches 1:(0.5-0.6), the internal resistance of the battery has a rising trend, and the specific capacity of the positive active material has a decreasing trend; the reason is that the excessive addition of the organic polymer reduces the overall ionic conductivity of the electrolyte.

[0150] Comparing Example 7 with Examples 1-6, it can be seen that the sulfide solid-state electrolyte has a higher ionic conductivity and a lower resistance than the oxide solid-state electrolyte; therefore, the prepared solid-state battery has a higher specific capacity and a lower resistance.

[0151] Examples 8-9 use ethylene oxide instead of 1,3-dioxolane to in-situ polymerize polyethylene oxide. Since the electrochemical window of polyethylene oxide (0-4.0V) is lower than that of poly-1,3-dioxolane (0-4.4V), the positive active material uses a lithium iron phosphate system.

[0152] Examples 10-13 differ from Example 4 only in that the oxide solid-state electrolyte loaded on the positive electrode sheet is different, and the performance of the batteries produced is not significantly different. This shows that using Li 1.3 Si 0.225 V 1.36 (PO4)3, Li 0.34 La 0.51 TiO 2.94 , Li7La3Zr2O 12 , Li 3.6 Ge 0.6 V 0.4 O4 and Li 1.3 Al 0.3 Ti 1.7 (PO4)3as the oxide solid-state electrolyte can produce the high-gram capacity and low-resistance solid-state battery of the present application.

[0153] Examples 14-15 differ from Example 7 only in that the sulfide solid-state electrolyte loaded on the positive electrode sheet is different, and the performance of the batteries produced is not significantly different. This shows that using Li2S-P2S5, Li2S-SiS2 and Li2S-B2S3 as the sulfide solid-state electrolyte can produce the high-gram capacity and low-resistance solid-state battery of the present application.

[0154] Detection of lithium dendrites

[0155] The button cells were charged and discharged at a current density of 0.5C, the cycle number at which the capacity retention rate of the button cell was 80% was tested, and the number of lithium dendrites on the surface of the solid-state electrolyte in contact with the positive electrode was tested. The test results are shown in Table 3.

[0156] Table 3 Test results of lithium dendrites

[0157]

[0158]

[0159] From the above detection results, when the mass ratio of the solid-state electrolyte particles to the monomer of the organic polymer is 1:0.1, there is a slight phenomenon of lithium dendrites penetrating the solid-state electrolyte separator; the solid-state battery without the addition of the organic polymer has a large number of lithium dendrites penetrating the solid-state electrolyte separator. This shows that the addition of an appropriate amount of the monomer of the organic polymer can effectively prevent the growth of lithium dendrites and improve the life and safety of lithium batteries.

[0160] The technical features of the above-described embodiments can be combined in any manner. For the sake of brevity, not all possible combinations of the technical features are described, but it is understood that the scope of the present disclosure includes all possible combinations.

[0161] The above-described embodiments are merely representative of several embodiments of the present disclosure, and the description is relatively specific and detailed, but should not be construed as limiting the scope of the patent. It should be noted that, for those skilled in the art, without departing from the concept of the present disclosure, a number of modifications and improvements can be made, which are all within the scope of the present disclosure. Therefore, the scope of the patent of the present disclosure should be subject to the appended claims.

Claims

1. A solid-state battery, characterized by, The battery includes a shell, a positive electrode sheet, a separator and a negative electrode sheet arranged in the shell, the positive electrode sheet and the negative electrode sheet are loaded with solid electrolyte particles, and the shell is filled with an organic polymer; The solid electrolyte particles include one or more of oxide solid electrolyte particles and sulfide solid electrolyte particles; at least part of the organic polymer is filled in the gap of the solid electrolyte particles; the mass ratio of the total mass of the solid electrolyte particles on the positive electrode sheet and the negative electrode sheet to the mass of the monomer of the organic polymer is 1:(0.3-0.4); The positive electrode sheet includes a positive electrode current collector, a positive electrode active material loaded on the positive electrode current collector, solid electrolyte particles, a conductive agent, a binder and a solvent; the mass ratio of the positive electrode active material to the solid electrolyte particles, the conductive agent and the binder on the positive electrode sheet is (85-95):(8-10):(0.5-1.5):(1-3).

2. The solid-state battery of claim 1, wherein, The organic polymer is obtained by in-situ polymerization of the monomer filled in the shell by heating.

3. The solid-state battery of claim 1, wherein, The organic polymer includes one or more of polyethylene oxide and polydioxolane.

4. The solid-state battery of claim 1, wherein, The monomer of the organic polymer includes one or more of ethylene oxide and 1,3-dioxolane.

5. The solid-state battery according to any one of claims 1 to 4, characterized by The molecular weight of the organic polymer is 12000 g / mol-35000 g / mol.

6. The solid-state battery according to any one of claims 1 to 4, characterized by the oxide solid state electrolyte is selected from one or more of Li 1.3 Si 0.225 V 1.36 (PO4)3, Li 0.34 La 0.51 TiO 2.94 , Li7La3Zr2O 12 , Li 3.6 Ge 0.6 V 0.4 O4 and Li 1.3 Al 0.3 Ti 1.7 (PO4)3; and / or, The sulfide solid electrolyte is selected from one or more of Li2S-P2S5, Li2S-SiS2 and Li2S-B2S3.

7. The solid-state battery according to any one of claims 1 to 4, characterized by The positive electrode active material is selected from one or more of lithium cobaltate, lithium iron phosphate, nickel-cobalt-manganese ternary material and nickel-cobalt-aluminum ternary material.

8. The method of producing a solid-state battery according to any one of claims 1 to 7, characterized by, The method includes the following steps: arranging the positive electrode sheet, the separator and the negative electrode sheet in the shell; injecting the monomer of the organic polymer into the shell; sealing the shell and heating to complete the in-situ polymerization of the monomer of the organic polymer.

9. The method of producing a solid-state battery according to claim 8, characterized by, The heating temperature is 50℃-70℃, and the heating time is 20h-30h.

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