Lithium metal battery as well as high-voltage wide-temperature-range gel polymer electrolyte, preparation method and application thereof

Abstract

The invention belongs to the field of solid-state batteries, and particularly relates to a lithium metal battery, a high-voltage wide-temperature-range gel polymer electrolyte of the lithium metal battery, a preparation method of the high-voltage wide-temperature-range gel polymer electrolyte and application of the high-voltage wide-temperature-range gel polymer electrolyte. The high-voltage wide-temperature-range gel polymer electrolyte is prepared; the composite monomer comprises a monomer 1 and a monomer 2 in a weight ratio of (1-2): (1-2), the monomer 1 comprises a compound as shown in a formula 1 (1), and the monomer 2 comprises a compound as shown in a formula 2 (2); the basic electrolyte comprises a conductive lithium salt and an ester ether solvent, and the conductive lithium salt comprises LiPF6; the ester-ether solvent comprises an ester solvent, a fluorinated ester solvent and hydrofluoroether in a weight ratio of (4-5): (2-3): (2-3). The electrolyte disclosed by the invention can meet the application requirements of high pressure and wide temperature range, and the high-pressure, low-temperature and high-temperature cycling stability of the electrolyte is improved.

Description

Technical Field

[0001] This invention belongs to the field of lithium secondary battery materials, specifically relating to the field of gel electrolytes for lithium secondary batteries. Technical Background

[0002] With the advancement of industrial globalization and intelligentization, lithium batteries are ushering in a golden age of technological breakthroughs, large-scale expansion, and diversified applications. However, the energy density provided by graphite anode lithium-ion batteries still cannot meet the high energy density requirements of next-generation batteries. Compared to graphite anodes, lithium metal anodes show greater potential—their theoretical specific capacity reaches as high as 3860 mAh g⁻¹. -1 It possesses the lowest reduction potential (-3.04 V vs. standard hydrogen electrode) and is widely recognized as the "holy grail" of anode materials, offering an absolute advantage in improving energy density. Especially when matched with a high-nickel layered oxide cathode, it holds promise for achieving high-energy-density lithium metal batteries.

[0003] Electrolytes, as a key component of battery systems, directly impact battery safety and electrochemical stability. Gel electrolytes, combining the advantages of liquid and solid electrolytes, are considered the optimal electrolyte choice for future lithium metal batteries. However, traditional gel electrolytes suffer from low ionic conductivity and slow kinetics, resulting in poor wide-temperature performance. High temperatures enhance the reactivity of the lithium metal anode and electrolyte, disrupting the internal chemical balance, while low temperatures increase interfacial impedance, significantly affecting battery life. Furthermore, traditional gel polymer electrolytes are prone to oxidative decomposition under high pressure, leading to active lithium loss and deterioration of the cathode-electrolyte interface, limiting their application in high-pressure environments. Moreover, current conventional gel polymer electrolytes often focus on improving single functions, such as introducing high-voltage resistant monomers (e.g., acrylate monomers) to enhance their high-voltage performance, or constructing weakened gel polymer electrolytes by adjusting the interaction between the polymer framework and encapsulated liquid components to achieve stable operation over a wide temperature range. These approaches struggle to synergistically meet the requirements of high voltage and wide temperature range for electrolytes. On one hand, under high pressure, internal side reactions intensify, leading to the formation of lithium dendrites and dead lithium, compromising battery cycle life. On the other hand, excessive weak solvation can cause ions at the interface, leading to an increase in the local electric field strength, which in turn can trigger interfacial side reactions and affect the overall performance of the battery.

[0004] Existing technologies also provide numerous modification schemes for modified gel electrolytes. For example, Chinese patent publication CN120015915A discloses a method for forming a gel polymer electrolyte between the positive and negative electrodes through in-situ solidification, fundamentally improving interfacial performance; and a method for improving the conductivity and safety of the system by introducing silica aerogel to change the coordination of lithium salts in the system. Chinese patent publication CN119481263A discloses a method for forming a gel polymer electrolyte in-situ within the battery by initiating 1,3-dioxolane polymerization with an initiator, improving interfacial compatibility and electrode interface stability, and enhancing the battery's room temperature rate performance and low-temperature performance. Chinese patent publication CN119361337A discloses a method for selectively introducing groups that interact with anions and solvent molecules into the polymer, utilizing the anion-Li... + - The double-bridged structure formed by solvent molecules slows down the diffusion of anions while achieving Li + Fast transition mode, improving Li in gel network + Transference number and electrode interface stability.

[0005] In summary, existing gel polymer electrolytes can improve the performance of high-nickel lithium metal batteries through various modification schemes, but they still cannot simultaneously meet the requirements of wide-temperature and high-voltage applications. Summary of the Invention

[0006] In view of the problems existing in the prior art, the first objective of the present invention is to provide a method for preparing a high-voltage wide-temperature-range gel polymer electrolyte (also referred to as gel polymer electrolyte), aiming to provide a gel polymer electrolyte that is suitable for high-voltage and wide-temperature-range use requirements.

[0007] The second objective of this invention is to provide a high-voltage, wide-temperature-range gel polymer electrolyte prepared by the aforementioned method and its application in lithium metal batteries.

[0008] The third objective of this invention is to provide a lithium metal battery comprising the aforementioned high-voltage, wide-temperature-range gel polymer electrolyte. Different electrolytes face different problems in application. For example, gel electrolytes suffer from poor interfacial compatibility and kinetic performance, making it difficult to simultaneously address lithium dendrite growth and long-term cycle stability. This characteristic is particularly pronounced at high voltages (operating voltage ≥ 4.3 V), low temperatures, and high temperatures. Furthermore, theoretically, using ester ether solvents containing hydrofluoroethers can improve electrolyte performance to some extent; however, these solvents are more susceptible to interfacial damage from HF in the system during high-voltage, low-temperature, and high-temperature cycling, making it difficult to achieve the desired results. To address the problems faced by gel electrolytes, this invention provides the following solutions:

[0009] A method for preparing a high-voltage wide-temperature-range gel polymer electrolyte involves in-situ polymerization of a precursor solution containing a composite monomer, a basic electrolyte, and an initiator to obtain the high-voltage wide-temperature-range gel polymer electrolyte.

[0010] The composite monomers include monomer 1 and monomer 2 in a weight ratio of 1~2:1~2, wherein monomer 1 includes compounds of formula 1 and monomer 2 includes compounds of formula 2.

[0011] The basic electrolyte comprises a conductive lithium salt and an ester ether solvent, wherein the conductive lithium salt comprises LiPF6; the ester ether solvent comprises an ester solvent, a fluorinated ester solvent, and a hydrofluoroether in a weight ratio of 4~5:2~3:2~3.

[0012] Formula 1

[0013] Formula 2

[0014] In Formula 1, at least three of the substituents in R1 to R5 are F, and the other substituents are H, F, C1 to C4 alkyl groups or C1 to C4 alkoxy groups;

[0015] In Equation 2, Y is C4~C 10 It contains 3 to 4 branched residues; R6 is H, C1 to C4 alkyl or acrylate group.

[0016] This invention innovatively employs the aforementioned special composite monomer, conductive lithium salt, and ester ether solvent for co-polymerization. By jointly controlling parameters such as the type and ratio of the composite monomer, the type of lithium salt, and the weight ratio of the ester ether solvent, the polymerization network can be optimized, lithium-ion conductivity can be improved, and the stability of HF can be enhanced. This allows it to be adapted to high-pressure, wide-temperature-range application requirements and improves its high-pressure, low-temperature, and high-temperature cycling stability.

[0017] In this invention, in monomer 1, the compound of formula 1 is formula 1A, which is a compound of formula 1 in which R1 to R5 are all F.

[0018] Preferably, the monomer 1 further comprises an auxiliary monomer, wherein the auxiliary monomer is at least one of formula B and formula C;

[0019] Formula B

[0020] Formula C.

[0021] The present invention also shows that using the preferred monomer 1, in combination with monomer 2, and with the joint control of the solvent, helps to further optimize the polymerization network and further improve the high-pressure and wide-temperature performance of the prepared electrolyte.

[0022] Preferably, in monomer 1, the content of compound of formula 1 is 50 wt.% or more, and more preferably 60 to 80 wt.%.

[0023] In this invention, Y is an alkyl residue or a residue containing an ether bond;

[0024] Preferably, the monomer 2 is at least one of formula 2A, formula 2B, and formula 2C;

[0025] Formula 2A

[0026] Formula 2B

[0027] Equation 2C.

[0028] Preferably, monomer 2 is of formula 2B and formula 2C with a weight ratio of 1:1 to 6; more preferably, it is of formula 2B and formula 2C with a weight ratio of 1:2 to 4. Studies have shown that the preferred monomer 2, combined with monomer 1, can be further adapted and synergistic, which helps to further optimize the polymerization network and improve its adaptability to high-pressure and wide-temperature systems.

[0029] In this invention, the weight ratio of monomer 1 to monomer 2 in the composite monomer is 1~1.5:1~1.5. Studies have shown that the preferred monomer 2, combined with the control of the aforementioned ratio, helps to further improve the battery interface compatibility and kinetic performance, thus contributing to obtaining better high-voltage and wide-temperature performance.

[0030] In this invention, the conductive lithium salt includes LiPF6; it also selectively includes at least one auxiliary lithium salt selected from LiBF4, LiDFOB, and LiTFSI. Preferably, the conductive lithium salt is LiPF6 and the auxiliary lithium salt in a molar ratio of 3 to 6:1. Studies have shown that the preferred combination of conductive lithium salts helps to adapt to the polymer network, further facilitates the homogenization and deposition of lithium metal, and improves its high-voltage and wide-temperature performance.

[0031] Preferably, the ester ether solvent includes one or more of propylene carbonate (PC), ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC).

[0032] Preferably, the fluorinated ester solvent includes at least one of FEC, FEMC, and FDMC;

[0033] Preferably, the hydrofluoroether comprises at least one of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, or 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether.

[0034] Preferably, in the ester ether solvent, the weight ratio of ester solvent, fluorinated ester solvent, and hydrofluoroether is 4.5~5:2.5~3:2.5~3.

[0035] In this invention, the concentration of conductive lithium salt in the basic electrolyte is 1~5M, and more specifically 1.0~2.5M.

[0036] Preferably, in the precursor solution, the weight percentage of the composite monomer is 1-5%, more preferably 1.5-3%, and even more preferably 2-2.5%.

[0037] In this invention, the initiator is a free radical initiator, specifically an azo compound, such as azobisisobutyronitrile (AIBN).

[0038] In this invention, the initiator is 0.1-1% of the weight of the composite monomer, and more specifically 0.2-0.6%.

[0039] Preferably, the polymerization temperature is 40~80℃, and more preferably 50~70℃;

[0040] Preferably, the polymerization time is 3 to 15 hours; more preferably, it is 10 to 14 hours.

[0041] The present invention also provides a high-voltage, wide-temperature-range gel polymer electrolyte prepared by the aforementioned preparation method.

[0042] In this invention, the preparation method can endow the prepared electrolyte with a special network structure, and the solid electrolyte with special characteristics obtained by the preparation method can unexpectedly adapt to the application requirements of lithium metal batteries and high-voltage cathodes, and can obtain wide-temperature stability.

[0043] The present invention also provides the application of the high-voltage wide-temperature-range gel polymer electrolyte prepared by the above preparation method, which is used as a solid electrolyte to prepare lithium metal batteries;

[0044] Preferably, it is used to prepare a lithium metal battery in which the positive electrode contains a high-voltage positive electrode active material.

[0045] The present invention also provides a lithium metal battery comprising a high-voltage, wide-temperature-range gel polymer electrolyte prepared by the preparation method described in the present invention.

[0046] The lithium metal battery of the present invention has an active material in the positive electrode that is a high-voltage positive electrode active material.

[0047] Preferably, the high-voltage positive electrode active material is a high-nickel positive electrode active material, wherein the nickel content accounts for more than 50% of the molar amount of metal elements in the active material; for example, it can be at least one of NCM622, NCM811, and NCM90.

[0048] The present invention also provides a method for preparing the lithium metal battery described above, which is either a non-in-situ preparation method or an in-situ preparation method.

[0049] The non-in-situ preparation method is as follows: a high-voltage wide-temperature-range gel polymer electrolyte is prepared in advance, and then the positive electrode, the high-voltage wide-temperature-range gel polymer electrolyte and the negative electrode are combined to form a cell, and then assembled to obtain a lithium metal battery.

[0050] The in-situ preparation method is as follows: the positive electrode and the negative electrode are pre-composite to form a precursor cell, and then the precursor solution is injected into the precursor cell for in-situ polymerization to prepare the lithium metal battery; or, the positive electrode and the precursor solution are pre-mixed and in-situ polymerized to form a high-voltage, wide-temperature-range gel polymer electrolyte on the positive electrode in situ, and then combined with the negative electrode to form a typical electrolyte, and assembled to obtain a lithium metal battery.

[0051] In this invention, a conventional polymer separator is also permitted between the positive and negative electrodes in the precursor cell.

[0052] Beneficial effects

[0053] This invention innovatively employs the special composite monomers to co-polymerize in a special basic electrolyte system. By jointly controlling parameters such as the type and ratio of the composite monomers, the type of lithium salt, the ester ether solvent and its weight ratio, the polymerization network can be optimized, the lithium-ion conduction can be improved, and the stability of HF can be improved. This makes it suitable for high-pressure and wide-temperature-range applications and improves its high-pressure, low-temperature, and high-temperature cycling stability.

[0054] The study also shows that using the preferred monomers 1 and 2, along with the conductive lithium salt and solvent, can further synergize and help optimize the polymerization network, thereby further improving the high-temperature and wide-temperature performance of the prepared electrolyte. Attached Figure Description

[0055] Figure 1 The long-cycle performance of the coin cells of Example 1 and Comparative Example 1, which are matched with lithium metal and high-nickel cathodes at 30°C and 4.5V, is compared.

[0056] Figure 2 The charge-discharge cycle data are for the coin cells of Example 1 and Comparative Example 1, which are matched with lithium metal and high-nickel cathode at -20°C and 4.5V.

[0057] Figure 3 The charge-discharge cycle data are for the coin cells of Example 1 and Comparative Example 1, which are matched with lithium metal and high-nickel cathode at 60°C and 4.5V.

[0058] Figure 4 The ionic conductivity is that of Example 1 and Comparative Example 1. Detailed Implementation

[0059] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Example 1

[0061] Step 1:

[0062] LiNi, the positive electrode active material 0.8 Co 0.1 Mn 0.1 Conductive agent carbon black and binder polyvinylidene fluoride (PVDF) are mixed thoroughly in an appropriate amount of n-methylpyrrolidone (NMP) solvent at a weight ratio of 8:1:1 to form a uniform positive electrode slurry. This positive electrode slurry is then coated onto the positive electrode current collector Al foil, and after drying and rolling, a positive electrode sheet is obtained. A lithium sheet with a thickness of 0.8–1.5 mm is used as the negative electrode.

[0063] Step 2:

[0064] Under an argon protective atmosphere with oxygen and water content both less than 1 ppm and below 20°C, the composite monomer (including monomer 1 and monomer 2 in a weight ratio of 1.5:1, monomer 1 being formula 1A and monomer 2 being formula 2A), the basic electrolyte, and the initiator were stirred for 20 minutes to obtain a precursor solution.

[0065] The basic electrolyte is formed by dissolving 1.2 mol / L lithium hexafluorophosphate in a solvent with a mass ratio of ethyl methyl carbonate (EMC), fluoroethylene carbonate (FEC), and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) of 5:2:3.

[0066] The total concentration of the complex monomers in the precursor solution was 2.5 wt.%.

[0067] The initiator is azobisisobutyronitrile, which accounts for 0.5 wt% of the weight of the composite monomer;

[0068] Step 3:

[0069] The positive / negative electrode sheets obtained in step 1 were assembled into button cells in a glove box with a water and oxygen content of <0.5ppm. The battery case model was 2016. The prepolymerization solution (precursor solution) obtained in step 2 was dropped onto the surface of the Celgard 2500 separator. The positive electrode battery case, positive electrode sheet, separator (PP), negative electrode sheet, and negative electrode battery case were stacked in sequence, sealed, and heated at 60℃ for 12h for in-situ polymerization to obtain a gel polymer electrolyte.

[0070] The lithium metal battery prepared in this embodiment, which improves interfacial compatibility and interfacial kinetics, was used in a high-voltage, wide-temperature-range gel polymer electrolyte, and its performance was tested as follows:

[0071] Test 1:

[0072] Figure 1 shows the 2C long-cycle data of 400 cycles for a coin cell with a high-voltage, wide-temperature-range gel polymer electrolyte and a lithium metal cathode matched with a high-nickel cathode at 30°C and 4.5V, demonstrating the ability of the high-voltage, wide-temperature-range composite electrolyte of lithium metal batteries to operate for a long time at high voltage.

[0073] Test 2:

[0074] Figure 2 The 0.2C charge-discharge / 50-cycle discharge data for a coin cell with a high-voltage, wide-temperature-range gel polymer electrolyte for lithium metal batteries, matched with a high-nickel cathode at -20℃ and 4.5V, demonstrate the stability of the high-voltage, wide-temperature-range composite electrolyte for lithium metal batteries at -20℃.

[0075] Test 3:

[0076] Figure 3 The 2C charge-discharge / 100-cycle data for a coin cell with a high-voltage, wide-temperature-range gel polymer electrolyte for lithium metal batteries, matched with a high-nickel cathode at 60°C and 4.5V, demonstrate the stability of lithium metal batteries under high-voltage, wide-temperature-range composite electrolyte conditions.

[0077] Test 4:

[0078] Figure 4 The test data on the ionic conductivity of a high-voltage, wide-temperature-range gel polymer electrolyte for lithium metal batteries in the temperature range of -20℃ to 60℃ demonstrates the improved kinetic performance of the high-voltage, wide-temperature-range composite electrolyte for lithium metal batteries in a wide temperature range.

[0079] Example 2

[0080] Compared with Example 1, the only difference is that the types of Formula 1 are changed, and the experimental groups are as follows:

[0081] Group A: Monomer 1 is Formula 1A + Formula B with a weight ratio of 3:1;

[0082] Group B: Monomer 1 is Formula 1A + Formula C with a weight ratio of 2:1;

[0083] Compared to Group A: Monomer 1 is replaced with Formula B;

[0084] Compared to Group B: Monomer 1 is replaced with Formula C;

[0085] The dosage of monomer 1 and other operations and parameters were the same as in Example 1, and the results are shown in Table 1:

[0086]

[0087] As can be seen from Table 1, Examples 1 and 2, using Formula 1A as monomer 1, especially using a combination monomer 1 that includes Formula 1A and selectively includes Formula B and Formula C, can further optimize the electrolyte network framework, making it suitable for high-voltage and wide-temperature applications, and improving the electrochemical performance of the battery under high voltage and wide temperature range.

[0088] Example 3

[0089] Compared with Example 1, the only difference is that the types of Formula 2 are changed, and the experimental groups are as follows:

[0090] Group A: Monomer 2 is Formula 2B;

[0091] Group B: Monomer 2 is Formula 2C;

[0092] Group C: Monomer 2 is Formula 2A + Formula 2B with a weight ratio of 1:3;

[0093] Group D: Monomer 2 is Formula 2A + Formula 2C with a weight ratio of 1:3;

[0094] Group E: Monomer 2 is Formula 2B + Formula 2C with a weight ratio of 1:3;

[0095] The dosage of monomer 2 and other operations and parameters were the same as in Example 1, and the results are shown in Table 2:

[0096]

[0097] As can be seen from Table 1 and Examples 1, 2 and 3, when Formula 2B and Formula 2C, especially when they are used together as Formula 2 as monomer 2 to form a gel polymer skeleton, the electrochemical performance of the battery under high voltage and wide temperature range is significantly improved.

[0098] Example 4

[0099] Compared to Example 1, the only difference is that the type of lithium salt was changed, and the experimental groups were as follows:

[0100] Group A: The lithium salt is LiPF6+LiDFOB with a molar concentration ratio of 5:1;

[0101] Group B: The lithium salt is LiPF6+LiTFSI with a molar concentration ratio of 3:1;

[0102] Compared to Group A: the lithium salt is LiDFOB;

[0103] Compared to Group B: the lithium salt is LiTFSI.

[0104] The total lithium salt concentration and other operations and parameters were the same as in Example 1, and the results are shown in Table 3:

[0105]

[0106] Example 5

[0107] Compared to Example 1, the only difference is the change in the solvent ratio; the experimental groups are as follows:

[0108] Group A: The EMC:FEC:TTE mass ratio of the solvent in the basic electrolyte is 4:3:3;

[0109] Group B: The EMC:FEC:TTE mass ratio of the solvent in the basic electrolyte is 5:3:2;

[0110] Compared to Group A: the EMC : FEC : TTE mass ratio of the solvent in the basic electrolyte is 7 : 2 : 1;

[0111] All other operations and parameters are the same as in Example 1, and the results are shown in Table 4:

[0112]

[0113] Example 6

[0114] Compared with Example 1, the only difference is that the ratio of the composite monomer is changed, and everything else is the same as Example 1.

[0115] Group A: In the composite monomer, the mass ratio of monomer 1 to monomer 2 is 2:3, and other operations and parameters are the same as in Example 1.

[0116] Group B: In the composite monomer, the mass ratio of monomer 1 to monomer 2 is 1:1, and other operations and parameters are the same as in Example 1.

[0117] Compared with Group A: In the composite monomer, the mass ratio of monomer 1 to monomer 2 is 1:4, and other operations and parameters are the same as in Example 1.

[0118] Compared to Group B: In the composite monomer, the mass ratio of monomer 1 to monomer 2 is 4:1, and other operations and parameters are the same as in Example 1.

[0119] The results are shown in Table 5:

[0120]

[0121] Example 7

[0122] Compared with Example 1, the only differences are that the total content of the composite monomers in the precursor solution is 3 wt.%; the concentration of lithium hexafluorophosphate in the basic electrolyte is 1.5 M; the amount of initiator is 0.3 wt.% of the weight of the composite monomers; the polymerization temperature is 65°C; and the polymerization time is 10 h. All other operations and parameters are the same as in Example 1. Experimental results are shown in Table 6.

[0123]

[0124] Comparative Example 1

[0125] Compared with Example 1, the only difference is that monomer 1 is missing, and the missing monomer 1 is supplemented by an equal amount of monomer 2. All other operations and parameters are the same as in Example 1.

[0126] Comparative Example 2

[0127] Compared with Example 1, the only difference is that monomer 2 is missing. The missing monomer 2 is supplemented by an equal amount of monomer 1. All other operations and parameters are the same as in Example 1.

[0128] Comparative Example 3

[0129] Compared with Example 1, the only difference is that the solvent of the basic electrolyte lacks 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, and the proportion of the remaining components, the total amount of solvent, and the other conditions are the same as in Example 1.

[0130] Comparative Example 4

[0131] Compared with Example 1, the only difference is that comparative formula A is used. Replace monomer 1, and perform the same operations and parameters as in Example 1.

[0132] The results are shown in Table 7:

[0133]

[0134] Through the examples, comparative examples, and comparative groups, it can be seen that the present invention innovatively uses the special composite monomer, conductive lithium salt, and ester ether solvent for co-polymerization. With the joint control of parameters such as the type and ratio of composite monomer, the type of lithium salt, and the weight of ester ether solvent, the polymerization network can be optimized, the lithium-ion conduction can be improved, and the stability of HF can be improved. This makes it suitable for high-pressure and wide-temperature-range application requirements and improves its high-pressure, low-temperature, and high-temperature cycling stability.

[0135] As can be seen from Examples 1 and 2, using the preferred monomer 1, which is combined with monomer 2, and in conjunction with the joint control of the solvent, helps to further optimize the polymerization network and further improve the high-temperature and wide-temperature performance of the prepared electrolyte.

[0136] As can be seen from Examples 1 and 3, the preferred monomer 2, combined with monomer 1, can be further adapted and synergistic, which helps to further optimize the polymerization network and improve its adaptability to high-pressure and wide-temperature systems.

Claims

1. A method for preparing a high-voltage, wide-temperature-range gel polymer electrolyte, characterized in that, The high-voltage, wide-temperature-range gel polymer electrolyte is prepared by in-situ polymerization of a precursor solution containing a composite monomer, a basic electrolyte, and an initiator. The composite monomers include monomer 1 and monomer 2 in a weight ratio of 1~2:1~2, wherein monomer 1 includes compounds of formula 1 and monomer 2 includes compounds of formula 2. The basic electrolyte comprises a conductive lithium salt and an ester ether solvent, wherein the conductive lithium salt comprises LiPF6; the ester ether solvent comprises an ester solvent, a fluorinated ester solvent, and a hydrofluoroether in a weight ratio of 4~5:2~3:2~3. Formula 1 Formula 2 In Formula 1, at least three of the substituents in R1 to R5 are F, and the other substituents are H, F, C1 to C4 alkyl groups or C1 to C4 alkoxy groups; In Equation 2, Y is C4~C 10 It contains 3 to 4 branched residues; R6 is H, C1 to C4 alkyl or acrylate group.

2. The method for preparing a high-voltage, wide-temperature-range gel polymer electrolyte as described in claim 1, characterized in that, In monomer 1, the compound of formula 1 is formula 1A, which is a compound of formula 1 in which R1 to R5 are all F; Preferably, the monomer 1 further comprises an auxiliary monomer, wherein the auxiliary monomer is at least one of formula B and formula C; Formula B Formula C; Preferably, in monomer 1, the content of compound of formula 1 is 50 wt.% or more.

3. The method for preparing a high-voltage, wide-temperature-range gel polymer electrolyte as described in claim 1, characterized in that, The Y is an alkyl residue or a residue containing an ether bond; Preferably, the monomer 2 is at least one of formula 2A, formula 2B, and formula 2C; Formula 2A Formula 2B Equation 2C; Preferably, monomer 2 is of formula 2B and formula 2C in a weight ratio of 1:1 to 6.

4. The method for preparing a high-voltage, wide-temperature-range gel polymer electrolyte as described in claim 1, characterized in that, In the composite monomer, the weight ratio of monomer 1 to monomer 2 is 1~1.5:1~1.

5.

5. The method for preparing a high-voltage, wide-temperature-range gel polymer electrolyte as described in claim 1, characterized in that, The conductive lithium salt may also selectively include at least one auxiliary lithium salt selected from LiBF4, LiDFOB, and LiTFSI. Preferably, the conductive lithium salt is LiPF6 and an auxiliary lithium salt in a molar ratio of 3 to 6:1; Preferably, the ester ether solvent includes one or more of propylene carbonate (PC), ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC). Preferably, the fluorinated ester solvent includes at least one of FEC, FEMC, and FDMC; Preferably, the hydrofluoroether comprises at least one of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, or 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether. Preferably, in the ester ether solvent, the weight ratio of ester solvent, fluorinated ester solvent, and hydrofluoroether is 4.5~5:2.5~3:2.5~3; Preferably, the concentration of the conductive lithium salt in the base electrolyte is 1~5M, more preferably 1.0~2.5M; Preferably, in the precursor solution, the weight percentage of the composite monomer is 1-5%, more preferably 1.5-3%, and even more preferably 2-2.5%. Preferably, the initiator is a free radical initiator; Preferably, the initiator is 0.1-1% of the weight of the composite monomer, more preferably 0.2-0.6%; preferably, the polymerization temperature is 40-80°C. Preferably, the polymerization time is 3 to 15 hours.

6. A high-voltage, wide-temperature-range gel polymer electrolyte prepared by the preparation method according to any one of claims 1 to 5.

7. The application of a high-voltage, wide-temperature-range gel polymer electrolyte prepared by the preparation method according to any one of claims 1 to 5, characterized in that, It can be used as a solid electrolyte to prepare lithium metal batteries; Preferably, it is used to prepare a lithium metal battery in which the positive electrode contains a high-voltage positive electrode active material.

8. A lithium metal battery, characterized in that, The high-voltage, wide-temperature-range gel polymer electrolyte is prepared by the method described in any one of claims 1 to 5.

9. The lithium metal battery as described in claim 8, characterized in that, The active material in the positive electrode of the lithium metal battery is a high-voltage positive electrode active material; Preferably, the high-voltage positive electrode active material is a high-nickel positive electrode active material, wherein the nickel content accounts for more than 50% of the molar amount of metal elements in the active material; preferably, at least one of NCM622, NCM811, and NCM90.

10. A method for preparing a lithium metal battery according to claim 8 or 9, characterized in that, It is either a non-in-situ preparation method or an in-situ preparation method; The non-in-situ preparation method is as follows: a high-voltage wide-temperature-range gel polymer electrolyte is prepared in advance, and then the positive electrode, the high-voltage wide-temperature-range gel polymer electrolyte and the negative electrode are combined to form a cell, and then assembled to obtain a lithium metal battery. The in-situ preparation method is as follows: the positive electrode and the negative electrode are pre-composite to form a precursor cell, and then the precursor solution is injected into the precursor cell using the preparation method described in any one of claims 1 to 5 for in-situ polymerization to prepare the lithium metal battery; or, the positive electrode and the precursor solution are pre-mixed and in-situ polymerized to form a high-voltage, wide-temperature-range gel polymer electrolyte on the positive electrode in situ, which is then combined with the negative electrode to form a typical electrolyte and assembled to obtain a lithium metal battery.

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