Preparation and application of all-solid-state battery and cross-linked functional polyether-based electrolyte thereof

Abstract

The application belongs to the field of all-solid-state batteries, and particularly relates to a preparation method of a crosslinked functional polyether-based all-solid-state electrolyte, which comprises the following steps: carrying out crosslinking polymerization on a precursor solution containing a monomer of formula A, a synergistic initiator and a crosslinking agent to obtain the electrolyte; the synergistic initiator comprises an initiator a of formula B and an initiator b; the initiator b is a lithium salt containing boron or phosphorus; and the crosslinking agent is a compound containing two or more epoxy groups. The application further comprises an all-solid-state battery containing the electrolyte and a preparation method of the all-solid-state battery. The method can realize crosslinking and solidification of the monomer of formula A, and can be used to prepare an all-solid-state battery with excellent performance.

Description

Technical Field

[0001] This invention relates to the field of all-solid-state lithium metal batteries, and more specifically to the technical field of an all-solid-state electrolyte for an all-solid-state battery. Background Technology

[0002] With the continuous development of human society, the demand for energy is constantly increasing, and improving the energy density of batteries has become a common goal for researchers worldwide. Replacing graphite anodes with lithium metal holds promise for achieving energy densities exceeding 500 Wh / kg at the system level. -1 While achieving high energy density is desirable, this requires new electrolyte technologies to address issues related to lithium metal anodes. Solid-state electrolytes can solve uncontrollable interface problems associated with lithium anodes that are difficult to resolve with liquid electrolytes. Compared to all-solid-state inorganic electrolytes, all-solid-state polymer electrolytes have attracted widespread attention due to their lower cost, easier processing, and better compatibility with electrode interfaces. Among them, poly(1,3-dioxopentane) electrolytes produced by in-situ polymerization are currently a research hotspot, but their linear structure leads to poor thermo-mechanical stability, and their tendency to crystallize reduces ion conductivity. Furthermore, incomplete in-situ polymerization is a common problem, with residual large amounts of highly active liquid monomers or oligomers easily leaking, seriously affecting battery safety performance. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a method for preparing a cross-linked functionalized polyether-based all-solid-state electrolyte, aiming to provide an all-solid-state cross-linked functionalized polyether-based all-solid-state electrolyte that balances excellent stability and ion conductivity.

[0004] The second objective of this invention is to provide a cross-linked functionalized polyether-based all-solid-state electrolyte prepared by the aforementioned method and its applications.

[0005] The third objective of this invention is to provide an all-solid-state battery comprising the cross-linked functionalized polyether-based all-solid-state electrolyte and a method for its in-situ preparation.

[0006] Alicyclic ethers can be polymerized as monomers to form polyether electrolytes, but existing polymerization methods make it difficult to crosslink them to form an all-solid-state polymeric network, which affects their thermo-mechanical stability and ionic conductivity. To address this problem, this invention, after in-depth research, provides the following improved method:

[0007] A method for preparing a cross-linked functionalized polyether-based all-solid-state electrolyte involves cross-linking and polymerizing a precursor solution containing a monomer of formula A, a co-initiator, and a cross-linking agent.

[0008] The synergistic initiator includes initiator a and initiator b of formula B; initiator b is a boron- or phosphorus-containing lithium salt; the crosslinking agent is a compound containing two or more epoxy groups;

[0009]

[0010] In formula A, X is O or CH2; Y is methylene or ethylene.

[0011] This invention innovatively uses Formula A as a monomer and performs crosslinking polymerization on it under the presence of initiators a and b containing Formula B and a crosslinking agent. This can synergistically enhance the crosslinking reaction, promote the formation of a crosslinking polymerization network of Formula A, improve the thermal and mechanical strength of the polymer, optimize the ion conduction pathway, improve the conduction efficiency, and thus improve its high-rate stability.

[0012] In this invention, the combination of synergistic initiators is key to the formation of an all-solid-state polymer network by induced A-crosslinking polymerization and to improving its stability and ion conductivity.

[0013] In the aforementioned synergistic initiator, initiator b includes at least one of lithium difluorooxalatoborate (LiDFOB), lithium tetrafluoroborate (LiBF4), lithium difluorodioxalatophosphate (LiDFOP), and lithium hexafluorophosphate (LiPF6), more preferably LiDFOB. Studies have shown that using the preferred initiator b, in combination with initiator a, exhibits superior synergy, further enhancing the crosslinking of formula A, optimizing its structure, and improving its performance.

[0014] In this invention, the crosslinking agent comprises at least one of Formulas 1 to 12:

[0015]

[0016]

[0017]

[0018] In Formulas 1 to 12, R1 is a branched and linear alkyl chain with 1 to 10 carbon atoms, and n, n1, n2, n3, and n4 are individually 0 to 10, or more specifically 1 to 3.

[0019] The present invention also shows that, under the aforementioned synergistic initiator, further joint control of the components of the crosslinking agent, especially the use of component 5 as the crosslinking component, can unexpectedly further enhance the synergy of the components, further optimize the crosslinking polymerization behavior of formula A, optimize its structure and surface, thereby further enhance its thermal and mechanical strength, improve its ionic conductivity, and thus improve its electrochemical performance.

[0020] In this invention, the content of initiator a in the precursor solution is 10 wt.% or more, preferably 20 to 60 wt.%, more preferably 25 to 40 wt.%, and even more preferably 30 to 40 wt.%.

[0021] The content of the initiator b is less than 20 wt.%, preferably 1 to 5 wt.%, and more preferably 1 to 2 wt.%.

[0022] The content of the crosslinking agent is less than 20 wt.%, preferably 1 to 10 wt.%.

[0023] In this invention, the precursor solution further comprises a modifier, which is a monoepoxide compound; preferably, it comprises a structure from Formula 13 to Formula 20:

[0024]

[0025]

[0026] In Formulas 13 to 20, R1 is a branched and linear alkyl chain with 1 to 10 carbon atoms.

[0027] Preferably, the content of the modifier in the precursor solution is less than 30 wt.%, more preferably 0 to 20 wt.%, and more preferably 1 to 10 wt.%.

[0028] In this invention, the addition of a modifier to the precursor solution can further optimize the polymerization behavior of Formula A, thereby unexpectedly enhancing the thermal and mechanical stability and ionic conductivity of the cross-linked polymerized solid electrolyte.

[0029] In this invention, the precursor solution can be crosslinked and polymerized on a diaphragm base membrane, and the crosslinked functionalized polyether-based all-solid electrolyte can be coated on the diaphragm base membrane.

[0030] In this invention, the diaphragm base membrane includes, for example, at least one of glass fiber, cellulose, cellulosic, polytetrafluoroethylene, polyester fiber, polypropylene, and polyethylene;

[0031] In this invention, the crosslinking polymerization temperature is 40–90°C, and more preferably 60–80°C;

[0032] In this invention, the crosslinking polymerization time is 20h to 48h.

[0033] The present invention also provides a cross-linked functionalized polyether-based all-solid-state electrolyte prepared by the preparation method described above.

[0034] The preparation method described in this invention can optimize the polymer network, endow the polymer with special physicochemical properties, and the solid electrolyte prepared by the method has excellent thermal and mechanical stability and improved electrochemical performance.

[0035] The present invention also provides an all-solid-state battery, comprising a cell composed of a positive electrode, a barrier layer and a negative electrode, wherein the barrier layer is a cross-linked functionalized polyether-based all-solid-state electrolyte prepared by the aforementioned preparation method.

[0036] In this invention, the barrier layer may also include a diaphragm base membrane and a cross-linked functionalized polyether-based all-solid electrolyte composite on the surface of the diaphragm base membrane.

[0037] In this invention, the all-solid-state battery is an all-solid-state lithium-ion battery.

[0038] The all-solid-state battery described in this invention, apart from containing the cross-linked functionalized polyether-based all-solid-state electrolyte described in this invention, can have other conventional components and structures.

[0039] For example, the positive electrode includes a current collector and a positive electrode material composited on its surface; the positive electrode material includes a positive electrode active material, a binder, and a conductive agent;

[0040] For example, the negative electrode is a lithium metal negative electrode; or a coated negative electrode; the lithium metal negative electrode is a lithium foil or a negative electrode carrying lithium metal; the coated negative electrode is a negative electrode containing at least one of carbon material, silicon material, and carbon-silicon composite material that can support active material.

[0041] The present invention also provides an in-situ preparation method for the all-solid-state battery, wherein the positive electrode, the separator base film, and the negative electrode are sequentially composited and then filled into the battery casing. Subsequently, the preparation method of the present invention involves injecting the precursor solution into the battery casing, followed by encapsulation and in-situ crosslinking polymerization to obtain the all-solid-state battery.

[0042] Beneficial effects

[0043] This invention demonstrates that the synergistic initiator is adapted to the characteristics of A-type polymerization, optimizing the crosslinking polymerization of A-type polymers and enabling the construction of an all-solid-state crosslinking network. This facilitates the acquisition of an all-solid-state polyether electrolyte, avoids crystallization, and thus improves thermal and mechanical stability, as well as solvent resistance. The study shows that the all-solid-state electrolyte prepared by the method of this invention possesses highly efficient and time-stable lithium-ion transport capabilities, and all-solid-state lithium batteries equipped with this electrolyte exhibit excellent capacity and stable electrochemical performance.

[0044] The present invention also shows that further optimization and control of the composition of the crosslinking agent can further optimize the crosslinking polymerization network, further optimize its stability and ion conductivity, and further improve its cycling stability at high rates. Attached Figure Description

[0045] Figure 1 The charging and discharging curves of the battery in Example 1 are shown.

[0046] Figure 2 This is the performance structure of the pouch battery after it has been cut in Example 1.

[0047] Figure 3 The results are the ion transport number test results of the electrolyte in Example 2.

[0048] Figure 4 The results are the tensile properties test results of the electrolyte in Example 4.

[0049] Figure 5 The first charge-discharge curves of the two battery groups in Example 5 are shown.

[0050] Figure 6 The polymerization test results are for the electrolytes in Comparative Example 2 and Example 2B.

[0051] Figure 7 The results are NMR test results for the liquid electrolyte in Comparative Example 3. Detailed Implementation

[0052] The present invention will be illustrated below through examples.

[0053] This invention discloses an optional method for preparing an all-solid-state lithium metal battery based on an in-situ catalytic crosslinking functionalized polyether-based electrolyte. The method involves assembling the positive electrode, separator, and negative electrode into a battery casing, subsequently injecting a precursor solution, encapsulating the battery, and then performing in-situ polymerization to obtain the final product. Conventional methods and procedures can be used for the in-situ polymerization.

[0054] The precursor solution comprises a solution of formula A, a co-initiator, and a crosslinking agent;

[0055] In this invention, formula A can be at least one of formula A-1 (formula A where both X and Y are CH2) and formula A-2 (formula A where X is O and Y is CH2).

[0056] In this invention, the synergistic initiator can provide a lithium source and synergistically catalyze the A-type crosslinking polymerization in the system, thereby crosslinking it to form an all-solid-state crosslinked polymer electrolyte.

[0057] In this invention, initiator a in the synergistic initiator is of formula B. Initiator b is one or more of lithium difluorooxalate borate (LiDFOB), lithium tetrafluoroborate (LiBF4), lithium difluorodioxalate phosphate (LiDFOP), and lithium hexafluorophosphate (LiPF6).

[0058] In this invention, the crosslinking agent Further, it can be a compound of formula 1 to formula 12.

[0059] The membrane substrate can be at least one of glass fiber, cellulose, cellulosic, polytetrafluoroethylene, polyester fiber, polypropylene and polyethylene.

[0060] Modifiers may also be added to the precursor solution. The modifier may be a compound of formula 13 to formula 20.

[0061] In this invention, the content of initiator a in the precursor solution is 10 wt.% or more, preferably 20 to 60 wt.%. The content of initiator b is 20 wt.% or less, preferably 1 to 5 wt.%. The content of crosslinking agent is 20 wt.% or less, preferably 1 to 10 wt.%.

[0062] Furthermore, in the precursor solution, the content of the modifier is less than 30 wt.%, preferably 0 to 20 wt.%.

[0063] The remaining component is formula A.

[0064] In this invention, the positive electrode, negative electrode, and battery structure can all be conventional.

[0065] For example, the cathode material contains lithium iron phosphate (LFP) powder, preferably, the LFP accounts for more than or equal to 60 wt.% of the cathode material by weight, and more preferably 70 to 90 wt.%.

[0066] The positive electrode material may also contain binders and conductive agents.

[0067] The binder is a fluoropolymer, more preferably at least one of polyvinylidene fluoride and poly(vinylidene fluoride-co-hexafluoropropylene). The binder accounts for less than or equal to 20 wt.% of the weight of the positive electrode material, and more preferably 5-15 wt.%.

[0068] The conductive agent is at least one of carbon powders, specifically Super P, acetylene black, carbon nanotubes, graphite, activated carbon, and Ketjen black. The conductive agent constitutes less than or equal to 20 wt.% of the weight of the cathode material, and more preferably 5–15 wt.%.

[0069] The negative electrode is a current collector made of lithium sheet, lithium powder, lithium alloy sheet, or carbon or copper material that does not contain metallic lithium.

[0070] After assembly, the battery is left to stand at room temperature or high temperature (40-90°C, or even 60-80°C) for 20-48 hours to achieve complete in-situ polymerization and solidification of the electrolyte. After solidification, the battery is an all-solid-state battery.

[0071] In this invention, the battery is assembled according to conventional methods, the precursor solution is injected into the separator, and the battery is assembled according to standard procedures.

[0072] In this invention, after the battery is assembled, it is left to stand at room temperature or high temperature (40-90°C, or even 60-80°C) for 20-48 hours to achieve complete in-situ polymerization and solidification of the electrolyte. After solidification, the battery is an all-solid-state battery.

[0073] According to the above method, the separator, negative electrode, etc. can all be conventional in the industry. For example, unless otherwise stated, as an example, the separator can be a glass fiber separator and the negative electrode can be lithium foil.

[0074] As an example, unless otherwise stated, the cathode mentioned in the following cases is an LFP (lithium iron phosphate) cathode, which includes an aluminum current collector and a cathode material composited on its surface, wherein the cathode material includes lithium iron phosphate, PVDF and conductive carbon black in a weight ratio of 9.5:0.3:0.2.

[0075] As examples, unless otherwise stated, the negative electrode mentioned in the following cases refers to lithium foil.

[0076] As examples, in the following cases, unless otherwise stated, the diaphragms used are made of glass fiber.

[0077] The solid-state battery is obtained using a conventional in-situ polymerization method. For example, the steps are as follows: a positive electrode, a separator, and a negative electrode are pre-composite to form a precursor cell; the precursor is placed inside a battery casing; then a precursor solution for forming a solid electrolyte is injected; after encapsulation, in-situ polymerization is performed to obtain the battery. The in-situ polymerization temperature can be 70°C, and the in-situ polymerization time is 24 hours.

[0078] The precursor solutions for each of the following cases are as follows:

[0079] Example 1

[0080] The precursor solution contains a solution of formula A-2 containing initiator a (formula B), initiator b (LiDFOB), and crosslinking agent (crosslinking agent a, which is formula 2 with n=1); wherein, the mass fraction of initiator a is 30%; the mass fraction of initiator b is 1.5%; and the mass fraction of crosslinking agent is 3.0%.

[0081] Figure 1 The charge-discharge curves are for the all-solid-state battery formed by in-situ crosslinking of the precursor solution in Example 1.

[0082] The in-situ catalytically cross-linked functionalized polyether electrolyte synthesized using this method exhibits a high ionic conductivity of 0.255 mS / cm. -1 The assembled LiFePO4 / Li battery retained 93.5% of its capacity after 100 cycles at a current density of 0.5C, exhibiting excellent rate performance. Pouch cells based on this electrolyte also demonstrate high safety under extreme conditions, such as... Figure 2 As shown, after cutting, the battery does not leak, smoke, or heat up, and can still discharge and light up the LED.

[0083] Example 2

[0084] Compared to Example 1, the difference lies in that the type of crosslinking agent was changed and its mass fraction was fixed at 10 wt%. The in-situ curing temperature was 60°C, and the curing time was 30 h. Other operations and parameters were the same as in Example 1. The experimental groups were as follows:

[0085] Group A: The crosslinking agent is Formula 4 (n1 = 1, n2 = 1);

[0086] Assembly and testing were performed according to the method in Example 1. The results showed that the in-situ catalytic cross-linked functionalized polyether electrolyte exhibited a high ionic conductivity of 0.417 mS / cm. -1 The electrochemical window exceeds 4.3V, the lithium-ion transference number is 0.38, and the assembled LiFePO4 / Li battery retains 95.1% of its capacity after 100 cycles at a current density of 0.5C.

[0087] Group B: The crosslinking agent is Formula 5 (n1 = 1, n2 = 1);

[0088] Figure 3 The ion transport number test results for this electrolyte are provided.

[0089] Assembly and testing were performed according to the method in Example 1, and the results showed that the in-situ catalytic cross-linked functionalized polyether-based electrolyte exhibited a high ionic conductivity of 0.451 mS / cm. -1The electrochemical window exceeds 4.4V, the lithium-ion transference number is 0.42, and the assembled LiFePO4 / Li battery retains 97.0% of its capacity after 100 cycles at a current density of 0.5C.

[0090] Group C: The crosslinking agent is Formula 6 (n1 = 2, n2 = 2);

[0091] Assembly and testing were performed according to the method in Example 1, and the results showed that the in-situ catalytic cross-linked functionalized polyether-based electrolyte exhibited a high ionic conductivity of 0.385 mS / cm. -1 With an electrochemical window exceeding 4.3V and a lithium-ion transference number of 0.42, the assembled LiFePO4 / Li battery retained 94.3% of its capacity after 100 cycles at a current density of 0.5C.

[0092] Group D: The crosslinking agent is Formula 7;

[0093] Assembly and testing were performed according to the method in Example 1, and the results showed that the in-situ catalytic cross-linked functionalized polyether-based electrolyte exhibited a high ionic conductivity of 0.374 mS / cm. -1 With an electrochemical window exceeding 4.3V and a lithium-ion transference number of 0.36, the assembled LiFePO4 / Li battery retained 93.4% of its capacity after 100 cycles at a current density of 0.5C.

[0094] The results of the AD group in Example 2 confirmed that different crosslinking agents have different effects on the overall conductivity and migration number of the electrolyte. Specifically, the meta-substituted crosslinking agent (Equation 5) has the greatest positive effect on conductivity.

[0095] Example 3

[0096] Compared to Example 1, the only difference is that a modifier was added to the precursor solution, and the mass fraction of the modifier in the precursor solution reached 5%, while other conditions remained unchanged. The experimental groups were as follows:

[0097] Group A: The modifier is Formula 13 (R1 is ethyl);

[0098] Assembly and testing were performed according to the method in Example 1, and the results showed that the in-situ catalytic cross-linked functionalized polyether-based electrolyte exhibited a high ionic conductivity of 0.357 mS / cm. -1 The electrochemical window reaches 4.30V, and the assembled LiFePO4 / Li battery retains 94.0% of its capacity after 100 cycles at a current density of 0.5C.

[0099] Group B: The modifier is Formula 14;

[0100] Assembly and testing were performed according to the method in Example 1. The results showed that the in-situ catalytic cross-linked functionalized polyether-based electrolyte exhibited a high ionic conductivity of 0.460 mS / cm. -1 The electrochemical window reaches 4.38V, and the assembled LiFePO4 / Li battery retains 94.3% of its capacity after 100 cycles at a current density of 0.5C.

[0101] Group C: The modifier is Formula 16;

[0102] Assembly and testing were performed according to the method in Example 1. The results showed that the in-situ catalytic cross-linked functionalized polyether-based electrolyte exhibited a high ionic conductivity of 0.502 mS / cm. -1 The electrochemical window reaches 4.25V, and the assembled LiFePO4 / Li battery retains 95.3% of its capacity after 100 cycles at a current density of 0.5C.

[0103] Group D: The modifier is Formula 18 (R1 is ethyl);

[0104] Assembly and testing were performed according to the method in Example 1. The results showed that the in-situ catalytic crosslinking functionalized polyether-based electrolyte exhibited a high ionic conductivity of 0.551 mS / cm. -1 The electrochemical window reaches 4.45V, and the assembled LiFePO4 / Li battery retains 95.1% of its capacity after 100 cycles at a current density of 0.5C.

[0105] Group E: The modifier is Formula 19;

[0106] Assembly and testing were performed according to the method in Example 1. The results showed that the in-situ catalytic cross-linked functionalized polyether electrolyte exhibited a high ionic conductivity of 0.536 mS / cm. -1 The electrochemical window can reach 4.05V, and the assembled LiFePO4 / Li battery retains 92.4% of its capacity after 100 cycles at a current density of 0.5C.

[0107] Compared with Example 1, the conductivity performance of Example 3 was improved, which means that the modifier has a positive effect, thereby enhancing the cycle performance of the battery.

[0108] Example 4

[0109] Compared to Example 2B, the only difference is that a modifier was added to the electrolyte to achieve a mass fraction of 5-10% in the solution, while other conditions remained unchanged. The experimental groups were as follows:

[0110] Group A: The modifier is Formula 16, with a mass fraction of 5%;

[0111] Group B: The modifier is Formula 16, with a mass fraction of 10%;

[0112] Figure 4 The tensile property test results of samples A (curve 1) and B (curve 2) are provided. The results show that the addition of modifier C can affect the mechanical properties of the electrolyte, enabling it to cope with greater strain.

[0113] The battery was assembled in situ according to the method in Example 1, and tested. The results were as follows:

[0114] Group A: Ionic conductivity 0.653 mS / cm -1 At a current density of 0.5C, the capacity retention rate is 97.5% after 100 cycles.

[0115] Group B: Ionic conductivity 0.587 mS / cm -1 At a current density of 0.5C, the capacity retention rate is 98.1% after 100 cycles.

[0116] Example 5

[0117] Compared with Example 2B, the difference is that the crosslinking agent is fixed as Formula 10, and its mass fraction is changed, while other conditions remain unchanged. The experimental groups are as follows:

[0118] Group A: The mass fraction of the crosslinking agent (Formula 10) is 1%.

[0119] Group B: The mass fraction of the crosslinking agent (Formula 10) is 5%.

[0120] Figure 5 The first charge-discharge curves of samples A (curve 1) and B (curve 2) are provided. The results show that excessive crosslinking agent (Equation 10) leads to excessive degradation of battery performance. This is mainly because the crosslinking agent structure of Equation 10 has a limited contribution to ion conduction, and excessive crosslinking restricts the movement of polymer matrix chain segments.

[0121] Group A: Ionic conductivity 0.354 mS / cm -1 It has an electrochemical window exceeding 4.20V and can operate at 60℃.

[0122] Group B: Ionic conductivity 0.158 mS / cm -1 With an electrochemical window exceeding 4.52V, it can operate at 100℃.

[0123] Example 6

[0124] Compared to Example 1, the only difference is the change in the type and content of the initiator. The experimental groups are as follows:

[0125] Group A: Initiator b is LiPF6;

[0126] Group B: Initiator b is LiDFOB, the content of initiator a is 40 wt.%, and the content of initiator b is 1.5 wt.%;

[0127] The battery was assembled in situ according to the method in Example 1, and tested. The results were as follows:

[0128] Group A: Ionic conductivity 0.098 mS / cm -1 At a current density of 0.5C, the capacity retention rate is 86.2% after 100 cycles.

[0129] Group B: Ionic conductivity 0.231 mS / cm -1 At a current density of 0.5C, the capacity retention rate is 94.7% after 100 cycles.

[0130] Comparative Example 1

[0131] Compared with Example 1, the only difference is that no crosslinking agent is added to the precursor solution, while the other conditions are the same as in Example 1.

[0132] Assembly and testing were performed according to the method in Example 1. The results showed that the in-situ catalytic crosslinking functionalized polyether-based electrolyte had a low ionic conductivity (<0.100 mS / cm) that decreased over time. -1 The lithium-ion transference number is 0.1–0.2, but the stability is poor; the assembled LiFePO4 / Li battery cannot cycle 100 times at a current density of 0.5C. Therefore, compared to Comparative Example 1, the performance of Example 1 is superior, confirming the positive impact of the presence of crosslinking agent A on battery performance.

[0133] Comparative Example 2

[0134] Compared with Example 1, the only difference is that initiator a is missing in the precursor solution, and the missing part is made up by initiator b in equal amount. The precursor solution is also sealed in a glass bottle for easy observation. Other conditions are the same as in Example 1 (polymerization temperature is 70°C, time is 24h).

[0135] In-situ polymerization was performed according to the method in Example 1, such as... Figure 6 As shown, the results indicate that the electrolyte in Comparative Example 2 could not polymerize completely, while the electrolyte in Example 1 could polymerize. This result confirms that the synergy of initiators a and b is key to the induced crosslinking of A into a solid electrolyte.

[0136] Comparative Example 3

[0137] Compared to Example 1, the only difference is that initiator b is missing from the precursor solution, and the missing portion is replenished by an equal amount of initiator a. All other operations and parameters are the same as in Example 1. As a result, the system cannot solidify and remains entirely liquid. Figure 7As shown, the NMR results indicate that formulation A did not undergo polymerization. This result confirms that the synergistic effect of initiators a and b is key to the induced crosslinking of formulation A into a solid electrolyte.

[0138] Comparative Example 4

[0139] Compared to Example 1, the only difference is that initiator a was replaced with other components in equal amounts, and the experimental groups were as follows:

[0140] Group A: The initiator is BF3. After heating, the electrolyte system rapidly releases heat and boils. After the reaction is completed and the system is restored to room temperature, the overall color of the electrolyte system is uneven and the consistency is poor.

[0141] Group B: The initiator is SnI4. After heating, the system slowly solidifies. After the reaction is complete, it returns to room temperature, and the electrolyte system shrinks, producing pores.

[0142] Group C: The initiator is AlCl3. After its addition, the viscosity of the system increases, but it cannot be completely solidified. A small amount of viscous fluid still seeps out, making it difficult to prepare an all-solid electrolyte.

[0143] Therefore, experiments have shown that other Lewis acids that can induce this reaction are ineffective.

Claims

1. A method for preparing a cross-linked functionalized polyether-based all-solid-state electrolyte, characterized in that, The precursor solution containing monomer A, co-initiator, and crosslinking agent is crosslinked and polymerized to obtain the product. The synergistic initiators include initiator a and initiator b of formula B; Formula A Formula B In formula A, X is O; Y is methylene. The initiator b is lithium difluorooxalate borate; The crosslinking agent includes at least one of Formula 4, Formula 5, Formula 6, and Formula 7; Formula 4 Formula 5 Formula 6 Formula 7 In Equations 4, 5, 6, and 7, n1 and n2 are individually 1 to 3; In the precursor solution, the content of initiator a is 20~60 wt.%; The content of the initiator b is 1~5 wt.%; The content of the crosslinking agent is 1~10 wt.%.

2. The preparation method of the cross-linked functionalized polyether-based all-solid-state electrolyte as described in claim 1, characterized in that, In the precursor solution, the content of initiator a is 25~40 wt.%; The content of the initiator b is 1~2 wt.%.

3. The method for preparing the cross-linked functionalized polyether-based all-solid-state electrolyte as described in claim 1, characterized in that, The precursor solution further comprises a modifier, which is a monoepoxide compound; it has the structure of formulas 13 to 20: Formula 13 Formula 14 Formula 15 Formula 16 Formula 17 Formula 18 Formula 19 Formula 20 In Formulas 13 to 20, R1 is a branched and linear alkyl chain with 1 to 10 carbon atoms.

4. The preparation method of the cross-linked functionalized polyether-based all-solid-state electrolyte as described in claim 3, characterized in that, In the precursor solution, the content of the modifier is 1~10 wt.%.

5. The method for preparing the cross-linked functionalized polyether-based all-solid-state electrolyte according to any one of claims 1 to 4, characterized in that, The precursor solution is crosslinked and polymerized on a diaphragm base membrane, and the crosslinked functionalized polyether-based all-solid electrolyte is coated on the diaphragm base membrane.

6. The method for preparing the cross-linked functionalized polyether-based all-solid-state electrolyte as described in claim 5, characterized in that, The diaphragm base membrane includes at least one of glass fiber, cellulose, cellulosic, polytetrafluoroethylene, polyester fiber, polypropylene, and polyethylene.

7. The method for preparing the cross-linked functionalized polyether-based all-solid-state electrolyte as described in claim 5, characterized in that, The cross-linking polymerization temperature is 40~90℃.

8. The method for preparing the cross-linked functionalized polyether-based all-solid-state electrolyte as described in claim 7, characterized in that, The cross-linking polymerization temperature is 60~80℃.

9. The method for preparing the cross-linked functionalized polyether-based all-solid-state electrolyte as described in claim 5, characterized in that, The cross-linking polymerization time is 20h~48h.

10. A cross-linked functionalized polyether-based all-solid-state electrolyte prepared by the preparation method according to any one of claims 1 to 9.

11. A solid-state battery, comprising a cell composed of a positive electrode, a barrier layer, and a negative electrode, characterized in that, The barrier layer is a cross-linked functionalized polyether-based all-solid electrolyte prepared by the preparation method according to any one of claims 1 to 9.

12. The all-solid-state battery as described in claim 11, characterized in that, The all-solid-state battery mentioned is an all-solid-state lithium-ion battery.

13. The all-solid-state battery as described in claim 11, characterized in that, The positive electrode includes a current collector and a positive electrode material composited on its surface; the positive electrode material includes a positive electrode active material, a binder, and a conductive agent; The negative electrode is a lithium metal negative electrode; or a coated negative electrode; the lithium metal negative electrode is a lithium foil or a negative electrode carrying lithium metal; the coated negative electrode is a negative electrode containing at least one of carbon material, silicon material, and carbon-silicon composite material that can support active material.

14. The in-situ preparation method of the all-solid-state battery according to any one of claims 10 to 13, characterized in that, The positive electrode, separator base film, and negative electrode are sequentially composited and then filled into the battery case. Subsequently, the precursor solution is injected into the battery case using the preparation method described in any one of claims 1 to 9. After encapsulation, in-situ crosslinking polymerization is performed to obtain the all-solid-state battery.

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