Hydrophobic solid electrolyte and all-solid-state battery

Abstract

The invention provides a hydrophobic solid electrolyte, and belongs to the field of lithium ion solid batteries. According to the hydrophobic solid electrolyte, the sulfide electrolyte composed of the specific chemical formula, the first hydrophobic oxide and the second hydrophobic oxide are compounded, good air stability is achieved, and the all-solid-state battery has good cycle stability and low impedance.

Description

Technical Field

[0001] This invention relates to the field of solid-state batteries, specifically to a hydrophobic solid electrolyte and an all-solid-state battery. Background Technology

[0002] With the advancement of the national strategy of "carbon peaking and carbon neutrality," an electric revolution has swept through the transportation sector, and the popularization of electric vehicles is rapidly progressing. However, in traditional lithium-ion batteries, the liquid electrolyte is generally a flammable organic compound, which can easily cause safety accidents. Therefore, using non-flammable ceramic solid electrolytes to replace liquid electrolytes has become a development trend in power batteries. Sulfide ceramic electrolytes are among the most promising solid electrolytes due to their high ionic conductivity, but they suffer from instability in air, poor interfacial stability with the positive and negative electrodes, and high impedance in the fabricated all-solid-state batteries, and their practical application still faces significant challenges. Summary of the Invention

[0003] This invention addresses the problems existing in the prior art by providing a hydrophobic solid electrolyte.

[0004] The specific technical solution is as follows: A hydrophobic solid electrolyte comprises a sulfide electrolyte, a first hydrophobic oxide, and a second hydrophobic oxide, wherein the first and second hydrophobic oxides are oxides surface-grafted with an alkenyl silane coupling agent, wherein: The alkenyl silane coupling agent on the surface of the first hydrophobic oxide forms a dense polysiloxane layer through alkenyl polymerization; The chemical formula of the sulfide electrolyte is Li 6-x+y P 1-y A y S 5-x-2y B 2y M 1+x In the formula, M is at least one of Cl, Br, or I; A is at least one of Sn, Si, Ge, Zr, Hf, or Ti; and B is at least one of Se, Te, or O. Wherein, 0 <x≤0.8,0<y≤0.1。

[0005] This invention combines a sulfide electrolyte with a specific chemical composition and a first hydrophobic oxide and a second hydrophobic oxide, which can improve the air stability of the hydrophobic solid electrolyte and the interfacial stability between the positive and negative electrodes and the hydrophobic solid electrolyte, thereby improving the high-temperature cycle stability of the all-solid-state battery and reducing the impedance of the all-solid-state battery.

[0006] Experiments revealed that the hydroxyl groups generated by the hydrolysis of silane coupling agents undergo a condensation reaction with the hydroxyl groups on the surface of oxide particles, thereby adhering to the surface of the oxide particles and improving their hydrophobicity. Furthermore, when using alkenyl-containing silanes, a dense polysiloxane layer can be formed on the oxide surface and between adjacent oxides through polymerization, significantly improving hydrophobicity and the elasticity of the solid electrolyte layer, thus improving the interfacial stability between the solid electrolyte and the positive and negative electrodes. Simultaneously, the alkenyl groups of the silane coupling agent can also undergo crosslinking reactions with the alkenyl groups in the polyacrylates of the positive and negative electrodes, further enhancing the interfacial stability between the positive and negative electrodes and the solid electrolyte.

[0007] Experiments have shown that doping the P site with element A and the S site with element B can improve the ionic conductivity of the sulfide electrolyte and also improve its air stability. The air stability refers to the sulfide electrolyte not reacting with water in the air.

[0008] Specifically, the alkenyl silane coupling agent is selected from one or more of allyltrimethoxysilane, 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, vinyltrimethoxysilane, and vinyltriisopropenoxysilane, with allyltrimethoxysilane being preferred. When allyltrimethoxysilane is selected as the silane coupling agent, it exhibits superior hydrophobic properties and interfacial stability.

[0009] Specifically, the alkenyl silane coupling agent on the surface of the second hydrophobic oxide does not require polymerization.

[0010] Specifically, the mass ratio of the first hydrophobic oxide to the second hydrophobic oxide is 20~80:80~20, preferably 40~60:60~40. Within this range, the mass ratio of the first hydrophobic oxide to the second hydrophobic oxide balances hydrophobicity and stability at the interfaces between the solid electrolyte and the positive and negative electrodes.

[0011] Specifically, the weight ratio of the silane coupling agent to the oxide is 1~5:100.

[0012] Specifically, the weight ratio of the total weight of the first hydrophobic oxide and the second hydrophobic oxide to the weight of the sulfide electrolyte is 1 to 10:100, more preferably 2 to 8:100.

[0013] Specifically, the oxide particles are selected from one or more of silicon dioxide (SiO2), tin dioxide (SnO2), titanium dioxide (TiO2), zinc oxide (ZnO), or magnesium oxide (MgO).

[0014] Specifically, the particle size of the oxide is 50 to 500 nanometers.

[0015] Preferably, the Li 6-x+y P 1-y A y S 5-x-2y B 2y M 1+x In this range, 0.4 ≤ x ≤ 0.8 and 0.01 ≤ y ≤ 0.04. Within this range, x and y exhibit better hydrophobicity and cycling stability.

[0016] Specifically, the particle size of the sulfide electrolyte is 1 to 10 micrometers.

[0017] The preparation method of the above-mentioned solid electrolyte includes the following steps: S1) Preparation of sulfide electrolytes; Preparation of S2) hydrophobic oxides; Preparation of hydrophobic solid electrolyte (S3).

[0018] In S1), preferably, the sulfide electrolyte Li 6-x+y P 1-y A y S 5-x-2y B 2y M 1+x The preparation was carried out using a solid-state method. Specifically, LiM, Li2S, AB2, and P2S5 were used as precursors, and the preparation was carried out by ball milling combined with heat treatment. The ball milling speed was 300-600 rpm, the ball milling atmosphere was inert, the ball milling time was 5-20 hours, and the heat treatment temperature was 450-550 °C. o C, The heat treatment atmosphere is an inert atmosphere, and the heat treatment time is 5~20 hours.

[0019] In S2), preferably, the hydrophobic oxide is prepared by a liquid-phase method.

[0020] Specifically, oxide particles, silane coupling agent and initiator are dispersed in a mixed solvent of water, ethanol and ammonia (28%), and the mixture is heated (40℃~80℃), stirred, centrifuged and vacuum dried to obtain the first hydrophobic oxide; The oxide particles and silane coupling agent were dispersed in a mixed solvent of water, ethanol and ammonia (28%), and the second hydrophobic oxide was obtained by thorough stirring, centrifugation and vacuum drying. The weight ratio of silane coupling agent to oxide particles is 0.2~1:1, the volume ratio of water, ethanol and ammonia is 1:5~15:0.2~0.6, the weight ratio of initiator to silane coupling agent is 0.5~2:100, the concentration of oxide is 5~30 g / L, and the vacuum drying temperature is 60~100℃. oC. The drying time is 6-24 hours. Preferably, the initiator is an azo initiator, which is selected from azobisisobutyronitrile, azobisisoheptanenitrile, or dimethyl azobisisobutyrate.

[0021] In step S3), preferably, the hydrophobic solid electrolyte is prepared by ball milling. Specifically, the sulfide electrolyte is mixed evenly with the first and second hydrophobic oxides, and then ball-milled to obtain the hydrophobic solid electrolyte. The ball milling speed is 300-600 rpm, the ball milling atmosphere is inert, and the ball milling time is 5-20 hours.

[0022] An all-solid-state battery includes an integrated negative electrode layer, a hydrophobic solid electrolyte layer, and an integrated positive electrode layer; The integrated negative electrode layer includes a negative electrode layer and a polymer electrolyte dispersed inside it or covering its surface, wherein the monomer of the polymer electrolyte is a polyacrylate. The integrated positive electrode layer consists of a positive electrode layer and a polymer electrolyte dispersed in the positive electrode layer, wherein the monomer of the polymer electrolyte is a polyacrylate. The hydrophobic solid electrolyte layer includes the aforementioned hydrophobic solid electrolyte; Wherein, the alkenyl groups on the surface of the second hydrophobic oxide are crosslinked with the alkenyl groups on the surface of the integrated negative electrode layer and / or the integrated positive electrode layer.

[0023] Experiments revealed that in-situ polymerization of polyacrylates can form cross-linked structures, leading to better integrated structures and increased electrode elasticity. Furthermore, the surface of the polymeric electrolyte formed by in-situ polymerization of polyacrylates can be controlled to possess a certain amount of active alkenyl groups, which can undergo cross-linking reactions with alkenyl-containing silane groups on the surface of the second hydrophobic oxide. This increases the interfacial stability and elasticity between the positive and negative electrodes and the solid electrolyte, thereby stabilizing the interfacial stability during battery operation and reducing interfacial resistance.

[0024] Preferably, the polymer electrolyte is formed by in-situ polymerization of monomers. In-situ polymerization allows the polymer electrolyte to come into closer contact with the active material, making it easier to form a uniform and dense integrated electrode.

[0025] Specifically, monomers, lithium salts, and initiators are mixed evenly and poured into the interior or surface of the negative electrode layer, and then polymerized in situ and rolled to obtain an integrated negative electrode layer.

[0026] Specifically, the monomer, lithium salt and initiator are mixed evenly and cast into the positive electrode layer, and then the integrated positive electrode layer is obtained by in-situ polymerization and roll pressing.

[0027] Preferably, the in-situ polymerization reaction temperature is 50°C. o C~80 o C, the polymerization time is 1~10 hours.

[0028] Specifically, the weight ratio of the initiator to the monomer is 0.5 to 2:100.

[0029] By controlling the temperature, time, and weight ratio of initiator to monomer in the in-situ polymerization reaction, the active alkenyl content of the polymer electrolyte can be adjusted, thereby regulating the degree of crosslinking between the positive and negative electrodes and the hydrophobic solid electrolyte layer, and ultimately controlling the interfacial stability between the positive and negative electrodes and the hydrophobic solid electrolyte layer.

[0030] Specifically, the polyacrylate is selected from ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, or pentaerythritol tetraacrylate, preferably ethoxylated trimethylolpropane triacrylate. Choosing ethoxylated trimethylolpropane triacrylate as the polyacrylate improves the interfacial stability and elasticity between the positive and negative electrodes and the solid electrolyte.

[0031] Specifically, the initiator is an azo initiator, which is selected from azobisisobutyronitrile, azobisisoheptanenitrile, or dimethyl azobisisobutyrate.

[0032] Specifically, the lithium salt is selected from at least one of lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethanesulfonate (LiTfO), lithium difluorooxalate borate (LiDFOB), and lithium bis(oxalate borate) (LiBOB).

[0033] Specifically, the weight ratio of the lithium salt to the monomer is 0.2 to 1:1.

[0034] Specifically, the total weight ratio of the lithium salt and monomer to the positive electrode active material is 5~20:100.

[0035] Specifically, the total weight ratio of the lithium salt and monomer to the negative electrode active material is 5~20:100.

[0036] Preferably, the thickness of the integrated negative electrode layer is 10~150 mm. Under these conditions, both cycle life and energy density of all-solid-state batteries can be achieved.

[0037] Specifically, the negative electrode layer includes a negative electrode active material, which is selected from one or more of graphite, silicon, silicon-carbon composite materials, metallic lithium, or lithium alloys.

[0038] Preferably, the lithium alloy is selected from lithium-magnesium alloy, lithium-tin alloy, lithium-aluminum alloy, lithium-silver alloy, lithium-zinc alloy, or lithium-boron alloy.

[0039] Preferably, the silicon content in the silicon-carbon composite material is 5% to 50%.

[0040] Specifically, when the negative electrode active material is metallic lithium or lithium alloy, the polymer electrolyte covers the surface of the negative electrode layer to form an integrated negative electrode layer; when the negative electrode active material is graphite, silicon or silicon-carbon composite material, the polymer electrolyte is dispersed inside the negative electrode layer.

[0041] Specifically, when the negative electrode active material is lithium metal or lithium alloy, the lithium metal or lithium alloy is rolled and compounded with direct copper foil to obtain the negative electrode layer; when the negative electrode active material is graphite, silicon or silicon-carbon composite material, the negative electrode layer loaded on the copper foil is obtained through conventional mixing, homogenization, coating, baking and rolling processes.

[0042] More specifically, when the negative electrode active material is selected from graphite, silicon, or silicon-carbon composite materials, the negative electrode layer also includes a conductive agent and a binder.

[0043] Preferably, the conductive agent is selected from one or more of graphene, acetylene black, Super P, carbon nanotubes, or carbon nanofibers.

[0044] Preferably, the adhesive is one or more of polyacrylic acid, sodium alginate, carboxymethyl cellulose, and styrene-butadiene rubber.

[0045] Preferably, the weight ratio of active material, binder and conductive agent in the negative electrode layer is 91~97:2~6:1~3.

[0046] Preferably, the thickness of the integrated positive electrode layer is 10-200. Under these conditions, both battery cycle life and energy density can be considered.

[0047] Specifically, the positive electrode layer is composed of a positive electrode active material, a conductive agent, and a binder.

[0048] Specifically, the positive electrode active material is selected from commercially available lithium spinel manganese oxide, lithium spinel nickel manganese oxide, lithium manganese phosphate, lithium iron phosphate, lithium manganese iron phosphate, lithium cobalt phosphate, lithium vanadium phosphate, lithium cobalt oxide, layered oxides, or lithium-rich manganese-based materials.

[0049] Specifically, the conductive agent is selected from one or more of graphene, acetylene black, Super P, carbon nanotubes, or carbon nanofibers.

[0050] Specifically, the adhesive is selected from at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, and perfluoroethylene propylene.

[0051] Specifically, the weight ratio of active material, binder and conductive agent in the positive electrode layer is 90~98:1~5:1~5.

[0052] Preferably, the thickness of the hydrophobic solid electrolyte layer is 10-100%. Under these conditions, both battery cycle life and energy density can be considered.

[0053] The above-mentioned method for preparing all-solid-state batteries includes the following steps: 1) Fabrication of an integrated negative electrode layer; 2) Preparation of a hydrophobic solid electrolyte layer; 3) Fabrication of an integrated positive electrode layer; 4) Finally, the solid-state battery is obtained through hot pressing and encapsulation.

[0054] Specifically, step 2) includes the following steps: S1) Preparation of sulfide electrolytes; Preparation of S2) hydrophobic oxides; Preparation of S3) hydrophobic solid electrolyte; S4) Preparation of hydrophobic solid electrolyte layer.

[0055] In S1), preferably, the sulfide electrolyte Li 6-x+y P 1-y A y S 5-x-2y B 2y M 1+x The preparation was carried out using a solid-state method. Specifically, LiM, Li2S, AB2, and P2S5 were used as precursors, and the preparation was carried out by ball milling combined with heat treatment. The ball milling speed was 300-600 rpm, the ball milling atmosphere was inert, the ball milling time was 5-20 hours, and the heat treatment temperature was 450-550 °C. o C, The heat treatment atmosphere is an inert atmosphere, and the heat treatment time is 5~20 hours.

[0056] In S2), preferably, the hydrophobic oxide is prepared by a liquid-phase method.

[0057] Specifically, oxide particles, silane coupling agent and initiator are dispersed in a mixed solvent of water, ethanol and ammonia (28%), and the mixture is heated (40℃~80℃), stirred, centrifuged and vacuum dried to obtain the first hydrophobic oxide; The oxide particles and silane coupling agent were dispersed in a mixed solvent of water, ethanol and ammonia (28%), and the second hydrophobic oxide was obtained by thorough stirring, centrifugation and vacuum drying. The weight ratio of silane coupling agent to oxide particles is 0.2~1:1, the volume ratio of water, ethanol and ammonia is 1:5~15:0.2~0.6, the weight ratio of initiator to silane coupling agent is 0.5~2:100, the concentration of oxide is 5~30 g / L, and the vacuum drying temperature is 60~100℃. oC. The drying time is 6-24 hours. Preferably, the initiator is an azo initiator, which is selected from azobisisobutyronitrile, azobisisoheptanenitrile, or dimethyl azobisisobutyrate.

[0058] In step S3), preferably, the hydrophobic solid electrolyte is prepared by ball milling. Specifically, the sulfide electrolyte is mixed evenly with the first and second hydrophobic oxides, and then ball-milled to obtain the hydrophobic solid electrolyte. The ball milling speed is 300-600 rpm, the ball milling atmosphere is inert, and the ball milling time is 5-20 hours.

[0059] In step S4), preferably, the hydrophobic solid electrolyte layer is prepared using a dry method. Specifically, the hydrophobic solid electrolyte and polytetrafluoroethylene (PTFE) binder are dry-shear-mixed and rolled into a film to obtain the hydrophobic solid electrolyte layer. Experiments have shown that during shear-mixing, PTFE is fibrous, which can more effectively bond the ceramic electrolyte. Preferably, the weight ratio of binder to ceramic electrolyte is 0.5~5:100.

[0060] Specifically, the hot-pressing temperature is 60~100℃, and the time is 30~120min. Within this range, the temperature and time of the hot-pressing can control the crosslinking between the second hydrophobic oxide and the positive and negative electrodes to a suitable degree, thus ensuring good interfacial stability between the sulfide electrolyte and the positive and negative electrodes.

[0061] Compared with the prior art, the present invention has the following advantages: The hydrophobic solid electrolyte of the present invention has good air stability, and the all-solid-state battery of the present invention has good high-temperature cycle stability and low impedance. Attached Figure Description

[0062] Figure 1 Impedance spectrum of the air-stabilized solid electrolyte prepared in Example 1; Figure 2 The amount of hydrogen sulfide produced over time by the air-stabilized solid electrolyte prepared in Example 1; Figure 3 Impedance spectrum of the all-solid-state battery prepared in Example 1; Figure 4 Impedance spectrum of the solid electrolyte prepared in Comparative Example 1; Figure 5 The hydrogen sulfide production of the solid electrolyte prepared in Comparative Example 1 over time; Figure 6 Impedance spectrum of the all-solid-state battery prepared for Comparative Example 8. Detailed Implementation

[0063] Example 1 Graphite, carboxymethyl cellulose / styrene-butadiene rubber (weight ratio 1:1), and Super P were mixed in deionized water at a weight ratio of 96:2:2. The mixture was homogenized, coated, baked, and rolled to obtain a negative electrode layer loaded on copper foil with a thickness of 55 micrometers. Ethoxylated trimethylolpropane triacrylate monomer, azobisisobutyronitrile, and LiTFSI were mixed uniformly to obtain an in-situ polymerization precursor. The weight ratio of LiTFSI to ethoxylated trimethylolpropane triacrylate monomer was 0.3:1, the weight ratio of azobisisobutyronitrile to ethoxylated trimethylolpropane triacrylate monomer was 1:100, and the total weight ratio of LiTFSI and ethoxylated trimethylolpropane triacrylate monomer to graphite was 10:100. The precursor was then cast into the negative electrode layer and subjected to 70... o In-situ polymerization at C for 4 hours followed by roll pressing yielded the integrated negative electrode layer. Using LiCl, SnO2, Li2S, and P2S5 as precursors, they were mixed in a molar ratio of 1.6:0.02:1.91:0.49, then ball-milled, and combined with 500... o Prepare sulfide solid electrolyte Li by heat treatment at C for 10 hours. 5.42 P 0.98 Sn 0.02 S 4.36 O 0.04 Cl 1.6 Allyltrimethoxysilane, SiO2 nanoparticles, and azobisisobutyronitrile (AIB) were dispersed in a mixed solvent of water, ethanol, and ammonia, wherein the volume ratio of water, ethanol, and ammonia was 1:8:0.4, the weight ratio of allyltrimethoxysilane to SiO2 was 0.4:1, the weight ratio of AIB to allyltrimethoxysilane was 1:100, and the concentration of SiO2 was 15 g / L. After thorough heating (60℃), stirring, centrifugation, and vacuum drying, the first hydrophobic SiO2 was obtained. Allyltrimethoxysilane and SiO2 nanoparticles were dispersed in a mixed solvent of water, ethanol, and ammonia, wherein the volume ratio of water, ethanol, and ammonia was 1:8:0.4, the weight ratio of allyltrimethoxysilane to SiO2 was 0.4:1, and the concentration of SiO2 was 15 g / L. g / L, after thorough stirring, centrifugation and vacuum drying, yielded the second hydrophobic SiO2; the first hydrophobic SiO2 and the second hydrophobic SiO2 were then reacted with Li 5.42 P 0.98 Sn 0.02 S 4.36 O 0.04 Cl 1.6 The ingredients were prepared by ball milling at a weight ratio of 2.5:2.5:100 to obtain a hydrophobic solid electrolyte. Electrochemical impedance spectroscopy (EIS) was then performed (frequency range 10 Hz). -2 ~10 5 (Hz, bias voltage 5 mV), ionic conductivity 4.35 × 10⁻⁶ -3S / cm, see Figure 1 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 71%, and the hydrogen sulfide production after 30 minutes of air exposure was 1.19 cm³. 3 / g, see Figure 2 Polytetrafluoroethylene (PTFE) and a hydrophobic solid electrolyte were mixed at a weight ratio of 1:100, then sheared, mixed, and rolled to form a film, resulting in a 50-micrometer-thick hydrophobic solid electrolyte layer. Commercial LiNi... 0.83 Co 0.11 Mn 0.06 O2, polyvinylidene fluoride (PVDF), and acetylene black were mixed in N-methylpyrrolidone (NMP) at a weight ratio of 96:2:2. The mixture was homogenized, coated, baked, and rolled to obtain a 60-micron-thick positive electrode layer loaded on aluminum foil. Ethoxylated trimethylolpropane triacrylate monomer, azobisisobutyronitrile (AIB), and LiTFSI were mixed uniformly to obtain an in-situ polymerization precursor. The weight ratio of LiTFSI to ethoxylated trimethylolpropane triacrylate monomer was 0.3:1, and the weight ratio of AIB to ethoxylated trimethylolpropane triacrylate monomer was 1:100. The total weight of LiTFSI and ethoxylated trimethylolpropane triacrylate monomer was [not specified in the original text]. 0.83 Co 0.11 Mn 0.06 The O2 weight ratio was 8:100, and then the above precursor was cast into the positive electrode layer, and subjected to 70... o In-situ polymerization at C for 4 hours followed by roll pressing yields an integrated positive electrode layer. An integrated negative electrode layer, a hydrophobic solid electrolyte layer, and an integrated positive electrode layer are sequentially stacked, and then hot-pressed and encapsulated to obtain an all-solid-state battery. The hot-pressing temperature is 80°C and the time is 75 minutes. Electrochemical impedance analysis shows that the interfacial impedance between the solid electrolyte layer and the positive and negative electrodes is 135 ohms. Figure 3 .

[0064] Example 2 Silicon-carbon composite material (10% silicon content), carboxymethyl cellulose / styrene-butadiene rubber (weight ratio 1:1), and carbon nanotubes were mixed in deionized water at a weight ratio of 95:3:2. After homogenization, coating, baking, and rolling, a negative electrode layer with a thickness of 50 micrometers was obtained and loaded onto copper foil. Trimethylolpropane triacrylate monomer, azobisisobutyronitrile (AIB), and LiDFOB were mixed uniformly to obtain an in-situ polymerization precursor. The weight ratio of LiDFOB to trimethylolpropane triacrylate monomer was 0.3:1, the weight ratio of AIB to trimethylolpropane triacrylate monomer was 1:100, and the total weight ratio of LiDFOB and trimethylolpropane triacrylate monomer to silicon-carbon composite material was 8:100. The precursor was then cast into the negative electrode layer and subjected to 70°C. oIn-situ polymerization at C for 4 hours followed by roll pressing yielded the integrated negative electrode layer. Using LiCl, LiBr, GeSe2, Li2S, and P2S5 as precursors, they were mixed in a molar ratio of 0.8:0.7:0.02:1.81:0.49, then ball-milled, and combined with 500... o Prepare sulfide solid electrolyte Li by heat treatment at C for 10 hours. 5.12 P 0.98 Ge 0.02 S 4.26 Se 0.04 Cl 0.8 Br 0.7 Vinyltriethoxysilane, TiO2 nanoparticles, and azobisisobutyronitrile (AIBN) were dispersed in a mixed solvent of water, ethanol, and ammonia, wherein the volume ratio of water, ethanol, and ammonia was 1:8:0.4, the weight ratio of vinyltriethoxysilane to TiO2 was 0.4:1, the weight ratio of AIBN to vinyltriethoxysilane was 1:100, and the concentration of TiO2 was 15 g / L. After thorough heating (60°C), stirring, centrifugation, and vacuum drying, a first hydrophobic TiO2 was obtained. Vinyltriethoxysilane and TiO2 nanoparticles were dispersed in a mixed solvent of water, ethanol, and ammonia, wherein the volume ratio of water, ethanol, and ammonia was 1:8:0.4, the weight ratio of vinyltriethoxysilane to TiO2 was 0.4:1, and the concentration of TiO2 was 15 g / L. After thorough stirring, centrifugation, and vacuum drying, a second hydrophobic TiO2 was obtained. The first and second hydrophobic TiO2 were then reacted with Li... 5.12 P 0.98 Ge 0.02 S 4.26 Se 0.04 Cl 0.8 Br 0.7 The ingredients were prepared by ball milling at a weight ratio of 2.5:2.5:100 to obtain a hydrophobic solid electrolyte. Electrochemical impedance spectroscopy showed an ionic conductivity of 4.18 × 10⁻⁶. -3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 68%, and the hydrogen sulfide production after 30 minutes of air exposure was 1.33 cm³. 3 / g; Polytetrafluoroethylene and hydrophobic solid electrolyte were mixed at a weight ratio of 1:100, and then sheared, mixed, and rolled to form a film, resulting in a 50-micron-thick hydrophobic solid electrolyte layer. Commercial LiNi 0.8 Co 0.1 Mn 0.1O2, polyvinylidene fluoride (PVDF), and acetylene black were mixed in NMP at a weight ratio of 96:2:2. The mixture was homogenized, coated, baked, and rolled to obtain a 65-micron-thick positive electrode layer loaded on aluminum foil. Trimethylolpropane triacrylate monomer, azobisisobutyronitrile (AIB), and LiDFOB were mixed uniformly to obtain an in-situ polymerization precursor. The weight ratio of LiDFOB to TBM was 0.3:1, and the weight ratio of AIB to TBM was 1:100. The total weight of LiDFOB and TBM was proportional to the weight of LiNi... 0.8 Co 0.1 Mn 0.1 The O2 weight ratio is 8:100, and then the above precursor is cast into the positive electrode layer, and subjected to 70... o In-situ polymerization at C for 4 hours followed by roll pressing yields an integrated positive electrode layer. An integrated negative electrode layer, a hydrophobic solid electrolyte layer, and an integrated positive electrode layer are then sequentially stacked, followed by hot pressing and encapsulation to obtain an all-solid-state battery. The hot pressing temperature is 80°C and the time is 75 minutes. Electrochemical impedance analysis shows that the interfacial impedance between the solid electrolyte layer and the positive and negative electrodes is 143 ohms.

[0065] Example 3 A 50-micron-thick lithium metal foil was pressed onto a copper foil to obtain the negative electrode layer. Pentaerythritol triacrylate monomer, azobisisobutyronitrile (AIBN), and LiTFSI were mixed uniformly to obtain an in-situ polymerization precursor, wherein the weight ratio of LiTFSI to pentaerythritol triacrylate monomer was 0.3:1, and the weight ratio of AIBN to pentaerythritol triacrylate monomer was 1:100. The precursor was then cast onto the lithium metal foil and subjected to 70°C... o In-situ polymerization at C for 4 hours followed by roll pressing yielded a 60-micron-thick integrated anode layer. Using LiCl, GeSe2, SiO2, Li2S, and P2S5 as precursors, they were mixed in a molar ratio of 1.5:0.01:0.01:1.81:0.49, then ball-milled, and combined with 500... o Prepare sulfide solid electrolyte Li by heat treatment at C for 10 hours. 5.12 P 0.98 Ge 0.01 Si 0.01 S 4.26 Se 0.0 2O 0.02 Cl 1.5Vinyltris(2-methoxyethoxy)silane, MgO nanoparticles, and azobisisobutyronitrile (AIBN) were dispersed in a mixed solvent of water, ethanol, and ammonia, wherein the volume ratio of water, ethanol, and ammonia was 1:8:0.4, the weight ratio of vinyltris(2-methoxyethoxy)silane to MgO was 0.4:1, the weight ratio of AIBN to vinyltris(2-methoxyethoxy)silane was 1:100, and the concentration of MgO was 15 g / L. After thorough heating (60°C), stirring, centrifugation, and vacuum drying, a first hydrophobic MgO was obtained. Vinyltris(2-methoxyethoxy)silane and MgO nanoparticles were dispersed in a mixed solvent of water, ethanol, and ammonia, wherein the volume ratio of water, ethanol, and ammonia was 1:8:0.4, the weight ratio of vinyltris(2-methoxyethoxy)silane to MgO was 0.4:1, and the concentration of MgO was 15 g / L. g / L, after thorough stirring, centrifugation and vacuum drying, yielded the second hydrophobic MgO; the first hydrophobic MgO and the second hydrophobic MgO were then reacted with Li 5.12 P 0.98 Ge 0.01 Si 0.01 S 4.26 Se 0.02 O 0.02 Cl 1.5 The ingredients were prepared by ball milling at a weight ratio of 2.5:2.5:100 to obtain a hydrophobic solid electrolyte. Electrochemical impedance spectroscopy showed an ionic conductivity of 3.95 × 10⁻⁶. - 3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 73%, and the hydrogen sulfide production after 30 minutes of air exposure was 1.21 cm³. 3 / g; Polytetrafluoroethylene and hydrophobic solid electrolyte were mixed at a weight ratio of 1:100, and then sheared, mixed, and rolled to form a film, resulting in a 60-micron-thick hydrophobic solid electrolyte layer. Commercial LiCoO2, polyvinylidene fluoride, and acetylene black were mixed in NMP at a weight ratio of 97:1:2, and then homogenized, coated, baked, and rolled to obtain a 60-micron-thick positive electrode layer loaded on aluminum foil. Pentaerythritol triacrylate monomer, azobisisobutyronitrile, and LiTFSI were mixed uniformly to obtain an in-situ polymerization precursor, wherein the weight ratio of LiTFSI to pentaerythritol triacrylate monomer was 0.3:1, the weight ratio of azobisisobutyronitrile to pentaerythritol triacrylate monomer was 1:100, and the weight ratio of the total weight of LiTFSI and pentaerythritol triacrylate monomer to LiCoO2 was 10:100. The above precursor was then cast into the positive electrode layer and subjected to 70 oIn-situ polymerization at C for 4 hours followed by roll pressing yields an integrated positive electrode layer. An integrated negative electrode layer, a hydrophobic solid electrolyte layer, and an integrated positive electrode layer are then sequentially stacked, followed by hot pressing and encapsulation to obtain an all-solid-state battery. The hot pressing temperature is 80°C and the time is 75 minutes. Electrochemical impedance spectroscopy analysis shows that the interfacial impedance between the solid electrolyte layer and the positive and negative electrodes is 141 ohms.

[0066] Example 4 The preparation method of the all-solid-state battery is as described in Example 1, except that the chemical formula of the sulfide solid electrolyte is Li. 5.41 P 0.99 Sn 0.01 S 4.38 O 0.02 Cl 1.6 Electrochemical impedance spectroscopy showed an ionic conductivity of 4.11 × 10⁻⁶. -3 After exposure to air at 30% relative humidity for 30 minutes, the ionic conductivity remained at 66%, and the hydrogen sulfide production after 30 minutes of air exposure was 1.25 cm³. 3 / g.

[0067] Example 5 The preparation method of the all-solid-state battery is as described in Example 1, except that the chemical formula of the sulfide solid electrolyte is Li. 5.44 P 0.96 Sn 0.04 S 4.32 O 0.08 Cl 1.6 Electrochemical impedance spectroscopy showed an ionic conductivity of 4.30 × 10⁻⁶. -3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 65%, and the hydrogen sulfide production after 30 minutes of air exposure was 1.28 cm³ / cm². 3 / g.

[0068] Example 6 The preparation method of the all-solid-state battery is as described in Example 1, except that the chemical formula of the sulfide solid electrolyte is Li. 5.62 P 0.98 Sn 0.02 S 4.56 O 0.04 Cl 1.4 Electrochemical impedance spectroscopy showed an ionic conductivity of 4.17 × 10⁻⁶. -3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 67%, and the hydrogen sulfide production after 30 minutes of air exposure was 1.30 cm³. 3 / g.

[0069] Example 7 The preparation method of the all-solid-state battery is as described in Example 1, except that the chemical formula of the sulfide solid electrolyte is Li. 5.22 P 0.98 Sn 0.02 S 4.16 O 0.04 Cl 1.8 Electrochemical impedance spectroscopy showed an ionic conductivity of 4.02 × 10⁻⁶. -3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 64%, and the hydrogen sulfide production after 30 minutes of air exposure was 1.23 cm³. 3 / g.

[0070] Example 8 The preparation method of the all-solid-state battery is as described in Example 1, except that hydrophobic SiO2 and Li are used together. 5.42 P 0.98 Sn 0.02 S 4.3 6O 0.04 Cl 1.6 The weight ratio is 2:100. Electrochemical impedance spectroscopy showed an ionic conductivity of 4.87 × 10⁻⁶. -3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 61%, and the hydrogen sulfide production after 30 minutes of air exposure was 1.35 cm³ / cm². 3 / g.

[0071] Example 9 The preparation method of the all-solid-state battery is as described in Example 1, except that hydrophobic SiO2 and Li are used together. 5.42 P 0.98 Sn 0.02 S 4.3 6O 0.04 Cl 1.6 The weight ratio is 8:100. Electrochemical impedance spectroscopy showed an ionic conductivity of 4.02 × 10⁻⁶. -3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 75%, and the hydrogen sulfide production after 30 minutes of air exposure was 1.08 cm³ / cm². 3 / g.

[0072] Example 10 The preparation method of the all-solid-state battery is as described in Example 1, except that the total weight ratio of LiTFSI and ethoxylated trimethylolpropane triacrylate monomers to graphite is 5:100.

[0073] Example 11 The preparation method of the all-solid-state battery is as described in Example 1, except that the total weight ratio of LiTFSI and ethoxylated trimethylolpropane triacrylate monomers to graphite is 20:100.

[0074] Example 12 The preparation method of the all-solid-state battery is as described in Example 1, except that the total weight of LiTFSI and ethoxylated trimethylolpropane triacrylate monomers is the same as that of LiNi. 0.83 Co 0.11 Mn 0.06 The weight ratio of O2 is 5:100.

[0075] Example 13 The preparation method of the all-solid-state battery is as described in Example 1, except that the total weight of LiTFSI and ethoxylated trimethylolpropane triacrylate monomers is the same as that of LiNi. 0.83 Co 0.11 Mn 0.06 The weight ratio of O2 is 20:100.

[0076] Example 14 The preparation method of the all-solid-state battery is as described in Example 1, except that the oxide used in the preparation of the hydrophobic solid electrolyte is replaced with tin dioxide (SnO2).

[0077] Example 15 The preparation method of the all-solid-state battery is as described in Example 1, except that the silane coupling agent used in the preparation of the hydrophobic solid electrolyte is replaced with 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane. Electrochemical impedance spectroscopy analysis showed that the interfacial impedance between the solid electrolyte layer and the positive and negative electrodes was 165 ohms.

[0078] Example 16 The preparation method of the all-solid-state battery is as described in Example 1, except that the polyacrylate used in the integrated positive and negative electrode layers is replaced with pentaerythritol tetraacrylate. Electrochemical impedance spectroscopy analysis showed that the interfacial impedance between the solid electrolyte layer and the positive and negative electrodes was 170 ohms.

[0079] Example 17 The preparation method of the all-solid-state battery is as described in Example 1, except that: the first hydrophobic SiO2, the second hydrophobic SiO2, and Li are mixed. 5.42 P 0.98 Sn 0.02 S 4.36 O 0.04 Cl 1.6 Mix ingredients in a weight ratio of 4:1:100.

[0080] Example 18 The preparation method of the all-solid-state battery is as described in Example 1, except that: the first hydrophobic SiO2, the second hydrophobic SiO2, and Li are mixed. 5.42 P 0.98 Sn 0.02 S 4.36 O 0.04 Cl 1.6 The ingredients were mixed by ball milling at a weight ratio of 1:4:100 to obtain a hydrophobic solid electrolyte.

[0081] Comparative Example 1 The preparation method of the all-solid-state battery is as described in Example 1, except that the chemical formula of the sulfide solid electrolyte is Li. 5.4 PS 4.4 Cl 1.6 That is, no Sn or O doping is performed. Electrochemical impedance spectroscopy showed an ionic conductivity of 3.77 × 10⁻⁶. -3 S / cm, see Figure 4 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 45%, and the hydrogen sulfide production after 30 minutes of air exposure was 2.62 cm³. 3 / g, see Figure 5 .

[0082] Comparative Example 2 The preparation method of the all-solid-state battery is as described in Example 1, except that the chemical formula of the sulfide solid electrolyte is Li. 5.4 PS 4.36 O 0.04 Cl 1.6 That is, only O doping was performed. Electrochemical impedance spectroscopy showed an ionic conductivity of 3.85 × 10⁻⁶. -3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 49%, and the hydrogen sulfide production after 30 minutes of air exposure was 2.52 cm³ / cm². 3 / g.

[0083] Comparative Example 3 The preparation method of the all-solid-state battery is as described in Example 1, except that the chemical formula of the sulfide solid electrolyte is Li. 5.42 P 0.98 Sn 0.02 S 4.4 Cl 1.6 That is, only Sn doping was performed. Electrochemical impedance spectroscopy showed an ionic conductivity of 3.90 × 10⁻⁶. -3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 53%, and the hydrogen sulfide production after 30 minutes of air exposure was 2.48 cm³ / cm². 3 / g.

[0084] Comparative Example 4 The preparation method of the all-solid-state battery is as described in Example 1, except that the chemical formula of the sulfide solid electrolyte is Li. 5.12 P 0.98 Sn 0.02 S 4.06 O 0.04 Cl 1.9 Electrochemical impedance spectroscopy showed an ionic conductivity of 3.68 × 10⁻⁶. -3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 55%, and the hydrogen sulfide production after 30 minutes of air exposure was 2.53 cm³. 3 / g.

[0085] Comparative Example 5 The preparation method of the all-solid-state battery is as described in Example 1, except that the chemical formula of the sulfide solid electrolyte is Li. 5.6 P 0.8 Sn 0.2 S 4.0 O 0.4 Cl 1.6 Electrochemical impedance spectroscopy showed an ionic conductivity of 3.41 × 10⁻⁶. -3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 51%, and the hydrogen sulfide production after 30 minutes of air exposure was 2.54 cm³ / cm². 3 / g.

[0086] Comparative Example 6 The preparation method of the all-solid-state battery is the same as in Example 1, except that the first and second hydrophobic SiO2 are not added. Electrochemical impedance spectroscopy showed an ionic conductivity of 4.77 × 10⁻⁶. -3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 31%, and the hydrogen sulfide production after 30 minutes of air exposure was 2.91 cm³ / cm². 3 / g.

[0087] Comparative Example 7 The all-solid-state battery was prepared as described in Example 1, except that unmodified SiO2 was added. Electrochemical impedance spectroscopy showed an ionic conductivity of 4.29 × 10⁻⁶. -3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 34%, and the hydrogen sulfide production after 30 minutes of air exposure was 2.87 cm³ / cm². 3 / g. Electrochemical impedance spectroscopy revealed that the interfacial impedance between the solid electrolyte layer and the positive and negative electrodes was 260 ohms.

[0088] Comparative Example 8 The preparation method of the all-solid-state battery is as described in Example 1, except that propyltrimethoxysilane is used instead of allyltrimethoxysilane to prepare the second hydrophobic SiO2, and the second hydrophobic SiO2 is then reacted with Li... 5.42 P 0.98 Sn 0.02 S 4.36 O 0.04 Cl 1.6 The ingredients were mixed at a weight ratio of 5:100 and ball-milled to obtain a hydrophobic solid electrolyte. Electrochemical impedance spectroscopy showed an ionic conductivity of 4.02 × 10⁻⁶. -3 After exposure to air at a relative humidity of 30% for 30 minutes, the ionic conductivity remained at 52%, and the hydrogen sulfide production after 30 minutes of air exposure was 1.72 cm³ / cm². 3 / g. Electrochemical impedance spectroscopy showed that the interfacial impedance between the solid electrolyte layer and the positive and negative electrodes was 241 ohms. See [link to relevant documentation]. Figure 6 .

[0089] Comparative Example 9 The all-solid-state battery was prepared as described in Example 1, except that no polymer electrolyte was added to the positive and negative electrodes. Electrochemical impedance spectroscopy showed that the interfacial impedance between the solid electrolyte layer and the positive and negative electrodes was 295 ohms.

[0090] Comparative Example 10 The preparation method of the all-solid-state battery is as described in Example 1, except that a polymer electrolyte is not added to the positive electrode.

[0091] Comparative Example 11 The preparation method of the all-solid-state battery is as described in Example 1, except that a polymer electrolyte is not added to the negative electrode.

[0092] The solid electrolytes prepared in the examples and comparative examples were subjected to ionic conductivity and air stability tests, and the prepared all-solid-state batteries were subjected to high-temperature cycling tests (60℃, 3~4.25V, 0.1C). The test results are summarized in the table below:

Claims

1. A hydrophobic solid electrolyte, characterized in that, It includes a sulfide electrolyte, a first hydrophobic oxide, and a second hydrophobic oxide, wherein the first and second hydrophobic oxides are oxides surface-grafted with alkenyl silane coupling agents, wherein: The alkenyl silane coupling agent on the surface of the first hydrophobic oxide forms a dense polysiloxane layer through alkenyl polymerization; The chemical formula of the sulfide electrolyte is Li 6-x+y P 1-y A y S 5-x-2y B 2y M 1+x In the formula, M is at least one of Cl, Br, or I; A is at least one of Sn, Si, Ge, Zr, Hf, or Ti; and B is at least one of Se, Te, or O. Wherein, 0 <x≤0.8,0<y≤0.1。 2. The hydrophobic solid electrolyte according to claim 1, characterized in that, The silane coupling agent is selected from one or more of allyltrimethoxysilane, 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane, vinyltriethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyltrimethoxysilane, and vinyltriisopropoxysilane.

3. The hydrophobic solid electrolyte according to claim 1, characterized in that, The oxide is selected from one or more of silicon dioxide, tin dioxide, titanium dioxide, zinc oxide, or magnesium oxide.

4. The hydrophobic solid electrolyte according to any one of claims 1 to 3, characterized in that, The mass ratio of the first hydrophobic oxide to the second hydrophobic oxide is 20~80:80~20.

5. The method for preparing the hydrophobic solid electrolyte according to any one of claims 1 to 4, characterized in that, Includes the following steps: The silane coupling agent, the oxide, and the initiator are reacted in an alkaline alcohol aqueous solution, and then separated and dried to obtain the first hydrophobic oxide. The silane coupling agent and the oxide are reacted in an alkaline alcohol aqueous solution, and then separated and dried to obtain the second hydrophobic oxide; The sulfide electrolyte and the first and second hydrophobic oxides are ball-milled until homogeneous to obtain the hydrophobic solid electrolyte.

6. The preparation method according to claim 5, characterized in that, The weight ratio of silane coupling agent to oxide particles is 0.2 to 1:1, and the weight ratio of initiator to silane coupling agent is 0.5 to 2:

100.

7. An all-solid-state battery, characterized in that, It includes an integrated negative electrode layer, a hydrophobic solid electrolyte layer, and an integrated positive electrode layer; The integrated negative electrode layer includes a negative electrode layer and a polymer electrolyte dispersed inside it or covering its surface, wherein the monomer of the polymer electrolyte is a polyacrylate. The integrated positive electrode layer consists of a positive electrode layer and a polymer electrolyte dispersed in the positive electrode layer, wherein the monomer of the polymer electrolyte is a polyacrylate. The hydrophobic solid electrolyte layer comprises any one of the hydrophobic solid electrolytes described in claims 1 to 4; Wherein, the alkenyl groups on the surface of the second hydrophobic oxide are cross-linked with the alkenyl groups at the interface of the integrated negative electrode layer and / or the integrated positive electrode layer.

8. The all-solid-state battery according to claim 7, characterized in that, The polyacrylate is selected from one or more of ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, or pentaerythritol tetraacrylate.

9. The all-solid-state battery according to claim 7, characterized in that, The polymer electrolyte is formed by in-situ polymerization of the monomer, and the in-situ polymerization reaction temperature is 50°C. o C~80 o C, the polymerization time is 1 to 10 hours, and the weight ratio of the initiator to the monomer is 0.5 to 2:

100.

10. The method for preparing the all-solid-state battery according to any one of claims 7 to 9, characterized in that, Includes the following steps: An all-solid-state battery is obtained by hot pressing and encapsulating an integrated negative electrode layer, a hydrophobic solid electrolyte, and an integrated positive electrode layer. The hot pressing temperature is 60~100℃, and the time is 30~120min.

Images