A low-pore high-cycle solid-state polar plate, battery, energy storage device

Abstract

This invention proposes a low-porosity, high-cycle solid-state electrode, the coating slurry of which includes a polymerizable composite electrolyte. The polymerizable composite electrolyte comprises a cyclic lactone-based ionic liquid with Formula I, a polymer monomer having at least one reactive active group, electrolyte nanoparticles, and an initiator. The cyclic lactone-based ionic liquid with Formula I has the following structural formula: [Formula omitted for brevity]. Where X is an oxocyclic group, Y... + The ionic liquid has a cationic group; R is any one of substituted or unsubstituted alkane, alkoxy, alkyl ester, unsaturated hydrocarbon, or cyclic hydrocarbon groups, and the substituent is selected from halogens; Z ‑ The ions are selected from one or more of halide ions, phosphate ions, perchlorate ions, sulfonylimide ions, oxalate-borate ions, sulfonate ions, and acetate ions. The low-porosity, high-cycle solidified electrode proposed in this invention improves the electrochemical performance of the electrode while reducing its porosity, thus obtaining a low-porosity, high-cycle solidified electrode.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of battery materials, and particularly relates to a low-pore high-cycle solidified electrode sheet. BACKGROUND

[0002] With the development of the new energy industry, the market demand for the capacity of batteries is also increasing, however, it is difficult to meet the demand for long endurance only by improving and optimizing the materials, and people have to find other ways to further improve the capacity density of the batteries. Among them, since a large amount of solvent is used in the wet coating process of the traditional battery coating roller pressing process, a large number of pores will be formed after drying, and it is difficult to achieve high density after roller pressing due to the limited stress of the substrate roller pressing, which undoubtedly limits the improvement ability of the battery capacity density. Therefore, one solution is to reduce the porosity of the electrode sheet to improve the capacity density of the battery, however, this brings another problem, that is, the low porosity may limit the ion conduction ability in the electrode and cause the heat to be difficult to dissipate. In addition, polyvinylidene fluoride (PVDF) is usually used as an adhesive in the traditional process, which may react with lithium metal during the operation of the battery, further releasing a large amount of heat, thereby seriously affecting the cycle performance and safety ability of the battery. At the same time, PVDF may also absorb too much electrolyte, causing uneven distribution of electrolyte in the battery, thereby further affecting the ion conductivity and overall conductivity of the battery. Under the combined action of low porosity and PVDF, the capacity of the battery has been improved to a certain extent, but the safety performance and cycle performance of the battery are often deteriorated sharply. How to fully utilize the advantages of low porosity and avoid its influence on the cycle and electrochemical performance has become a big difficulty in current research. SUMMARY

[0003] To solve the problems in the prior art, the application provides a low-pore high-cycle solidified electrode sheet, which replaces the slurry solvent with a polymerizable composite electrolyte, and utilizes the compounding action among the lactone-based ionic liquid, polymer monomer and electrolyte nanoparticles in the polymerizable composite electrolyte to optimize the performance of the electrode sheet from three aspects of the preparation of the slurry, the preparation of the electrode sheet and the cycle of the battery, solves the problem of energy density waste caused by high porosity of the traditional electrode sheet, and improves the ion conductivity and overall conductivity of the electrode sheet, thereby obtaining an electrode sheet with low porosity and high cycle performance.

[0004] In a first aspect, the present application provides a low-pore high-cycle solid-state electrode, comprising a current collector and an active material layer disposed on the current collector and comprising a modified material: wherein the synthetic monomer of the modified material comprises a first type of monomer and a second type of monomer; the first type of monomer comprises a cyclic lactone-based ionic liquid having a structure of Formula I, and the second type of monomer comprises a polymer monomer having at least one reactive active group, the polymer monomer having a carbon-carbon unsaturated bond, and the electrode further comprises electrolyte nanoparticles.

[0005] The cyclic lactone-based ionic liquid having a structure of Formula I is

[0006]

[0007] wherein X is an oxacyclic group, Y + is an ionic liquid cation group;

[0008] R is one of a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkyl ester group, a substituted or unsubstituted unsaturated alkyl group, a substituted or unsubstituted cyclic alkyl group, and when substituted, the substituent is selected from halogen;

[0009] Z - is selected from one or more of halide ion, phosphate ion, perchlorate ion, sulfonimide ion, oxalate borate ion, sulfonate ion, acetate ion;

[0010] The reactive active group is selected from any one or a combination of two or more of a vinyl group, an allyl group, an epoxypropyl group, an amine group, and a hydroxyl group.

[0011] As a further solution, the oxacyclic group is selected from one of a cyclic carbonate group, a cyclic sulfate group, a sultone group, a cyclic phosphonate group, and a carboxylate group; the ionic liquid cation group is selected from one of an imidazole-based, a pyridine-based, a quaternary ammonium-based, a quaternary phosphonium-based, a pyrrolidine-based, and a piperidine-based functionalized ionic liquid cation group; and R is selected from one of a C1-C8 substituted or unsubstituted alkyl group, a C1-C8 substituted or unsubstituted alkoxy group, a C1-C8 substituted or unsubstituted alkyl ester group, a C2-C8 substituted or unsubstituted unsaturated alkyl group, and a C3-C8 substituted or unsubstituted cyclic alkyl group, and when substituted, the substituent is selected from halogen.

[0012] As a further solution, the oxacyclic group is selected from a cyclic carbonate group, the ionic liquid cation group is selected from one of a quaternary ammonium-based and an imidazole-based ionic liquid cation group, and R is selected from a C1-C6 substituted or unsubstituted alkyl ester group, and when substituted, the substituent is selected from halogen.

[0013] As some exemplary solutions, the cyclic lactone-based ionic liquid having a structure of Formula I is selected from

[0014]

[0015]

[0016] Any one or several of them.

[0017] As a further solution, the polymer monomer is selected from a chain polymer monomer with unsaturated carbon-carbon bond at the end.

[0018] As a further solution, the chain polymer monomer with unsaturated carbon-carbon bond at the end is selected from a double-end chain polymer monomer with unsaturated carbon-carbon bond at the end. The double-end chain polymer monomer with unsaturated carbon-carbon bond at the end helps to further optimize the cross-linking structure during polymerization, forming a more ordered and stable cross-linking network, thereby improving the bonding strength and electrode chemical ability.

[0019] As a further solution, the electrolyte nanoparticles have a particle size less than 500 nm.

[0020] As a further solution, the material of the electrolyte nanoparticles is selected from any one or several of inorganic ceramic electrolyte, inorganic salt electrolyte, phosphate electrolyte, and sulfate electrolyte.

[0021] As a further solution, the material of the electrolyte nanoparticles is selected from inorganic ceramic electrolyte.

[0022] As a further solution, the polymerizable composite electrolyte further includes a lithium salt.

[0023] As a further solution, the lithium salt is selected from a lithium salt with a decomposition temperature higher than 80℃.

[0024] As a further solution, the active material layer further includes an initiator.

[0025] As a further solution, the initiator is selected from at least one of peroxide, azo compound, and persulfate.

[0026] As a further solution, the mass ratio of the cyclic lactone-based ionic liquid with structure I, the polymer monomer, the electrolyte nanoparticles, and the lithium salt in the polymerizable composite electrolyte is selected from the range of (50-95):(0.1-40):(0.1-20):(5-20).

[0027] As a further solution, the mass fraction of the cyclic lactone-based ionic liquid with structure I in the polymerizable composite electrolyte is selected from 55-85wt%

[0028] As a further solution, the mass ratio of the polymer monomer with at least one reactive group in the polymerizable composite electrolyte is selected from 10-30wt%.

[0029] As a further solution, the mass ratio of the initiator to the total mass of the cyclic lactone-based ionic liquid and the polymer monomer is (0.5-5):100.

[0030] As a further solution, the mass ratio of the polymerizable composite electrolyte in the coating slurry is 10-35wt%.

[0031] As a further solution, the low-porosity high-cycle solid-state electrode sheet further includes active material particles and conductive additives in the coating slurry.

[0032] As a further solution, the type of active material particles is not limited in principle, for example, can be selected from any one of carbon-based materials, silicon-based materials, metal oxides.

[0033] As a further solution, the type of conductive additives is not limited in principle, for example, can be selected from any one or several of conductive carbon black, conductive polymers, graphite, graphene oxide, reduced graphene oxide, carbon nanotubes, conductive carbon fibers, activated carbon, porous carbon materials, copper powder, aluminum powder, conductive silicates, polyaniline, polypyrrole, polyvinylpyrrolidone, nitrogen-doped carbon materials, carbon microspheres.

[0034] As a further solution, the mass ratio of the conductive additives in the coating slurry is 3-15wt%.

[0035] As a further solution, the mass ratio of the active material particles in the coating slurry is 60-85wt%.

[0036] As a further solution, the low-porosity high-cycle solid-state electrode sheet further includes a current collector.

[0037] As a further solution, the material of the current collector is not limited in principle, for example, can be selected from any one of aluminum foil, copper foil, nickel foil, stainless steel.

[0038] As a further solution, the porosity of the low-porosity high-cycle solid-state electrode sheet is 0.5-10%.

[0039] As a further solution, the low-porosity high-cycle solid-state electrode sheet can be any one of a positive electrode sheet and a negative electrode sheet.

[0040] As a further solution, the low-porosity high-cycle solid-state electrode sheet is preferably a positive electrode sheet.

[0041] As a further solution, the areal capacity of the low-porosity high-cycle solid-state electrode sheet is 17-25mg / cm2 .

[0042] In a second aspect, the present application provides a method for synthesizing a low-porosity high-cycle solid-state electrode, comprising the following steps:

[0043] S1.1: uniformly mix the first monomer, the second monomer, the electrolyte nanoparticles, and the lithium salt according to the measurement ratio to obtain a first solution;

[0044] S1.2: uniformly mix the initiator into the first solution according to the measurement ratio to obtain a second solution, then coat and solidify to obtain a low-porosity high-cycle solid-state electrode;

[0045] The active material and the conductive agent are introduced into the low-porosity high-cycle solid-state electrode by one of the following two methods.

[0046] Method 1: The active material and the conductive agent are arranged in an active material layer on the surface of the current collector, the second solution obtained in step S1.2 is coated on the surface of the active material layer, and then solidified to obtain a low-porosity high-cycle solid-state electrode.

[0047] Method 2: The active material and the conductive agent are added to the second solution in step S1.2, then coated on the surface of the current collector, and then solidified to obtain a low-porosity high-cycle solid-state electrode.

[0048] As a further aspect, the specific steps of the method 1 are as follows:

[0049] S2.1: according to the measurement ratio, the active material and the conductive agent are added to the solvent, and uniformly mixed to obtain a current collector provided with an active material layer;

[0050] S2.2: uniformly mix the first monomer, the second monomer, the electrolyte nanoparticles, and the lithium salt according to the measurement ratio to obtain a first solution;

[0051] S2.3: according to the measurement ratio, the initiator is added to the first solution to obtain a second solution, the second solution is coated on the surface of the active material layer on the current collector, and then heat-solidified to obtain a low-porosity high-cycle solid-state electrode.

[0052] As a further aspect, the specific steps of the method 2 are as follows:

[0053] S3.1: uniformly mix the first monomer, the second monomer, the electrolyte nanoparticles, and the lithium salt according to the measurement ratio to obtain a first solution;

[0054] S3.2: according to the measurement ratio, the initiator, the active material, and the conductive agent are added to the first solution to obtain a second solution, the second solution is coated on the surface of the current collector, and then heat-solidified to obtain a low-porosity high-cycle solid-state electrode.

[0055] As a further solution, the preferred synthesis method is method 2.

[0056] As a further solution, the heat curing condition is 70-90℃ in vacuum environment, and the curing time is 10-14h.

[0057] As a further solution, the solvent is not limited in principle, and the skilled person can select the corresponding solvent according to the needs.

[0058] As a further solution, the synthesis method of the first type of monomer comprises the following steps:

[0059] S4.1: heating the first reactant with the structure of X-R-M and the ionic liquid to reflux in the first solvent, cooling, washing, and distilling under reduced pressure to obtain the cyclic lactone-based ionic liquid, wherein X is an oxacyclic group, and M is halogen;

[0060] The ratio of the first reactant to the ionic liquid is 1:1.05-2, preferably 1:1.1-1.5.

[0061] S4.2: stirring the cyclic lactone-based ionic liquid and the alkali metal salt in the second solvent, and washing to obtain the electrolyte additive.

[0062] The mass ratio of the cyclic lactone-based ionic liquid to the alkali metal salt is 1:1.05-2, preferably 1:1.1-1.5.

[0063] As a further solution, the first solvent in step S4.1 is ethyl acetate.

[0064] As a further solution, the ionic liquid in step S4.1 is selected from one of imidazoles, pyridines, quaternary ammoniums, quaternary phosphoniums, pyrrolidines, piperidines, and functionalized ionic liquids.

[0065] As some preferred solutions, the ionic liquid is selected from one of N-methyl imidazole, triethylamine, 4-methyl pyridine, 1-methyl pyrrolidine, N-methyl piperidine, and N,N-diethylmethylamine.

[0066] As a further solution, the temperature for heating to reflux in step S4.1 is 60-90℃.

[0067] As a further solution, the second solvent in step S4.2 is deionized water.

[0068] As a further solution, the alkali metal salt in step S4.2 is selected from one or more of halide ions, phosphate ions, perchlorate ions, sulfonimide ions, oxalate borate ions, sulfonate ions, and acetate ions.

[0069] As a further solution, in the step S4.2, the stirring time is 2-24 h.

[0070] In a third aspect, the present application also provides a battery using the low-porosity high-cycle solidified electrode plate as the electrode plate.

[0071] In a fourth aspect, the present application also provides an energy storage device comprising the battery.

[0072] Compared with the prior art, the present application has at least the following beneficial effects:

[0073] The present application proposes an innovative low-porosity high-cycle solidified electrode plate to improve the capacity density of the battery and optimize the cycle performance of the battery. The present application realizes the preparation of a low-porosity electrode by using a polymerizable composite electrolyte comprising a cyclic lactone-based ionic liquid, a reactive active group polymer monomer, and solid electrolyte nanoparticles. The composite electrolyte forms a crosslinked network during solidification, replaces the traditional PVDF as an adhesive, and at the same time improves the heat dissipation and ion conduction capacity. The introduction of inorganic ceramic electrolyte nanoparticles adjusts the polymer crosslinking density, constructs an ion transport channel, improves the conductivity and ion transference number, and adsorbs impurities in the electrolyte, thereby enhancing the safety performance of the battery. During the cycle of the battery, the cyclic lactone-based ionic liquid undergoes ring-opening polymerization to form a solid electrolyte film, which further improves the ion conductivity and suppresses the side reactions. In combination of these effects, the present application effectively reduces the porosity of the electrode plate, optimizes the electrochemical performance, improves the cycle performance of the battery, and significantly improves the overall performance and service life of the battery. DETAILED DESCRIPTION

[0074] For the convenience of understanding, the present application will be described more fully below, and embodiments of the present application will be given, but the scope of the present application is not limited thereto.

[0075] In a first aspect, the present application also provides a low-porosity high-cycle solidified electrode plate, comprising a current collector and an active material layer disposed on the current collector and comprising a modified material: wherein the synthetic monomer of the modified material comprises a first type of monomer and a second type of monomer; the first type of monomer comprises a cyclic lactone-based ionic liquid having a structure of Formula I, and the second type of monomer comprises a polymer monomer having at least one reactive active group, the polymer monomer having a carbon-carbon unsaturated bond, and the electrode plate further comprises electrolyte nanoparticles, the cyclic lactone-based ionic liquid having a structure of Formula I is

[0076]

[0077] wherein X is an oxygen heterocyclic group, Y + is an ionic liquid cation group;

[0078] R is one of substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkyl ester, substituted or unsubstituted unsaturated alkyl, substituted or unsubstituted cycloalkyl, and when substituted, the substituent is selected from halogen;

[0079] Z - one or more selected from halide ion, phosphate ion, perchlorate ion, sulfonimide ion, oxalate borate ion, sulfonate ion, acetate ion;

[0080] The reactive group is selected from any one or a combination of two or more of vinyl, allyl, epoxy propyl, amine, hydroxyl.

[0081] To further improve the battery capacity density and optimize the battery cycle performance, the present application provides a low-pore high-cycle solidified electrode sheet, which can polymerize the cyclic lactone-based ionic liquid with the structure of formula I, the polymer monomer with at least one reactive group, and the solid electrolyte nanoparticles in the polymerizable composite electrolyte of the electrode sheet, and the mutual matching of the solidification and battery cycle can reduce the porosity of the electrode sheet while optimizing the ionic conductivity and improving the battery cycle capacity.

[0082] Specifically, in the polymerizable composite electrolyte of the low-pore high-cycle solidified electrode sheet, the cyclic lactone-based ionic liquid with the structure of formula I and the polymer monomer with at least one reactive group can first be uniformly dispersed in the active material particles and solutes such as conductive agents in the slurry as a solvent, thereby replacing the solvent in the traditional process and avoiding the problem of excessively high porosity caused by solvent volatilization, thereby obtaining a low-porosity electrode and improving the surface loading of the electrode.

[0083] Subsequently, in the crosslinking and solidification process of the polymer monomer with at least one reactive group, the uniformly dispersed solutes and cyclic lactone-based ionic liquid are uniformly fixed in the crosslinked network. The crosslinked polymer monomer network can act as an adhesive to fix the active material particles and solutes such as conductive agents, and can further improve the heat dissipation capacity of the battery. On the other hand, the crosslinked network helps to build ion transmission channels, thereby improving the ion conductivity of the electrode sheet. The high crosslinking strength of the polymer helps to ensure the effectiveness of the adhesion, but excessively high crosslinking density may have an adverse effect on ion conductivity. Therefore, we further introduce electrolyte nanoparticles into the polymerizable composite electrolyte raw materials. The introduction of electrolyte nanoparticles helps to adjust the polymer crosslinking density while ensuring the adhesion strength, and also cooperates with the polymer crosslinked network to build ion transmission channels, thereby improving the conductivity and ion migration number. In addition, the introduction of electrolyte nanoparticles can also adsorb trace impurities (such as moisture) in the electrolyte, thereby improving the safety and cycle performance of the battery.

[0084] In the process of cycling, the ring-opening polymerization of the lactone in the lactone-based ionic liquid evenly coated on the solute occurs, forming a dense solid-state electrolyte film around the active material particles and the conductive agent particles, thereby further improving the ionic conductivity, inhibiting the side reaction between the active material particles and the electrolyte, and under the joint action of the lactone-based ionic liquid having the structure of formula I, the polymer and the solid-state electrolyte nanoparticles, the polymerizable composite electrolyte provided by the application can effectively reduce the porosity of the electrode sheet, optimize the electrochemical capacity of the electrode sheet and improve the cycling performance of the battery.

[0085] As a further solution, the oxygen heterocyclic group is selected from one of cyclic carbonate, cyclic sulfate, sultone, cyclic phosphonate, carboxylate; the ionic liquid cation group is selected from one of imidazolium, pyridinium, quaternary ammonium, quaternary phosphonium, pyrrolidinium, piperidinium functionalized ionic liquid cation group; the R is selected from one of C1-C8 substituted or unsubstituted alkyl, C1-C8 substituted or unsubstituted alkoxy, C1-C8 substituted or unsubstituted alkyl ester, C2-C8 substituted or unsubstituted unsaturated alkyl, C3-C8 substituted or unsubstituted cyclic alkyl, and the substituent is selected from halogen when substituted.

[0086] As a further solution, the oxygen heterocyclic group is selected from one of cyclic carbonate, cyclic sulfate, sultone, cyclic phosphonate, carboxylate; the ionic liquid cation group is selected from one of imidazolium, pyridinium, quaternary ammonium, quaternary phosphonium, pyrrolidinium, piperidinium functionalized ionic liquid cation group; the R is selected from one of C1-C8 substituted or unsubstituted alkyl, C1-C8 substituted or unsubstituted alkoxy, C1-C8 substituted or unsubstituted alkyl ester, C2-C8 substituted or unsubstituted unsaturated alkyl, C3-C8 substituted or unsubstituted cyclic alkyl, and the substituent is selected from halogen when substituted.

[0087] As some exemplary solutions, the lactone-based ionic liquid having the structure of formula I is selected from

[0088]

[0089] any one or several of the following:

[0090] As a further solution, the polymer monomer is selected from a chain polymer monomer with unsaturated carbon-carbon bond at the end. The chain polymer monomer with unsaturated carbon-carbon bond at the end helps to further optimize the cross-linking network structure, building a higher content of lithium ion channels, thus optimizing the electrode electrochemical capacity.

[0091] As a further solution, the chain polymer monomer with unsaturated carbon-carbon bond at the end is selected from a double-end chain polymer monomer with unsaturated carbon-carbon bond at the end. The double-end chain polymer monomer with unsaturated carbon-carbon bond at the end helps to further optimize the cross-linking structure during polymerization, forming a more ordered and stable cross-linking network, thus improving the bonding strength and electrode electrochemical capacity.

[0092] As a further solution, the electrolyte nanoparticles have a particle size of less than 500 nm.

[0093] As a further solution, the material of the electrolyte nanoparticles is selected from any one or several of inorganic ceramic electrolyte, inorganic salt electrolyte, phosphate electrolyte, and sulfate electrolyte.

[0094] As a further solution, the material of the electrolyte nanoparticles is preferably inorganic ceramic electrolyte, which is selected from any one or several of aluminum fluoride, lithium oxide, aluminum oxide, lithium sulfide, sodium oxide, calcium oxide, zirconium oxide, lithium phosphate, Li 1.3 Al 0.3 Ti 1.7 (PO4)3, Li7La3Zr2O 12 , TiO2, AlO2, SiO2.

[0095] As a further solution, the polymerizable composite electrolyte further includes lithium salt. The addition of lithium salt helps to further promote the construction of ion channels and improve the electrochemical performance of the battery.

[0096] As a further solution, the lithium salt is selected from a lithium salt with a decomposition temperature higher than 80℃.

[0097] As a further solution, the lithium salt is selected from one or several of lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium bis(oxalato)borate, lithium tetrafluoroborate, and lithium hexafluorophosphate.

[0098] As a further solution, the active material layer further includes an initiator.

[0099] As a further solution, the initiator is selected from at least one of peroxide, azo compound, and persulfate.

[0100] As a further solution, the peroxide is selected from at least one of dibenzoyl peroxide, dialkyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide.

[0101] As a further solution, the azo compound is selected from at least one of azobis isobutyronitrile, azobis isohexylnitrile, azobis phenyl nitrile, azobis sodium diacetate.

[0102] As a further solution, the persulfate is selected from at least one of potassium persulfate, ammonium persulfate, sodium persulfate, calcium persulfate.

[0103] As a further solution, the mass ratio of the cyclic lactone-based ionic liquid having the structure of Formula I, the polymer monomer, the electrolyte nanoparticle, and the lithium salt in the polymerizable composite electrolyte is selected from the range of (50-95):(0.1-40):(0.1-20):(5-20).

[0104] As a further solution, the mass percentage of the cyclic lactone-based ionic liquid having the structure of Formula I in the polymerizable composite electrolyte is selected from the range of 55-85wt%.

[0105] As a further solution, the mass percentage of the polymer monomer having at least one reactive group in the polymerizable composite electrolyte is selected from the range of 10-30wt%.

[0106] As a further solution, the ratio of the initiator to the total mass of the cyclic lactone-based ionic liquid and the polymer monomer is selected from the range of (0.5-5):100.

[0107] As a further solution, the mass percentage of the polymerizable composite electrolyte in the coating slurry is selected from the range of 10-35wt%.

[0108] As a further solution, the coating slurry of the low-porosity high-cycle solid-state electrode plate further comprises active material particles and conductive additives.

[0109] As a further solution, the type of active material particles is not limited in principle, and can be selected from any one of carbon-based materials, silicon-based materials, and metal oxides.

[0110] As a further solution, the carbon-based material is selected from any one of graphite, graphene oxide, reduced graphene oxide, carbon nanotubes, carbon fibers, activated carbon, carbon black, foam carbon, carbon microspheres, and porous carbon materials.

[0111] As a further solution, the silicon-based material is selected from any one of silicon, silicon oxide, silicon-carbon composite materials, and porous silicon.

[0112] As a further solution, the metal oxide is selected from any one of cobalt oxide, manganese oxide, nickel oxide, iron oxide, sodium tungstate, zinc oxide, composite metal oxide.

[0113] As a further solution, the composite metal oxide is selected from any one of NCM811, lithium cobaltate, lithium manganate, nickel-manganese oxide, lithium iron phosphate, LiMn 1.5 Ni 0.5 O4.

[0114] As a further solution, the conductive additive species is not limited in principle and can be selected from any one or several of conductive carbon black, conductive polymer, graphite, graphene oxide, reduced graphene oxide, carbon nanotube, conductive carbon fiber, activated carbon, porous carbon material, copper powder, aluminum powder, conductive silicate, polyaniline, polypyrrole, polyvinylpyrrolidone, nitrogen-doped carbon material, carbon microsphere.

[0115] As a further solution, the mass percentage of the conductive additive in the coating slurry is 3-15wt%.

[0116] As a further solution, the mass percentage of the active material particles in the coating slurry is 60-85wt%.

[0117] As a further solution, the low-porosity high-cycle solidified electrode plate has a surface loading of 17-25mg / cm 2 .

[0118] As a further solution, the low-porosity high-cycle solidified electrode plate further comprises a current collector.

[0119] As a further solution, the current collector material is not limited in principle and can be selected from any one of aluminum foil, copper foil, nickel foil, stainless steel.

[0120] As a further solution, the low-porosity high-cycle solidified electrode plate has a porosity of 0.5-10%.

[0121] As a further solution, the low-porosity high-cycle solidified electrode plate can be any one of positive electrode plate and negative electrode plate.

[0122] As a further solution, the low-porosity high-cycle solidified electrode plate is preferably a positive electrode plate. When the prepared low-porosity high-cycle solidified electrode plate is a positive electrode plate, the presence of the second type of monomer helps to replace PVDF as the adhesive to achieve the fixation of the positive active material particles and the solutes such as conductive agent.

[0123] In a second aspect, the present solution provides a synthesis method of a low-porosity high-cycle solidified electrode plate, comprising the following steps:

[0124] S1.1: uniformly mix the first monomer, the second monomer, the electrolyte nanoparticles, and the lithium salt according to the metering ratio to obtain a first solution;

[0125] S1.2: uniformly mix the initiator into the first solution according to the metering ratio to obtain a second solution, then coat and solidify to obtain the low-porosity high-cycle solid-state electrode sheet;

[0126] The active material and the conductive agent are introduced into the low-porosity high-cycle solid-state electrode sheet by one of the following two ways.

[0127] Method 1: The active material and the conductive agent are arranged in an active material layer on the surface of the current collector, the second solution prepared in step S1.2 is coated on the surface of the active material layer, and then solidified to obtain the low-porosity high-cycle solid-state electrode sheet.

[0128] Method 2: The active material and the conductive agent are added to the second solution in step S1.2, then coated on the surface of the current collector, and then solidified to obtain the low-porosity high-cycle solid-state electrode sheet.

[0129] As a further solution, the specific steps of the method 1 are as follows:

[0130] S2.1: according to the metering ratio, the active material and the conductive agent are added to the solvent, mixed uniformly, and then coated on the surface of the current collector to obtain a current collector provided with an active material layer;

[0131] S2.2: uniformly mix the first monomer, the second monomer, the electrolyte nanoparticles, and the lithium salt according to the metering ratio to obtain a first solution;

[0132] S2.3: according to the metering ratio, the initiator is added to the first solution to obtain a second solution, the second solution is coated on the surface of the active material layer on the current collector, and then heat-solidified to obtain the low-porosity high-cycle solid-state electrode sheet.

[0133] As a further solution, the specific steps of the method 2 are as follows:

[0134] S3.1: uniformly mix the first monomer, the second monomer, the electrolyte nanoparticles, and the lithium salt according to the metering ratio to obtain a first solution;

[0135] S3.2: according to the metering ratio, the initiator, the active material, and the conductive agent are added to the first solution to obtain a second solution, the second solution is coated on the surface of the current collector, and then heat-solidified to obtain the low-porosity high-cycle solid-state electrode sheet.

[0136] The two low-pore high-cycle solid-state electrode preparation methods provided in the scheme can obtain low-pore high-cycle solid-state electrode with low porosity. When the low-pore high-cycle solid-state electrode is prepared by method 1, the presence of the cyclic lactone-based ionic liquid and the polymer monomer with the structure of formula I in the modified material helps to synergize the PVDF in the active material layer, further optimizes the bonding ability of the PVDF, and constructs the low-pore high-cycle solid-state electrode. When the low-pore high-cycle solid-state electrode is prepared by method 2, the cyclic lactone-based ionic liquid and the polymer monomer with the structure of formula I can not only act as a solvent to realize the dispersion of the solute, but also replace / synergize the PVDF to play the role of the bonding agent. Especially when the positive electrode is prepared by method 2, the cyclic lactone-based ionic liquid and the polymer monomer with the structure of formula I can effectively realize the fixation of the positive active material and the conductive agent, thereby replacing the PVDF and improving the heat dissipation and ion conduction performance of the electrode.

[0137] As a further scheme, the synthesis method is preferably method 2.

[0138] As a further scheme, the thermal initiation condition is 70-90°C in a vacuum environment for 10-14h.

[0139] As a further scheme, the solvent is not limited in principle, and the skilled person can select the corresponding solvent according to the needs.

[0140] As a further scheme, the synthesis method of the first type of monomer comprises the following steps:

[0141] S4.1: heating and refluxing the first reactant with the structure of X-R-M and the ionic liquid in the first solvent, cooling, washing, and reducing pressure distillation to obtain the cyclic lactone-based ionic liquid, wherein X is an oxacyclic group, and M is halogen;

[0142] The ratio of the first reactant to the ionic liquid is 1:1.05-2, preferably 1:1.1-1.5.

[0143] S4.2: stirring the cyclic lactone-based ionic liquid and the alkali metal salt in the second solvent, and washing to obtain the electrolyte additive.

[0144] The mass ratio of the cyclic lactone-based ionic liquid to the alkali metal salt is 1:1.05-2, preferably 1:1.1-1.5.

[0145] As a further scheme, the first solvent in step S4.1 is ethyl acetate.

[0146] As a further scheme, the ionic liquid in step S4.1 is selected from one of imidazoles, pyridines, quaternary ammoniums, quaternary phosphoniums, pyrrolidines, piperidines, and functionalized ionic liquids.

[0147] As some preferred solutions, the ionic liquid is selected from the group consisting of N-methyl imidazole, triethylamine, 4-methyl pyridine, 1-methyl pyrrolidine, N-methyl piperidine, N,N-diethyl methylamine.

[0148] As further solutions, the temperature of heating reflux in step S4.1 is 60-90℃, for example, 60℃, 62℃, 64℃, 66℃, 68℃, 70℃, 72℃, 74℃, 76℃, 78℃, 80℃, 82℃, 84℃, 86℃, 88℃, 90℃, and the reflux time is 24-72h, for example, 24h, 28h, 32h, 36h, 40h, 44h, 48h, 52h, 56h, 60h, 64h, 68h, 72h. In the reaction of step S4.1, the higher the temperature of heating reflux, the longer the time, and the higher the yield of cyclic lactone ionic liquid, but at the same time, more side reactions occur. When the reflux temperature of 60-90℃ and the reflux time of 24-72h are selected, the yield can be effectively guaranteed while reducing the occurrence of side reactions.

[0149] As further solutions, in step S4.2, the second solvent is deionized water.

[0150] As further solutions, in step S4.2, the alkali metal salt is selected from one or more of halide ion, phosphate ion, perchlorate ion, sulfonimide ion, oxalate borate ion, sulfonate ion, acetate ion.

[0151] As further solutions, in step S4.2, the stirring time is 2-24h, for example, 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h.

[0152] In a third aspect, the present solutions also provide a battery using the low-pore high-cycle solid-state electrode sheet as an electrode sheet.

[0153] In a fourth aspect, the present solutions also provide an energy storage device including the battery. The energy storage device refers to a modular device combined by a plurality of batteries, used for storing and releasing electrical energy.

[0154] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, and do not represent all possible embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0155] The chemical raw materials involved in the following examples and comparative examples are all prior art and are all obtained by commercial purchase. The experimental devices, testing devices and the like involved in the following examples and comparative examples are all conventional devices in the art, without special requirements and limitations.

[0156] Example 1

[0157] Lactone-based ionic liquid I-3 Preparation

[0158] First, 20 g of hydroxymethyl dioxolone (CAS No.: 931-40-8), 18 g of chloroacetic acid, and 50 g of chloroform were added to a reactor, stirred at 85°C under reflux for 5 h, cooled to room temperature after stirring, washed with 50 mL of deionized water three times, and distilled under reduced pressure to obtain a halogenated lactone after distillation under reduced pressure;

[0159] 20 g of halogenated lactone, 30 g of triethylamine, and 40 g of ethyl acetate were added to a reactor, stirred at 85°C under reflux for 24 h, cooled to room temperature after stirring, washed with 40 mL of ethyl acetate three times, and distilled under reduced pressure to obtain a lactone-based ionic liquid after distillation under reduced pressure;

[0160] Subsequently, 20 g of lactone-based ionic liquid, 20 g of LiTFSI were dissolved in 30 mL of deionized water, stirred at room temperature for 2 h, washed with 50 mL of deionized water three times, and a lactone-based ionic liquid I-3 was obtained.

[0161] Preparation of positive electrode sheet:

[0162] 2.4 g of lactone-based ionic liquid I-3, 0.6 g of diethylene glycol diacrylate, 0.15 g of Li 1.3 Al 0.3 Ti 1.7 (PO4)3(LATP), and 0.3 g of lithium bis(trifluoromethylsulfonyl)imide were uniformly mixed to obtain a first solution;

[0163] 0.012 g of aluminum fluoride, 0.003 g of azobisisobutyronitrile, 6.5 g of LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811), and 0.5 g of conductive carbon black (Super P) were added to the first solution, uniformly dispersed, and a second solution which can be used as a positive electrode slurry was obtained. The positive electrode slurry was uniformly coated on the surface of an aluminum foil, the coating thickness was 200 μm, vacuum heating was performed at 80°C for 12 h, and the lactone-based ionic liquid monomer and the polymer monomer in the cured electrode sheet were cured to obtain a low-pore high-cycle solid-state electrode sheet.

[0164] Preparation of battery

[0165] A 25 pm-thick PP separator was used, the negative electrode was 0.6 mm-thick lithium metal, and an electrolyte (1 mol / L LiPF6EC:DMC:EMC = 1:1:1) was added. In this electrolyte formulation, EC (ethylene carbonate), DMC (dimethyl carbonate), and EMC (ethyl methyl carbonate) were mixed in a volume ratio of 1:1:1. An NCM-lithium metal button cell was assembled.

[0166] Example 2

[0167] The synthesis method and preparation steps were the same as in Example 1, except that the amount of cyclic lactone-based ionic liquid I-3 added was 2.1 g.

[0168] Example 3

[0169] The synthesis method and preparation steps were the same as in Example 1, except that 0.3 g of diethylene glycol diacrylate was added.

[0170] Example 4

[0171] The synthesis method and preparation steps were the same as in Example 1, except that 0.15 g of Li 10 GeP2S 12 (LGPS) was used instead of LATP.

[0172] Example 5

[0173] Preparation of cyclic lactone-based ionic liquid I-1

[0174] First, 20 g of 4-(chloromethyl)-1,3-dioxolane-2-one (CAS No.: 2463-45-8), 15 g of N-methylimidazole, and 20 g of ethyl acetate were added to a reactor, and reflux stirring was performed at 85°C for 24 h. After stirring, the temperature was cooled to room temperature, and the mixture was washed three times with 30 mL of ethyl acetate. After distillation under reduced pressure, the cyclic lactone-based ionic liquid was obtained. Subsequently, 20 g of the cyclic lactone-based ionic liquid obtained in step (1) and 20 g of LiTFSI were dissolved in 30 mL of deionized water, and stirring was performed at room temperature for 2 h. The mixture was then washed three times with 50 mL of deionized water to obtain the cyclic lactone-based ionic liquid after ion exchange, which is the electrolyte additive.

[0175] The positive electrode sheet preparation method and steps were the same as in Example 1, except that the cyclic lactone-based ionic liquid I-1 was used instead of the cyclic lactone-based ionic liquid I-3.

[0176] Example 6

[0177] Preparation of cyclic lactone-based ionic liquid I-6

[0178] ​​First, 20 g of 1,2-oxaphospholane-4-methanol-2-methoxy-2-oxide (CAS No.: 633278-49-6), 18 g of bromopropionic acid, and 50 g of chloroform were added to a reactor, stirred at 85°C under reflux for 5 h, cooled to room temperature after stirring, distilled under reduced pressure, washed with 50 mL of deionized water three times, and distilled under reduced pressure to obtain a halogenated lactone;

[0179] Subsequently, 20 g of the halogenated lactone, 30 g of N-methylpiperidine, and 40 g of ethyl acetate were added to a reactor, stirred at 85°C under reflux for 24 h, cooled to room temperature after stirring, washed with 40 mL of ethyl acetate three times, and distilled under reduced pressure to obtain a lactone-based ionic liquid;

[0180] Finally, 20 g of the lactone-based ionic liquid obtained in step (1) and 20 g of LiClO4 were dissolved in 30 mL of deionized water, stirred at room temperature for 2 h, washed with 50 mL of deionized water three times, and the electrolyte additive was obtained.

[0181] The positive electrode tab preparation method and steps were the same as in Example 1, except that the lactone-based ionic liquid I-6 was used to replace the lactone-based ionic liquid I-3.

[0182] Comparative Example 1

[0183] 0.3 g of PVDF was mixed with 2.7 g of NMP to obtain a positive electrode slurry, and the slurry was uniformly coated on the surface of an aluminum foil and vacuum heated at 80°C for 12 h to obtain an electrode tab.

[0184] A 25 μm thick PP separator was used, the negative electrode was 0.6 mm thick lithium metal, and an electrolyte (1 mol / L LiPF6 EC:DMC:EMC=1:1:1) was added. In this electrolyte formulation, EC (ethylene carbonate), DMC (dimethyl carbonate), and EMC (methyl ethyl carbonate) were mixed in a volume ratio of 1:1:1 to assemble an NCM-lithium metal button cell.

[0185] Comparative Example 2

[0186] The synthesis method and preparation steps were the same as in Example 1, except that diethylene glycol diacrylate was not added.

[0187] Comparative Example 3

[0188] The synthesis method and preparation steps were the same as in Example 1, except that the lactone-based ionic liquid I-3 was not added.

[0189] Comparative Example 4

[0190] The synthesis method and preparation steps were the same as in Example 1, except that LATP was not added.

[0191] Comparative Example 5

[0192] The synthesis method and preparation steps are the same as Example 1, except that the vinyl imidazole bis-trifluoromethanesulfonylimide salt is used instead of the cyclic lactone-based ionic liquid I-3.

[0193] Comparative Example 6

[0194] The synthesis method and preparation steps are the same as Example 1, except that the amine-containing piperidine bis-trifluoromethanesulfonylimide salt is used instead of the cyclic lactone-based ionic liquid I-3.

[0195] Specific parameters of Examples 1-6 and Comparative Examples 1-6 are shown in Table 1.

[0196] Performance test

[0197] Cycle performance test

[0198] The battery long cycle charge-discharge test was carried out at 0.5C. The voltage range was 2.5-4.3V.

[0199] Peeling force test

[0200] The positive electrode sheet was cut into 400m*15mm size using the FHSD-LX30 universal electronic tensile testing machine, and the 180℃ peeling experiment was carried out.

[0201] First coulombic efficiency = (first discharge capacity / first charge capacity)*100%

[0202] Secondary discharge specific capacity = first discharge capacity / mass of active sulfur

[0203] 200 cycle capacity retention rate = (200th discharge capacity / first discharge capacity)*100%

[0204] The test results are shown in Table 2.

[0205] Table 1

[0206]

[0207]

[0208] Table 2

[0209]

[0210] Compared with Comparative Examples 1-6, Examples 1-6 exhibit lower porosity, and while ensuring porosity, exhibit better first efficiency and first cycle discharge specific capacity, and better cycle capacity retention rate, indicating that the addition of the polymerizable composite electrolyte can effectively reduce the porosity of the electrode sheet, optimize the first efficiency and the first cycle discharge specific capacity, and improve the cycle performance of the battery.

[0211] From Example 1, it can be observed that when no polymerizable composite electrolyte is added, the surface loading and porosity of Comparative Example 1 are obviously worse than those of Example 1, and its electrochemical performance and cycle capacity are also weaker than those of Example 1, which again shows that the addition of the modified material can effectively reduce the porosity of the pole piece and optimize the electrochemical performance.

[0212] From Example 1, it can be observed that in order to sufficiently improve the surface loading, reduce the porosity, and optimize the electrochemical performance, the cyclic lactone-based ionic liquid, the polymer monomer, and the inorganic ceramic electrolyte nanoparticles are all indispensable, which may be because in order to optimize the electrochemical capacity of the pole piece while ensuring low porosity of the pole piece, the cooperation of the three needs to be fully played. In the un-solidified slurry stage, the cyclic lactone-based ionic liquid with the structure of Formula I and the polymer monomer with at least one reactive active group can be used as a solvent to uniformly disperse the active material and the conductive agent, avoiding the pore problem caused by the volatilization of the traditional solvent, thereby obtaining a dense and low-porosity electrode and improving the surface loading. In the solidification process, the solute and the ionic liquid are fixed in the cross-linked network, replacing the traditional PVDF, enhancing the battery heat dissipation capacity, and constructing a lithium ion transmission channel, improving the ion conductivity. In addition, the introduction of the inorganic ceramic electrolyte nanoparticles helps to adjust the cross-linking density, construct the ion transmission channel, improve the conductivity and ion transference number, and at the same time, absorb impurities and improve the safety performance. Finally, the cyclic lactone-based ionic liquid undergoes ring-opening polymerization in the cycle process to form a solid-state electrolyte film, enhancing the ion conductivity and inhibiting the side reaction. In summary, the polymerizable composite electrolyte of the present application effectively reduces the porosity of the pole piece, optimizes the electrochemical performance, and improves the cycle performance of the battery.

[0213] It can be observed from Example 1 and Comparative Examples 5-6 that when the conventional ionic liquid is used to replace the cyclic lactone-based ionic liquid with the structure of Formula I proposed in the present application, the performance of Comparative Examples 5-6 is lower than that of Example 1, which may be because the ionic liquid used in Comparative Examples 5-6 has a poor cooperation effect with the polymer monomer with at least one reactive active group and the inorganic ceramic electrolyte nanoparticles, and it is difficult to fully play the compounding effect of the three, so the overall performance of Comparative Examples 5-6 is lower than that of Example 1.

[0214] It can be observed from Examples 1-2 that Example 1 exhibits better initial efficiency and cycle capacity retention rate than Example 2, which may be because compared with Example 2, the content of the cyclic lactone-based ionic liquid I-3 in Example 1 can form a more stable CEI film, thereby optimizing the performance of Example 1. It can also be observed in Examples 1 and 3 that Example 1 has a stronger bonding capacity than Example 3, which may be because the diethylene glycol diacrylate in Example 1 can cooperate with the cyclic lactone-based ionic liquid I-3 to construct a three-dimensional network structure with more uniform cross-linking, thereby enhancing the bonding capacity.

[0215] The effect of inorganic solid-state electrolyte on its performance is discussed in Examples 1 and 4, it can be observed that, on the basis of similar surface load, Example 1 has better electrochemical capacity compared to Example 4, which may be because, compared to LGPS, when inorganic ceramic electrolyte nanoparticles are used, it helps to further match the cyclic lactone-based ionic liquid I-3 and diethylene glycol diacrylate to build a better ion transport channel, thereby optimizing the electrochemical performance of Example 1.

[0216] It can be observed in Examples 1, 5 and 6 that Examples 1 and 5 exhibit stronger peel strength and better initial efficiency, first-cycle specific capacity and cycle capacity retention than Example 6, although the porosity in Example 6 is slightly better than that in Examples 1 and 5, the overall performance of Examples 1 and 5 is still better than that of Example 6, which may be because the ionic liquid cationic groups selected from quaternary ammonium and imidazole in Examples 1 and 5 can on the one hand combine with the polymer monomer dispersion solute, thereby building a more uniform and stable crosslinked network, thereby improving the adhesion and ion conductivity of Examples 1 and 5, on the other hand, the presence of quaternary ammonium and imidazole ionic liquid cationic groups may also be able to build a more stable CEI film during the recycling process, thereby protecting the active material particles during the recycling process, thereby improving the cycle performance of Examples 1 and 5.

[0217] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not contradict each other, they should be considered within the scope of the present disclosure. Although the embodiments of the present disclosure have been shown and described above, it should be understood that the above-described embodiments are exemplary and should not be construed as limiting the present disclosure, and those skilled in the art can modify, replace, substitute and deform the above-described embodiments within the scope of the present disclosure. In addition, those skilled in the art can combine and combine the features of different embodiments or examples described in the present disclosure and different embodiments or examples.

Claims

1. A low-porosity high-cycle solid-state electrode, characterized by, The application relates to a low-pore high-cycle solid-state electrode sheet, which comprises a current collector and an active material layer arranged on the current collector and comprising a polymerizable composite electrolyte, wherein the polymerizable composite electrolyte comprises a first type of monomer, a second type of monomer and electrolyte nanoparticles; the first type of monomer comprises a cyclic lactone-based ionic liquid with the structure of formula I; the second type of monomer comprises a polymer monomer with at least one reactive active group, and the polymer monomer has a carbon-carbon unsaturated bond. The cyclic lactone-based ionic liquid with the structure of formula I is Formula I, wherein X is an oxacyclic group selected from one of a cyclic carbonate group, a cyclic sulfate group, a sultone group, a cyclic phosphonate group, a carboxylate group, Y + is an ionic liquid cation group; R is one of substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted alkyl ester, substituted or unsubstituted unsaturated alkyl, substituted or unsubstituted cyclic alkyl, and the substituent is selected from halogen when substituted. Z - one or more selected from the group consisting of halide ions, phosphate ions, perchlorate ions, sulfonimide ions, oxalate borate ions, sulfonate ions, acetate ions; The reactive active group is selected from any one or a combination of two or more of vinyl, allyl, epoxy propyl, amine and hydroxyl.

2. The low-pore high-cycle solid-state electrode sheet according to claim 1, wherein The ionic liquid cation group is selected from one of imidazole, pyridine, quaternary ammonium, quaternary phosphonium and pyrrolidine; R is selected from one of C1-C8 substituted or unsubstituted alkyl, C1-C8 substituted or unsubstituted alkoxy, C1-C8 substituted or unsubstituted alkyl ester, C2-C8 substituted or unsubstituted unsaturated alkyl and C3-C8 substituted or unsubstituted cyclic alkyl, and the substituent is selected from halogen when substituted. The polymer monomer is selected from a chain polymer monomer with a terminal unsaturated carbon-carbon bond.

3. The low-porosity high-cycle solid-state electrode of claim 1, wherein, The oxygen heterocyclic group is selected from a cyclic carbonate group, the ionic liquid cation group is selected from one of quaternary ammonium and imidazole, and R is selected from C1-C6 substituted or unsubstituted alkyl ester, and the substituent is selected from halogen when substituted.

4. The low-porosity, high-cycle, solid-state polar plate of claim 2, wherein, The chain polymer monomer with a terminal unsaturated carbon-carbon bond is selected from a double-end chain polymer monomer with a terminal unsaturated carbon-carbon bond.

5. The low-porosity, high-cycle, solid-state polar plate of claim 1, wherein, The cyclic lactone-based ionic liquid having the structure of Formula I is selected from Formula I-1, Formula I-2, Formula I-3, Formula I-4, Formula I-5, Formula I-6, Formula I-7.

6. The low-porosity, high-cycle, solid-state polar plate of claim 1, wherein, The electrolyte nanoparticles have a particle size of less than 500 nm. The material of the electrolyte nanoparticles is selected from any one or several of inorganic ceramic electrolytes and inorganic salt electrolytes.

7. The low-porosity, high-cycle, solid-state polar plate of claim 1, wherein, The material of the electrolyte nanoparticles is selected from inorganic ceramic electrolytes.

8. The low-porosity, high-cycle, solid-state polar plate of claim 1, wherein, The polymerizable composite electrolyte further comprises a lithium salt. The lithium salt is selected from a lithium salt with a decomposition temperature higher than 80 DEG C. The active material layer further comprises an initiator. The initiator is selected from at least one of peroxide, azo compound and persulfate. The mass ratio of the cyclic lactone-based ionic liquid with the structure of formula I, the polymer monomer, the electrolyte nanoparticles and the lithium salt in the polymerizable composite electrolyte ranges from (50-95):(0.1-40):(0.1-20):(5-20).

9. The low-porosity, high-cycle, solid-state polar plate of claim 1, wherein, The mass proportion of the cyclic lactone-based ionic liquid with the structure of formula I in the polymerizable composite electrolyte ranges from 55wt% to 85wt%.

10. The low-porosity, high-cycle, solid-state polar plate of claim 1, wherein, The mass proportion of the polymer monomer with at least one reactive active group in the polymerizable composite electrolyte ranges from 10wt% to 30wt%.

11. The low-porosity, high-cycle, solid-state polar plate of claim 8, wherein, The ratio of the initiator to the total mass of the cyclic lactone-based ionic liquid and the polymer monomer is (0.5-5):

100.

12. The low-porosity, high-cycle, solid-state polar plate of claim 1, wherein, The polymerizable composite electrolyte accounts for 10-35wt% in the coating slurry.

13. The low-porosity, high-cycle, solid-state polar plate of claim 1, wherein, The coating slurry of the low-porosity high-cycle solid-state polar piece further comprises active material particles and conductive additives; The conductive additives account for 3-15wt% in the coating slurry; The active material particles account for 60-85wt% in the coating slurry.

14. The low-porosity, high-cycle, solid-state polar plate of claim 1, wherein, The low-porosity high-cycle solid-state polar piece has a porosity of 0.5-10%.

15. The low-porosity, high-cycle, solid-state polar plate of claim 1, wherein, The low-porosity high-cycle solid-state polar piece is selected from any one of a positive polar piece and a negative polar piece.

16. The low-porosity, high-cycle, solid-state polar plate of claim 1, wherein, The low-porosity high-cycle solid-state polar piece is a positive polar piece.

17. A method of synthesizing the low-porosity, high-cycle solid-state electrode of claim 1, wherein, The method comprises the following steps: S1.1: uniformly mix the first monomer, the second monomer, the electrolyte nanoparticles and the lithium salt according to the metering ratio to obtain a first solution; S1.2: uniformly mix the initiator into the first solution according to the metering ratio to obtain a second solution, then coat and solidify to obtain the low-porosity high-cycle solid-state polar piece; The active material and the conductive agent are introduced into the low-porosity high-cycle solid-state polar piece in one of the following two ways: Method 1: The active material and the conductive agent are arranged in an active material layer on the surface of the current collector, the second solution prepared in step S1.2 is coated on the surface of the active material layer, and then solidified to obtain the low-porosity high-cycle solid-state polar piece; Method 2: The active material and the conductive agent are added into the second solution in step S1.2, then coated on the surface of the current collector, and then solidified to obtain the low-porosity high-cycle solid-state polar piece.

18. The method of synthesis of claim 17, wherein, The specific steps of the method 1 are as follows: S2.1: coat the current collector provided with an active material layer on the surface of the current collector by uniformly mixing the active material and the conductive agent into the solvent according to the metering ratio; S2.2: uniformly mix the first monomer, the second monomer, the electrolyte nanoparticles and the lithium salt according to the metering ratio to obtain a first solution; S2.3: uniformly mix the initiator into the first solution according to the metering ratio to obtain a second solution, coat the second solution on the surface of the active material layer on the current collector, and then heat solidify to obtain the low-porosity high-cycle solid-state polar piece; The specific steps of the method 2 are as follows: S3.1: uniformly mix the first monomer, the second monomer, the electrolyte nanoparticles and the lithium salt according to the metering ratio to obtain a first solution; S3.2: add the active material and the conductive agent into the first solution according to the metering ratio to obtain a second solution, coat the second solution on the surface of the current collector, and then heat solidify to obtain the low-porosity high-cycle solid-state polar piece; In the method 1 and the method 2, the heat solidification condition is a vacuum environment at 70-90℃, and the solidification time is 10-14h.

19. The method of synthesis of claim 17, wherein, The first monomer is synthesized by the following steps: S4.1: heat the first reactant with a structural formula of X-R-M and an ionic liquid to reflux in a first solvent, cool, wash, and distill under reduced pressure to obtain a cyclic lactone-based ionic liquid, wherein X is an oxygen heterocyclic group, and M is halogen; The ratio of the first reactant to the ionic liquid is 1:1.05-2; S4.2: stir the cyclic lactone-based ionic liquid and an alkali metal salt in a second solvent, and wash to obtain the first monomer; The mass ratio of the cyclic lactone-based ionic liquid to the alkali metal salt is 1:1.05-2.

20. The method of synthesis of claim 19, wherein, In the step S4.1, the ratio of the first reactant to the ionic liquid is 1:1.1-1.

5.

21. The method of synthesis of claim 19, wherein, In the step S4.2, the mass ratio of the cyclic lactone-based ionic liquid to the alkali metal salt is 1:1.1-1.

5.

22. The method of synthesis of claim 19, wherein, In the step S4.1, the first solvent is ethyl acetate.

23. The method of synthesis of claim 19, wherein, In the step S4.1, the ionic liquid is selected from one of imidazole, pyridine, quaternary ammonium, quaternary phosphonium, pyrrolidine, piperidine functionalized ionic liquid.

24. The method of synthesis of claim 19, wherein, In the step S4.1, the ionic liquid is one of N-methyl imidazole, triethylamine, 4-methyl pyridine, 1-methyl pyrrolidine, N-methyl piperidine, N,N-diethylmethylamine.

25. The method of synthesis of claim 19, wherein, In the step S4.1, the temperature of the heating reflux is 60-90℃.

26. The method of synthesis of claim 19, wherein, In the step S4.2, the second solvent is deionized water.

27. The method of synthesis of claim 19, wherein, In the step S4.2, the alkali metal salt is selected from one or more of halogen ion, phosphate ion, perchlorate ion, sulfonimide ion, oxalate borate ion, sulfonate ion, acetate ion.

28. The method of synthesis of claim 19, wherein, In the step S4.2, the stirring time is 2-24h.

29. A battery, characterized by The low-porosity high-cycle solid-state electrode piece of any one of claims 1-16 or synthesized by the synthesis method of any one of claims 17-28.

30. An energy storage device, comprising: The low-porosity high-cycle solid-state electrode piece of any one of claims 1-16 or synthesized by the synthesis method of any one of claims 17-28.

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