Solid electrolyte and preparation method thereof, battery and electric device

Abstract

The invention provides a solid electrolyte, a preparation method of the solid electrolyte, a battery and a power utilization device, and aims to solve the problems that the solid electrolyte of the existing battery is easy to generate side reaction at an interface, the interface impedance is increased, and the charge and discharge performance of the battery is influenced. The composite electrolyte layer comprises a polymer electrolyte basement membrane and a filler, and the filler is distributed in the polymer electrolyte basement membrane; the filler comprises one or more of oxide solid electrolyte, sulfide solid electrolyte and halide solid electrolyte; and the inorganic solid electrolyte layer comprises one or more of oxide solid electrolyte, sulfide solid electrolyte and halide solid electrolyte.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and in particular relates to a solid electrolyte and a preparation method thereof, a battery and an electrical device. Background Art

[0002] In semi-solid batteries or solid-state batteries, side reactions occur at the interface between the electrolyte and the negative electrode or positive electrode, increasing the interfacial impedance and affecting the battery's charge and discharge performance. Summary of the invention

[0003] In view of the problem that solid electrolytes in existing batteries are prone to side reactions at the interface, increasing interface impedance and affecting battery charge and discharge performance, the present invention provides a solid electrolyte and a preparation method thereof, a battery and an electrical device.

[0004] The technical solution adopted by the present invention to solve the above technical problems is as follows: In a first aspect, the present invention provides a solid electrolyte, comprising an inorganic solid electrolyte layer and a composite electrolyte layer, wherein the composite electrolyte layer comprises a polymer electrolyte substrate membrane and a filler, wherein the filler is distributed in the polymer electrolyte substrate membrane; the filler comprises one or more of an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte; The inorganic solid electrolyte layer includes one or more of an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte.

[0005] Optionally, the composite electrolyte layer is provided with two layers, the inorganic solid electrolyte layer is provided with one layer, and the inorganic solid electrolyte layer is located between the two composite electrolyte layers.

[0006] Optionally, the composite electrolyte layer is provided with one layer, and the inorganic solid electrolyte layer is provided with one layer.

[0007] Optionally, the thickness of the composite electrolyte layer is 5µm to 300µm; the thickness of the inorganic solid electrolyte layer is 5µm to 300µm.

[0008] Optionally, the ionic conductivity of the inorganic solid electrolyte layer is greater than or equal to 1 mS / cm.

[0009] Optionally, the particle size of the filler is 5nm to 3µm.

[0010] Optionally, the particle size of the filler is 50nm to 300nm.

[0011] Optionally, the mass of the filler is 0.1% to 10% of the mass of the polymer electrolyte substrate membrane.

[0012] Optionally, the mass of the filler is 0.5% to 5% of the mass of the polymer electrolyte substrate membrane.

[0013] Optionally, the halide solid electrolyte includes Li a (M b )X c X' d , wherein M includes one or more of Ga, Y, In, Mg, Sr, Sc, Sn, Pb, Ti, Zr, Hf, Nb, Ta, W, Fe, Ru, Al, and lanthanide metal elements; X includes one or more of halogens; X' includes one or more of halide ions, N ions, oxygen-containing anion groups, and pseudohalide anions; 0.5≤a≤5, 0.2≤b≤4, c+d=a+bε, wherein ε is the weighted average valence of the M element; And / or, the oxide solid electrolyte includes one or more of a NASICON-type electrolyte, a perovskite-type electrolyte, an antiperovskite-type electrolyte, a LISICON-type electrolyte and a garnet-type electrolyte; And / or, the sulfide solid electrolyte includes Li 6-x PS 5-x Cl 1+x ,0≤x≤0.8, Li2S-P2S5, Li 10 GeP2S 12 , Li3PS4 or more.

[0014] Optionally, the oxygen-containing anion group includes O 2- , S 2- , CN - 、CO3 2- PO4 3- 、P2O7 4- 、SO4 2- One or more of; the pseudohalide anion includes SCN - PF6 - NH2 - 、AlF4 - , or BF4 - One or more of .

[0015] Optionally, the filler includes LLTO, LATP, LAGP, LLZO, Li2S-P2S5, Li6PS5Cl, Li2MnCl4, Li2ZnCl4, Li2ZrOCl4, LiYbF4, LiAlF4, Li3YCl6, Li3InCl6, Li3InCl 5.5 F 0.5 、Li3TaCl6、Li 0.388 Ta 0.238 La0.475 One or more of Cl3, Li6CoCl8.

[0016] Optionally, the filler is uniformly distributed in the polymer electrolyte base membrane.

[0017] In a second aspect, the present invention provides a method for preparing the solid electrolyte as described above, comprising the following steps: The polymer and the lithium salt are dispersed in a mixed solvent, and then a filler is added, mixed and cast on a substrate, and the mixed solvent is removed by drying to obtain a composite electrolyte layer; the mixed solvent includes a first solvent that is mutually soluble in the polymer and a second solvent that is insoluble in the polymer; An inorganic solid electrolyte and a binder are mixed, and then pre-fiberized to obtain a blank, and the blank is rolled into a film to obtain the inorganic solid electrolyte layer; The inorganic solid electrolyte layer and the composite electrolyte layer are composited to obtain the solid electrolyte.

[0018] Optionally, the mass of the mixed solvent is 3 to 15 times the mass of the polymer, and the mass ratio of the first solvent to the second solvent is 1:10 to 10:1.

[0019] Optionally, the first solvent includes one or more of acetonitrile, acetone, ethyl acetate, butanone, diethyl ether, hexane, n-heptane, chloroform, tetrahydrofuran, N,N-dimethylacetamide, N,N-dimethylacetamide, 2,2,2-trifluoro-N,N-dimethylformamide, and N-methylpyrrolidone; The second solvent includes one or more of butyl butyrate, ethyl butyrate, isobutyl isobutyrate, ethanol, and butanol.

[0020] Optionally, the drying temperature is 60 to 160° C., the drying time is 6 to 24 hours, and the relative vacuum degree during drying is -0.1 to 0 MPa.

[0021] Optionally, the binder includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, silicone rubber, styrene-butadiene rubber, hydrogenated nitrile rubber, boronated polyethylene glycol, cellulose, cellulose ester, cellulose ether, nitrocellulose, carboxyalkyl cellulose, cellulose salt, sodium carboxymethyl cellulose and cellulose salt derivatives, polyacrylic acid, polyamide, polyvinyl alcohol, polyethylene imine, and polyimide.

[0022] Optionally, the binder has a mass content of 0.1% to 10% in the inorganic solid electrolyte layer.

[0023] In a third aspect, the present invention provides a battery, comprising a positive electrode, a negative electrode, and also comprising a solid electrolyte as described in any one of the above items; or, comprising a solid electrolyte prepared by the method for preparing a solid electrolyte as described in any one of the above items; the solid electrolyte is located between the positive electrode and the negative electrode.

[0024] Optionally, the composite solid electrolyte includes an inorganic solid electrolyte layer and a composite electrolyte layer, the composite electrolyte layer is located between the negative electrode and the inorganic solid electrolyte layer; and / or, the composite electrolyte layer is located between the positive electrode and the inorganic solid electrolyte layer.

[0025] Optionally, the battery further includes an electrolyte, and the polymer electrolyte substrate membrane is a porous film.

[0026] Optionally, the electrolyte includes a fourth solvent, a lithium salt, a first additive and a second additive; The fourth solvent includes at least one of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methylpropyl carbonate, dimethyl sulfite, diethyl sulfite, dipropyl sulfite, ethylene sulfite, methyl acetate, ethyl acetate, ethyl formate, ethyl propionate, methyl propionate, ethylene glycol n-butyl ether, methyl butyl ether, methyl tert-butyl ether, dibutyl ether, ethylene glycol dimethyl ether, 1,3-dioxolane, tetraethylene glycol dimethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether; The lithium salt includes at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium hexafluoroantimonate, lithium bis(trifluoromethanesulfonimide), lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium perchlorate, lithium iodide, lithium magnesium bis(fluorosulfonyl)imide, lithium bisoxalatoborate and lithium difluorooxalatoborate; The first additive includes at least one of tripropynyl phosphate, 4-nitrophenyl trifluoroacetate, fluoroether 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,3-propane sultone, vinyl sulfate, toluene, 1,2-xylene, 1,3-xylene, 1,4-xylene, fluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene, 1,2,4-trifluorobenzene, 1,3,5-trifluorobenzene, 1,2,3,4-tetrafluorobenzene, 1,2,3,5-tetrafluorobenzene, 1,2,4,5-tetrafluorobenzene, pentafluorobenzene, and hexafluorobenzene; The second additive includes at least one of vinylene carbonate, fluoroethylene carbonate, and LiNO 3 .

[0027] Optionally, the volume ratio of the fourth solvent to the first additive is (1:10) to (10:1); And / or, the mass content of the second additive in the electrolyte is 0.1% to 10%.

[0028] Optionally, the concentration of the lithium salt in the electrolyte is 0.5 mol / L to 5 mol / L.

[0029] In a fourth aspect, the present invention provides an electrical device comprising a battery as described in any one of the above items.

[0030] The solid electrolyte of the first aspect of the present invention comprises an inorganic solid electrolyte layer and a composite electrolyte layer, forming at least a double-layer solid electrolyte, and combining the flexibility of the polymer electrolyte and the high ionic conductivity of the inorganic solid electrolyte, improving the interface contact, reducing the interface impedance, and improving the overall performance of the electrolyte. The filler in the composite electrolyte layer is distributed in the polymer electrolyte substrate membrane, has a certain flexibility and mechanical strength, can absorb and release the stress accumulation generated during the battery cycle, thereby maintaining the structural integrity and stability of the electrolyte membrane, effectively solving the problem of electrolyte membrane rupture and performance attenuation caused by stress accumulation during the battery cycle, and enhancing the cycle stability and life of the battery.

[0031] The preparation method of the second aspect of the present invention selects two solvents with different solubility from the polymer as a mixed solvent. As the mixed solvent evaporates, the interfacial tension and force of the mixed solvent cause the polymer and the inorganic solid electrolyte to phase separate during the casting process, forming many tiny droplets or particles arranged into a porous structure. When drying, the droplets or particles fuse to form a stable porous film structure. The phase separation method realizes the precise pore size and pore distribution control of the composite electrolyte layer, simplifies the preparation process of the composite electrolyte layer, improves the stability and controllability of the process, solves the problem of complex process and poor stability of the existing composite electrolyte layer, and reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of a battery provided by an embodiment of the present invention; Figure 2 is a schematic diagram of a battery provided by another embodiment of the present invention; Figure 3 is a schematic diagram of a battery provided by another embodiment of the present invention.

[0033] Markings in the accompanying drawings: 1. Inorganic solid electrolyte layer; 2. Composite electrolyte layer; 3. Positive electrode; 4. Negative electrode. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] An embodiment of the present invention provides a solid electrolyte, comprising an inorganic solid electrolyte layer 1 and a composite electrolyte layer 2, wherein the composite electrolyte layer 2 comprises a polymer electrolyte substrate membrane and a filler; the filler is distributed in the polymer electrolyte substrate membrane; the filler comprises one or more of an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte; The inorganic solid electrolyte layer 1 includes one or more of an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte.

[0036] The term "plurality" in the present application refers to two or more than two.

[0037] In the present invention, the solid electrolyte includes an inorganic solid electrolyte layer 1 and a composite electrolyte layer 2, which can form at least a double-layer solid electrolyte, and combines the flexibility of the polymer electrolyte and the high ionic conductivity of the inorganic solid electrolyte, improves the interface contact, reduces the interface impedance, and improves the overall performance of the electrolyte. The filler in the composite electrolyte layer 2 is distributed in the polymer electrolyte base membrane, has a certain flexibility and mechanical strength, can absorb and release the stress accumulation generated during the battery cycle, thereby maintaining the structural integrity and stability of the electrolyte membrane, effectively solving the problem of electrolyte membrane rupture and performance attenuation caused by stress accumulation during the battery cycle, and enhancing the cycle stability and life of the battery.

[0038] In one embodiment, the filler is uniformly distributed in the polymer electrolyte base membrane.

[0039] The filler is evenly distributed in the polymer electrolyte substrate membrane, significantly improving the ionic conductivity of the solid electrolyte. The filler forms an efficient ion conduction channel in the polymer electrolyte substrate membrane, ensuring that lithium ions can move efficiently inside the battery, thereby improving the battery's charge and discharge performance. The polymer electrolyte substrate membrane provides the necessary flexibility and mechanical strength for the solid electrolyte, allowing the electrolyte membrane to adapt to deformation and stress changes inside the battery, preventing mechanical damage to the solid electrolyte during use.

[0040] In one embodiment, the composite electrolyte layer 2 is provided with two layers, the inorganic solid electrolyte layer 1 is provided with one layer, and the inorganic solid electrolyte layer 1 is located between the two composite electrolyte layers 2. Composite electrolyte layers 2 are provided on both sides of the inorganic solid electrolyte layer 1. On the one hand, the side reaction between the negative electrode 4 and the inorganic solid electrolyte layer 1 is effectively avoided, and the chemical reaction between the electrolyte and the negative electrode material is reduced. On the other hand, the flexibility and mechanical strength of the solid electrolyte are improved.

[0041] In one embodiment, the composite electrolyte layer 2 is provided with one layer, and the inorganic solid electrolyte layer 1 is provided with one layer. When the composite electrolyte layer 2 is located between the negative electrode 4 and the inorganic solid electrolyte layer 1, the side reaction between the negative electrode 4 and the inorganic solid electrolyte layer 1 is effectively avoided, and the chemical reaction between the electrolyte and the negative electrode material is reduced. When the composite electrolyte layer 2 is located between the positive electrode 3 and the inorganic solid electrolyte layer 1, the inorganic solid electrolyte layer 1 prevents the further growth of lithium dendrites through the passivation reaction, prevents the lithium dendrites from piercing the electrolyte layer, and can effectively inhibit the growth of lithium dendrites, ensuring the safety and long-term stability of the battery.

[0042] In one embodiment, the thickness of the composite electrolyte layer 2 is 5µm to 300µm; the thickness of the inorganic solid electrolyte layer 1 is 5µm to 300µm. The thickness of the composite electrolyte layer 2 and the inorganic solid electrolyte 1 can be, for example, 5µm, 50µm, 100µm, 150µm, 200µm, 300µm. Within this thickness range, the flexibility of the composite electrolyte layer 2 and the ionic conductivity and mechanical strength of the inorganic solid electrolyte layer 1 are matched, so that the solid electrolyte has high ionic conductivity and effectively absorbs and releases the stress accumulation generated during the battery cycle.

[0043] In one embodiment, the thickness of the composite electrolyte layer 2 is 10µm to 30µm; the thickness of the inorganic solid electrolyte layer 1 is 10µm to 30µm. The thickness of the composite electrolyte layer 2 and the inorganic solid electrolyte 1 can be, for example, 10µm, 20µm, or 30µm. Within this thickness range, the solid electrolyte has high ionic conductivity and mechanical strength.

[0044] In one embodiment, the ionic conductivity of the inorganic solid electrolyte layer 1 is greater than or equal to 1 mS / cm, and may be, for example, 1 mS / cm, 1.2 mS / cm, 1.5 mS / cm, or 2 mS / cm. Higher ionic conductivity can improve the cycle performance and rate performance of the battery.

[0045] In one embodiment, the particle size of the filler is 5 nm to 3 µm, such as 5 nm, 30 nm, 100 nm, 500 nm, 1 µm, 2 µm, and 3 µm.

[0046] By selecting fillers within the above-mentioned particle size range, the fillers are evenly distributed in the polymer electrolyte substrate membrane, forming an efficient ion conduction channel, ensuring that lithium ions can move efficiently inside the battery, thereby improving the battery's charge and discharge performance. In addition, by selecting fillers within the above-mentioned particle size range, it is easy to regulate their distribution in the polymer electrolyte substrate membrane. Filler particles that are too small or too large affect their uniformity in the polymer electrolyte substrate membrane, thereby affecting the mechanical properties of the solid electrolyte. Among them, when the particle size of the filler is 50nm to 300nm, such as 50nm, 100nm, 150nm, 200nm, and 300nm, the effect can be further improved.

[0047] In one embodiment, the mass of the filler is 0.1% to 10% of the mass of the polymer electrolyte substrate membrane, such as 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, 1.5%, 1.7%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%. By controlling the content of the filler in the polymer electrolyte substrate membrane, the ionic conductivity and mechanical strength of the formed composite electrolyte layer 2 are adjusted to further enhance the overall mechanical properties of the composite electrolyte layer 2, ensuring that the composite electrolyte layer 2 maintains structural integrity during multiple charge and discharge cycles. Wherein, the mass of the filler is 0.5% to 5% of the mass of the polymer electrolyte substrate membrane, such as 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, 1.5%, 1.7%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, the effect can be further improved.

[0048] In one embodiment, the halide solid electrolyte includes Li a (M b )X c X' d , wherein M includes one or more of Ga, Y, In, Mg, Sr, Sc, Sn, Pb, Ti, Zr, Hf, Nb, Ta, W, Fe, Ru, Al, and lanthanide metal elements. X includes one or more of halogens. X' includes one or more of halide ions, N ions, oxygen-containing anion groups, and pseudohalide anions. 0.5≤a≤5, 0.2≤b≤4, c+d=a+bε, wherein ε is the weighted average valence of the M element.

[0049] And / or, the oxide solid electrolyte includes one or more of a NASICON (sodium fast ion conductor) type electrolyte, a perovskite type electrolyte, an antiperovskite type electrolyte, a LISICON (lithium fast ion conductor) type electrolyte and a garnet type electrolyte; And / or, the sulfide solid electrolyte includes Li 6-x PS 5-x Cl 1+x ,0≤x≤0.8, Li2S-P2S5, Li 10 GeP2S 12 , Li3PS4 or more.

[0050] By selecting the above-mentioned halide solid electrolyte, oxide solid electrolyte, and sulfide solid electrolyte, it is possible to better form ion conduction channels in the solid electrolyte, improve the ion conductivity of the solid electrolyte, and further enhance the charge and discharge performance of the battery.

[0051] In one embodiment, the oxygen-containing anion group includes O 2- , S 2- , CN - 、CO3 2- PO4 3- 、P2O7 4- 、SO4 2- The pseudohalide anion includes SCN - PF6 - NH2 - 、AlF4 - , or BF4 - By selecting the above-mentioned halide solid electrolyte, it is possible to better form ion conduction channels in the solid electrolyte, improve the ion conductivity of the solid electrolyte, and further improve the charge and discharge performance of the battery.

[0052] In one embodiment, in the inorganic solid electrolyte layer 1, the halide solid electrolyte includes Li2MnCl4, Li2ZnCl4, Li2ZrOCl4, LiYbF4, LiAlF4, Li3YCl6, Li3InCl6, Li3InCl 5.5 F 0.5 、Li3TaCl6、Li 0.388 Ta 0.238 La 0.475 One or more of Cl3, Li6CoCl8.

[0053] The oxide solid electrolyte includes Li 3x La 2 / 3−x TiO (LLTO, 0≤x≤0.16), Li 1+x Al x Ti 2−x (PO4)3(LATP), Li 1+x Al x Ge 2−x(PO4)3(LAGP), Li7La3Zr2O 12 (LLZO) or more.

[0054] The sulfide solid electrolyte includes one or more of Li2S-P2S5 and Li6PS5Cl. The inorganic solid electrolyte layer 1 can be prepared by using these to effectively inhibit the growth of lithium dendrites and ensure the safety and long-term stability of the battery.

[0055] In one embodiment, the filler includes LLTO, LATP, LAGP, LLZO, Li2S-P2S5, Li6PS5Cl, Li2MnCl4, Li2ZnCl4, Li2ZrOCl4, LiYbF4, LiAlF4, Li3YCl6, Li3InCl6, Li3InCl 5.5 F 0.5 、Li3TaCl6、Li 0.388 Ta 0.238 La 0.475 One or more of Cl3, Li6CoCl8. Selecting these fillers can achieve higher ion conductivity.

[0056] In one embodiment, the polymer electrolyte substrate membrane includes a polymer and a lithium salt, and the molar ratio of the polymer to the lithium salt is (5:1) to (20:1). Specifically, the molar ratio of the polymer to the lithium salt includes but is not limited to 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 12:1, 15:1, 16:1, 17:1, 18:1, 19:1 or 20:1. By limiting the molar ratio of the polymer to the lithium salt, the flexibility of the polymer electrolyte substrate membrane is adjusted, so that the solid electrolyte can adapt to the deformation and stress changes inside the battery, and prevent the solid electrolyte from being mechanically damaged during use.

[0057] In one embodiment, the polymer includes at least one of polyethylene oxide, polyacrylate, polyvinylidene fluoride, polyvinylidene fluoride hexafluoropropylene copolymer, polysiloxane, polyethylene glycol, sodium polystyrene sulfonate, polysulfone, polyether sulfone, polypropylene carbonate, polymethyl methacrylate, polyacrylonitrile, and polyimide. The above polymers are selected to facilitate the adjustment of the flexibility and mechanical strength of the polymer electrolyte substrate membrane.

[0058] And / or, the lithium salt includes at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium hexafluoroantimonate, lithium bis(trifluoromethanesulfonate imide), lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium perchlorate, lithium iodide, lithium magnesium bis(fluorosulfonyl)imide, lithium bis(oxalatoborate) and lithium difluorooxalatoborate.

[0059] In a second aspect, an embodiment of the present invention further provides a method for preparing the solid electrolyte as described above, comprising the following steps: The polymer and the lithium salt are dispersed in a mixed solvent, and then a filler is added, mixed and cast on a substrate, and the mixed solvent is removed by drying to obtain a composite electrolyte layer 2; the mixed solvent includes a first solvent miscible with the polymer and a second solvent insoluble with the polymer; An inorganic solid electrolyte and a binder are mixed, and then pre-fiberized to obtain a blank, and the blank is rolled into a film to obtain the inorganic solid electrolyte layer 1; specifically, the pre-fiberization is to apply shear force to the inorganic solid electrolyte and the binder to fiberize the binder.

[0060] The inorganic solid electrolyte layer 1 and the composite electrolyte layer 2 are composited to obtain the solid electrolyte.

[0061] By selecting two solvents with different solubility from the polymer as a mixed solvent, as the mixed solvent evaporates, the interfacial tension and force of the mixed solvent cause the polymer and the inorganic solid electrolyte to separate during the casting process, forming many tiny droplets or particles arranged into a porous structure. When drying, the droplets or particles fuse to form a stable porous film structure. Through this phase separation method, the precise pore size and pore distribution control of the composite electrolyte layer 2 is achieved, the preparation process of the composite electrolyte layer 2 is simplified, the stability and controllability of the process are improved, the problem of complex process and poor stability of the existing composite electrolyte layer 2 is solved, and the production cost is reduced.

[0062] In one embodiment, the mass of the mixed solvent is 3 to 15 times the mass of the polymer, and the mass ratio of the first solvent to the second solvent is 1:10 to 10:1. When the mass ratio of the first solvent to the second solvent is within this range, the pore size and pores formed by the solid electrolyte are uniform. If the content of the first solvent or the second solvent is too high, the pore size of the composite electrolyte layer 2 is greatly differentiated, which affects the mechanical strength of the composite electrolyte layer 2.

[0063] In one embodiment, the first solvent includes one or more of acetonitrile, acetone, ethyl acetate, butanone, diethyl ether, hexane, n-heptane, chloroform, tetrahydrofuran, N,N-dimethylacetamide, N,N-dimethylacetamide, 2,2,2-trifluoro-N,N-dimethylformamide, and N-methylpyrrolidone.

[0064] The second solvent includes one or more of butyl butyrate, ethyl butyrate, isobutyl isobutyrate, ethanol, and butanol. By selecting the above solvents, it is convenient to achieve precise pore size and pore distribution control of the composite electrolyte layer 2 by phase separation method.

[0065] In one embodiment, the drying temperature is 60-160° C., the drying time is 6-24 hours, and the relative vacuum degree during drying is -0.1-0 MPa. By regulating the drying temperature and drying time, the precise pore size and pore distribution control of the composite electrolyte layer 2 is achieved.

[0066] In one embodiment, the binder includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, silicone rubber, styrene-butadiene rubber, hydrogenated nitrile rubber, boronized polyethylene glycol, cellulose, cellulose ester, cellulose ether, nitrocellulose, carboxyalkyl cellulose, cellulose salt, sodium carboxymethyl cellulose and cellulose salt derivatives, polyacrylic acid, polyamide, polyvinyl alcohol, polyethylene imine, and polyimide. By adding the above binder, it is convenient to prepare the inorganic solid electrolyte layer 1.

[0067] In one embodiment, the mass content of the binder in the inorganic solid electrolyte layer 1 is 0.1% to 10%, such as 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, 1.5%, 1.7%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%. By controlling the content of the binder in the inorganic solid electrolyte layer 1, the ionic conductivity of the solid electrolyte is regulated.

[0068] In a third aspect, an embodiment of the present invention further provides a battery, comprising a positive electrode 3, a negative electrode 4, and also comprising a solid electrolyte as described in any one of the above embodiments; or, comprising a solid electrolyte prepared by the preparation method of the solid electrolyte as described in any one of the above embodiments; the solid electrolyte is located between the positive electrode 3 and the negative electrode 4.

[0069] The battery adopts the solid electrolyte in the above embodiment. When the composite electrolyte layer 2 is located between the negative electrode 4 and the inorganic solid electrolyte layer 1, the side reaction between the negative electrode 4 and the inorganic solid electrolyte is effectively avoided, and the chemical reaction between the electrolyte and the negative electrode 4 material is reduced.

[0070] When the composite electrolyte layer 2 is located between the positive electrode 3 and the inorganic solid electrolyte layer 1, the inorganic solid electrolyte layer 1 prevents the further growth of lithium dendrites through a passivation reaction, prevents the lithium dendrites from piercing the electrolyte layer, and can effectively inhibit the growth of lithium dendrites to ensure the safety and long-term stability of the battery.

[0071] In one embodiment, the battery further includes an electrolyte, and the polymer electrolyte substrate membrane is a porous film.

[0072] The polymer electrolyte base membrane is a porous membrane, and its pores not only help to improve the ionic conductivity of the electrolyte, but also can be used in combination with a variety of electrolytes to adapt to different electrolytes. At the same time, the pores of the polymer electrolyte base membrane provide a larger interface contact area, further improving the ion conduction efficiency and the overall performance of the battery.

[0073] In one embodiment, the electrolyte includes a fourth solvent, a lithium salt, a first additive, and a second additive.

[0074] The fourth solvent includes at least one of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, dimethyl sulfite, diethyl sulfite, dipropyl sulfite, ethylene sulfite, methyl acetate, ethyl acetate, ethyl formate, ethyl propionate, methyl propionate, ethylene glycol n-butyl ether, methyl butyl ether, methyl tert-butyl ether, dibutyl ether, ethylene glycol dimethyl ether, 1,3-dioxolane, tetraethylene glycol dimethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether.

[0075] The lithium salt includes at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium hexafluoroantimonate, lithium bis(trifluoromethanesulfonylimide), lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium perchlorate, lithium iodide, lithium magnesium bis(fluorosulfonyl)imide, lithium bis(oxalatoborate) and lithium difluorooxalatoborate.

[0076] The first additive includes at least one of tripropynyl phosphate, 4-nitrophenyl trifluoroacetate, fluoroether 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,3-propane sultone, vinyl sulfate, toluene, 1,2-xylene, 1,3-xylene, 1,4-xylene, fluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene, 1,2,4-trifluorobenzene, 1,3,5-trifluorobenzene, 1,2,3,4-tetrafluorobenzene, 1,2,3,5-tetrafluorobenzene, 1,2,4,5-tetrafluorobenzene, pentafluorobenzene, and hexafluorobenzene.

[0077] The second additive includes at least one of vinylene carbonate, fluoroethylene carbonate, and LiNO 3 .

[0078] By selecting the first additive and using it in combination with the solid electrolyte, the stability of the electrolyte and the electrolyte is improved, and the cycle life of the battery is further improved. In one embodiment, the volume ratio of the fourth solvent to the first additive is (1:10) to (10:1).

[0079] And / or, the mass content of the second additive in the electrolyte is 0.1% to 10%. By adjusting the content of the first additive and the second additive, the stability of the electrolyte and the electrolyte is further improved, the cycle life of the battery is improved, and the coulombic efficiency is improved.

[0080] In one embodiment, the electrolyte includes an ester organic solvent and a lithium salt, and the ester organic solvent includes at least one of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, dimethyl sulfite, diethyl sulfite, dipropyl sulfite, vinyl sulfite, methyl acetate, ethyl acetate, ethyl formate, ethyl propionate, and methyl propionate.

[0081] The lithium salt includes at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium hexafluoroantimonate, lithium bis(trifluoromethanesulfonylimide), lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium perchlorate, lithium iodide, lithium magnesium bis(fluorosulfonyl)imide, lithium bis(oxalatoborate) and lithium difluorooxalatoborate.

[0082] In one embodiment, the electrolyte includes an ether organic solvent and a lithium salt, and the ether organic solvent includes at least one of ethylene glycol n-butyl ether, methyl butyl ether, methyl tert-butyl ether, dibutyl ether, ethylene glycol dimethyl ether, 1,3-dioxolane, tetraethylene glycol dimethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether.

[0083] The lithium salt includes at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium hexafluoroantimonate, lithium bis(trifluoromethanesulfonylimide), lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium perchlorate, lithium iodide, lithium magnesium bis(fluorosulfonyl)imide, lithium bis(oxalatoborate) and lithium difluorooxalatoborate.

[0084] In one embodiment, the electrolyte includes an ionic liquid and a lithium salt, and the ionic liquid includes one or more of imidazole ionic liquids, pyridine ionic liquids, quaternary ammonium ionic liquids, quaternary phosphonium ionic liquids, pyrrolidine ionic liquids, and piperidine ionic liquids.

[0085] The lithium salt includes at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium hexafluoroantimonate, lithium bis(trifluoromethanesulfonylimide), lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium perchlorate, lithium iodide, lithium magnesium bis(fluorosulfonyl)imide, lithium bis(oxalatoborate) and lithium difluorooxalatoborate.

[0086] In one embodiment, the imidazole ionic liquid includes one or more of 1-alkylimidazole, 1-alkyl 3-methylimidazole, and 1-alkyl-2,3-dimethylimidazole, wherein the alkyl group includes methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl or octadecyl; and the anion includes one of chlorine, bromine, iodine, tetrafluoroboric acid, hexafluorophosphoric acid, acetic acid, bistrifluoromethanesulfonyl imide, nitric acid, perchloric acid, hydrogen sulfate, dihydrogen phosphate, trifluoromethanesulfonic acid, trifluoroacetic acid, and p-toluenesulfonic acid.

[0087] Preferably, the imidazolium ionic liquid includes one or more of 1-methylimidazolium chloride, 1-methylimidazolium tetrafluoroborate, N-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium tetrafluoroborate, and 1-octyl-3-methylimidazolium hexafluorophosphate.

[0088] In one embodiment, the cation of the pyridinium ionic liquid includes N-alkylpyridine, wherein the alkyl group includes ethyl, butyl, hexyl or octyl; and the anion includes chloride, bromide, tetrafluoroborate, hexafluorophosphate or bistrifluoromethanesulfonimide.

[0089] Preferably, the pyridine ionic liquid includes one of N-ethylpyridinium chloride, N-ethylpyridinium tetrafluoroborate, and N-ethylpyridinium bis(trifluoromethanesulfonyl)imide; In one embodiment, the quaternary ammonium ionic liquid cation includes tetraethylammonium, tetrabutylammonium, alkyltriethylammonium, alkyltributylammonium, wherein the alkyl includes ethyl, butyl, hexyl or octyl; the anion includes chloride, bromide, tetrafluoroborate, hexafluorophosphate or bistrifluoromethanesulfonimide.

[0090] Preferably, the quaternary ammonium ionic liquid includes one or more of trimethylamine hydrochloride, N,N-diethylmethylammonium trifluoromethanesulfonate, and triethylammonium hydrochloride; In one embodiment, the quaternary phosphonium ionic liquid cation includes alkyl tributyl phosphonium, wherein the alkyl group includes ethyl, butyl, hexyl or octyl, and the anion includes bromine, tetrafluoroborate or bistrifluoromethanesulfonimide.

[0091] Preferably, the quaternary phosphonium ionic liquid includes one or more of methyl tributyl phosphonium bis(trifluoromethanesulfonyl)imide, ethyl tributyl phosphonium bis(trifluoromethanesulfonyl)imide, propyl tributyl phosphonium bis(trifluoromethanesulfonyl)imide, N-n-hexyl quaternary ammonium bis(trifluoromethanesulfonyl)imide, N-trimethyl-N-n-pentyl quaternary ammonium trifluoromethanesulfonyl imide, and N-trimethyl-N-butyl quaternary ammonium trifluoromethanesulfonyl imide.

[0092] In one embodiment, the pyrrolidine ionic liquid cation includes N-alkyl-N-methylpyrrolidine, wherein the alkyl group includes ethyl, propyl, butyl, hexyl or octyl; the anion includes one of bromine, tetrafluoroborate, hexafluorophosphate, and bistrifluoromethanesulfonimide.

[0093] Preferably, the pyrrolidine ionic liquid includes one or more of N-ethyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide, N-propyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide, and N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide.

[0094] In one embodiment, the piperidine ionic liquid cation includes N-alkyl-N-methylpiperidine, wherein the alkyl group includes ethyl, propyl, butyl, hexyl or octyl; the anion includes one of bromine, tetrafluoroborate, hexafluorophosphate, and bistrifluoromethanesulfonimide.

[0095] Preferably, the piperidine ionic liquid includes one or more of N-ethyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide, N-propyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide, and N-butyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide.

[0096] In one embodiment, the concentration of the lithium salt in the electrolyte is 0.5 mol / L to 5 mol / L, which can improve ion conductivity.

[0097] In one embodiment, the positive electrode 3 includes a positive electrode active material, and the positive electrode active material includes one or more of lithium nickel cobalt manganese oxide, NCA (nickel cobalt aluminum), NCMA (nickel cobalt manganese aluminum), lithium iron manganese phosphate, lithium iron phosphate, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium manganese rich base, lithium nickel manganese oxide, and lithium vanadium phosphate.

[0098] The negative electrode 4 includes a negative electrode active material, and the negative electrode active material includes one or more of graphite, LTO, Si, silicon oxide, silicon dioxide, Si-C, lithium metal, lithium alloy, Sn, Sn-C, SnO2, and tin alloy.

[0099] The negative electrode 4 may also only contain a current collector, wherein the current collector may be pure copper or a copper composite current collector.

[0100] The composite current collector includes a polymer base film and a conductive layer, wherein the conductive layer is on both sides of the polymer base film, wherein the polymer base film includes polyethylene, polyethylene terephthalate, polyimide, polypropylene, polyethylene, polyamide, polyphenylene sulfide or a combination thereof, and has a thickness of 1 to 300 μm.

[0101] The conductive layer is made of copper and has a thickness of 0.01-100 μm.

[0102] In a fourth aspect, an embodiment of the present invention provides an electrical device, comprising a battery as described in any one of the above items. It should be noted that the battery can be a laminated, wound or cylindrical semi-solid battery.

[0103] The present invention is further described below by way of examples.

[0104] Example 1 This embodiment is used to illustrate the solid electrolyte and its preparation method and battery disclosed in the present invention, and includes the following steps: Composite electrolyte layer 2: Polymer polyethylene oxide and lithium salt lithium bis(trifluoromethanesulfonyl)imide are dispersed in a mixed solvent, the mass ratio of the first solvent acetonitrile and the second solvent butyl butyrate in the mixed solvent is 1:1, and then filler Li2MnCl4 is added, mixed and cast on a substrate, and dried at 100°C and 0MPa for 12h to remove the mixed solvent to obtain a composite electrolyte layer 2, and the thickness of the composite electrolyte layer 2 is 20µm.

[0105] The inorganic solid electrolyte Li2ZrOCl4 and the binder PVDF are mixed in a mass ratio of 95:5, and then pre-fiberized to obtain a blank, and the blank is rolled into a film to obtain the inorganic solid electrolyte layer 1. The thickness of the inorganic solid electrolyte layer 1 is 20 µm.

[0106] The solid electrolyte is obtained by compounding the inorganic solid electrolyte layer 1 with the two composite electrolyte layers 2.

[0107] The molar ratio of the polymer to the lithium salt is 10:1, the filler is 3% of the total mass of the polymer and the lithium salt, the mass of the mixed solvent is 7 times the mass of the polymer, and the average particle size of Li2MnCl4 is 200nm.

[0108] Preparation of positive electrode The positive electrode active material NCM811, the conductive carbon black Super-P and the binder polyvinylidene fluoride (PVDF) are mixed in a mass ratio of 93:4:3, and then dispersed in an appropriate amount of N-methyl-2-pyrrolidone (NMP) to obtain the positive electrode slurry. The obtained slurry is evenly coated on both sides of the aluminum foil, dried, rolled and vacuum dried, and welded with an aluminum lead wire using an ultrasonic welder to obtain a positive electrode sheet with a thickness of 120-150μm.

[0109] Preparation of negative electrode The negative electrode uses a metallic lithium negative electrode.

[0110] Preparation of electrolyte The fourth solvent ethylene carbonate and ethyl methyl carbonate are mixed in a mass ratio of 1:1, the first additive tripropynyl phosphate and the second additive vinylene carbonate are added to the solvent, and after dispersion, lithium salt lithium hexafluorophosphate is added, and the lithium salt concentration is 1 mol / L. The content of the first additive tripropynyl phosphate in the electrolyte is 1%, and the content of the second additive in the electrolyte is 0.5%.

[0111] Preparation of battery cells A solid electrolyte is placed between the positive electrode sheet and the negative electrode sheet prepared above, and then a sandwich structure consisting of the positive electrode sheet, the negative electrode sheet and the solid electrolyte is stacked and packaged with an aluminum-plastic film to prepare a soft-pack battery cell with a capacity of 1Ah ready for liquid injection.

[0112] The battery is obtained after the battery core is injected with liquid and formed.

[0113] Example 2 Example 2 is used to illustrate the solid electrolyte disclosed in the present invention, and includes most of the operating steps in the above-mentioned Example 1, except that the solid electrolyte is obtained by compounding an inorganic solid electrolyte layer 1 with a composite electrolyte layer 2. The composite electrolyte layer 2 is located between the negative electrode 4 and the inorganic solid electrolyte layer 1.

[0114] Example 3 Example 3 is used to illustrate the solid electrolyte disclosed in the present invention, and includes most of the operating steps in the above-mentioned Example 1, except that the solid electrolyte is obtained by compounding an inorganic solid electrolyte layer 1 with a composite electrolyte layer 2. The composite electrolyte layer 2 is located between the positive electrode 3 and the inorganic solid electrolyte layer 1.

[0115] Embodiments 4 to 23 Examples 4 to 23 are used to illustrate the solid electrolyte disclosed in the present invention, and include most of the operating steps in the above-mentioned Example 1, except that the formula in Table 1 is used.

[0116] Table 1 Embodiments 24 to 30 Examples 24 to 30 are used to illustrate the preparation method of the solid electrolyte disclosed in the present invention, which include most of the operating steps in the above-mentioned Example 1, and the difference is that: the formula in Table 2 is used.

[0117] Table 2 Embodiments 31 to 35 Examples 31 to 35 are used to illustrate the battery disclosed in the present invention, and include most of the operating steps in the above-mentioned Example 1, except that the formula in Table 3 is used.

[0118] Table 3 Comparative Examples 1 to 3 Comparative Examples 1 to 3 are used to compare and illustrate the solid electrolyte and preparation method thereof disclosed in the present invention, and include most of the operation steps in Example 1, except that the formulations in Table 1 and Table 2 are used.

[0119] Comparative Example 4 Comparative Example 4 is used to compare and illustrate the solid electrolyte and the preparation method thereof disclosed in the present invention, and includes most of the operation steps in the above-mentioned Example 1, except that the preparation of the solid electrolyte includes the following steps: Polymer polyethylene oxide, inorganic solid electrolyte Li2MnCl4 and lithium salt lithium bis(trifluoromethanesulfonyl)imide are dispersed in acetonitrile, mixed and cast on a substrate, and then dried at 100°C and 0MPa for 12h to remove the mixed solvent to form the first composite electrolyte layer. The molar ratio of polymer to lithium salt is 10:1, and the filler is 30% of the total mass of polymer and lithium salt. Polymer polyethylene oxide, inorganic solid electrolyte Li2MnCl4 and lithium salt lithium bis(trifluoromethanesulfonyl)imide are dispersed in acetonitrile, mixed and cast on a substrate, and then dried at 100°C and 0MPa for 12h to remove the mixed solvent to form a second composite electrolyte layer. The molar ratio of polymer to lithium salt is 10:1, and the polymer and lithium salt account for 30% of the total mass of the inorganic solid electrolyte.

[0120] The thickness of the first composite electrolyte layer and the second composite electrolyte layer are both 20 μm. The first composite electrolyte layer and the second composite electrolyte layer are composited to obtain a solid electrolyte.

[0121] Performance Testing 1. The batteries prepared in the above examples and comparative examples were subjected to the following performance tests: 1. Cycling stability at room temperature: The lithium-ion battery prepared above was charged at 1C at 25±2°C and in the range of 3.0-4.3V, left for 5 min, and then discharged at 1C and left for 30 min after discharge. The capacity retention rate after 200 cycles was recorded.

[0122] 2. Ionic conductivity measurement: The solid electrolyte is sandwiched between two pieces of stainless steel and placed in a 2032 battery case. The electrochemical impedance spectroscopy is used for measurement. The ionic conductivity is calculated using the formula: σ = L / AR, where L is the thickness of the solid electrolyte, A is the area of ​​the stainless steel sheet at room temperature, and R is the measured impedance.

[0123] 3. High temperature cycle stability test: After being placed at 45±2℃ for 2 hours, perform standard charge and discharge cycles, cycle rate 1C, charging voltage 3.0-4.3V, and calculate the capacity retention rate of the battery after the cycle. The calculation formula is as follows: The capacity retention rate of the nth cycle (%) = (discharge capacity of the nth cycle) / (discharge capacity of the first cycle) * 100%.

[0124] The test results are shown in Table 4.

[0125] Table 4 The ionic conductivities in Table 4 are numerical values ​​expressed in scientific notation.

[0126] From the test results of Examples 1 to 3 and Comparative Examples 2 and 4 in Table 4, it can be seen that by providing the inorganic solid electrolyte layer 1 on the side of the composite electrolyte layer 2 facing the positive electrode 3 or the negative electrode 4, the cycle performance of the battery can be effectively improved. It can be seen from the test results of Example 1 and Comparative Example 1 that when the composite electrolyte layer 2 does not contain fillers, the ionic conductivity of the solid electrolyte decreases, and the room temperature and high temperature cycle performance of the battery decreases.

[0127] It can be seen from the test results of Examples 1, 4 to 7 that when the thickness of the composite electrolyte layer 2 is too low, it is easy to cause a short circuit in the battery. When the thickness of the composite electrolyte layer 2 is too high, the ionic conductivity of the solid electrolyte is reduced, and the normal temperature and high temperature cycle performance of the battery is reduced. It can be seen from the test results of Examples 1, 8 to 12 that filler particles with too large a particle size reduce the ionic conductivity of the formed solid electrolyte, further reducing the normal temperature and high temperature cycle performance of the battery. When the particle size of the filler exceeds 3μm, a short circuit in the battery is caused. It can be seen from the test results of Examples 1, 13 to 17 that when the filler content is too low, the ionic conductivity of the solid electrolyte is reduced. When the filler content is too high, the filler is unevenly dispersed or even the filler cannot be evenly dispersed in the composite electrolyte layer 2, which reduces the ionic conductivity of the solid electrolyte.

[0128] It can be seen from the test results of Examples 1 and 20 to 23 that as the molar ratio of the polymer and the lithium salt changes, the cycle performance and ionic conductivity of the battery are affected. When the polymer content is too high, the porosity of the composite electrolyte layer 2 decreases, which further reduces the ionic conductivity of the solid electrolyte, thereby deteriorating the capacity retention rate of the battery. However, when the polymer content is too low, the mechanical properties of the composite electrolyte layer 2 will decrease.

[0129] It can be seen from the test results of Examples 1, 24 to 27 that in the preparation process of the electrolyte membrane, when the quality of the mixed solvent is too low, the polymer cannot be completely dissolved. It can be seen from the test results of Examples 1, 28 to 30 and Comparative Example 3 that in the preparation process of the electrolyte membrane, when the second solvent content is too much, the porosity is too large, resulting in a large pore size difference, further affecting the ionic conductivity of the solid electrolyte. When the first solvent content is too much, the porosity of the composite electrolyte layer 2 is too small, the ionic conductivity of the solid electrolyte is reduced, and the capacity retention rate of the battery is affected.

[0130] It can be seen from the test results of Examples 1 and 31 to 35 that the electrolyte membrane is suitable for electrolytes of different systems.

[0131] The embodiment of the present application further provides an electric device, the electric device comprising the battery. The electric device may be a vehicle, an aircraft, a computer, a mobile phone, etc.

[0132] The term "and / or" in this application is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist at the same time, and B exists alone.

[0133] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A solid electrolyte, characterized in that It comprises an inorganic solid electrolyte layer and a composite electrolyte layer, wherein the composite electrolyte layer comprises a polymer electrolyte substrate membrane and a filler; the filler is distributed in the polymer electrolyte substrate membrane; the filler comprises one or more of an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte; The inorganic solid electrolyte layer includes one or more of an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte.

2. The solid electrolyte according to claim 1, characterized in that The composite electrolyte layer is provided with two layers, the inorganic solid electrolyte layer is provided with one layer, and the inorganic solid electrolyte layer is located between the two composite electrolyte layers.

3. The solid electrolyte according to claim 1, characterized in that The composite electrolyte layer is provided with one layer, and the inorganic solid electrolyte layer is provided with one layer.

4. The solid electrolyte according to claim 1, characterized in that The thickness of the composite electrolyte layer is 5µm to 300µm; the thickness of the inorganic solid electrolyte layer is 5µm to 300µm.

5. The solid electrolyte according to claim 1, characterized in that The ion conductivity of the inorganic solid electrolyte layer is greater than or equal to 1 mS / cm.

6. The solid electrolyte according to claim 1, characterized in that The particle size of the filler is 5nm to 3µm.

7. The solid electrolyte according to claim 6, characterized in that The particle size of the filler is 50nm to 300nm.

8. The solid electrolyte according to claim 1, characterized in that The mass of the filler is 0.1% to 10% of the mass of the polymer electrolyte substrate membrane.

9. The solid electrolyte according to claim 8, characterized in that The mass of the filler is 0.5% to 5% of the mass of the polymer electrolyte substrate membrane.

10. The solid electrolyte according to claim 1, characterized in that The halide solid electrolyte includes Li a (M b )X c X' d , wherein M includes one or more of Ga, Y, In, Mg, Sr, Sc, Sn, Pb, Ti, Zr, Hf, Nb, Ta, W, Fe, Ru, Al, and lanthanide metal elements; X includes one or more of halogens; X' includes one or more of halide ions, N ions, oxygen-containing anion groups, and pseudohalide anions; 0.5≤a≤5, 0.2≤b≤4, c+d=a+bε, wherein ε is the weighted average valence of the M element; And / or, the oxide solid electrolyte includes one or more of a NASICON-type electrolyte, a perovskite-type electrolyte, an antiperovskite-type electrolyte, a LISICON-type electrolyte and a garnet-type electrolyte; And / or, the sulfide solid electrolyte includes Li 6-x PS 5-x Cl 1+x ,0≤x≤0.8, Li2S-P2S5, Li 10 GeP2S 12 , Li3PS4 or more.

11. The solid electrolyte according to claim 10, characterized in that The oxygen-containing anion groups include O 2- , S 2- , CN - 、CO3 2- PO4 3- 、P2O7 4- 、SO4 2- One or more of; the pseudohalide anion includes SCN - PF6 - NH2 - 、AlF4 - , or BF4 - One or more of .

12. The solid electrolyte according to claim 1, characterized in that The filler includes LLTO, LATP, LAGP, LLZO, Li2S-P2S5, Li6PS5Cl, Li2MnCl4, Li2ZnCl4, Li2ZrOCl4, LiYbF4, LiAlF4, Li3YCl6, Li3InCl6, Li3InCl 5.5 F 0.5 、Li3TaCl6、Li 0.388 Ta 0.238 La 0.475 One or more of Cl3, Li6CoCl8.

13. The solid electrolyte according to claim 1, characterized in that The filler is uniformly distributed in the polymer electrolyte base membrane.

14. A method for preparing a solid electrolyte according to any one of claims 1 to 13, characterized in that: The following steps are involved: The polymer and the lithium salt are dispersed in a mixed solvent, and then a filler is added, mixed and cast on a substrate, and the mixed solvent is removed by drying to obtain a composite electrolyte layer; the mixed solvent includes a first solvent that is mutually soluble in the polymer and a second solvent that is insoluble in the polymer; An inorganic solid electrolyte and a binder are mixed, and then pre-fiberized to obtain a blank, and the blank is rolled into a film to obtain the inorganic solid electrolyte layer; The inorganic solid electrolyte layer and the composite electrolyte layer are composited to obtain the solid electrolyte.

15. The method for preparing a solid electrolyte according to claim 14, characterized in that: The mass of the mixed solvent is 3 to 15 times the mass of the polymer, and the mass ratio of the first solvent to the second solvent is 1:10 to 10:

1.

16. The method for preparing a solid electrolyte according to claim 14, characterized in that: The first solvent includes one or more of acetonitrile, acetone, ethyl acetate, butanone, diethyl ether, hexane, n-heptane, chloroform, tetrahydrofuran, N,N-dimethylacetamide, N,N-dimethylacetamide, 2,2,2-trifluoro-N,N-dimethylformamide, and N-methylpyrrolidone; The second solvent includes one or more of butyl butyrate, ethyl butyrate, isobutyl isobutyrate, ethanol, and butanol.

17. The method for preparing a solid electrolyte according to claim 14, characterized in that: The drying temperature is 60 to 160° C., the drying time is 6 to 24 hours, and the relative vacuum degree during drying is -0.1 to 0 MPa.

18. The method for preparing a solid electrolyte according to claim 14, characterized in that: The binder includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, silicone rubber, styrene-butadiene rubber, hydrogenated nitrile rubber, boronated polyethylene glycol, cellulose, cellulose ester, cellulose ether, nitrocellulose, carboxyalkyl cellulose, cellulose salt, sodium carboxymethyl cellulose and cellulose salt derivatives, polyacrylic acid, polyamide, polyvinyl alcohol, polyethylene imine, and polyimide.

19. The method for preparing a solid electrolyte according to claim 14, characterized in that: The mass content of the binder in the inorganic solid electrolyte layer is 0.1% to 10%.

20. A battery, characterized in that: The invention comprises a positive electrode, a negative electrode, and a solid electrolyte as claimed in any one of claims 1 to 13; or comprises a solid electrolyte prepared by the method for preparing a solid electrolyte as claimed in any one of claims 14 to 19; the solid electrolyte is located between the positive electrode and the negative electrode.

21. The battery according to claim 20, characterized in that The composite electrolyte layer is located between the negative electrode and the inorganic solid electrolyte layer; or, the composite electrolyte layer is located between the positive electrode and the inorganic solid electrolyte layer.

22. The battery according to claim 20, characterized in that The battery further comprises an electrolyte, and the polymer electrolyte substrate membrane is a porous film.

23. The battery according to claim 22, characterized in that The electrolyte includes a fourth solvent, a lithium salt, a first additive and a second additive; The fourth solvent includes at least one of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methylpropyl carbonate, dimethyl sulfite, diethyl sulfite, dipropyl sulfite, ethylene sulfite, methyl acetate, ethyl acetate, ethyl formate, ethyl propionate, methyl propionate, ethylene glycol n-butyl ether, methyl butyl ether, methyl tert-butyl ether, dibutyl ether, ethylene glycol dimethyl ether, 1,3-dioxolane, tetraethylene glycol dimethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether; The lithium salt includes at least one of lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium tetrafluoroborate, lithium hexafluoroantimonate, lithium bis(trifluoromethanesulfonimide), lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium perchlorate, lithium iodide, lithium magnesium bis(fluorosulfonyl)imide, lithium bisoxalatoborate and lithium difluorooxalatoborate; The first additive includes at least one of tripropynyl phosphate, 4-nitrophenyl trifluoroacetate, fluoroether 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,3-propane sultone, vinyl sulfate, toluene, 1,2-xylene, 1,3-xylene, 1,4-xylene, fluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene, 1,2,4-trifluorobenzene, 1,3,5-trifluorobenzene, 1,2,3,4-tetrafluorobenzene, 1,2,3,5-tetrafluorobenzene, 1,2,4,5-tetrafluorobenzene, pentafluorobenzene, and hexafluorobenzene; The second additive includes at least one of vinylene carbonate, fluoroethylene carbonate, and LiNO 3 .

24. The battery according to claim 23, characterized in that The volume ratio of the fourth solvent to the first additive is (1:10) to (10:1); And / or, the mass content of the second additive in the electrolyte is 0.1% to 10%.

25. The battery according to claim 23, characterized in that The concentration of the lithium salt in the electrolyte is 0.5 mol / L to 5 mol / L.

26. An electrical device, characterized in that: A battery comprising any one of claims 20 to 25.

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