Self-repairing all-solid-state sulfidation electrode layer and preparation method and application thereof

Abstract

The application relates to a self-repairing all-solid-state sulfuration electrode layer and a preparation method and application thereof. The self-repairing all-solid-state sulfuration electrode layer comprises a conductive substrate and a solid-state electrolyte layer arranged on the conductive substrate; and the solid-state electrolyte layer is filled with polyethylene imine and polyvinylpyrrolidone in pores. The preparation method comprises the following steps: performing heat pressing treatment on the electrolyte layer filled with the polyethylene imine and the polyvinylpyrrolidone in the pores, so that the self-repairing all-solid-state sulfuration electrode layer is obtained. The polyethylene imine and the polyvinylpyrrolidone ensure the self-repairing performance of the electrode layer through the action of hydrogen bonds, solve the risk of cracking of the solid-state electrolyte layer, the preparation method is simple, and the conductive performance of the electrode layer can be ensured.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, and relates to an all-solid-state electrode layer, and more particularly to a self-healing all-solid-state sulfidation electrode layer, its preparation method and application. Background Technology

[0002] Lithium-ion batteries are rechargeable batteries that primarily rely on the movement of lithium ions between the positive and negative electrodes to achieve charging and discharging. The applications of lithium-ion batteries have gradually expanded from consumer electronics and power tools to emerging fields such as new energy electric vehicles, electric ships, electric aircraft, and robotics. These fields not only require lithium-ion batteries to have greater capacity but also place increasingly higher demands on their energy density.

[0003] Liquid batteries suffer from drawbacks such as continuous SEI layer growth, transition metal dissolution, oxygen evolution in the cathode material, electrolyte oxidation, lithium plating, high-temperature failure, and volume expansion. Solid-state batteries can simultaneously address these drawbacks. The interface contact in solid-state batteries is primarily a solid-solid interface, and ensuring good interface contact is crucial for battery performance. However, the immense pressure during solid-state battery use, coupled with significant deformation of the positive and negative electrode materials, can cause the electrode layers to tear due to the alternating tension and relaxation, leading to electrode layer fracture and irreversible capacity loss in both the positive and negative electrodes. Summary of the Invention

[0004] The purpose of this invention is to provide a self-healing all-solid-state sulfurized electrode layer, its preparation method, and its application. The self-healing all-solid-state sulfurized electrode layer has self-healing properties, which can avoid the danger caused by cracking of the solid electrolyte layer; and the obtained self-healing all-solid-state sulfurized electrode layer has excellent electrochemical performance.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a self-healing all-solid-state sulfidation electrode layer, the self-healing all-solid-state sulfidation electrode layer comprising a conductive substrate and a solid electrolyte layer disposed on the conductive substrate;

[0007] The pores of the solid electrolyte layer are filled with polyethyleneimine and polyvinylpyrrolidone.

[0008] The conductive substrate of the present invention includes at least one of copper foil, aluminum foil, carbon-coated aluminum foil, or stainless steel foil.

[0009] Because the electrolyte particles in the solid electrolyte layer have irregular morphologies, traditional dry or wet methods struggle to ensure close contact between the electrolyte particles and the cathode particles. This invention fills the pores of the solid electrolyte layer with polyethyleneimine (PEI) and polyvinylpyrrolidone (PVP). PEI and PVP can ensure the self-healing properties of the electrode layer through hydrogen bonding, thus eliminating the risk of cracking in the solid electrolyte layer.

[0010] The number average molecular weight of the polyethyleneimine described in this invention is from 20,000 to 100,000, for example, it can be 20,000, 30,000, 40,000, 50,000, 60,000, 70,000, 80,000, 90,000 or 100,000, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 40,000 to 60,000.

[0011] The number average molecular weight of the polyvinylpyrrolidone described in this invention is from 1,000 to 500,000, for example, it can be 1,000, 5,000, 10,000, 50,000, 80,000, 100,000, 150,000, 200,000, 250,000, 300,000, 350,000, 400,000, 450,000, or 500,000, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0012] Preferably, the molar ratio of polyethyleneimine to polyvinylpyrrolidone is 1.8:1 to 2.4:1, for example, it can be 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1 or 2.4:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0013] Preferably, the porosity of the solid electrolyte layer is 5% to 6.5%, for example, it can be 5%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6%, 6.1%, 6.2%, 6.3%, 6.4% or 6.5%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] Secondly, the present invention provides a method for preparing a self-healing all-solid-state sulfide electrode layer as described in the first aspect, the method comprising the following steps:

[0015] An electrolyte layer containing polyethyleneimine and polyvinylpyrrolidone is cast into the pores and then subjected to hot pressing to obtain the self-healing all-solid-state sulfurized electrode layer.

[0016] Due to the irregular morphology of electrolyte particles, conventional dry and wet methods for preparing electrode layers often fail to ensure close contact between the electrolyte and positive electrode particles. This invention addresses this by using PEI and PVP, casting them into the pores of the electrolyte layer's framework. The hydrogen bonding between PEI and PVP ensures the material's self-healing properties. Post-casting hot-pressing further guarantees the integrity and film-forming properties of the resulting self-healing, all-solid-state sulfurized electrode layer.

[0017] The preparation method of the present invention is carried out in an argon-filled glove box with water ≤0.1ppm, oxygen ≤0.1ppm and carbon dioxide ≤0.1ppm; the water content of the materials used in the preparation method is ≤10ppm.

[0018] Preferably, the casting process includes the following steps: casting with an alcoholic solution of polyethyleneimine and polyvinylpyrrolidone, followed by vacuum drying to remove the alcohol solvent.

[0019] Preferably, the casting satisfies any one of the following conditions (a) to (b):

[0020] (a) The solid content of the alcohol solution is 30% to 40%, for example, 30%, 32%, 35%, 36%, 38% or 40%, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] When the solid content of the alcohol solution is too low, the content of polyethyleneimine and polyvinylpyrrolidone in the solid electrolyte layer is low, and the relative solvent content is too high. The porosity of the resulting solid electrolyte layer is large, which is not conducive to electron and ion conduction. When the solid content of the alcohol solution is high, the alcohol solution is too viscous, making casting more difficult.

[0022] The volume of the alcohol solution used during casting according to the present invention is the pore volume in the electrolyte layer, which is obtained by multiplying the volume of the electrolyte layer by its porosity.

[0023] (b) The alcohol solvent includes methanol and / or ethanol.

[0024] (c) The vacuum drying temperature is 80°C to 100°C, for example, 80°C, 82°C, 85°C, 88°C, 90°C, 92°C, 95°C, 96°C, 98°C or 100°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] (d) The vacuum drying time is more than 10 hours, for example, it can be 10 hours, 11 hours, 12 hours, 14 hours, 15 hours, 16 hours or 18 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0026] Preferably, the hot pressing treatment satisfies any one of the following conditions (e) to (i):

[0027] (e) The hot pressing method includes isostatic pressing.

[0028] During the casting process described in this invention, solvent evaporation occurs, which can cause the electrolyte layer to shrink and create voids. Hot pressing can ensure the integrity and film-forming properties of the resulting self-healing all-solid-state sulfurized electrode layer.

[0029] (f) The pressure of the hot pressing treatment is from 420 MPa to 480 MPa, for example, it can be 420 MPa, 430 MPa, 440 MPa, 450 MPa, 460 MPa, 470 MPa or 480 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] (g) The hot pressing time is 100 min to 150 min, for example, it can be 100 min, 110 min, 120 min, 130 min, 140 min or 150 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] (i) The temperature of the hot pressing treatment is 80°C to 90°C, for example, 80°C, 82°C, 84°C, 85°C, 86°C, 88°C or 90°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] Preferably, the raw materials for preparing the electrolyte layer include an inorganic pore-forming agent.

[0033] Preferably, the particle size D50 of the inorganic pore-forming agent of the present invention is 1 μm to 15 μm, for example, it can be 1 μm, 3 μm, 5 μm, 8 μm, 10 μm, 12 μm or 15 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 5 μm to 10 μm.

[0034] The inorganic pore-forming agent of the present invention includes any one or a combination of at least two of selenium disulfide (SeS2), calcium carbonate, silicon oxide, magnesium oxide, or zinc oxide. Typical but non-limiting combinations include a combination of selenium disulfide and calcium carbonate, a combination of silicon oxide and magnesium oxide, a combination of silicon oxide, magnesium oxide, and zinc oxide, a combination of calcium carbonate, silicon oxide, magnesium oxide, and zinc oxide, or a combination of selenium disulfide, calcium carbonate, silicon oxide, magnesium oxide, and zinc oxide, preferably selenium disulfide.

[0035] Preferably, the method for preparing the electrolyte layer according to the second aspect of the present invention includes the following steps:

[0036] A binder, conductive agent, pore-forming agent, positive electrode particles, electrolyte particles, and solvent are mixed and degassed to obtain an electrode slurry. The electrode slurry is coated onto a conductive substrate and then subjected to a first vacuum drying, a rolling press, and a second vacuum drying to obtain the electrolyte layer.

[0037] The adhesive comprises any one or a combination of at least two of polyvinylidene fluoride (PVDF), sodium carboxymethyl cellulose, styrene-butadiene rubber, sodium alginate, or polyacrylic acid. Typical but non-limiting combinations include combinations of PVDF and sodium carboxymethyl cellulose, combinations of styrene-butadiene rubber and sodium alginate, combinations of sodium alginate and polyacrylic acid, combinations of PVDF, sodium carboxymethyl cellulose, and styrene-butadiene rubber, or combinations of PVDF, sodium carboxymethyl cellulose, styrene-butadiene rubber, sodium alginate, and polyacrylic acid, preferably PVDF.

[0038] The conductive agent includes any one or a combination of at least two of conductive carbon black (Super-P), acetylene black, Ketjen black, carbon nanofibers, graphene, conductive graphite, or carbon nanotubes. Typical but non-limiting combinations include combinations of conductive carbon black and acetylene black, combinations of Ketjen black and carbon nanofibers, combinations of graphene, conductive graphite, and carbon nanotubes, combinations of carbon nanotubes, graphene, conductive graphite, and carbon nanotubes, combinations of conductive carbon black, acetylene black, Ketjen black, and carbon nanofibers, or combinations of conductive carbon black (Super-P), acetylene black, Ketjen black, carbon nanofibers, graphene, conductive graphite, and carbon nanotubes.

[0039] The cathode particles include ternary cathode material particles, preferably any one or a combination of at least two of NCM811, NCM622 or NCM523. Typical but non-limiting combinations include combinations of NCM811 and NCM622, NCM622 and NCM523, NCM811 and NCM523, or NCM811, NCM622 and NCM523.

[0040] Preferably, the particle size D50 of the positive electrode particles is 10μm to 20μm, for example, it can be 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm or 20μm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0041] The electrolyte particles include, but are not limited to, lithium phosphorus sulfur chlorine (Li6PS5Cl).

[0042] Preferably, the particle size D50 of the electrolyte particles is 7 μm to 15 μm, for example, it can be 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or 15 μm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0043] The solvents include, but are not limited to, any one or at least two combinations of diisopropyl ketone, anisole, tetrachloromethane, toluene, xylene, or tetrahydrofuran. Typical but non-limiting combinations include combinations of diisopropyl ketone and anisole, tetrachloromethane and toluene, xylene and tetrahydrofuran, diisopropyl ketone, tetrachloromethane and xylene, anisole, toluene and tetrahydrofuran, or diisopropyl ketone, anisole, tetrachloromethane, toluene, xylene and tetrahydrofuran.

[0044] Preferably, the mass ratio of the positive electrode particles, binder, electrolyte particles, conductive agent, and pore-forming agent is (68 to 72):(1 to 2):(18 to 22):(1 to 2):(6 to 8), for example, it can be 68:1:18:1:6, 68:2:22:2:8, 70:1.5:20:1.5:7, 72:1:18:1:6, or 72:2:22:2:8, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0045] Preferably, the solid content of the obtained electrode slurry is 65% to 70%, for example, it can be 65%, 66%, 67%, 68%, 69% or 70%, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0046] Preferably, the degassing and stirring includes a first stirring and a second stirring performed sequentially; the first stirring is performed at a speed of 1800 rpm to 2400 rpm for 8 to 12 minutes; the second stirring is performed at a speed of 300 rpm to 600 rpm for 3 to 6 minutes.

[0047] The first stirring speed is from 1800 rpm to 2400 rpm, for example, it can be 1800 rpm, 1900 rpm, 2000 rpm, 2100 rpm, 2200 rpm, 2300 rpm or 2400 rpm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0048] The first stirring time is 8 to 12 minutes, for example, it can be 8 minutes, 9 minutes, 10 minutes, 11 minutes or 12 minutes, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0049] The second stirring speed is 300 rpm to 600 rpm, for example, it can be 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm or 600 rpm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0050] The second stirring time is 3 to 6 minutes, for example, it can be 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes, 5 minutes, 5.5 minutes or 6 minutes, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0051] Preferably, the temperature of the first vacuum drying is 10°C to 30°C, for example, it can be 10°C, 15°C, 20°C, 25°C or 30°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0052] The first vacuum drying is used to remove the solvent.

[0053] The thickness of the electrolyte material layer obtained after rolling is 65μm to 70μm, for example, it can be 65μm, 66μm, 67μm, 68μm, 69μm or 70μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0054] Preferably, the temperature of the second vacuum drying is 140°C to 160°C, for example, it can be 140°C, 145°C, 150°C, 155°C or 160°C, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0055] During the second vacuum drying process, the pore-forming agent completely evaporates, and a uniform porous structure is formed inside the electrolyte layer, which facilitates the casting of polyethyleneimine and polyvinylpyrrolidone.

[0056] Thirdly, the present invention provides an electrochemical device comprising a self-healing all-solid-state sulfide electrode layer as described in the first aspect.

[0057] Fourthly, the present invention provides an electronic device comprising the electrochemical device as described in the third aspect.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The self-healing all-solid-state sulfided electrode layer provided by this invention utilizes the synergistic use of polyethyleneimine and polyvinylpyrrolidone to ensure the self-healing property of the electrode layer by taking advantage of the hydrogen bonding between polyethyleneimine and polyvinylpyrrolidone. This solves the risk of cracking of the solid electrolyte layer, resulting in a self-healing all-solid-state sulfided electrode layer with good cycle capacity retention, high rate performance, and a short self-healing time. Detailed Implementation

[0060] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0061] Example 1

[0062] This embodiment provides a self-healing all-solid-state sulfurized electrode layer, which includes an aluminum foil conductive substrate and a solid electrolyte layer disposed on the aluminum foil conductive substrate; the pores of the solid electrolyte layer are filled with polyethyleneimine (number average molecular weight of 50,000) and polyvinylpyrrolidone (number average molecular weight of 100,000).

[0063] The method for preparing the self-healing all-solid-state sulfide electrode layer includes the following steps:

[0064] The electrolyte layer was cast using an ethanol solution of polyethyleneimine and polyvinylpyrrolidone, and then vacuum dried at 100°C for 12 hours to remove the ethanol. It was then subjected to isostatic pressing at a pressure of 450 MPa and a temperature of 85°C for 120 minutes to obtain the self-healing all-solid-state sulfidated electrode layer.

[0065] The ethanol solution contains polyethyleneimine to polyvinylpyrrolidone in a molar ratio of 2:1 and has a solid content of 36%. The volume of the ethanol solution used during casting is the pore volume of the electrolyte layer, obtained by multiplying the volume of the electrolyte layer by its porosity.

[0066] The electrolyte layer is prepared using the following method:

[0067] A mixture of PVDF binder, Super-P conductive agent, SeS2 pore-forming agent with a particle size D50 of 8 μm, NCM811 positive electrode particles with a particle size D50 of 15 μm, Li6PS5Cl electrolyte particles with a particle size D50 of 10 μm, and diisopropyl ketone was stirred and degassed to obtain an electrode slurry with a solid content of 68%. The electrode slurry was coated onto an aluminum foil conductive substrate and then subjected to a first vacuum drying at 20°C, a rolling process to a particle size of 68 μm, and a second vacuum drying at 150°C to obtain the electrolyte layer.

[0068] The mass ratio of PVDF, Super-P, SeS2, NCM811 and Li6PS5Cl is 1.5:1.5:7:70:20; the degassing and stirring includes a first stirring and a second stirring performed sequentially, the first stirring being at a speed of 2000 rpm for 10 min; the second stirring being at a speed of 500 rpm for 5 min.

[0069] Example 2

[0070] This embodiment provides a self-healing all-solid-state sulfurized electrode layer, which includes an aluminum foil conductive substrate and a solid electrolyte layer disposed on the aluminum foil conductive substrate; the pores of the solid electrolyte layer are filled with polyethyleneimine (number average molecular weight of 50,000) and polyvinylpyrrolidone (number average molecular weight of 100,000).

[0071] The method for preparing the self-healing all-solid-state sulfide electrode layer includes the following steps:

[0072] The electrolyte layer was cast using an ethanol solution of polyethyleneimine and polyvinylpyrrolidone, and then vacuum dried at 90°C for 10 hours to remove the ethanol. It was then subjected to isostatic pressing at a pressure of 420 MPa and a temperature of 80°C for 150 minutes to obtain the self-healing all-solid-state sulfurized electrode layer.

[0073] The ethanol solution contains polyethyleneimine to polyvinylpyrrolidone in a molar ratio of 1.8:1 and has a solid content of 30%. The volume of the ethanol solution used during casting is the pore volume of the electrolyte layer, obtained by multiplying the volume of the electrolyte layer by its porosity.

[0074] The electrolyte layer is prepared using the following method:

[0075] A mixture of PVDF binder, Super-P conductive agent, SeS2 pore-forming agent with a particle size D50 of 5 μm, NCM811 positive electrode particles with a particle size D50 of 10 μm, Li6PS5Cl electrolyte particles with a particle size D50 of 7 μm, and diisopropyl methyl ketone was stirred and degassed to obtain an electrode slurry with a solid content of 65%. The electrode slurry was coated onto an aluminum foil conductive substrate and then subjected to a first vacuum drying at 10°C, a rolling process to a particle size of 65 μm, and a second vacuum drying at 140°C to obtain the electrolyte layer.

[0076] The mass ratio of PVDF, Super-P, SeS2, NCM811 and Li6PS5Cl is 1:1:8:68:22; the degassing and stirring includes a first stirring and a second stirring performed sequentially, the first stirring is performed at a speed of 1800 rpm for 12 min; the second stirring is performed at a speed of 300 rpm for 6 min.

[0077] Example 3

[0078] This embodiment provides a self-healing all-solid-state sulfurized electrode layer, which includes an aluminum foil conductive substrate and a solid electrolyte layer disposed on the aluminum foil conductive substrate; the pores of the solid electrolyte layer are filled with polyethyleneimine (number average molecular weight of 50,000) and polyvinylpyrrolidone (number average molecular weight of 100,000).

[0079] The method for preparing the self-healing all-solid-state sulfide electrode layer includes the following steps:

[0080] The electrolyte layer was cast using an ethanol solution of polyethyleneimine and polyvinylpyrrolidone, and then vacuum dried at 80°C for 14 hours to remove the ethanol. It was then subjected to isostatic pressing at a pressure of 480 MPa and a temperature of 90°C for 100 minutes to obtain the self-healing all-solid-state sulfurized electrode layer.

[0081] The ethanol solution contains polyethyleneimine to polyvinylpyrrolidone in a molar ratio of 2.4:1 and has a solid content of 40%. The volume of the alcohol solution used during casting is the pore volume of the electrolyte layer, obtained by multiplying the volume of the electrolyte layer by its porosity.

[0082] The electrolyte layer is prepared using the following method:

[0083] A slurry with a solid content of 70% was obtained by mixing a binder PVDF, a conductive agent Super-P, a pore-forming agent SeS2 with a particle size D50 of 10 μm, positive electrode particles NCM811 with a particle size D50 of 20 μm, electrolyte particles Li6PS5Cl with a particle size D50 of 15 μm, and diisopropyl methyl ketone. The slurry was coated onto an aluminum foil conductive substrate and then subjected to a first vacuum drying at 30°C, a rolling process to a particle size of 70 μm, and a second vacuum drying at 160°C to obtain the electrolyte layer.

[0084] The mass ratio of PVDF, Super-P, SeS2, NCM811 and Li6PS5Cl is 2:2:6:72:18; the degassing and stirring includes a first stirring and a second stirring performed sequentially, the first stirring is performed at a speed of 2400 rpm for 8 minutes; the second stirring is performed at a speed of 600 rpm for 3 minutes.

[0085] Except for the change in the molar ratio of polyethyleneimine to polyvinylpyrrolidone shown in Table 4, Examples 4 and 5 are the same as Example 1.

[0086] Except for the changes in the pore-forming agent of equal mass shown in Table 5, Examples 6 to 9 are the same as Example 1.

[0087] Except for the number-average molecular weight changes of polyethyleneimine and polyvinylpyrrolidone shown in Table 6, Examples 10 and 11 are the same as Example 1.

[0088] Comparative Example 1 was identical to Example 1 except that polyethyleneimine was replaced with an equimolar amount of polyetherimide (CAS: 61128-46-9).

[0089] Comparative Example 2 was identical to Example 1 except that an equimolar amount of polyethyleneimine was replaced with polyvinylpyrrolidone.

[0090] Comparative Example 3 was identical to Example 1 except that an equal molar amount of polyvinylpyrrolidone was replaced with polyethyleneimine.

[0091] Performance testing

[0092] The electrode layers provided in Examples 1 to 11 and Comparative Examples 1 to 3 were assembled into lithium indium half-cells for performance testing. The assembly steps of the lithium indium half-cells included the following process:

[0093] (1) The electrode layer was pressed into a sulfide electrolyte layer under a pressure of 200MPa using a tablet press;

[0094] (2) Indium foil and lithium metal are rolled into lithium-indium alloy and punched into φ8 round pieces using a punching machine;

[0095] (3) The positive electrode sheet is punched into a φ6 round sheet, the aluminum foil of the sulfide electrolyte layer is removed, and the battery is assembled according to the lithium indium alloy | sulfide electrolyte layer | positive electrode sheet.

[0096] The positive electrode in step (3) consists of NCM622, LSPCl, PVDF and conductive carbon black in a mass ratio of 70:22:3:5.

[0097] The test results are shown in Tables 3 to 5.

[0098] Cyclic capacity retention testing was conducted under the conditions shown in Table 1:

[0099] Table 1

[0100]

[0101]

[0102] The room temperature rate performance test was conducted under the conditions shown in Table 2:

[0103] Table 2

[0104]

[0105]

[0106] Self-healing time test: Cut a 5cm long incision in the electrode layer, then attach the incision to the surface and determine the time required for the incision to heal completely from attachment to complete healing.

[0107] Porosity testing: The porosity of the electrolyte layer is calculated by taking the true density of the electrode layer material, the thickness of the electrode layer, and its mass.

[0108] Table 3

[0109]

[0110]

[0111] Table 4

[0112]

[0113] Table 5

[0114]

[0115]

[0116] Table 6

[0117]

[0118] As shown in Tables 3 and 6, by filling the pores of the solid electrolyte layer with polyethyleneimine and polyvinylpyrrolidone, the resulting self-healing all-solid-state sulfurized electrode layer has both good cycle performance and rate performance, as well as good self-healing performance.

[0119] As shown in Table 4, when the molar ratio of polyethyleneimine to polyvinylpyrrolidone deviates from the range of 1.8:1 to 2.4:1, the cycle performance and rate performance of the obtained self-healing all-solid-state sulfurized electrode layer decrease slightly, and the self-healing time is longer.

[0120] As shown in Table 5, when SeS2 is used as an inorganic pore-forming agent in the preparation of the self-healing all-solid-state sulfurized electrode layer of the present invention, it can shorten the self-healing time of the self-healing all-solid-state sulfurized electrode layer and has excellent cycle performance and rate performance.

[0121] In summary, the self-healing all-solid-state sulfided electrode layer provided by this invention, through the synergistic use of polyethyleneimine and polyvinylpyrrolidone, can utilize the hydrogen bonding between polyethyleneimine and polyvinylpyrrolidone to ensure the self-healing property of the electrode layer, thus solving the risk of cracking of the solid electrolyte layer. This results in a self-healing all-solid-state sulfided electrode layer with good cycle capacity retention, high rate performance, and a short self-healing time.

[0122] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A self-healing all-solid-state sulfurized electrode layer, characterized in that, The self-healing all-solid-state sulfidation electrode layer includes a conductive substrate and a solid electrolyte layer disposed on the conductive substrate. The pores of the solid electrolyte layer are filled with polyethyleneimine and polyvinylpyrrolidone; The molar ratio of polyethyleneimine to polyvinylpyrrolidone is from 1.8:1 to 2.4:1; The number-average molecular weight of the polyethyleneimine is 20,000 to 100,000, and the number-average molecular weight of the polyvinylpyrrolidone is 1,000 to 500,000. The porosity of the solid electrolyte layer is 5% to 6.5%; The method for preparing the self-healing all-solid-state sulfide electrode layer includes the following steps: An electrolyte layer containing polyethyleneimine and polyvinylpyrrolidone is cast into the pores and then subjected to hot pressing to obtain the self-healing all-solid-state sulfurized electrode layer.

2. A method for preparing a self-healing all-solid-state sulfidation electrode layer as described in claim 1, characterized in that, The preparation method includes the following steps: An electrolyte layer containing polyethyleneimine and polyvinylpyrrolidone is cast into the pores and then subjected to hot pressing to obtain the self-healing all-solid-state sulfurized electrode layer.

3. The preparation method according to claim 2, characterized in that, The casting process includes the following steps: casting with an alcoholic solution of polyethyleneimine and polyvinylpyrrolidone, followed by vacuum drying to remove the alcohol solvent.

4. The preparation method according to claim 3, characterized in that, The casting satisfies any one of the following conditions (a) to (d): (a) The solid content of the alcohol solution is 30% to 40%; (b) The alcohol solvent includes methanol and / or ethanol; (c) The vacuum drying temperature is 80°C to 100°C; (d) The vacuum drying time is more than 10 hours.

5. The preparation method according to claim 2, characterized in that, The hot pressing process satisfies any one of the following conditions (e) to (i): (e) The hot pressing method includes isostatic pressing; (f) The pressure of the hot pressing treatment is 420 MPa to 480 MPa; (g) The hot pressing treatment time is 100 min to 150 min; (i) The temperature of the hot pressing treatment is 80°C to 90°C.

6. The preparation method according to claim 2, characterized in that, The raw materials used to prepare the electrolyte layer include an inorganic pore-forming agent.

7. An electrochemical device, characterized in that, The electrochemical device includes the self-healing all-solid-state sulfidation electrode layer as described in claim 1.

8. An electronic device, characterized in that, The electronic device includes the electrochemical device as described in claim 7.

Images