Multi-component in-situ polymerized gel solid electrolyte as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of lithium ion battery solid electrolytes, and discloses a multi-component in-situ polymerized gel solid electrolyte and a preparation method and application thereof, the gel solid electrolyte is prepared by adding an amide cross-linking agent and a polymeric monomer into a basic electrolyte to obtain a precursor solution, then adding an initiator, and carrying out in-situ polymerization at 45-70 DEG C for 6-12 hours, the amide cross-linking agent is one or more of N, N '-methylene bisacrylamide, polyacrylamide, poly (2-acrylamide-2-methyl-1-propanesulfonic acid), polymethacrylamide, polyethylene glycol diacrylamide, polyether amide or adipamide. The first coulombic efficiency of an LCOLi button cell assembled by the multi-component in-situ polymerization solid-state gel electrolyte reaches 94.81%, the capacity retention rate after 500 cycles at 3-4.6 V still reaches 80% or above, and the LCOLi button cell can safely pass a needle test and can be applied to the field of solid-state electrolytes.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium ion battery solid electrolytes, and more specifically, relates to a multi-component in-situ polymerized gel solid electrolyte and a preparation method and application thereof. Background Art

[0002] With the rapid increase in the number of new energy vehicles, power batteries are prone to thermal runaway under high temperature, overcharging, collision and other conditions, leading to fire or explosion, which seriously threatens people's lives and property. The mandatory national standard "Safety Requirements for Power Batteries for Electric Vehicles" (GB38031-2025) formulated by the Ministry of Industry and Information Technology was recently released, which puts forward stricter requirements on the safety of electric vehicle power batteries, "no fire, no explosion", and zero tolerance for battery explosion. Compared with liquid electrolyte batteries, solid-state batteries are more likely to achieve this standard. They can not only achieve high safety but also high energy density. However, the process involves processes such as ball milling and calcination. Although people have continuously simplified and optimized the production process of all-solid-state electrolytes in recent years, such as CN119650876A discloses a preparation method for all-solid-state batteries, which replaces the ball milling process with the acoustic resonance method, improves the pulverization efficiency and shortens the time, there are still problems in expanding production. It is difficult to ensure uniform pulverization and mixing of particles in large-scale production, such as kilogram-level production, and the inherent interface problems of all-solid-state batteries still restrict their large-scale production. Gel solid electrolytes have simple processes, low costs, and take into account the advantages of solid-state batteries and liquid batteries. They are the solid electrolyte materials with the greatest potential for large-scale industrialization. However, how to balance safety and electrochemical performance has always been a problem. For example, CN119764548A discloses a gel solid electrolyte. Although the use of phosphazene flame retardant additives can achieve self-extinguishing, it is not conducive to long-term stable circulation, and the addition amount is large and the cost is high. Summary of the Invention

[0003] In order to solve the above-mentioned deficiencies and shortcomings of the prior art, the object of the present invention is to provide a multi-component in-situ polymerized gel solid electrolyte.

[0004] Another object of the present invention is to provide a method for preparing the aforementioned multi-component in-situ polymerized gel solid electrolyte. This method uses in-situ thermal polymerization to form the gel solid electrolyte, introducing a variety of functional molecules with polymerization activity and containing specialized functional groups to coordinate contact issues at the polymer interface and optimize interfacial properties, while simultaneously improving electrochemical performance and safety. This method enables soft-pack batteries to safely pass a needle penetration test at a full charge of 4.5V.

[0005] Another object of the present invention is to provide the use of the multi-component in-situ polymerized gel solid electrolyte in lithium batteries. This gel solid electrolyte, which balances safety and electrochemical performance, is an in-situ polymerized solid electrolyte. Its industrialization has important practical value in promoting the further development of lithium-ion battery technology.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A multi-component in-situ polymerized gel solid electrolyte is prepared by adding an amide crosslinking agent and a polymerizable monomer to a basic electrolyte to obtain a precursor solution, then adding an initiator and in-situ polymerizing at 45-70°C for 6-12 hours. The amide crosslinking agent is one or more of N,N'-methylenebisacrylamide (MBA), polyacrylamide (PAAm), poly(2-acrylamide-2-methyl-1-propanesulfonic acid), polymethacrylamide, polyethylene glycol diacrylamide, polyetheramide (PEA) or adipic acid amide.

[0008] Preferably, the polymerizable monomer is one or more of nitrile compounds, phosphate esters, polyfluoroacrylates, multi-branched acrylates or vinyl siloxanes.

[0009] More preferably, the nitrile compound is one or more of acrylonitrile, methacrylonitrile, 2-trifluoromethylacrylonitrile, methyl acrylate 3-(3-cyanophenyl), 3-cyclopentylacrylonitrile, 2,4-hexadienenitrile, 3,3-dichloroacrylonitrile, and 3-(dimethylamino)-3-ethoxyacrylonitrile;

[0010] The phosphate ester is one or more of dimethyl vinyl phosphate, diethyl vinyl phosphate, di[2-(methacryloyloxy)ethyl]phosphate, 10-(2-methacryloyloxy)monodecyl phosphate, and 2-methacryloyloxyethylphosphocholine;

[0011] The polyfluoroacrylate is one or more of 2,2,3,3,4,4,4-heptafluorobutyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, nonacosanol acrylate, perfluoroalkylethyl methacrylate, tritriacontadecanol acrylate, 2-perfluorododecylethyl methacrylate, and 2-[ethyl[(tridecafluorohexyl)sulfonyl]amino]ethyl-2-acrylate;

[0012] The multi-branched acrylate is one or more of tetraethylene glycol diacrylate, ethoxylated trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, cyclohexanedimethanol dimethacrylate, neopentyl glycol dimethacrylate, cyclohexanedimethanol-1,4-diacrylate, and ditrimethylolpropane tetraacrylate;

[0013] The vinyl siloxane is one or more of vinyl trimethoxysiloxane, vinyl tris(dimethylsiloxy)silane, vinyl pentamethyl disiloxane, vinyl polydimethylsiloxane, hexavinyl disiloxane, divinyl tetramethyl disiloxane, divinyl tetraphenyl disiloxane, 1,5-divinyl-hexamethyltrisiloxane, pentamethylpentavinylcyclopentasiloxane, tris(trimethylsilyl)oxyvinylsilane, methacryloxypropyl tris(vinyldimethylsiloxy)silane, and 3-[[dimethyl(vinyl)silyl]oxy]-1,1,5,5-tetramethyl-3-phenyl-1,5-divinyltrisiloxane.

[0014] Preferably, the mass ratio of the nitrile compound, the phosphate ester, the polyfluoroacrylate, the multi-branched acrylate and the vinyl siloxane is 1:(0-4):(0-4):(0-2):(0-1).

[0015] Preferably, the basic electrolyte is prepared by adding fluoroethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7 to 0.8-1.2 mol / L LiPF6 and stirring thoroughly.

[0016] Preferably, the amide cross-linking agent is 2-4 wt% of the base electrolyte, the polymerizable monomer is 1-3 wt% of the base electrolyte; and the initiator is 0.2-1 wt% of the precursor solution.

[0017] Preferably, the initiator is azobisisobutyronitrile (AIBN) or 2,2′-azobis(2,4-dimethylvaleronitrile) (AVBN).

[0018] The method for preparing the multi-component in-situ polymerized gel solid electrolyte comprises the following specific steps:

[0019] S1. Adding an amide crosslinker and a polymerizable monomer to the base electrolyte to obtain a precursor solution;

[0020] S2. Add an initiator to the precursor solution and carry out in situ polymerization at 45-70°C for 6-12 hours to prepare a multi-component in situ polymerized gel solid electrolyte.

[0021] Application of the multi-component in-situ polymerized gel solid electrolyte in lithium-ion batteries.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention uses in-situ polymerization to form a gel solid electrolyte inside a lithium-ion battery. By adding a variety of polymerization monomers with polymerization activity and regulating the types and proportions of the polymerization monomers, the gel solid electrolyte has better interface contact performance with the electrode material, thereby improving the rate performance and capacity retention of the electrolyte. The 1Ah lithium cobalt oxide graphite soft-pack battery safely passed the needle penetration test at a full charge of 4.5V, thereby improving the electrochemical performance and safety performance of the gel solid electrolyte.

[0024] 2. The LCO||Li battery assembled with the multi-component in-situ polymerized solid gel electrolyte of the present invention achieved an initial coulombic efficiency of 94.81%, and the capacity retention rate reached over 80% after 500 cycles at 1C (1C = 200 mAh / g) in the voltage range of 3-4.6V. This superior cycling performance is superior to that of batteries using only gel solid electrolytes, and its rate performance is comparable to that of liquid batteries. This gel solid electrolyte has excellent guiding significance for promoting the popularization and application of in-situ polymerized gel solid electrolytes in the field of solid electrolytes.

[0025] 3. The in-situ polymerized gel solid electrolyte of the present invention has better safety performance than conventional liquid electrolytes. On the basis of existing cross-linking agents, by introducing multiple polymer monomer components, a 1Ah soft-pack battery can pass the needle penetration test under the condition of full charge of 4.5V, achieving high safety. The performance in the field of high-voltage fast charging has achieved preliminary results. Under the conditions of changing the basic electrolyte and other related components, it is expected to conduct universal verification in other fields such as extreme temperature and wide temperature range.

[0026] 4. The multi-component in-situ polymerized gel solid electrolyte of the present invention is compounded with a variety of functional molecules, has simple process operation, low cost, short time consumption, and is easy to be put into soft packs for expansion of production, providing important practical value for realizing the diversified application of lithium-ion solid electrolytes. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Comparison of the electrochemical cycling performance of LCO||Li button cells assembled with the electrolytes of Examples 1-2 and Comparative Examples 1-2 at 1C at 3-4.6V;

[0028] Figure 2 Comparison of the electrochemical cycling performance of LCO||Li button cells assembled with the electrolytes of Examples 3-4 and Comparative Examples 1-2 at 1C at 3-4.6V;

[0029] Figure 3 Comparison of the electrochemical cycling performance of LCO||Li button cells assembled with the electrolytes of Examples 5-6 and Comparative Examples 1-2 at 1C at 3-4.6V;

[0030] Figure 4Comparison of electrochemical cycling performance of LCO||Li button cells assembled with the electrolytes of Examples 7-8 and Comparative Examples 1-2 at 1C at 3-4.6V;

[0031] Figure 5 Comparison of electrochemical cycling performance of LCO||Li button cells assembled with the electrolytes of Examples 9-10 and Comparative Examples 1-2 at 1C at 3-4.6V;

[0032] Figure 6 Comparison of the rate performance of LCO||Li button cells assembled with the electrolytes of Examples 9-10 and Comparative Examples 1-2 at 3-4.6V;

[0033] Figure 7 Comparison of 1Ah LCO||graphite soft-pack batteries assembled with the electrolytes of Example 9 and Comparative Examples 1-2 before and after the needle penetration test at 4.5V under full charge;

[0034] Figure 8 Voltage and temperature curves of a 1Ah LCO||graphite soft-pack battery assembled with the electrolyte of Example 9 during a needle penetration test at a full charge of 4.5V;

[0035] Figure 9 These are SEM photos of the lithium cobalt oxide positive electrodes of Examples 9-10 and Comparative Examples 1-2 after cycling. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0037] Example 1

[0038] 1. To the base electrolyte (FEC and EMC in a volume ratio of 3:7 were added to 1 mol / L LiPF6 and stirred thoroughly), 3 wt% of N,N'-methylenebisacrylamide (MBA) and 1 wt% of a polymerization monomer (acrylonitrile and 2,2,3,3,4,4,4-heptafluorobutyl acrylate in a mass ratio of 1:4) were added to obtain a precursor solution.

[0039] 2. 0.5 wt% of AIBN initiator was added to the precursor solution and in-situ polymerized at 60° C. for 6 h to prepare a multi-component in-situ polymerized gel solid electrolyte.

[0040] In order to test the performance of the multi-component in-situ polymerized gel solid electrolyte in the battery, lithium cobalt oxide||lithium metal (LCO||Li) button cells were assembled using the multi-component in-situ polymerized gel solid electrolyte. 0.5wt% of the initiator AIBN was added to the precursor solution and mixed thoroughly before being injected into the LCO||Li button cell. The solution was in-situ polymerized at 60°C for 6h to obtain LCO|multi-component in-situ polymerized gel solid electrolyte|Li, which is a battery with an in-situ gel solid electrolyte.

[0041] Example 2

[0042] The difference from Example 1 is that in step 1, 3 wt% of a polymerization monomer (acrylonitrile and 2,2,3,3,4,4,4-heptafluorobutyl acrylate in a mass ratio of 1:4) is added to the basic electrolyte.

[0043] Example 3

[0044] The difference from Example 1 is that in step 1, 1 wt% of a polymerization monomer (acrylonitrile and vinyl dimethyl phosphate in a mass ratio of 1:4) is added to the basic electrolyte.

[0045] Example 4

[0046] The difference from Example 3 is that in step 1, 3 wt% of the polymerization monomer (acrylonitrile and vinyl dimethyl phosphate in a mass ratio of 1:4) is added to the basic electrolyte.

[0047] Example 5

[0048] The difference from Example 1 is that in step 1, 1 wt% of polymerization monomers (acrylonitrile, 2,2,3,3,4,4,4-heptafluorobutyl acrylate and vinyl dimethyl phosphate in a mass ratio of 1:2:2) are added to the basic electrolyte.

[0049] Example 6

[0050] The difference from Example 5 is that in step 1, 3 wt% of polymerization monomers (acrylonitrile, 2,2,3,3,4,4,4-heptafluorobutyl acrylate and vinyl dimethyl phosphate in a mass ratio of 1:2:2) are added to the basic electrolyte.

[0051] Example 7

[0052] The difference from Example 1 is that in step 1, 1 wt% of polymerization monomers (acrylonitrile, 2,2,3,3,4,4,4-heptafluorobutyl acrylate, vinyl dimethyl phosphate and ditrimethylolpropane tetraacrylate in a mass ratio of 1:4:4:1) are added to the basic electrolyte.

[0053] Example 8

[0054] The difference from Example 7 is that in step 1, 3 wt% of the polymerization monomers (acrylonitrile, 2,2,3,3,4,4,4-heptafluorobutyl acrylate, vinyl dimethyl phosphate and ditrimethylolpropane tetraacrylate in a mass ratio of 1:4:4:1) are added to the basic electrolyte.

[0055] Example 9

[0056] The difference from Example 1 is that in step 1, 1 wt% of the polymerization monomer (acrylonitrile, 2,2,3,3,4,4,4-heptafluorobutyl acrylate, vinyl dimethyl phosphate, ditrimethylolpropane tetraacrylate and vinyl pentamethyldisiloxane in a mass ratio of 1:2:1:1:1) is added to the basic electrolyte.

[0057] Example 10

[0058] The difference from Example 9 is that in step 1, 3 wt% of the polymerization monomers (acrylonitrile, 2,2,3,3,4,4,4-heptafluorobutyl acrylate, vinyl dimethyl phosphate, ditrimethylolpropane tetraacrylate and vinyl pentamethyldisiloxane in a mass ratio of 1:2:1:1:1) are added to the basic electrolyte.

[0059] Comparative Example 1

[0060] The difference from Example 1 is that the basic electrolyte LE, that is, FEC and EMC in a volume ratio of 3:7, is added to 1 mol / L LiPF6 and fully stirred.

[0061] Comparative Example 2

[0062] The difference from Example 1 is that: 3 wt% of N,N'-methylenebisacrylamide is added to the basic electrolyte (FEC and EMC in a volume ratio of 3:7 are added to 1 mol / LLiPF6 and fully stirred), and the solution is fully stirred to obtain a precursor solution; 0.5% of AIBN is added to the precursor solution, and stirring is continued until it is fully mixed, and in situ polymerization is carried out at 60°C for 6 hours to obtain a gel solid electrolyte.

[0063] In order to test the performance of the gel composite solid electrolyte in the battery, a lithium cobalt oxide||lithium (LCO||Li) button cell was assembled using the gel composite electrolyte. 0.5% of the initiator AIBN was added to the precursor solution and mixed thoroughly before being injected into the LCO||Li button cell. The solution was in situ polymerized at 60°C for 6h to obtain LCO|gel composite solid electrolyte|Li, which is a gel composite solid-state battery.

[0064] Figure 1Comparison of electrochemical cycle performance of LCO||Li button cells assembled with electrolytes of Examples 1-2 and Comparative Examples 1-2 at 1C at 3-4.6V. Figure 1 It can be seen that although the initial discharge specific capacity of the LCO||Li button cells assembled in Examples 1-2 is reduced by adding acrylonitrile and 2,2,3,3,4,4,4-heptafluorobutyl acrylate, the capacity retention rate is significantly improved, and the initial discharge specific capacity corresponding to the total amount of polymerized monomers in Example 1 is 1% is higher than that in Example 2 when the total amount is 3%. Figure 2 Comparison of electrochemical cycle performance of LCO||Li button cells assembled with electrolytes of Examples 3-4 and Comparative Examples 1-2 at 1C at 3-4.6V; Figure 2 It can be seen that with the addition of acrylonitrile and dimethyl vinyl phosphate, the initial discharge specific capacity of Example 3 is closer to that of Comparative Examples 1-2, and the capacity retention rate is better than that of Comparative Examples 1-2. Figure 3 Comparison of electrochemical cycle performance of LCO||Li button cells assembled with electrolytes of Examples 5-6 and Comparative Examples 1-2 at 1C at 3-4.6V; Figure 3 It can be seen that when acrylonitrile, 2,2,3,3,4,4,4-heptafluorobutyl acrylate and vinyl dimethyl phosphate are added at the same time, the initial discharge specific capacity of Example 6 is closer to that of the liquid state, and the reduced distribution of the two components of 2,2,3,3,4,4,4-heptafluorobutyl acrylate and vinyl dimethyl phosphate is beneficial to the improvement of the initial discharge specific capacity. At the same time, the capacity retention rate is also improved compared with Comparative Examples 1-2. Figure 4 Comparison of electrochemical cycle performance of LCO||Li button cells assembled with electrolytes of Examples 7-8 and Comparative Examples 1-2 at 1C at 3-4.6V; Figure 4 It can be seen that the capacity retention rate is significantly improved by adding acrylonitrile, 2,2,3,3,4,4,4-heptafluorobutyl acrylate, vinyl dimethyl phosphate and ditrimethylolpropane tetraacrylate at the same time compared with comparative examples 1-2, and the trend in the figure can be clearly judged that the advantages of subsequent cycle examples 7-8 will be more obvious. Figure 5 The electrochemical cycle performance of LCO||Li button cells assembled with the electrolytes of Examples 9-10 and Comparative Examples 1-2 at 1C at 3-4.6V is compared. Figure 5It can be seen that when acrylonitrile, 2,2,3,3,4,4,4-heptafluorobutyl acrylate, vinyl dimethyl phosphate, ditrimethylolpropane tetraacrylate and vinyl pentamethyl disiloxane are added at the same time, the capacity retention rate of comparative examples 1-2 reaches about 80% at about 200 cycles in a long cycle of 500 cycles, while the multi-component in Example 9 can achieve a more stable long cycle and reach a capacity retention rate of 80% at 500 cycles. In Example 10, more multi-component polymerization monomers are added, and the capacity retention rate is better than that of comparative examples 1-2, but its capacity retention rate is lower than that of Example 9. Figures 1 to 5 It can be seen that the cycle performance of LCO||Li under high voltage 1C can be improved by introducing different proportions of polymer monomers with functional side chains. This advantage is mainly reflected in the capacity retention rate of the cycle, and increasing the polymer ratio has a certain effect on the initial discharge specific capacity loss, which is unavoidable for most solid-state batteries; combined with Table 1, the capacity retention rate of Examples 1 to 10 at 1C cycle under 3 to 4.6 V voltage conditions is improved compared with Comparative Examples 1 to 2. Although the initial capacity is reduced, the cycle stability is greatly improved.

[0065] Figure 6 The figure shows the rate performance comparison of LCO||Li button cells assembled with the electrolytes of Examples 9-10 and Comparative Examples 1-2 at 3-4.6V. Figure 6 It can be seen that in the system where only MBA polymerization is introduced, that is, the rate performance of Example 2 does not change much compared with that of Example 1. However, after introducing the polymerization monomer with multifunctional side chains, the rate performance can still be maintained at the same level as the liquid state, or even better. This solves the pain point of most solid-state batteries, namely, the problem of poor rate performance caused by the obstruction of ion diffusion / migration due to poor contact at the solid-liquid interface.

[0066] Figure 7 Comparison of the 1Ah LCO||graphite soft pack battery assembled with the electrolyte of Example 9 and Comparative Examples 1-2 before and after the needle penetration test under the condition of full charge and 4.5V. Figure 7 Comparative Examples 1 and 2 both exhibited combustion and explosion after the needle puncture test, whereas Example 9 achieved flame retardancy by introducing only 1 wt% of the multifunctional polymerized monomer component based on that of Comparative Example 2. Temperature and voltage changes during the needle puncture process in Example 9 indicate that the temperature did not exceed 50°C, and the voltage drop was only approximately 0.2V. This indicates that the introduced multifunctional side chain polymerized monomers coordinate with each other during the in-situ polymerization process, suppressing a series of decomposition reactions caused by the intense heat generated by the short circuit, thereby ensuring safety.

[0067] Figure 8 The voltage and temperature curves of the 1Ah LCO||graphite soft pack battery assembled in Example 9 during the needle penetration test at 4.5V full charge. Figure 8It can be seen that in Comparative Example 1 in which MBA is not introduced and Comparative Example 2 in which MBA is introduced, there are many dispersed luminescent particles on the surface of the LCO electrode in Comparative Example 1, all of which are lithium cobalt oxide active particles. After MBA is introduced in Comparative Example 2, the LCO electrode is covered with a thin film to cover the lithium cobalt oxide active particles, but only MBA is introduced for in-situ polymerization, and the polymer cross-linked network formed is sparse and scattered; Example 9 introduces 1wt% of the multifunctional polymer component, and the polymer cross-linked network formed is dense and thin, while Example 10 introduces 3wt% of the multifunctional polymer monomer component, and the polymer cross-linked network layer formed is thick. This can be directly reflected in the degree of cracking, and the grooves are deep, indicating that a high proportion of polymer monomer components is not conducive to the improvement of electrochemical performance. A thicker in-situ polymer layer may lead to a loss of initial discharge specific capacity and poor rate performance. Figure 9 The SEM photos of the lithium cobalt oxide positive electrodes of Examples 9-10 and Comparative Examples 1-2 after cycling. Figure 9 It can be seen that the introduction of an appropriate proportion of multifunctional polymer components can protect the LCO active particles to a certain extent and reduce the adverse effects of high pressure on the LCO active particles. The components grafted to the gel polymer network on the surface of the LCO active particles form a customizable CEI layer between the LCO and its interface. On the one hand, it can optimize the interfacial contact properties between LCO and the gel polymer network. On the other hand, the formed inorganic-rich CEI layer can effectively protect the LCO active particles. This shows that by rationally adjusting the proportion of multifunctional polymer monomers, the negative effects of increasing the proportion of polymer monomers can be significantly reduced.

[0068] Table 1 First discharge specific capacity, first coulombic efficiency and capacity retention rate of Examples 1 to 10 and Comparative Examples 1 to 2 at 3 to 4.6 V for 1C cycle

[0069]

[0070] Table 1 shows the initial discharge specific capacity, initial coulombic efficiency, and capacity retention of Examples 1-10 and Comparative Examples 1-2 under 3-4.6V voltage conditions for a 1C cycle. As can be seen from Table 1, in Examples 1-10, the initial discharge specific capacity is lower when the proportion of polymerized monomers with functional side chains is increased. However, the improved discharge specific capacity in Examples 6 and 10 may be related to the coordinated ratio of 2,2,3,3,4,4,4-heptafluorobutyl acrylate to vinyl dimethyl phosphate. Furthermore, the initial coulombic efficiency of the Examples is significantly improved compared to Comparative Examples 1-2, indicating that the addition of polymerized monomers with special functional groups can contribute to the formation of the SEI / CEI layer during the initial charge and discharge process.

[0071] The above embodiments are preferred implementations of the present invention, but the implementations of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A multi-component in-situ polymerized gel solid electrolyte, characterized in that: The gel solid electrolyte is prepared by adding an amide crosslinking agent and a polymerization monomer to a basic electrolyte to obtain a precursor solution, then adding an initiator and in-situ polymerization at 45-70° C. for 6-12 hours; the amide crosslinking agent is one or more of N,N'-methylenebisacrylamide, polyacrylamide, poly(2-acrylamide-2-methyl-1-propanesulfonic acid), polymethacrylamide, polyethylene glycol diacrylamide, polyether amide or adipic acid amide.

2. The multi-component in-situ polymerized gel solid electrolyte according to claim 1, characterized in that: The polymerizable monomer is one or more of nitrile compounds, phosphates, polyfluoroacrylates, multi-branched acrylates or vinyl siloxanes.

3. The multi-component in-situ polymerized gel solid electrolyte according to claim 2, characterized in that: The nitrile compound is one or more of acrylonitrile, methacrylonitrile, 2-trifluoromethylacrylonitrile, methyl acrylate 3-(3-cyanophenyl), 3-cyclopentylacrylonitrile, 2,4-hexadienenitrile, 3,3-dichloroacrylonitrile, and 3-(dimethylamino)-3-ethoxyacrylonitrile; The phosphate ester is one or more of dimethyl vinyl phosphate, diethyl vinyl phosphate, di[2-(methacryloyloxy)ethyl]phosphate, 10-(2-methacryloyloxy)monodecyl phosphate, and 2-methacryloyloxyethylphosphocholine; The polyfluoroacrylate is one or more of 2,2,3,3,4,4,4-heptafluorobutyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, nonacosanol acrylate, perfluoroalkylethyl methacrylate, tritriacontadecanol acrylate, 2-perfluorododecylethyl methacrylate, and 2-[ethyl[(tridecafluorohexyl)sulfonyl]amino]ethyl-2-acrylate; The multi-branched acrylate is one or more of tetraethylene glycol diacrylate, ethoxylated trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, cyclohexanedimethanol dimethacrylate, neopentyl glycol dimethacrylate, cyclohexanedimethanol-1,4-diacrylate, and ditrimethylolpropane tetraacrylate; The vinyl siloxane is one or more of vinyl trimethoxysiloxane, vinyl tris(dimethylsiloxy)silane, vinyl pentamethyl disiloxane, vinyl polydimethylsiloxane, hexavinyl disiloxane, divinyl tetramethyl disiloxane, divinyl tetraphenyl disiloxane, 1,5-divinyl-hexamethyltrisiloxane, pentamethylpentavinylcyclopentasiloxane, tris(trimethylsilyl)oxyvinylsilane, methacryloxypropyl tris(vinyldimethylsiloxy)silane, and 3-[[dimethyl(vinyl)silyl]oxy]-1,1,5,5-tetramethyl-3-phenyl-1,5-divinyltrisiloxane.

4. The multi-component in-situ polymerized gel solid electrolyte according to claim 2, characterized in that: The mass ratio of nitrile compound, phosphate, polyfluoroacrylate, multi-branched acrylate and vinyl siloxane is 1:(0-4):(0-4):(0-2):(0-1).

5. The multi-component in-situ polymerized gel solid electrolyte according to claim 1, characterized in that: The basic electrolyte is prepared by adding fluoroethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7 to 0.8-1.2 mol / L LiPF6 and fully stirring.

6. The multi-component in-situ polymerized gel solid electrolyte according to claim 1, characterized in that: The amide cross-linking agent accounts for 2-4 wt% of the basic electrolyte, the polymerizable monomer accounts for 1-3 wt% of the basic electrolyte; and the initiator accounts for 0.2-1 wt% of the precursor solution.

7. The multi-component in-situ polymerized gel solid electrolyte according to claim 1, characterized in that: The initiator is azobisisobutyronitrile or 2,2'-azobis(2,4-dimethylvaleronitrile).

8. The method for preparing a multi-component in-situ polymerized gel solid electrolyte according to any one of claims 1 to 7, characterized in that: The specific steps include: S1. Adding an amide crosslinker and a polymerizable monomer to the base electrolyte to obtain a precursor solution; S2. Add an initiator to the precursor solution and carry out in situ polymerization at 45-70°C for 6-12 hours to prepare a multi-component in situ polymerized gel solid electrolyte.

9. Use of the multi-component in-situ polymerized gel solid electrolyte according to any one of claims 1 to 7 in lithium-ion batteries.

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