Solid-state electrode plate, preparation method thereof and battery

Abstract

The invention belongs to the field of batteries, and particularly relates to a solid-state electrode plate, a preparation method thereof and a battery. The preparation method comprises the following steps: 1) preparing slurry by a wet method; the slurry comprises an active substance, a first conductive agent and a mixed solvent; the mixed solvent is a mixture of acrylonitrile and a weak (non) polar solvent; 2) polymerizing and drying the slurry obtained in the step 1) to obtain first mixture powder; 3) performing dry mixing to obtain second mixture powder; the second mixture powder comprises an adhesive capable of being fiberized, a second conductive agent and a solid electrolyte; the preparation method comprises the following steps: firstly, carrying out wet homogenization on a positive active material and a conductive agent in a mixed solvent of acrylonitrile and a weak (non) polar solvent to ensure that the active material and the conductive agent are uniformly mixed, then adding an initiator to polymerize acrylonitrile, and then drying, so that the generated polyacrylonitrile can play a bonding role, and meanwhile, the Young modulus is reduced; contact with a solid electrolyte is improved.

Description

Technical Field

[0001] The present invention belongs to the field of batteries, and particularly relates to a solid-state electrode sheet, a preparation method thereof, and a battery. Background Art

[0002] With the rapid development of lithium-ion battery technology, higher requirements for battery safety performance have been put forward in the fields of new energy vehicles, energy storage, etc. Solid-state batteries use non-flammable solid-state battery electrolytes to replace liquid electrolytes and polymer diaphragms using flammable organic solvents, significantly improving the safety of battery monomers and battery systems. At the same time, they can better adapt to high-energy-density cathode and anode materials, realizing synchronous improvement of battery energy density. In all-solid-state batteries, solid-state electrolytes are usually added to the electrodes to improve lithium-ion conduction ability. The reasonable distribution and sufficient contact of substances such as active materials, solid-state electrolytes, binders, and conductive agents are beneficial to the conduction of solid-phase electrons and lithium ions in the electrodes. Therefore, electrode preparation is a key technical link in all-solid-state batteries.

[0003] Electrode preparation usually adopts a wet process, that is, active materials, solid-state electrolytes, binders, and conductive agents are mixed in a solvent to obtain a slurry, and then processes such as coating, drying, and rolling are carried out to obtain an electrode sheet. However, the choice of solvent type has a great influence on the mixing and drying effects of active materials, binders, and conductive agents. The use of polar solvents will also cause a decrease in the stability of sulfide solid-state electrolytes, thereby affecting the performance of the electrodes. The solvents used in the process of preparing the slurry may also have the disadvantages of high toxicity and high cost, and the residual solvents will reduce the ionic conductivity of the electrodes.

[0004] To solve the problems existing in the wet process, researchers have developed a dry process, that is, an electrode preparation method without using solvents, directly mixing active materials, solid-state electrolytes, binders, and conductive agents, thereby avoiding the influence of solvents on the mixing effect and drying process. The dry process has the following advantages: 1. The energy consumption can be greatly reduced without the wet coating and drying processes; 2. The use of a large amount of organic solvents is avoided, reducing production costs and environmental pollution; 3. The phenomenon of electrode sheet delamination when preparing relatively thick electrodes is avoided; 4. Solvents that react with sulfide solid-state electrolytes are not used during the dry film-forming process, and only a very small amount of binder is required, which is particularly suitable for preparing sulfide all-solid-state batteries. However, the dry preparation of electrodes also has the problem that the mixing effect is not as uniform as that of the wet process. At the same time, the positive electrode sheet prepared by the dry method has poor toughness and is prone to fragmentation during the process of pressing with the solid-state electrolyte.

[0005] Therefore, developing an electrode preparation method that can not only ensure the uniform mixing of substances such as active materials, solid-state electrolytes, binders, and conductive agents but also avoid the negative effects of solvents is an important technical problem faced in the current field of all-solid-state batteries. Summary of the Invention

[0006] The object of the present invention is to overcome the drawbacks in the prior art and provide a solid-state electrode sheet, a preparation method thereof, and a battery.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A preparation method of a solid-state electrode sheet, comprising the following steps:

[0009] 1) Preparing a slurry by a wet method; the slurry includes an active material, a first conductive agent, and a mixed solvent; the mixed solvent is a mixture of acrylonitrile and a solvent;

[0010] 2) Polymerizing and drying the slurry obtained in step 1) to obtain a first mixture powder;

[0011] 3) Mixing by a dry method to obtain a second mixture powder; the second mixture powder includes a fibrillatable binder, a second conductive agent, a solid electrolyte, and the first mixture powder obtained in step 2);

[0012] 4) Performing hot roll pressing on the second mixture powder in step 3) to obtain an electrode film;

[0013] 5) Thermally pressing and laminating the electrode film with a current collector to obtain an electrode.

[0014] The mass ratio of the active material, the solid electrolyte, the conductive agent, and the fibrillatable binder is (50 - 90):(15 - 40):(0.5 - 5):(1 - 6); preferably 66.5:27:2.5:4.

[0015] Preferably, the conductive agent includes a first conductive agent and a second conductive agent; the ratio of the first conductive agent to the second conductive agent is 1:(3 - 9); preferably 1:4.

[0016] In step 1), the total solid content of the first conductive agent and the active material is 70 - 80%;

[0017] Preferably, the first conductive agent is a linear conductive agent, carbon nanotubes; preferably, the solvent is a weakly polar solvent or a non-polar solvent, and preferably, the solvent is at least one of heptane, toluene, and xylene;

[0018] The mass ratio of acrylonitrile to the solvent is 1:(4 - 9), more preferably 1:5.

[0019] Any one or more of the layered structure oxide material, the spinel structure material, and the olivine structure material.

[0020] The specific steps of step 1) are as follows: Add the first conductive agent and the mixed solvent into a double planetary homogenizer for stirring. Slow stirring at 50 - 500 rpm and fast stirring at 500 - 5000 rpm are carried out simultaneously. The stirring time is 20 - 60 min. Then add the active material and carry out slow stirring at 50 - 500 rpm for 10 - 30 min, and then fast stirring at 2000 - 5000 rpm for 30 - 900 min.

[0021] The specific steps of step 2) are as follows: Add an initiator to the slurry in step 1) to cause the polymerization reaction of acrylonitrile to generate a mixture containing polyacrylonitrile; carry out drying at 90 - 150 °C, and obtain the first mixture powder after pulverization with a ball mill;

[0022] Preferably, the initiator is at least one of cumene hydroperoxide, benzoyl peroxide, tert-butyl hydroperoxide, hydrogen peroxide, persulfate, azobisisobutyronitrile; the addition amount of the initiator is 0.5 - 2% of the acrylonitrile content; preferably 1%.

[0023] The specific steps of step 3) are as follows: Add the fibrillatable binder, the second conductive agent, and the solid electrolyte into a mixer and stir at a slow speed of 50 - 500 rpm to mix uniformly in the dry state. Then add the first mixture powder in step 2), keep the temperature at 25 - 200 °C, and then use a high-speed mixer to carry out fibrillization treatment at a rotation speed of 1000 - 8000 to obtain the second mixture powder;

[0024] Preferably, the solid electrolyte is a sulfide solid electrolyte, including Li (6-x) PS (5-x) M (1+x) or at least one of yLi2S·(1 - y)P2S5, Li 10 GeP2S 12 where 0 ≤ x ≤ 0.6, 0.2 ≤ y ≤ 0.8, M = Cl, Br, I;

[0025] Preferably, the fibrillatable binder has a molecular weight ≥ 4×10 6 g / mol and includes any one or more of polytetrafluoroethylene, ultra-high molecular weight polyethylene, polyvinylidene fluoride, polyvinylidene fluoride - hexafluoropropylene, polyethylene oxide, polypropylene, and polyacrylonitrile.

[0026] The temperature of the hot roll pressing treatment in step 4) is 25 - 200 °C, and the rolling pressure in the horizontal and vertical directions is 1 - 60 t. Preferably 150 °C, 20 t.

[0027] The specific steps of step 5) are that the electrode film and the current collector are thermocompression bonded at 80-180 °C and 1-60 t; preferably, the current collector is at least one of aluminum foil, carbon-coated aluminum foil, and composite aluminum foil.

[0028] The present invention also includes a solid electrode sheet obtained by the preparation method described above.

[0029] The present invention also includes a battery comprising the solid electrode sheet.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] The technical solution of the present application aims at the problems that the solvent in the wet process affects the stability of the solid electrolyte and the ionic conductivity of the electrode sheet, and the mixing uniformity of various substances in the dry process is poor. The present invention provides a method for preparing an electrode sheet and an all-solid-state battery. First, the positive active material and the conductive agent are wet-milled in a mixed solvent of acrylonitrile and a solvent to ensure uniform mixing of the active material and the conductive agent. Then, an initiator is added to polymerize acrylonitrile and then dried. The generated polyacrylonitrile can play a binding role, while reducing the Young's modulus and improving the contact with the solid electrolyte. The obtained product is mixed with the solid electrolyte using a dry process, which can not only ensure uniform mixing of various substances but also avoid the negative impact of using a solvent, achieving the purpose of improving the electrode performance. Detailed implementation manners

[0032] In order to enable those skilled in the art of the present technology to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with the best embodiments.

[0033] Example 1

[0034] A method for preparing a solid electrode sheet, comprising the following steps:

[0035] 1) Wet preparation of the slurry; the positive electrode material active substance lithium nickel cobalt manganese oxide (LiNi 0.9 Co 0.05 Mn 0.05 O2), solid electrolyte (Li6PS5Cl), first conductive agent linear conductive agent carbon nanotubes, second conductive agent carbon black, and fibrillable binder polytetrafluoroethylene (PTFE, molecular weight ≥ 4×10 6 g / mol, the same below) are weighed according to a mass ratio of 66.5:27:0.5:2:4;

[0036] The linear conductive agent carbon nanotubes and a mixed solvent of acrylonitrile and heptane with a mass mixing ratio of 1:4 are added to a double planetary homogenizer for stirring. Slow stirring at 200 rpm and fast stirring at 3000 rpm are carried out simultaneously, and the stirring time is 40 min. Then, the positive electrode material active substance lithium nickel cobalt manganese oxide (LiNi0.9 Co 0.05 Mn 0.05 O2), stir slowly at 200 rpm for 15 min, and then stir quickly at 3000 rpm for 60 min to make the active material of the positive electrode, lithium nickel cobalt manganese oxide (LiNi 0.9 Co 0.05 Mn 0.05 O2), and carbon nanotubes, a linear conductive agent, are mixed evenly in a wet state to obtain slurry A1 with a solid content of 70%;

[0037] 2) Polymerize and dry the slurry obtained in step 1) to obtain the first mixture powder;

[0038] Add initiator azobisisobutyronitrile (1% of the mass of acrylonitrile) to slurry A1 to cause acrylonitrile to undergo a polymerization reaction to form a mixture containing polyacrylonitrile, obtaining B1. Dry B1 at 110 °C to remove the solvent, and pulverize it with a ball mill to obtain the first mixture powder C1;

[0039] 3) Dry mixing to obtain the second mixture powder; Add fibrillatable polytetrafluoroethylene (PTFE), carbon black, and solid electrolyte (Li6PS5Cl) to a mixer and stir slowly at 200 rpm to mix evenly in a dry state. Then add the first mixture powder C1, keep the temperature at 150 °C, and then use a high-speed mixer to perform fibrillation treatment at a rotational speed of 6000 rpm to obtain the second mixture powder D1;

[0040] 4) Perform hot roll pressing on the second mixture powder in step 3) to obtain an electrode film; Perform hot roll pressing on the second mixture powder D1. The temperature of the hot roll pressing treatment is 150 °C, and the calendering force in the horizontal and vertical directions is 20 t to obtain an electrode film. Then perform edge trimming on the electrode film to obtain a regular electrode film;

[0041] 5) Thermally press and composite the electrode film with a current collector to obtain an electrode. Thermally press and composite the electrode film with aluminum foil as the current collector at 120 °C and 20 t conditions to obtain an electrode, and use a manual slicer to obtain a positive electrode sheet E1 with a diameter of Φ9 mm.

[0042] Example 2

[0043] A method for preparing a solid-state electrode sheet, comprising the following steps:

[0044] 1) Wet preparation of slurry; The active material of the positive electrode, lithium nickel cobalt manganese oxide (LiNi 0.9 Co 0.05 Mn 0.05Oxygen (O₂), solid electrolyte (Li₆PS₅Cl), first conductive agent (linear conductive agent carbon nanotubes), second conductive agent (carbon black), and fibrillatable binder (polytetrafluoroethylene, PTFE) are weighed according to a mass ratio of 66.5:27:0.5:2:4.

[0045] The linear conductive agent carbon nanotubes and a mixed solvent of acrylonitrile and heptane with a mass mixing ratio of 1:5 are added to a double planetary homogenizer for stirring. Slow stirring at 200 rpm and fast stirring at 3000 rpm are carried out simultaneously for 40 minutes. Then, the cathode active material lithium nickel cobalt manganese oxide (LiNi 0.9 Co 0.05 Mn 0.05 O₂) is added, and slow stirring at 200 rpm is carried out for 15 minutes, followed by fast stirring at 3000 rpm for 60 minutes, so that the cathode active material lithium nickel cobalt manganese oxide (LiNi 0.9 Co 0.05 Mn 0.05 O₂) and the linear conductive agent carbon nanotubes are uniformly mixed in the wet state to obtain a slurry A2 with a solid content of 70%.

[0046] 2) The slurry obtained in step 1) is polymerized and dried to obtain a first mixture powder.

[0047] An initiator azobisisobutyronitrile (1% of the mass of acrylonitrile) is added to slurry A2 to cause the polymerization reaction of acrylonitrile, generating a mixture containing polyacrylonitrile to obtain B2. B2 is dried at 110 °C to remove the solvent, and then pulverized by a ball mill to obtain a first mixture powder C2.

[0048] 3) Dry mixing is carried out to obtain a second mixture powder; the fibrillatable polytetrafluoroethylene (PTFE), carbon black, and solid electrolyte (Li₆PS₅Cl) are added to a mixer and stirred at a slow speed of 200 rpm to be uniformly mixed in the dry state. Then, the first mixture powder C2 is added, and the temperature is maintained at 150 °C. Then, a high-speed mixer is used for fibrillation treatment at a rotational speed of 6000 rpm to obtain a second mixture powder D2.

[0049] 4) The second mixture powder obtained in step 3) is subjected to hot roll pressing to obtain an electrode film; the second mixture powder D2 is subjected to hot roll pressing. The temperature of the hot roll pressing treatment is 150 °C, and the rolling force in the horizontal and vertical directions is 20 t to obtain an electrode film. Then, the electrode film is trimmed to obtain a regular electrode film.

[0050] 5) The electrode film and the current collector are thermally pressed and compounded to obtain an electrode. The electrode film and the current collector aluminum foil are thermally pressed and compounded at 120 °C and 20 t to obtain an electrode, and a Φ9 mm positive electrode sheet E2 is obtained by a manual slicing machine.

[0051] Example 3

[0052] 1) Prepare the slurry by the wet method; Weigh the cathode material active substance lithium nickel cobalt manganese oxide (LiNi 0.9 Co 0.05 Mn 0.05 O2), solid-state electrolyte (Li6PS5Cl), the first conductive agent linear conductive agent carbon nanotubes, the second conductive agent carbon black, and the fibrillatable binder polytetrafluoroethylene (PTFE) according to a mass ratio of 66.5:27:0.5:2:4;

[0053] Add the linear conductive agent carbon nanotubes and a mixed solvent of acrylonitrile and heptane with a mass mixing ratio of 1:7 to a double planetary homogenizer for stirring. Stir at a low speed of 200 rpm and a high speed of 3000 rpm simultaneously for 40 min. Then add the cathode material active substance lithium nickel cobalt manganese oxide (LiNi 0.9 Co 0.05 Mn 0.05 O2), and stir at a low speed of 200 rpm for 15 min, then stir at a high speed of 3000 rpm for 60 min to uniformly mix the cathode material active substance lithium nickel cobalt manganese oxide (LiNi 0.9 Co 0.05 Mn 0.05 O2) and the linear conductive agent carbon nanotubes in the wet state to obtain a slurry A3 with a solid content of 70%;

[0054] 2) Polymerize and dry the slurry obtained in step 1) to obtain the first mixture powder;

[0055] Add an initiator azobisisobutyronitrile (1% of the mass of acrylonitrile) to the slurry A3 to cause the polymerization reaction of acrylonitrile to generate a mixture containing polyacrylonitrile, obtaining B3. Dry B3 at 110 °C to remove the solvent, and pulverize it with a ball mill to obtain the first mixture powder C3;

[0056] 3) Mix by the dry method to obtain the second mixture powder; Add the fibrillatable polytetrafluoroethylene (PTFE), carbon black, and solid-state electrolyte (Li6PS5Cl) to a mixer and stir at a low speed of 200 rpm to mix uniformly in the dry state. Then add the first mixture powder C3, keep the temperature at 150 °C, and then use a high-speed mixer to perform fibrillization treatment at a speed of 6000 rpm to obtain the second mixture powder D3;

[0057] 4) Perform hot roll pressing on the second mixture powder in step 3) to obtain the electrode film; Perform hot roll pressing on the second mixture powder D3. The temperature of the hot roll pressing treatment is 150 °C, and the calendering force in the horizontal and vertical directions is 20 t to obtain the electrode film. Then perform edge trimming on the electrode film to obtain a regular electrode film;

[0058] 5) The electrode film and the current collector are hot-pressed and compounded to obtain an electrode. The electrode film and the aluminum foil current collector are hot-pressed and compounded at 120 °C and 20 t to obtain an electrode, and a positive electrode sheet E3 with a diameter of Φ9 mm is obtained using a manual slicing machine.

[0059] Example 4

[0060] 1) Prepare the slurry by the wet method; the active material of the positive electrode material, lithium nickel cobalt manganese oxide (LiNi 0.9 Co 0.05 Mn 0.05 O2), solid-state electrolyte (Li6PS5Cl), the first conductive agent, linear conductive agent carbon nanotubes, the second conductive agent carbon black, and the fibrillatable binder polytetrafluoroethylene (PTFE) are weighed according to a mass ratio of 66.5:27:0.5:2:4;

[0061] The linear conductive agent carbon nanotubes and a mixed solvent of acrylonitrile and heptane with a mass mixing ratio of 1:9 are added to a double planetary homogenizer for stirring. Slow stirring at 200 rpm and fast stirring at 3000 rpm are carried out simultaneously, and the stirring time is 40 min. Then, the active material of the positive electrode material, lithium nickel cobalt manganese oxide (LiNi 0.9 Co 0.05 Mn 0.05 O2) is added, and slow stirring at 200 rpm is carried out for 15 min, and then fast stirring at 3000 rpm is carried out for 60 min, so that the active material of the positive electrode material, lithium nickel cobalt manganese oxide (LiNi 0.9 Co 0.05 Mn 0.05 O2) and the linear conductive agent carbon nanotubes are uniformly mixed in a wet state to obtain a slurry A4 with a solid content of 70%;

[0062] 2) The slurry obtained in step 1) is polymerized and dried to obtain a first mixture powder;

[0063] An initiator, azobisisobutyronitrile (1% of the mass of acrylonitrile), is added to the slurry A4 to cause the polymerization reaction of acrylonitrile to generate a mixture containing polyacrylonitrile, and B4 is obtained. B4 is dried at 110 °C to remove the solvent, and after being pulverized by a ball mill, a first mixture powder C4 is obtained;

[0064] 3) Dry mixing is carried out to obtain a second mixture powder; the fibrillatable polytetrafluoroethylene (PTFE), carbon black, and solid-state electrolyte (Li6PS5Cl) are added to a mixer and stirred at a slow speed of 200 rpm, and are uniformly mixed in a dry state. Then, the first mixture powder C4 is added, and the temperature is maintained at 150 °C. Then, a high-speed mixer is used for fibrillating treatment at a rotation speed of 6000 rpm to obtain a second mixture powder D4;

[0065] 4) The second mixture powder in step 3) is subjected to hot roll pressing to obtain an electrode film; the second mixture powder D4 is subjected to hot roll pressing. The temperature of the hot roll pressing is 150 °C, and the rolling force in the horizontal and vertical directions is 20 t to obtain an electrode film. Then, the electrode film is trimmed to obtain a regular electrode film;

[0066] 5) The electrode film and the current collector are hot-pressed and compounded to obtain an electrode. The electrode film and the aluminum foil current collector are hot-pressed and compounded at 120 °C and 20 t to obtain an electrode, and a positive electrode sheet E4 with a diameter of Φ9 mm is obtained using a manual slicing machine.

[0067] Comparative Example 1

[0068] The active material of the positive electrode, lithium nickel cobalt manganate (LiNi 0.9 Co 0.05 Mn 0.05 O2), solid-state electrolyte (Li6PS5Cl), linear conductive agent carbon nanotubes, carbon black, and polytetrafluoroethylene (PTFE, the same as in the example) are weighed according to a mass ratio of 66.5:27:0.5:2:4. The solid-state electrolyte (Li6PS5Cl), polytetrafluoroethylene, linear conductive agent carbon nanotubes, carbon black, and heptane solvent are added to a double planetary homogenizer for stirring. Slow stirring at 200 rpm and fast stirring at 3000 rpm are carried out simultaneously for 40 min. Then, the active material of the positive electrode, lithium nickel cobalt manganate (LiNi 0.9 Co 0.05 Mn 0.05 O2) is added, and slow stirring at 200 rpm is carried out for 15 min, and then fast stirring at 3000 rpm is carried out for 60 min to make the active material of the positive electrode, lithium nickel cobalt manganate (LiNi 0.9 Co 0.05 Mn 0.05 O2), solid-state electrolyte (Li6PS5Cl), linear conductive agent carbon nanotubes, carbon black, and polytetrafluoroethylene are uniformly mixed in a wet state to obtain a slurry A5 with a solid content of 70%; the slurry A5 is uniformly coated on the aluminum foil current collector and dried at 120 °C to obtain an electrode, and a positive electrode sheet D5 with a diameter of Φ9 mm is obtained using a manual slicing machine.

[0069] Comparative Example 2

[0070] The active material of the positive electrode, lithium nickel cobalt manganate (LiNi 0.9 Co 0.05 Mn 0.05O2), solid electrolyte (Li6PS5Cl), linear conductive agent carbon nanotubes, carbon black, and polytetrafluoroethylene (PTFE) were weighed according to a mass ratio of 66.5:27:0.5:2:4, placed in an agate mortar, and ground for 30 min to obtain a mixture powder C6. The mixed material C6 was added to a mold battery, and a pressure of 3 t was applied using a manual hydraulic press to obtain an electrode D6.

[0071] The assembly method of the solid-state battery is as follows:

[0072] (1) Weigh the solid electrolyte (Li6PS5Cl) and the composite positive electrode material sheet in a ratio of 3:1, use a hydraulic press to apply pressure and press them into a mold battery, and hold for 3 min to preliminarily form the solid electrolyte.

[0073] (2) Take the composite positive electrode material sheet, use a hydraulic press to apply pressure and press it into a mold battery, and hold for 3 min to closely combine the positive electrode sheet and the solid electrolyte.

[0074] (3) Take a pure indium sheet with a diameter of Φ9 mm and a thickness of 100 μm and a pure lithium sheet with a diameter of Φ9 mm and a thickness of 50 μm, composite the two with a little pressure, and press them into the other side of the solid electrolyte with a pressure of 1 t to finally assemble a mold battery.

[0075] The method for testing the electrochemical performance is as follows:

[0076] At room temperature, the constant current charge-discharge performance of the all-solid-state battery was tested at a voltage range of 2.5 - 4.2 V and a current density of 0.1 C.

[0077] The test results are listed in Table 1:

[0078]

[0079] It can be seen from Examples 1 - 4 in Table 1 that the first charge capacity of the examples prepared by combining the dry method and the wet method of the present application is 242 - 246 mAh / g, and the first discharge capacity is 202 - 212 mAh / g, which are generally higher than those of Comparative Examples 1 and 2. This shows that the conductive agent and the solid electrolyte of the electrode sheet prepared by combining the dry method and the wet method are evenly distributed, forming a conductive network structure. The all-solid-state mold battery assembled from the electrode sheet has a high discharge specific capacity, a high first discharge efficiency, and excellent cycling performance.

[0080] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a solid electrode sheet, characterized in that: The steps include: 1) preparing slurry by wet method; the slurry comprises active material, a first conductive agent and a mixed solvent; the mixed solvent is a mixture of acrylonitrile and a solvent; 2) polymerizing and drying the slurry obtained in step 1) to obtain a first mixture powder; 3) dry mixing to obtain a second mixture powder; the second mixture powder comprises a fiberizable binder, a second conductive agent, a solid electrolyte and the first mixture powder obtained in step 2); 4) subjecting the second mixture powder of step 3) to hot roller pressing to obtain an electrode film; 5) The electrode film and the current collector are hot-pressed to obtain an electrode.

2. The method for preparing a solid electrode sheet according to claim 1, characterized in that: The mass ratio of the active material, the solid electrolyte, the conductive agent, and the fiberizable binder is (50-90): (15-40): (0.5-5): (1-6); Preferably, the conductive agent includes a first conductive agent and a second conductive agent; the ratio of the first conductive agent to the second conductive agent is 1:(3-9); preferably 1:

4.

3. The method for preparing a solid electrode sheet according to claim 1, characterized in that: In step 1), the total solid content of the first conductive agent and the active material is 70-80%; Preferably, the first conductive agent is a linear conductive agent carbon nanotube; preferably, the solvent is a weak polar solvent or a non-polar solvent, preferably, the solvent is at least one of heptane, toluene and xylene; Preferably, the mass ratio of acrylonitrile to solvent is 1:(4-9); more preferably 1:5; Preferably, any one or more of the layered structure oxide material, spinel structure material and olivine structure material.

4. The method for preparing a solid electrode sheet according to claim 3, characterized in that: The specific steps of step 1) are: adding the first conductive agent and the mixed solvent into a double planetary homogenizer for stirring, stirring at a slow speed of 50-500 rpm and a fast speed of 500-5000 rpm at the same time, and the stirring time is 20-60 min, and then adding the active substance, stirring at a slow speed of 50-500 rpm for 10-30 min, and then stirring at a fast speed of 2000-5000 rpm for 30-900 min.

5. The method for preparing a solid electrode sheet according to claim 1, characterized in that: The specific steps of step 2) are: adding an initiator to the slurry of step 1) to polymerize acrylonitrile to generate a mixture containing polyacrylonitrile; drying at 90-150° C., and crushing with a ball mill to obtain a first mixture powder; Preferably, the initiator is at least one of cumene hydroperoxide, dibenzoyl peroxide, tert-butyl hydroperoxide, hydrogen peroxide, persulfate, and azobisisobutyronitrile; the added amount of the initiator is 0.5-2% of the acrylonitrile content; preferably 1%.

6. The method for preparing a solid electrode sheet according to claim 1, characterized in that: The specific steps of step 3) are: Add the fiberizable binder, the second conductive agent, and the solid electrolyte to a mixer and stir slowly at 50-500 rpm, mix them evenly in a dry state, then add the first mixture powder of step 2), keep the temperature at 25-200° C., and then use a high-speed mixer at a speed of 1000-8000 to perform fiberization treatment to obtain a second mixture powder; Preferably, the solid electrolyte is a sulfide solid electrolyte, including Li (6-x) PS (5-x) M (1+x) or yLi2S·(1-y)P2S5, Li 10 GeP2S 12 At least one of 0≤x≤0.6, 0.2≤y≤0.8, M=Cl, Br, I; Preferably, the fiberizable binder has a molecular weight of ≥4×10 6 g / mol, including any one or more of polytetrafluoroethylene, ultra-high molecular weight polyethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyethylene oxide, polypropylene and polyacrylonitrile.

7. The method for preparing a solid electrode sheet according to claim 1, characterized in that: In step 4), the temperature of the hot roller pressing treatment is 25-200° C., and the calendering force in the horizontal and vertical directions is 1-60 t.

8. The method for preparing a solid electrode sheet according to claim 1, characterized in that: The specific steps of step 5) are to hot-press the electrode film and the current collector at 80-180°C and 1-60t; preferably 150°C and 20t; preferably, the current collector is at least one of aluminum foil, carbon-coated aluminum foil, and composite aluminum foil.

9. A solid electrode sheet obtained by the preparation method according to any one of claims 1 to 8.

10. A battery, characterized in that: Comprising the solid electrode sheet as described in claim 9.

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