Solid electrolyte precursor solution, solid electrolyte, battery and preparation method thereof

Abstract

The invention discloses a solid electrolyte precursor solution, a solid electrolyte, a battery and a preparation method thereof, the solid electrolyte precursor solution comprises a lithium salt solution, pentaerythritol glycidyl ether and lithium difluoro (oxalato) borate, and the lithium salt solution comprises a lithium salt and a solvent. The solid electrolyte prepared from the solid electrolyte precursor solution disclosed by the invention has relatively high ionic conductivity.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a solid electrolyte precursor solution, a solid electrolyte, a battery and a preparation method thereof. Background Art

[0002] In recent years, safety issues caused by electrolyte leakage have occurred frequently, and research on solid electrolytes is urgent. However, the current problems of low ionic conductivity of solid electrolytes and difficulty in solving solid-solid interfaces (interfaces formed by solid phases, that is, the interface between solid electrolytes and electrodes and the interface between solid electrolytes and diaphragms) have slowed down the development of solid electrolytes, and quasi-solid electrolytes have become the only way for liquid electrolytes to become solid electrolytes. Among them, in-situ solidification technology has attracted extensive research by scientific researchers due to its advantages of simple process and easy industrialization.

[0003] However, the solid electrolyte precursor solution used in the existing in-situ curing requires the addition of a large amount of monomers, initiators, and cross-linking agents for polymerization, resulting in low ionic conductivity of the prepared solid electrolyte. Summary of the invention

[0004] In view of this, the present application provides a solid electrolyte precursor solution, a solid electrolyte and a preparation method thereof, a battery and a preparation method thereof, aiming to improve the problem of low ionic conductivity of the solid electrolyte prepared from the existing solid electrolyte precursor solution.

[0005] The embodiment of the present application is implemented as follows: a solid electrolyte precursor solution includes a lithium salt solution, pentaerythritol glycidyl ether and lithium difluorooxalate borate, wherein the lithium salt solution includes a lithium salt and a solvent.

[0006] Optionally, in some embodiments, in the lithium salt solution, the mass ratio of the lithium salt to the solvent is (0.08-0.25): 1; and / or In the solid electrolyte precursor solution, the mass of the lithium difluorooxalatoborate is 0.1-1% of the mass of the lithium salt solution; and / or In the solid electrolyte precursor solution, the mass of the pentaerythritol glycidyl ether is 1.5-8% of the mass of the lithium salt solution.

[0007] Optionally, in some embodiments, the lithium salt includes one or more of LiPF6, LiBF4, LiCl, LiAlCl4, LiSbF6, LiSCN, LiCl, LiCF3SO3, LiCF3CO2, LiN(CF3SO2)2, LiAsF6, LiBC4O8, and LiN(FSO2)2.

[0008] Optionally, in some embodiments, the solvent includes one or more of an ether solvent, an ester solvent, a sulfone solvent, and an ionic liquid solvent, wherein: The ether solvent includes one or more of dimethyl ether, ethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, ethylene glycol dibutyl ether, 2,2,2-trifluoroethyl ether, ethylene glycol bis(propionitrile) ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether; and / or The ester solvent includes one or more of ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate, fluoroethylene carbonate, methyl trifluoroethyl carbonate, difluoroethylene carbonate, tris(2,2,2-trifluoroethyl) phosphate, bis(2,2,2-trifluoroethyl) carbonate, and ethyl trifluoroacetate; and / or The sulfone solvent includes one or more of sulfolane and dimethyl sulfoxide; and / or The ionic liquid solvent includes one or more of 1-methyl-1-propylpyrrolidinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide salt, N-propyl-N-methylpyrrolidine hexafluorophosphate, N-butyl-N-methylpyrrolidine hexafluorophosphate, and N-ethyl-N-methylpyrrolidine bis(fluorosulfonyl)imide.

[0009] Accordingly, the present application also provides a method for preparing a solid electrolyte, comprising the following steps: Providing the solid electrolyte precursor solution; The solid electrolyte precursor solution is solidified to obtain a solid electrolyte.

[0010] Optionally, in some embodiments, the step of curing the solid electrolyte precursor solution comprises thermal curing, wherein: The temperature range of the thermal curing is 40-120°C; and / or The time range of the thermal curing is 2 to 18 hours.

[0011] Optionally, in some embodiments, the stopping condition of the thermal curing is: stopping if the curing texture does not change with the extension of time.

[0012] Correspondingly, the present application also provides a solid electrolyte, which is prepared by the solid electrolyte preparation method.

[0013] Correspondingly, the present application also provides a battery, comprising the solid electrolyte.

[0014] Accordingly, the present application also provides a method for preparing a battery, comprising the following steps: Providing a battery housing including a positive electrode, a negative electrode and a separator; The solid electrolyte precursor solution is injected into the battery housing to convert the solid electrolyte precursor solution into a solid electrolyte to obtain a battery.

[0015] The solid electrolyte precursor solution described in the present application uses pentaerythritol glycidyl ether as a monomer. The molecular structure of the pentaerythritol glycidyl ether has four three-membered ring ethers, which greatly improves the monomer utilization rate. The solid electrolyte precursor solution can be completely polymerized by adding a small amount of monomer, thereby improving the ionic conductivity of the prepared solid electrolyte, thereby reducing the internal resistance of the battery including the solid electrolyte, improving the capacity retention rate and rate performance of the battery, etc., and broadening the electrochemical window of the battery.

[0016] In addition, based on the superior polymerization properties of pentaerythritol glycidyl ether, the solid electrolyte precursor solution only needs to add this monomer to polymerize, and the solid electrolyte obtained by polymerization can be free of residual liquid, which can effectively avoid the safety problems caused by leakage of residual liquid in the solid electrolyte.

[0017] Furthermore, the present application only uses lithium difluorooxalatoborate as an initiator, without the need for other initiators, to effectively initiate the polymerization of pentaerythritol glycidyl ether, and lithium difluorooxalatoborate can also act as a lithium salt additive, which can effectively avoid the influence of other initiators on the performance of the solid electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 is a flow chart of a method for preparing a solid electrolyte provided in an embodiment of the present application; Figure 2 is a flow chart of a method for preparing a battery provided in an embodiment of the present application; Figure 3 is a diagram showing that the solid electrolyte precursor solution of Example 1 of the present application is completely solidified; Figure 4 is a diagram showing that the solid electrolyte precursor solution of Comparative Example 2 of the present application is not completely solidified; Figure 5 This is a diagram of the layered solidification of the solid electrolyte precursor solution of Comparative Example 7 of the present application. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0021] In this application, unless otherwise stated, directional words such as "upper" and "lower" generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. In addition, in the description of this application, the term "including" means "including but not limited to". The terms first, second, third, etc. are used only as labels and do not impose numerical requirements or establish an order.

[0022] In this application, "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural.

[0023] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0024] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0025] The technical solution of this application is as follows: In a first aspect, an embodiment of the present application provides a solid electrolyte precursor solution for preparing a solid electrolyte. The solid electrolyte precursor solution includes a lithium salt solution, a monomer, and an initiator, wherein the lithium salt solution includes a lithium salt and a solvent, the initiator is lithium difluorooxalatoborate (LIDFOB), and the monomer is pentaerythritol glycidyl ether.

[0026] The solid electrolyte precursor solution described in the present application uses pentaerythritol glycidyl ether as a monomer. The molecular structure of the pentaerythritol glycidyl ether has four three-membered ring ethers, which greatly improves the monomer utilization rate. The solid electrolyte precursor solution can be completely polymerized by adding a small amount of monomer, thereby improving the ionic conductivity of the prepared solid electrolyte, thereby reducing the internal resistance of the battery including the solid electrolyte, improving the capacity retention rate and rate performance of the battery, etc., and broadening the electrochemical window of the battery.

[0027] In addition, based on the superior polymerization properties of pentaerythritol glycidyl ether, the solid electrolyte precursor solution only needs to add this monomer to polymerize, and the solid electrolyte obtained by polymerization can be free of residual liquid, which can effectively avoid the safety problems caused by leakage of residual liquid in the solid electrolyte.

[0028] Furthermore, the present application only uses lithium difluorooxalatoborate as an initiator, without the need for other initiators, to effectively initiate the polymerization of pentaerythritol glycidyl ether, and lithium difluorooxalatoborate can also act as a lithium salt additive, which can effectively avoid the influence of other initiators on the performance of the solid electrolyte.

[0029] In some embodiments, in the lithium salt solution, the mass ratio of the lithium salt to the solvent is (0.08-0.25):1, for example, 0.08:1, 0.09:1, 0.1:1, 0.11:1, 0.12:1, 0.13:1, 0.14:1, 0.15:1, 0.16:1, 0.17:1, 0.18:1, 0.19:1, 0.2:1, 0.21:1, 0.22:1, 0.23:1, 0.24:1, 0.25:1 and any range between two ratios. Within the range, the prepared solid electrolyte can have a higher ionic conductivity.

[0030] In some embodiments, in the solid electrolyte precursor solution, the mass of the initiator is 0.1-1% of the mass of the lithium salt solution, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% and any range between two values, etc. Within the range, the prepared solid electrolyte can have a higher ionic conductivity.

[0031] In some embodiments, in the solid electrolyte precursor solution, the mass of the monomer is 1.5-8% of the mass of the lithium salt solution, for example, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8% and any range between two values, etc. Within the range, it is beneficial for the solidification of the solid electrolyte precursor solution and for the prepared solid electrolyte to have a higher ionic conductivity.

[0032] In some embodiments, the lithium salt includes but is not limited to one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium chloride (LiCl), lithium tetrachloroaluminate (LiAlCl4), lithium hexafluoroantimonate (LiSbF6), lithium cyanosulfide (LiSCN), lithium trifluoromethanesulfonate (LiCF3SO3), LiCF3CO2, lithium bis(trifluoromethanesulfonyl imide) (LiN(CF3SO2)2, referred to as LiTFSI), lithium hexafluoroarsenate (LiAsF6), lithium bis(oxalatoborate) (LiBC4O8), and lithium bis(fluorosulfonyl imide) (LiN(FSO2)2, referred to as LiFSI).

[0033] In some embodiments, the solvent includes, but is not limited to, one or more of an ether solvent, an ester solvent, a sulfone solvent, and an ionic liquid solvent.

[0034] In some embodiments, the ether solvent includes but is not limited to one or more of dimethyl ether (DME), ethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, ethylene glycol dibutyl ether, 2,2,2-trifluoroethyl ether, ethylene glycol bis(propionitrile) ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether.

[0035] In some embodiments, the ester solvent includes but is not limited to one or more of ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), propylene carbonate (PC), fluoroethylene carbonate (FEC), methyl trifluoroethyl carbonate (FEMC), bisfluoroethylene carbonate (DFEC), tris(2,2,2-trifluoroethyl) phosphate (TFEP), bis(2,2,2-trifluoroethyl) carbonate (TFEC), and ethyl trifluoroacetate (ETFA).

[0036] In some embodiments, the sulfone solvent includes, but is not limited to, one or more of sulfolane and dimethyl sulfoxide.

[0037] In some embodiments, the ionic liquid solvent includes but is not limited to one or more of 1-methyl-1-propylpyrrolidinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-propyl-N-methylpyrrolidine hexafluorophosphate, N-butyl-N-methylpyrrolidine hexafluorophosphate, and N-ethyl-N-methylpyrrolidine bis(fluorosulfonyl)imide.

[0038] It is understood that the organic solvent can be a single solvent or a mixed solvent. In certain embodiments, the organic solvent is a mixed solvent. Further, in at least some embodiments, the mixed solvent is a mixed solvent of ethylene carbonate, diethyl carbonate and fluoroethylene carbonate, and the volume ratio of the ethylene carbonate, diethyl carbonate and fluoroethylene carbonate is 4:4:2.

[0039] In some embodiments, the method for preparing the solid electrolyte precursor solution includes: mixing a lithium salt, a monomer, an initiator, and a solvent in proportion to obtain the solid electrolyte precursor solution.

[0040] In at least one embodiment, the method for preparing the solid electrolyte precursor solution includes: mixing a lithium salt and a solvent in proportion to obtain a lithium salt solution, and adding a monomer and an initiator in proportion to the lithium salt solution to obtain the solid electrolyte precursor solution.

[0041] Second, see Figure 1 The present invention provides a method for preparing a solid electrolyte, comprising the following steps: Step S11, providing a solid electrolyte precursor solution; Step S12, solidifying the solid electrolyte precursor solution to obtain a solid electrolyte.

[0042] The solid electrolyte precursor solution is as described above and will not be described again here.

[0043] In some embodiments, the stopping condition of the thermal curing is: stopping when the curing texture does not change with the extension of time.

[0044] In some embodiments, the method of curing the solid electrolyte precursor solution includes thermal curing.

[0045] In some embodiments, the temperature range of the thermal curing is 40-120°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, and any range between two values, etc.; the time range of the thermal curing is 2-18 h, for example, 2 h, 3 h, 5 h, 6 h, 8 h, 10 h, 12 h, 13 h, 15 h, 16 h, 18 h, and any range between two values, etc. Within the temperature and time range, it is beneficial to fully cure the solid electrolyte precursor solution, so that the prepared solid electrolyte has no obvious flowing liquid, and it is beneficial to make the prepared solid electrolyte have higher ionic conductivity.

[0046] The solid electrolyte precursor solution used in the preparation method of the solid electrolyte described in the present application adopts pentaerythritol glycidyl ether as a monomer. The molecular structure of the pentaerythritol glycidyl ether has four three-membered ring ethers, which greatly improves the monomer utilization rate. The solid electrolyte precursor solution can be completely polymerized by adding a small amount of monomer, thereby improving the ionic conductivity of the prepared solid electrolyte, thereby reducing the internal resistance of the battery including the solid electrolyte, improving the capacity retention rate and rate performance of the battery, etc., and widening the electrochemical window of the battery.

[0047] In addition, based on the superior polymerization properties of pentaerythritol glycidyl ether, the solid electrolyte precursor solution only needs to add this monomer to polymerize, and the solid electrolyte obtained by polymerization can be free of residual liquid, which can effectively avoid the safety problems caused by leakage of residual liquid in the solid electrolyte.

[0048] Furthermore, the present application only uses LIDFOB as an initiator, without the need for other initiators, to effectively initiate the polymerization of pentaerythritol glycidyl ether, and LIDFOB can also act as a lithium salt additive, which can effectively avoid the influence of other initiators on the performance of the solid electrolyte.

[0049] In a third aspect, an embodiment of the present application further provides a solid electrolyte, which is prepared by the above-mentioned preparation method.

[0050] In a fourth aspect, an embodiment of the present application further provides a battery, comprising a positive electrode, a negative electrode, a separator and the solid electrolyte described above.

[0051] In some embodiments, the battery is a lithium-ion battery.

[0052] The anode includes an anode current collector and an anode active material bonded to at least one surface of the anode current collector.

[0053] The material of the anode current collector may include, but is not limited to, at least one of the materials known in the art for the anode current collector, such as copper, nickel, stainless steel, and titanium.

[0054] The anode active material may include but is not limited to at least one of graphite carbon materials, non-graphite carbon materials, metallic lithium, lithium alloys, silicon-based alloys, tin-based alloys, conductive oxides and conductive polymers. The conductive oxide may include but is not limited to Li x Fe2O3、Li x At least one of WO2, SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4 and Bi2O5, wherein 0<x<1; the conductive polymer may include but is not limited to at least one of polyacetylene, polyaniline and polythiophene.

[0055] The cathode includes a cathode current collector and a cathode active material bonded to at least one surface of the cathode current collector.

[0056] The material of the cathode current collector may include, but is not limited to, at least one of materials known in the art for use in cathode current collectors, such as aluminum and nickel.

[0057] The cathode active material may include but is not limited to at least one of lithium iron phosphate, lithium manganese oxide, lithium iron manganese phosphate, nickel cobalt manganese ternary material, nickel cobalt aluminum ternary material, sodium vanadium phosphate, sodium iron pyrophosphate, Prussian white, sodium cobaltate and sodium nickel iron manganese oxide. Specifically, the cathode active material may include but is not limited to LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li(Ni a Co b Mn c )O2、LiNi a Co b Al c O2、LiNi y Co 1-y O2、LiCo y Mn 1-y O2、LiCo y Al 1-y O2、LiCo y B 1-y O2、LiCo y Mg 1-y O2、LiCoy Ti 1-y O2、LiCo y Mo 1-y O2、LiCo y Sn 1-y O2、LiCo y Ca 1-y O2、LiCo y Cu 1-y O2、LiCo y V 1- y O2、LiCo y Zr 1-y O2、LiCo y Si 1-y O2、LiCo y W 1-y O2、LiCo y Y 1-y O2、LiCo y La 1-y O2、LiCo y Mn 1-y O2、LiNi y Mn 1-y O2, LiCoPO4, LiFePO4, LiMn y Fe 1-y PO4, Na3V2(PO4)3, Na8Fe4(P2O7)5, Na2Fe2(Fe(CN)6)3, Na(Ni a Fe b Mn c )O2. Wherein, 0<a<1, 0<b<1, a+b+c=1, 0<y<1.

[0058] It can be understood that the membrane can be a membrane known to be used in batteries, such as one or more of an oxide-based solid electrolyte membrane, a glass-based solid electrolyte membrane, a polymer-based solid electrolyte membrane, and a carbon-based solid electrolyte membrane, wherein the material of the oxide-based solid electrolyte membrane includes but is not limited to one or more of zirconium oxide and perovskite oxide, the material of the glass-based solid electrolyte membrane includes but is not limited to one or more of silicate glass and phosphate glass, the material of the polymer-based solid electrolyte membrane includes but is not limited to one or more of polyethylene oxide (PEO) and polyacrylonitrile (PAN), and the material of the carbon-based solid electrolyte membrane includes but is not limited to one or more of carbon nanotubes and graphene.

[0059] Fifth, please refer to Figure 2 The present application also provides a method for preparing a battery, comprising the following steps: Step S21, providing a battery housing including a positive electrode, a negative electrode and a separator; Step S22: injecting a solid electrolyte precursor solution into the battery housing to convert the solid electrolyte precursor solution into a solid electrolyte to obtain a battery.

[0060] The positive electrode, the negative electrode, the separator, and the solid electrolyte precursor solution are as described above and will not be described in detail here.

[0061] In some embodiments, the method of converting a solid electrolyte precursor solution into a solid electrolyte comprises thermal curing.

[0062] In some embodiments, the temperature range of the thermal curing is 40-120°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, and any range between two values, etc.; the time range of the thermal curing is 2-18 h, for example, 2 h, 3 h, 5 h, 6 h, 8 h, 10 h, 12 h, 13 h, 15 h, 16 h, 18 h, and any range between two values, etc. Within the temperature and time range, it is beneficial to fully cure the solid electrolyte precursor solution, to make the prepared solid electrolyte have higher ionic conductivity, and thus to make the prepared battery have better electrical properties such as capacity retention rate.

[0063] The battery described in the present application is prepared by in-situ curing of the solid electrolyte precursor solution. The solid electrolyte precursor solution uses pentaerythritol glycidyl ether as a monomer. The molecular structure of the pentaerythritol glycidyl ether has four three-membered ring ethers, which greatly improves the monomer utilization rate. The solid electrolyte precursor solution can be completely polymerized by adding a small amount of monomer, thereby improving the ionic conductivity of the prepared solid electrolyte, thereby reducing the internal resistance of the battery including the solid electrolyte, improving the capacity retention rate and rate performance of the battery, etc., and broadening the electrochemical window of the battery.

[0064] In addition, based on the superior polymerization properties of pentaerythritol glycidyl ether, the solid electrolyte precursor solution only needs to add this monomer to polymerize, and the solid electrolyte obtained by polymerization can be free of residual liquid, which can effectively avoid the safety problems caused by leakage of residual liquid in the solid electrolyte.

[0065] Furthermore, the present application only uses lithium difluorooxalatoborate as an initiator, without the need for other initiators, to effectively initiate the polymerization of pentaerythritol glycidyl ether, and lithium difluorooxalatoborate can also act as a lithium salt additive, which can effectively avoid the influence of other initiators on the performance of the solid electrolyte.

[0066] The present application is described in detail below through specific embodiments. The following embodiments are only partial embodiments of the present application and are not limitations of the present application.

[0067] Example 1 The method for preparing the solid electrolyte precursor solution of this embodiment includes: EC, DEC and FEC are mixed in a volume ratio of 4:4:2 to obtain a solvent, LiPF6 is added to the solvent, wherein the mass ratio of LiPF6 to the solvent is 0.125:1, and a lithium salt solution is obtained after uniform stirring; LIDFOB and pentaerythritol glycidyl ether are added to the lithium salt solution, wherein the mass of LIDFOB is 0.2% of the mass of the lithium salt solution, and the mass of pentaerythritol glycidyl ether is 2% of the mass of the lithium salt solution, to obtain a solid electrolyte precursor solution.

[0068] Example 2 This embodiment is substantially the same as Embodiment 1, except that the lithium salt solution in this embodiment includes lithium salt LiFSI, and solvents DME and TTE, wherein the volume ratio of DME to TTE is 1:3.62, and the mass ratio of LiFSI to the solvent is 1:4.3.

[0069] Example 3 This embodiment is substantially the same as Embodiment 1, except that the solvent in this embodiment comprises TMS and FEC in a volume ratio of 6:2, the lithium salt in this embodiment is LiTFSI, and the mass of LiTFSI is 22% of the mass of the solvent.

[0070] Example 4 This embodiment is substantially the same as Embodiment 1, except that in this embodiment, the mass of LIDFOB is 0.1% of the mass of the lithium salt solution.

[0071] Example 5 This embodiment is substantially the same as Embodiment 1, except that in this embodiment, the mass of LIDFOB is 0.5% of the mass of the lithium salt solution.

[0072] Example 6 This embodiment is substantially the same as Embodiment 1, except that in this embodiment, the mass of LIDFOB is 1% of the mass of the lithium salt solution.

[0073] Example 7 This embodiment is substantially the same as Embodiment 1, except that in this embodiment, the mass of pentaerythritol glycidyl ether is 1.5% of the mass of the lithium salt solution.

[0074] Example 8 This embodiment is substantially the same as Embodiment 1, except that in this embodiment, the mass of pentaerythritol glycidyl ether is 4% of the mass of the lithium salt solution.

[0075] Example 9 This embodiment is substantially the same as Embodiment 1, except that in this embodiment, the mass of pentaerythritol glycidyl ether is 8% of the mass of the lithium salt solution.

[0076] Comparative Example 1 This comparative example is substantially the same as Example 1, except that 1,3,5-trioxane is used to replace the pentaerythritol glycidyl ether in Example 1.

[0077] Comparative Example 2 This comparative example is substantially the same as Example 1, except that in this comparative example, the mass of LIDFOB is 0.05% of the mass of the lithium salt solution.

[0078] Comparative Example 3 This comparative example is substantially the same as Example 1, except that in this comparative example, the mass of LIDFOB is 1.5% of the mass of the lithium salt solution.

[0079] Comparative Example 4 This comparative example is substantially the same as Example 1, except that in this comparative example, the mass of pentaerythritol glycidyl ether is 1% of the mass of the lithium salt solution.

[0080] Comparative Example 5 This comparative example is substantially the same as Example 1, except that in this comparative example, the mass of pentaerythritol glycidyl ether is 10% of the mass of the solvent.

[0081] Comparative Example 6 This comparative example is substantially the same as Example 1, except that in this comparative example, the pentaerythritol glycidyl ether in Example 1 is replaced by cyclic ether monomer DOX (1,3-dioxane).

[0082] Comparative Example 7 This comparative example is basically the same as Example 1, except that in this comparative example, the pentaerythritol glycidyl ether in Example 1 is replaced by PETEA (pentaerythritol tetraacrylate) which is polymerized in a ring-opening manner.

[0083] Comparative Example 8 This comparative example is substantially the same as Example 1, except that in this comparative example, the initiator LIDFOB in Example 1 is replaced by initiator Al(OTF)3 (aluminum trifluoromethanesulfonate).

[0084] Performance Testing: The solid electrolyte precursor solutions of Examples 1 to 9 and Comparative Examples 1 to 8 were cured at 80° C. for 3 hours to obtain solid electrolytes, and the curing states were observed. The curing state results are shown in Tables 1 and Figure 3 to Figure 4 ,in, Figure 3 is a diagram showing that the solid electrolyte precursor solution of Example 1 is completely solidified. Figure 4 This is a picture of the solid electrolyte precursor solution of Comparative Example 2 that is not completely solidified. Figure 5 This is a diagram of the layered solidification of the solid electrolyte precursor solution of Example 7.

[0085] The solid electrolytes of Examples 1-9 and Comparative Examples 1-8 were subjected to ion conductivity RT tests at a temperature of 25° C. The test results are shown in Table 1.

[0086] The solid-state batteries of Examples 1 to 9 and Comparative Examples 1 to 8 were respectively subjected to electrical performance tests to obtain the 60th cycle capacity retention rate of the battery. The test results are shown in Table 1.

[0087] Among them, the test method of ion conductivity test is: assemble button battery in the order of positive electrode shell, gasket, PP diaphragm, precursor solution, gasket, shrapnel, and negative electrode shell, the amount of precursor solution is 80 microliters, the battery is left to stand for 8 hours after assembly, and AC impedance test is performed at room temperature using an electrochemical workstation, the AC voltage is 5mV, the test frequency is 0.1Hz to 100kHz, and the R value is obtained, and then the ion conductivity is calculated according to the following formula: ; Among them, σ is the ionic conductivity, R is the bulk resistance, L is the thickness of the PP diaphragm, and S is the area of ​​the spring.

[0088] The method for testing the electrical performance is as follows: assembling batteries using the solid electrolyte precursor solutions of Examples 1 to 9 and Comparative Examples 1 to 8, wherein the positive electrode uses NCM811 ternary material, and the loading capacity of the ternary material is 3.2 mAh / cm 2 The negative electrode uses 20 μm lithium metal and the separator uses PP film. After assembly, it is left to stand for 24 hours and then placed at 80°C for 3 hours to allow the solid electrolyte precursor solution to undergo a solidification reaction, thereby forming a quasi-solid-state battery. Then, a blue electric cycle tester is used to perform battery cycle tests at 0.33C charging and 1C discharging.

[0089] Table 1:

[0090] Among them, since the solid electrolyte precursor solution in Comparative Example 2 and Comparative Example 4 cannot be completely solidified and cannot form a solid electrolyte, the ionic conductivity and capacity retention rate thereof were not detected.

[0091] From Table 1, we can see that: Compared with the solid electrolytes prepared from the solid electrolyte precursor solutions of Comparative Examples 1 to 8, the solid electrolytes prepared from the solid electrolyte precursor solutions of Examples 1 to 9 have higher ionic conductivity. It can be seen that the solid electrolyte prepared using the solid electrolyte precursor solution described in the present application has higher ionic conductivity. The reason may be that the solid electrolyte precursor solution described in the present application uses pentaerythritol glycidyl ether as a monomer, and the molecular structure of the pentaerythritol glycidyl ether has 4 three-membered ring ethers, which greatly improves the monomer utilization rate. When a small amount of monomer is added, the solid electrolyte precursor solution can be completely polymerized, thereby improving the ionic conductivity of the prepared solid electrolyte; in addition, the present application only uses lithium difluorooxalate borate as an initiator, without other initiators, to effectively initiate the polymerization of pentaerythritol glycidyl ether, and lithium difluorooxalate borate can also act as a lithium salt additive, which can effectively avoid the influence of other initiators on the performance of the solid electrolyte; Compared with the batteries prepared with the solid electrolyte precursor solutions of Comparative Examples 1 to 8, the batteries prepared with the solid electrolyte precursor solutions of Examples 1 to 9 have a higher capacity retention rate at the 60th cycle. It can be seen that the batteries prepared with the solid electrolyte precursor solutions described in the present application have a higher capacity retention rate. The reason may be that the solid electrolyte prepared with the solid electrolyte precursor solutions described in the present application has a higher ionic conductivity.

[0092] The technical solutions provided by the embodiments of the present application are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A solid electrolyte precursor solution, characterized in that: The invention comprises a lithium salt solution, pentaerythritol glycidyl ether and lithium difluorooxalate borate, wherein the lithium salt solution comprises a lithium salt and a solvent.

2. The solid electrolyte precursor solution according to claim 1, characterized in that The mass ratio of the lithium salt to the solvent is (0.08-0.25):1; and / or The mass of the lithium difluorooxalatoborate is 0.1-1% of the mass of the lithium salt solution; and / or The mass of the pentaerythritol glycidyl ether is 1.5-8% of the mass of the lithium salt solution.

3. The solid electrolyte precursor solution according to claim 1, characterized in that The lithium salt includes one or more of LiPF6, LiBF4, LiCl, LiAlCl4, LiSbF6, LiSCN, LiCl, LiCF3SO3, LiCF3CO2, LiN(CF3SO2)2, LiAsF6, LiBC4O8, and LiN(FSO2)2.

4. The solid electrolyte precursor solution according to claim 1, characterized in that The solvent includes one or more of ether solvents, ester solvents, sulfone solvents, and ionic liquid solvents, wherein: The ether solvent includes one or more of dimethyl ether, ethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, ethylene glycol dibutyl ether, 2,2,2-trifluoroethyl ether, ethylene glycol bis(propionitrile) ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether; and / or The ester solvent includes one or more of ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate, fluoroethylene carbonate, methyl trifluoroethyl carbonate, difluoroethylene carbonate, tris(2,2,2-trifluoroethyl) phosphate, bis(2,2,2-trifluoroethyl) carbonate, and ethyl trifluoroacetate; and / or The sulfone solvent includes one or more of sulfolane and dimethyl sulfoxide; and / or The ionic liquid solvent includes one or more of 1-methyl-1-propylpyrrolidinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide salt, N-propyl-N-methylpyrrolidine hexafluorophosphate, N-butyl-N-methylpyrrolidine hexafluorophosphate, and N-ethyl-N-methylpyrrolidine bis(fluorosulfonyl)imide.

5. A method for preparing a solid electrolyte, characterized in that: The steps include: Providing a solid electrolyte precursor solution according to any one of claims 1 to 4; The solid electrolyte precursor solution is solidified to obtain a solid electrolyte.

6. The preparation method according to claim 5, characterized in that: The step of curing the solid electrolyte precursor solution comprises thermal curing, wherein: The temperature range of the thermal curing is 40-120°C; and / or The time range of the thermal curing is 2 to 18 hours.

7. The preparation method according to claim 6, characterized in that: The stopping condition of the thermal curing is: stopping if the curing texture does not change with the extension of time.

8. A solid electrolyte, characterized in that The solid electrolyte is prepared by the preparation method according to any one of claims 5 to 7.

9. A battery, characterized in that: Comprising the solid electrolyte as claimed in claim 8.

10. A method for preparing a battery, characterized in that: The steps include: Providing a battery housing including a positive electrode, a negative electrode and a separator; The solid electrolyte precursor solution according to any one of claims 1 to 4 is injected into the battery housing to convert the solid electrolyte precursor solution into a solid electrolyte to obtain a battery.

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