CN116525934A

CN116525934A - Composite solid electrolyte and preparation method and application thereof

Info

Publication number: CN116525934A
Application number: CN202310655114.9A
Authority: CN
Inventors: 谭强强; 宋洁尘; 徐宇兴
Original assignee: Institute of Process Engineering of CAS
Current assignee: Institute of Process Engineering of CAS
Priority date: 2023-06-05
Filing date: 2023-06-05
Publication date: 2023-08-01

Abstract

The invention provides a composite solid electrolyte, a preparation method and application thereof, wherein the preparation raw materials of the composite solid electrolyte comprise a modified matrix with vertical pore channels, a polymer, a monomer, lithium salt and an initiator; the modified matrix with vertical pore channels comprises an inorganic or organic matrix with carbon-carbon double bonds on the inner walls of the pore channels; the polymer comprises a polymer which is capped at two ends by double bonds and contains ether oxygen structural units; the monomer comprises a linear compound terminated by double bonds at one or two ends, and the structure of the linear compound comprises any one or a combination of at least two of amide groups, carbonyl groups or ether oxygen functional groups. The preparation method of the composite solid electrolyte provided by the invention is simple, and the composite solid electrolyte has the characteristics of high ionic conductivity, good mechanical strength and low interface impedance, and the prepared all-solid lithium metal battery has good cycling stability.

Description

Composite solid electrolyte and preparation method and application thereof

Technical Field

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a composite solid electrolyte, a preparation method and application thereof.

Background

Along with the gradual increase of permeability of the new energy automobile in daily life, the demand of the power battery is continuously increased, but corresponding safety problems such as fire, spontaneous combustion and the like of the new energy automobile are increasingly prominent, and higher requirements are put forward on the safety performance of the power battery. Unlike the traditional lithium ion battery which is produced in mass at present, the all-solid-state lithium metal battery changes flammable liquid electrolyte into solid electrolyte, and meanwhile, metal lithium with higher theoretical specific capacity is used as a negative electrode, so that the all-solid-state lithium metal battery has the advantages of high safety, high energy density and the like, and has important significance in research.

As the core of all-solid-state lithium metal batteries, solid-state electrolytes are required to have high ionic conductivity, high mechanical strength and good interface contact with electrodes and electrolytes, and lithium dendrites are inhibited while lithium ions can be ensured to rapidly migrate between positive and negative electrodes, so that long-term stable circulation of the battery is maintained. At present, constructing a fast one-dimensional lithium ion migration path inside a solid electrolyte, and constructing an interface with low interface impedance with an electrode and the electrolyte is one of effective methods for improving the performance of the solid electrolyte.

CN108923062a discloses an organic/inorganic composite solid electrolyte based on quasi-one-dimensional oxide and application, the composite solid electrolyte is formed by compositing quasi-one-dimensional oxide filler, lithium salt and polymer. According to the technical scheme, the one-dimensional fibrous or rod-shaped filler with submicron or nanometer level is introduced into a polycarbonate polymer system to prepare the composite solid electrolyte with high ionic conductivity and high tensile strength, and the assembled lithium ion battery shows good cycle performance.

CN112038688A discloses a preparation method of a one-dimensional nano-morphology LLZO-based solid electrolyte material, the preparation method comprises the steps of taking a carbon nano-tube as a template, uniformly mixing the carbon nano-tube with water-soluble nitrate and a surfactant, drying and calcining to obtain the one-dimensional nano-morphology LLZO-based solid electrolyte material, and the one-dimensional nano-morphology LLZO-based solid electrolyte material prepared by the technical scheme has remarkable effects in forming a continuous lithium ion conducting channel and improving the ion conductivity of an electrolyte membrane of a solid lithium ion battery and an anode of the solid lithium ion battery, and has good ion conductivity with a composite solid electrolyte formed by mixing the carbon nano-tube, a polyethylene polymer, lithium salt and the like.

CN113206288A discloses a composite solid electrolyte membrane based on surface defect titanium dioxide, a preparation method and application thereof, the composite solid electrolyte membrane comprises: titanium dioxide, polymers, lithium salts; the titanium dioxide is a titanium dioxide nano rod with oxygen vacancy defects on the surface. According to the technical scheme, a one-dimensional structure of the titanium dioxide nanorod can be used for providing a continuous ion conduction channel, so that the ion conductivity of the solid electrolyte is increased, and the prepared composite solid electrolyte membrane has the characteristics of high lithium ion conductivity, wide electrochemical window and high thermal stability.

According to the scheme, although the solid electrolyte material is prepared by the one-dimensional inorganic material, the performance of the solid electrolyte is improved by constructing the one-dimensional lithium ion migration path, the preparation method is complex, the migration path of lithium ions in the solid electrolyte is not the shortest path between the anode and the cathode, and the lithium ion path still needs to be continuously optimized. In addition, the mechanical strength of the solid electrolyte is considered to inhibit lithium dendrite while the lithium ion transmission path between the anode and the cathode is optimized to the greatest extent, the interface between the solid electrolyte and the electrode is regulated and controlled, and the interface impedance is reduced, so that the stable long cycle of the all-solid lithium metal battery is realized.

Therefore, there is a need to develop a composite solid electrolyte that is simple in preparation method, has a fast lithium ion migration path, good mechanical strength, and low interfacial resistance.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a composite solid electrolyte, a preparation method and application thereof, wherein the composite solid electrolyte is prepared by in-situ polymerizing a polymer and a monomer in an inorganic or organic matrix containing carbon-carbon double bonds on the inner wall of a pore canal, has high ionic conductivity and better mechanical strength, and an all-solid lithium metal battery prepared by adopting the composite solid electrolyte has excellent electrochemical performance.

In order to achieve the aim of the invention, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a composite solid state electrolyte, the composite solid state electrolyte being prepared from a starting material comprising a combination of a modified matrix having vertical channels, a polymer, a monomer, a lithium salt, and an initiator;

the modified matrix with vertical pore channels comprises an inorganic or organic matrix with carbon-carbon double bonds on the inner walls of the pore channels;

the polymer comprises a polymer which is capped at two ends by double bonds and contains ether oxygen structural units;

the monomer comprises a linear compound terminated by double bonds at one or two ends, and the structure of the linear compound comprises any one or a combination of at least two of amide groups, carbonyl groups or ether oxygen functional groups.

In the invention, the modified matrix with the vertical pore canal and the polymer containing the ether oxygen structural unit are polymerized in situ on the inner wall of the pore canal by utilizing the modified matrix with the vertical pore canal, so that the modified matrix with the vertical pore canal and the polymer are crosslinked, a rapid lithium ion migration channel is constructed in one-dimensional direction, meanwhile, the prepared composite solid electrolyte is distributed with abundant lithium ion binding sites in the vertical arranged pore canal, the lithium ion transmission path is optimized, the migration rate of lithium ions between the positive electrode and the negative electrode is improved, and in addition, the modified matrix with the vertical pore canal has certain mechanical strength, so that the solid electrolyte can be ensured to have good capability of inhibiting lithium dendrites.

Preferably, the modified matrix with vertical channels comprises a silane coupling agent modified matrix with vertical channels.

Preferably, the silane coupling agent includes a double bond-containing silane coupling agent.

In the invention, the substrate with the vertical pore canal is modified by the silane coupling agent, so that the carbon-carbon double bond is attached to the surface of the inner wall of the pore canal of the substrate, the modified substrate with the vertical pore canal can be crosslinked with the polymer containing the carbon-carbon double bond, and a rapid lithium ion migration channel is constructed in one-dimensional direction.

Preferably, the silane coupling agent includes 3- (methacryloyloxy) propyl trimethoxysilane (MPS).

Preferably, the matrix having vertical channels includes any one of an Anodic Aluminum Oxide (AAO) film having vertical channels, a Polycarbonate (PC) film having vertical channels, a polyethylene terephthalate (PET) film having vertical channels, or a Polyimide (PI) film having vertical channels, and more preferably, the anodic aluminum oxide film having vertical channels.

Preferably, the modified matrix with vertical channels is prepared by a process comprising:

(1) Mixing a silane coupling agent with a solvent, adding acid to adjust the pH, and stirring to obtain a hydrolysis solution; mixing a matrix with vertical pore channels with hydrogen peroxide solution to obtain a hydroxylation matrix.

(2) And (3) mixing the hydrolysis solution obtained in the step (1) with the matrix subjected to hydroxylation treatment to obtain the modified matrix with vertical pore channels.

Preferably, the solvent of step (1) comprises methanol and water, more preferably methanol and deionized water, and the acid comprises acetic acid, and the pH is adjusted by adding an acid to adjust the pH to 3 to 4, e.g., 3, 3.1, 3.2, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9 or 4, etc.

Preferably, the temperature of the stirring in the step (1) is 40 to 80 ℃ (e.g., 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 72 ℃, 75 ℃, 78 ℃, 80 ℃ or the like), more preferably 50 to 60 ℃, and the stirring time is 8 to 12 hours (e.g., 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours, 10.5 hours, 11 hours, 11.5 hours, 12 hours or the like), still more preferably 10 to 11 hours.

In the invention, if the stirring temperature in the step (1) is too high and the stirring time is too long, the silane coupling agent is subjected to perhydrolysis and self-polymerization, which is unfavorable for the modification of the silane coupling agent on the matrix with the vertical pore canal, so that the synergistic effect of the matrix and the polymer component is reduced, and the electrochemical performances of the solid electrolyte and the all-solid lithium metal battery are reduced; if the stirring temperature in the step (1) is too low and the stirring time is too short, the hydrolysis degree of the silane coupling agent is reduced, namely the hydroxyl content in the silane coupling agent is reduced, so that the reaction of the silane coupling agent with the polymer and the monomer is seriously influenced, the interaction of the polymer, the monomer and the vertical pore canal is further reduced, the rapid transmission of lithium ions in the one-dimensional pore canal is not facilitated, and finally the electrochemical performances of the solid electrolyte and the all-solid lithium metal battery are reduced

Preferably, the volume ratio of the silane coupling agent, methanol and water is 1:2 to 7:1, for example 1:2:1, 1:3:1, 1:4:1, 1:5:1, 1:6:1 or 1:7:1, etc.

Preferably, the substrate having vertical cells and the hydrogen peroxide solution are mixed such that the substrate having vertical cells is immersed in the hydrogen peroxide solution, wherein the hydrogen peroxide solution comprises 25 to 35% by mass of hydrogen peroxide, such as 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34% or 35% by mass, etc.

Preferably, the mixing time of the substrate with vertical pore canal and the hydrogen peroxide solution is 20-40 min, for example 20min, 22min, 25min, 28min, 30min, 32min, 35min, 38min, 39min or 40min, etc.

Preferably, the mixing of the substrate with vertical channels with the hydrogen peroxide solution further comprises washing and drying.

Preferably, the washing and drying comprises a water rinse and an argon purge drying.

Preferably, the mixing in step (2) is performed by immersing the hydroxylated substrate obtained in step (1) in a hydrolysis solution.

Preferably, the mixing time in step (2) is 10 to 120min, for example 10min, 20min, 40min, 50min, 60min, 70min, 80min, 90min, 100min or 120min, etc., and more preferably 30 to 60min.

In the invention, the mixing time in the step (2) is 10-120 min, and if the mixing time in the step (2) is too short, the effect of the matrix with vertical pore canals and the silane coupling agent is insufficient, so that the synergistic effect of the modified matrix with vertical pore canals and the polymer is reduced; in addition, as the silane coupling agent has saturated concentration in the matrix, the mixing time is too long, more silane coupling agent cannot be combined in the pore canal of the matrix, the electrochemical performance of the solid electrolyte and the all-solid-state lithium metal battery cannot be improved, the efficiency can be reduced, the cost can be increased, the synergy of the modified matrix with the vertical pore canal and the polymer component is strong and weak, the mechanical strength of the composite solid electrolyte is directly influenced, the synergy is strong, the tensile strength is high, and otherwise, the tensile strength is reduced.

Preferably, the mixing further comprises a vacuum drying treatment.

The temperature of the vacuum drying is preferably 50 to 100 ℃ (e.g., 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, etc.), more preferably 60 to 80 ℃, and the time of the vacuum drying is 1 to 4 hours (e.g., 1 hour, 1.2 hours, 1.5 hours, 2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.5 hours, 4 hours, etc.), still more preferably 1.5 to 2 hours.

Preferably, the polymer comprises polyethylene glycol diacrylate (PEGDA), polyethylene glycol dimethacrylate (PEGDMA) or an acrylate polymer composed of ethoxylated trimethylol propane triacrylate monomer, more preferably polyethylene glycol diacrylate.

Preferably, the monomer comprises any two or at least three of N, N-Methylenebisacrylamide (MBA), acetoacetoxyethyl methacrylate (AAEM), acrylamide (AM) or N, N-vinylbisacrylamide (EBA), more preferably a combination of N, N-methylenebisacrylamide and acetoacetoxyethyl methacrylate.

In the invention, the monomer is preferably a combination of AAEM and MBA, and the crosslinking of the AAEM and the MBA can provide a large number of binding sites (-C=O) for the migration of lithium ions, and simultaneously amino in amide groups in the MBA can attract anions of lithium salts, promote the dissociation of the lithium salts, further improve the content of freely moving lithium ions in a system, and facilitate the improvement of ionic conductivity.

Preferably, the acetoacetate-based ethyl methacrylate is 0.5 to 0.9 (e.g., 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, or 0.9, etc.), more preferably 0.6 to 0.7, in terms of the total mole fraction of the acetoacetate-based ethyl methacrylate and the N, N-methylenebisacrylamide being 1.

Preferably, the lithium salt comprises any one or a combination of at least two of lithium perchlorate, lithium hexafluorophosphate, lithium difluorooxalato borate, lithium trifluoromethane sulfonate, lithium bistrifluoromethane sulfonyl imide, lithium tetrafluoroborate or lithium bisoxalato borate, and further preferably lithium bistrifluoromethane sulfonyl imide.

Preferably, the initiator comprises a photoinitiator and/or a thermal initiator, more preferably a thermal initiator.

Preferably, the thermal initiator comprises dibenzoyl peroxide and/or azobisisobutyronitrile, preferably azobisisobutyronitrile.

Preferably, the mass ratio of the polymer to the monomer is 0.5 to 5:1, more preferably 1 to 1.5:1.

In the invention, the mass ratio of the polymer to the monomer is 0.5-5:1, wherein the polymer can introduce ether oxygen functional groups, and the ether oxygen functional groups and lithium ions have higher bonding energy, so that the ether oxygen functional groups with too high content are not beneficial to the rapid transmission of the lithium ions, and on the other hand, the polymer is beneficial to forming a polymerization network with higher crosslinking degree and improving the tensile strength. Therefore, if the mass ratio of polymer to monomer is too low, the monomer ratio increases over the lithium ion binding sites, but the low polymer ratio is detrimental to the construction of a continuous lithium ion migration path within the system and the tensile strength is low; if the mass ratio of polymer to monomer is too high, the ionic conductivity decreases.

Preferably, the molar ratio of ether oxygen structural units to lithium salt in the polymer is 10 to 20:1, e.g. 10:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1 or 20:1, etc., further preferably 12 to 16:1.

In the invention, the molar ratio of the ether oxygen structural unit to the lithium salt in the polymer is 10-20:1, if the content of the lithium salt is too high, on one hand, the lithium ion concentration is too high, the migration of lithium ions in the system is blocked, so that the ion conductivity of the composite solid electrolyte is reduced, but on the other hand, because of the interaction between the lithium ions, the polymer and the monomer, the improvement of the content of the lithium salt is beneficial to strengthening the connection between polymer networks, and more excellent tensile strength is obtained; if the content of the lithium salt is too small, enough carriers are absent in the system, the connection effect between the crosslinked networks is weakened, and the solid electrolyte is unfavorable for obtaining excellent ionic conductivity, electrochemical performance and mechanical strength.

Preferably, the mass of the initiator is 0.5 to 2.5% of the total mass of polymer and monomer, e.g. 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.3%, 2.4% or 2.5% etc.

In a second aspect, the present invention provides a method for preparing a composite solid electrolyte according to the first aspect, the method comprising the steps of:

(S1) mixing a polymer, a monomer, lithium salt and an initiator to obtain a solid electrolyte precursor solution.

(S2) mixing the modified matrix with the vertical pore canal with the solid electrolyte precursor liquid obtained in the step (S1) for reaction to obtain the composite solid electrolyte.

Preferably, the temperature of the mixing in step (S1) is room temperature, and the mixing time is 6 to 24 hours (e.g., 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, etc.), and more preferably 10 to 12 hours.

Preferably, the mixing in step (S2) is performed by adding the solid electrolyte precursor droplets to the modified substrate surface with vertical channels, and scraping off the superfluous liquid from the surface.

Preferably, the volume of the solid electrolyte precursor solution in the step (S2) is 40 to 100. Mu.L (e.g., 40. Mu.L, 45. Mu.L, 50. Mu.L, 55. Mu.L, 60. Mu.L, 65. Mu.L, 70. Mu.L, 75. Mu.L, 80. Mu.L, 90. Mu.L, 95. Mu.L, 100. Mu.L, etc.), and more preferably 60 to 80. Mu.L.

Preferably, the temperature of the reaction in step (S2) is 55 to 75 ℃ (e.g., 55 ℃, 58 ℃, 60 ℃, 62 ℃, 65 ℃, 68 ℃, 70 ℃, 72 ℃, 73 ℃, 75 ℃ or the like), more preferably 65 to 70 ℃, and the reaction time is 2 to 6 hours (e.g., 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours or the like), still more preferably 3 to 4 hours.

In a third aspect, the invention provides an all-solid-state lithium metal battery, which comprises a positive electrode plate, a solid electrolyte and a negative electrode plate which are sequentially stacked; the solid electrolyte comprises a composite solid electrolyte as described in the first aspect.

Preferably, the positive electrode sheet comprises a lithium iron phosphate positive electrode sheet, and the negative electrode sheet comprises a metallic lithium negative electrode sheet.

In a fourth aspect, the present invention provides a method for preparing an all-solid-state lithium metal battery according to the third aspect, the method comprising the steps of:

and sequentially stacking the anode plate, the modified matrix with the vertical pore canal and the cathode plate, wherein the modified matrix with the vertical pore canal is immersed with solid electrolyte precursor liquid prepared from polymer, monomer, lithium salt and initiator, and then assembling and heating the solid electrolyte precursor liquid to obtain the all-solid lithium metal battery.

According to the invention, the composite solid electrolyte is adopted to prepare the all-solid lithium metal battery, the polymer and the monomer can be tightly formed into a film at the interface between the solid electrolyte and the electrode, the interface impedance between the composite solid electrolyte and the electrode can be reduced, and the prepared all-solid lithium metal battery has excellent cycling stability.

Preferably, the preparation method comprises the following steps: and (3) placing the modified matrix with the vertical pore canal on the surface of a metal lithium negative electrode plate, dripping solid electrolyte precursor liquid prepared from polymer, monomer, lithium salt and initiator, then placing a lithium iron phosphate positive electrode plate on the surface of the matrix with the vertical pore canal, which is soaked with the solid electrolyte precursor liquid, assembling, and heating and curing to obtain the all-solid lithium metal battery.

The volume of the solid electrolyte precursor solution is preferably 40 to 100. Mu.L (for example, 40. Mu.L, 45. Mu.L, 50. Mu.L, 55. Mu.L, 60. Mu.L, 65. Mu.L, 70. Mu.L, 75. Mu.L, 80. Mu.L, 90. Mu.L, 95. Mu.L, 100. Mu.L, etc.), and more preferably 60 to 80. Mu.L.

Preferably, the diameter of the negative electrode plate is 12-14 mm, for example 12mm, 12.3mm, 12.5mm, 12.8mm, 13mm, 13.2mm, 13.5mm, 13.8mm or 14mm, etc., the diameter of the modified matrix with vertical pore canal is 13-16 mm, for example 13mm, 13.3mm, 13.5mm, 13.8mm, 14mm, 14.5mm, 15mm, 15.5mm or 16mm, etc., and the diameter of the positive electrode plate is 10-12 mm, for example 10mm, 10.3mm, 10.5mm, 10.8mm, 11mm, 11.2mm, 11.5mm, 11.8mm or 12mm, etc.

In a fifth aspect, the present invention provides a power plant comprising a composite solid state electrolyte as described in the first aspect and/or an all solid state lithium metal battery as described in the third aspect.

Compared with the prior art, the invention has the following beneficial effects:

the preparation method of the composite solid electrolyte is simple, and a modified matrix with vertical pore canals is used for crosslinking with polymers and monomers to construct a rapid lithium ion migration channel along one-dimensional inner wall, wherein the rapid lithium ion migration channel is a one-dimensional lithium ion migration channel vertical to the positive electrode and the negative electrode, so that lithium ions migrate between the positive electrode and the negative electrode along a relatively shortest path through the composite solid electrolyte, and the ion conductivity of the solid electrolyte is improved; the polymer and the monomer in the internal cavity of the composite solid electrolyte are crosslinked and a plurality of lithium ion binding sites are introduced, so that the rapid migration of lithium ions in the composite solid electrolyte is further promoted; according to the all-solid-state lithium metal battery provided by the invention, through in-situ polymerization of the polymer and the monomer, a film can be tightly formed at the interface of the solid electrolyte and the electrode, so that the interface impedance of the solid electrolyte and the electrode can be reduced, and the circulation stability of the all-solid-state lithium metal battery can be improved.

The ionic conductivity of the composite solid electrolyte provided by the invention is 0.8-8.3X10 ^-4 S/cm, the tensile strength reaches 30-50 MPa, the initial discharge specific capacity of the all-solid-state lithium metal battery comprising the composite solid-state electrolyte is 137.46-158.43 mAh/g, the specific capacity after 150 circles of circulation is 105.84-155.26 mAh/g, and the capacity retention rate is 77-98%.

Drawings

FIG. 1 is a schematic illustration of the composite solid electrolyte provided in example 1 and its internal lithium ion transport;

wherein, 1-the composite solid electrolyte; 2-vertical duct.

Detailed Description

The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.

Preparation example 1

A modified substrate with vertical pore channels, in particular to a modified AAO film A with vertical pore channels, which is prepared by the following steps:

(1) Mixing MPS, methanol and deionized water according to the volume ratio of 1:5:1, adding acetic acid to adjust the pH value to 3 so as to promote hydrolysis, and then stirring in a water bath at 50 ℃ for 10 hours to obtain a hydrolysis solution; the substrate with vertical pore channels was immersed in a 30wt% hydrogen peroxide solution for 30min, rinsed with deionized water, and purged with dry argon to obtain a hydroxylated substrate.

(2) And (3) putting the hydroxylated substrate obtained in the step (1) into a hydrolysis solution, soaking for 60min, taking out, and vacuum drying at 80 ℃ for 2h to obtain the modified AAO film A with vertical pore channels.

The matrix with vertical pore canal is AAO membrane (Beijing research materials and technologies development Co., ltd.) with vertical pore canal, pore diameter of 250nm, porosity of 50%, thickness of 50 μm, and diameter of 13mm.

Preparation example 2

A modified substrate with vertical pore channels, in particular to a modified AAO film B with vertical pore channels, which is prepared by the following steps:

(1) Mixing MPS, methanol and deionized water according to the volume ratio of 1:2:1, adding acetic acid to adjust the pH to 4 so as to promote hydrolysis, and then stirring in a water bath at 60 ℃ for 11 hours to obtain a hydrolysis solution; the substrate with vertical pore channels was immersed in 35wt% hydrogen peroxide solution for 20min, rinsed with deionized water, and purged with dry argon to obtain a hydroxylated substrate.

(2) And (3) putting the hydroxylated substrate obtained in the step (1) into a hydrolysis solution, soaking for 45min, taking out, and vacuum drying at 50 ℃ for 4h to obtain the modified AAO film B with vertical pore channels.

Preparation example 3

A modified matrix with vertical pore channels, in particular a modified AAO film C with vertical pore channels, which is prepared by the following steps:

(1) Mixing MPS, methanol and deionized water according to the volume ratio of 1:7:1, adding acetic acid to adjust the pH value to 3.5 so as to promote hydrolysis, and then stirring in a water bath at 55 ℃ for 10.5 hours to obtain a hydrolysis solution; the substrate with vertical pore channels was immersed in 25wt% hydrogen peroxide solution for 40min, rinsed with deionized water, and purged with dry argon to obtain a hydroxylated substrate.

(2) And (3) putting the hydroxylated substrate obtained in the step (1) into a hydrolysis solution, soaking for 30min, taking out, and vacuum drying at 100 ℃ for 1h to obtain the modified AAO film C with vertical pore channels.

Preparation example 4

A modified substrate with vertical pore channels, specifically a modified AAO film D with vertical pore channels, is different from preparation example 1 only in that the stirring temperature in the step (1) is 80 ℃, the water bath stirring time is 12h, and other raw materials, the dosage and the preparation method are the same as those in preparation example 1.

Preparation example 5

A modified substrate with vertical pore channels, specifically a modified AAO film E with vertical pore channels, is different from preparation example 1 only in that the stirring temperature in the step (1) is 40 ℃, the water bath stirring time is 8 hours, and other raw materials, the dosage and the preparation method are the same as those in preparation example 1.

Preparation example 6

A modified substrate with vertical pore channels, specifically a modified AAO film F with vertical pore channels, is different from preparation example 1 only in that the soaking time in the step (2) is 10min, and other raw materials, the dosage and the preparation method are the same as those in preparation example 1.

Preparation example 7

A modified substrate with vertical pore channels, specifically a modified AAO film G with vertical pore channels, is different from preparation example 1 only in that the soaking time in the step (2) is 120min, and other raw materials, amounts and preparation methods are the same as those in preparation example 1.

Preparation example 8

The modified matrix with vertical channels, specifically a modified PC film with vertical channels, differs from preparation example 1 only in that the matrix with vertical channels is a PC film with vertical channels (Belgium it4ip Co., ltd.), the pore size is 200nm, the porosity is 15.7%, the thickness is 25 μm, and other raw materials, the amount and the preparation method are the same as those of preparation example 1.

Preparation example 7

The modified matrix with vertical channels, specifically a modified PET film with vertical channels, differs from preparation example 1 only in that the matrix with vertical channels is a PET film with vertical channels (Belgium it4ip Co., ltd.), the pore size is 200nm, the porosity is 15.7%, the thickness is 23 μm, and other raw materials, the amount and the preparation method are the same as those of preparation example 1.

Preparation example 8

The modified matrix with vertical channels, specifically a modified PI membrane with vertical channels, differs from preparation example 1 only in that the matrix with vertical channels is a PI membrane with vertical channels (belgium it4ip limited), the pore size is 200nm, the porosity is 15.7%, the thickness is 25 μm, and other raw materials, amounts and preparation methods are the same as those of preparation example 1.

Example 1

The present example provides a composite solid electrolyte, as shown in fig. 1, and its preparation method and application, wherein the preparation raw materials of the composite solid electrolyte include modified AAO film A, PEGDA (number average molecular weight 575, sigma, cat# 437441), AAEM (94%, aladine, cat# a 107223), MBA (99%, aladine, cat# M128783), lithium bis (trifluoromethane sulfonyl imide) (99.99%, sigma, cat# 919977) and thermal initiator (azobisisobutyronitrile, 98%, aladine, cat# a 104255);

The ratio of the mass of the PEGDA to the total mass of the AAEM and the MBA is 1.5:1, the mole fraction of the AAEM is 0.7, and the total mole fraction of the AAEM and the MBA is 1;

the molar ratio of the ether oxygen structural unit of the PEGDA to the lithium bistrifluoromethane sulfonyl imide is 16:1, and the mass of the azodiisobutyronitrile is 0.5% of the total mass of the PEGDA, the MBA and the AAEM.

The preparation method comprises the following steps:

(S1) 0.560g of PEGDA, 0.283g of AAEM, 0.087g of MBA, 0.178g of lithium bistrifluoromethane-sulfonyl imide and 4.65mg of azobisisobutyronitrile were thoroughly mixed and stirred at room temperature for 12 hours to obtain a solid electrolyte precursor solution.

(S2) dripping 80 mu L of solid electrolyte precursor onto the modified AAO film A with vertical pore channels, gently scraping off superfluous surface liquid by using a blade, and heating and curing for 3 hours at 70 ℃ on a heating disc to obtain the composite solid electrolyte film.

An all-solid-state lithium metal battery comprises a lithium iron phosphate positive electrode plate, the composite solid electrolyte membrane and a lithium metal negative electrode plate;

the preparation method of the all-solid-state lithium metal battery comprises the following steps: and (3) placing the modified AAO film A with the vertical pore canal on the surface of a metal lithium negative electrode plate with the diameter of 12mm, dripping the solid electrolyte precursor liquid obtained in the step (2), dripping 80 mu L of the solid electrolyte precursor liquid, placing the lithium iron phosphate positive electrode plate with the diameter of 10mm on the surface of a matrix soaked with the precursor liquid, finally packaging the lithium iron phosphate positive electrode plate in a CR2032 button cell shell, and heating and curing the lithium iron phosphate positive electrode plate on a heating disc at the temperature of 70 ℃ for 3 hours to obtain the all-solid lithium metal battery.

Example 2

The embodiment provides a composite solid electrolyte, and a preparation method and application thereof, wherein the preparation raw materials of the composite solid electrolyte comprise modified AAO film B, PEGDMA (with number average molecular weight of 550, sigma, product No. 409510), AM (99.0%, allatin, product No. A108465), EBA (96%, allatin, product No. E124733), lithium hexafluorophosphate (97%, allatin, product No. L157770) and thermal initiator (azobisisobutyronitrile, 98%, allatin, product No. A104255);

the ratio of the mass of the PEGDMA to the total mass of the EBA and the AM is 1:1, the total mole fraction of the EBA and the AM is 1, and the mole fraction of the EBA is 0.8;

the molar ratio of the ether oxygen structural unit of PEGDMA to lithium hexafluorophosphate is 16:1, and the mass of the azodiisobutyronitrile is 1% of the total mass of PEGDA, EBA and AM.

The preparation method comprises the following steps:

(S1) 0.550g of PEGDMA, 0.053g of AM, 0.497g of EBA, 0.119g of lithium hexafluorophosphate and 11.00mg of azobisisobutyronitrile were thoroughly mixed and stirred at room temperature for 6 hours to obtain a solid electrolyte precursor solution.

(S2) dripping 60 mu L of solid electrolyte precursor onto the modified AAO film B with vertical pore channels, gently scraping off superfluous surface liquid by a blade, and heating and curing for 6h at 55 ℃ on a heating disc to obtain the composite solid electrolyte film.

the preparation method of the all-solid-state lithium metal battery comprises the following steps: and (3) placing the modified AAO film B with the vertical pore canal on the surface of a metal lithium negative electrode plate with the diameter of 12mm, dripping the solid electrolyte precursor liquid obtained in the step (2), dripping 60 mu L of the solid electrolyte precursor liquid, placing the lithium iron phosphate positive electrode plate with the diameter of 10mm on the surface of a matrix soaked with the precursor liquid, finally packaging the lithium iron phosphate positive electrode plate in a CR2032 button cell shell, and heating and curing the lithium iron phosphate positive electrode plate on a heating disc at 55 ℃ for 6 hours to obtain the all-solid lithium metal battery.

Example 3

The embodiment provides a composite solid electrolyte, and a preparation method and application thereof, wherein the preparation raw materials of the composite solid electrolyte comprise modified AAO film C, PEGDA (number average molecular weight 575, sigma, product No. 437441), AAEM (94%, allatin, product No. A107223), MBA (99%, allatin, product No. M128783), lithium perchlorate and thermal initiator (azodiisobutyronitrile, 98%, allatin, product No. A104255);

the ratio of the mass of the PEGDA to the total mass of the AAEM and the MBA is 1.25:1, the mole fraction of the AAEM is 0.7, and the total mole fraction of the AAEM and the MBA is 1;

The molar ratio of the ether oxygen structural unit of the PEGDA to the lithium bistrifluoromethane sulfonyl imide is 14:1, and the mass of the azodiisobutyronitrile is 2.5% of the total mass of the PEGDA, the MBA and the AAEM.

The preparation method comprises the following steps:

(S1) 0.560g of PEGDA, 0.342g of AAEM, 0.106g of MBA, 0.261g of lithium bistrifluoromethane-sulfonyl imide and 25.20mg of azobisisobutyronitrile were thoroughly mixed and stirred at room temperature for 24 hours to obtain a solid electrolyte precursor solution.

(S2) 70 mu L of solid electrolyte precursor is dripped on the modified AAO film C with vertical pore channels, and after the superfluous surface liquid is gently scraped off by a blade, the solid electrolyte precursor is heated and solidified on a heating disc at 75 ℃ for 2 hours, and the composite solid electrolyte film is obtained.

the preparation method of the all-solid-state lithium metal battery comprises the following steps: and (3) placing the modified AAO film C with the vertical pore canal on the surface of a metal lithium negative electrode plate with the diameter of 12mm, dripping the solid electrolyte precursor liquid obtained in the step (2), dripping 70 mu L of the solid electrolyte precursor liquid, placing the lithium iron phosphate positive electrode plate with the diameter of 10mm on the surface of a matrix soaked with the precursor liquid, finally packaging the lithium iron phosphate positive electrode plate in a CR2032 button cell shell, and heating and curing the lithium iron phosphate positive electrode plate on a heating disc at the temperature of 75 ℃ for 2 hours to obtain the all-solid lithium metal battery.

Example 4

This example provides a composite solid electrolyte, and a preparation method and application thereof, which are different from example 1 only in that the modified AAO film a with vertical channels is replaced with a modified AAO film D with vertical channels, and other raw materials, amounts and preparation methods are the same as example 1.

Example 5

This example provides a composite solid electrolyte, and a preparation method and application thereof, which are different from example 1 only in that the modified AAO film a with vertical channels is replaced by a modified AAO film E with vertical channels, and other raw materials, amounts and preparation methods are the same as example 1.

Example 6

This example provides a composite solid electrolyte, and a preparation method and application thereof, which are different from example 1 only in that the modified AAO film a with vertical channels is replaced by a modified AAO film F with vertical channels, and other raw materials, amounts and preparation methods are the same as example 1.

Example 7

This example provides a composite solid electrolyte, and a preparation method and application thereof, which are different from example 1 only in that the modified AAO film a with vertical channels is replaced with a modified AAO film G with vertical channels, and other raw materials, amounts and preparation methods are the same as example 1.

Example 8

This example provides a composite solid electrolyte and a preparation method and application thereof, which are different from example 1 only in that the ratio of the mass of PEGDA to the total mass of AAEM and MBA is 0.5:1, the mass of PEGDA in step (S1) is 0.560g, the mass of AAEM is 0.856g, the mass of MBA is 0.264g, the mass of azobisisobutyronitrile is 8.40mg, and other raw materials, amounts and preparation methods are the same as example 1.

Example 9

This example provides a composite solid electrolyte and a preparation method and application thereof, which are different from example 1 only in that the ratio of the mass of PEGDA to the total mass of AAEM and MBA is 5:1, the mass of PEGDA in step (S1) is 0.560g, the mass of AAEM is 0.086g, the mass of MBA is 0.026g, the mass of azobisisobutyronitrile is 3.36mg, and other raw materials, amounts and preparation methods are the same as example 1.

Example 10

This example provides a composite solid electrolyte and a preparation method and application thereof, which are different from example 1 only in that the total mole fraction of AAEM and MBA is 1, the mole fraction of AAEM is 0.5, the mass of AAEM in step (S1) is 0.217g, the mass of MBA is 0.156g, the mass of azobisisobutyronitrile is 4.67mg, and other raw materials, amounts and preparation methods are the same as example 1.

Example 11

This example provides a composite solid electrolyte and a preparation method and application thereof, which are different from example 1 only in that the total mole fraction of AAEM and MBA is 1, the mole fraction of AAEM is 0.6, the mass of AAEM in step (S1) is 0.252g, the mass of MBA is 0.121g, the mass of azobisisobutyronitrile is 4.67mg, and other raw materials, amounts and preparation methods are the same as example 1.

Example 12

This example provides a composite solid electrolyte and a preparation method and application thereof, which are different from example 1 only in that the total mole fraction of AAEM and MBA is 1, the mole fraction of AAEM is 0.8, the mass of AAEM in step (S1) is 0.316g, the mass of MBA is 0.057g, the mass of azobisisobutyronitrile is 4.67mg, and other raw materials, amounts and preparation methods are the same as example 1.

Example 13

This example provides a composite solid electrolyte and a preparation method and application thereof, which are different from example 1 only in that the total mole fraction of AAEM and MBA is 1, the mole fraction of AAEM is 0.9, the mass of AAEM in step (S1) is 0.345g, the mass of MBA is 0.028g, the mass of azobisisobutyronitrile is 4.67mg, and other raw materials, amounts and preparation methods are the same as example 1.

Example 14

This example provides a composite solid electrolyte and its preparation method and application, which only differ from example 1 in that the molar ratio of ether oxygen structural unit of PEGDA to lithium bistrifluoromethane sulfonyl imide is 10:1, the mass of PEGDA in step (S1) is 0.560g, the mass of lithium bistrifluoromethane sulfonyl imide is 0.365g, and other raw materials, amounts and preparation methods are the same as those of example 1.

Example 15

This example provides a composite solid electrolyte and its preparation method and application, which only differ from example 1 in that the molar ratio of ether oxygen structural unit of PEGDA to lithium bis (trifluoromethanesulfonyl) imide is 20:1, the mass of PEGDA in step (S1) is 0.560g, the mass of lithium bis (trifluoromethanesulfonyl) imide is 0.182g, and other raw materials, amounts and preparation methods are the same as those of example 1.

Example 16

This example provides a composite solid electrolyte and its preparation method and application, which differ from example 1 only in that the volume of the solid electrolyte precursor in step (S2) and the preparation method of the all-solid lithium metal battery is 40 μl, and other raw materials, amounts and preparation methods are the same as those of example 1.

Example 17

This example provides a composite solid electrolyte with vertical channels, which differs from example 1 only in that the volume of the solid electrolyte precursor in step (S2) and the preparation method of the all-solid lithium metal battery is 100 μl, and other raw materials, amounts and preparation methods are the same as those of example 1.

Example 18

This example provides a composite solid electrolyte and its preparation method and application, which differ from example 1 only in that the modified AAO film a with vertical channels is replaced with a modified PC film with vertical channels, and other raw materials, amounts and preparation methods are the same as example 1.

Example 19

This example provides a composite solid electrolyte and its preparation method and application, which is different from example 1 only in that the modified AAO film a with vertical channels is replaced with a modified PET film with vertical channels, and other raw materials, amounts and preparation methods are the same as example 1.

Example 20

This example provides a composite solid electrolyte and its preparation method and application, which only differ from example 1 in that the modified AAO membrane a with vertical channels is replaced with a modified PI membrane with vertical channels, and other raw materials, amounts and preparation methods are the same as example 1.

Comparative example 1

This comparative example provides a composite solid electrolyte and a preparation method and application thereof, which are different from example 1 only in that the preparation raw materials of the composite solid electrolyte do not include AAEM and MBA, the mass of the azobisisobutyronitrile is 0.5% of the mass of PEGDA, and other raw materials, amounts and preparation methods are the same as example 1.

Comparative example 2

This comparative example provides a composite solid electrolyte, and a preparation method and application thereof, wherein the preparation raw materials of the composite solid electrolyte comprise PEGDA (number average molecular weight 575, sigma, cat No. 437441), AAEM (94%, aladine, cat No. a 107223), MBA (99%, aladine, cat No. M128783), lithium bis (trifluoromethane) sulfonyl imide (99.99%, sigma, cat No. 919977) and thermal initiator (azobisisobutyronitrile, 98%, aladine, cat No. a 104255);

the ratio of the mass of the PEGDA to the total mass of the AAEM and the MBA is 1.5:1, and the mol ratio of the AAEM to the MBA is 7:3;

The preparation method comprises the following steps:

The preparation method comprises the steps of thoroughly mixing 0.560g of PEGDA, 0.283g of AAEM, 0.087g of MBA, 0.178g of lithium bistrifluoromethane sulfonyl imide and 4.65mg of azodiisobutyronitrile, stirring for 12 hours at room temperature to obtain a solid electrolyte precursor solution, pouring the solid electrolyte precursor solution between two glass plates, and heating and curing the solid electrolyte precursor solution on a heating disc at 70 ℃ for 3 hours to obtain the composite solid electrolyte membrane.

The thickness of the solid electrolyte membrane was the thickness of a polypropylene gasket used between two glass plates, which was 50 μm.

the preparation method of the all-solid-state lithium metal battery comprises the following steps: and sequentially stacking the lithium iron phosphate positive electrode plate, the composite solid electrolyte membrane and the metal lithium negative electrode plate, and packaging the lithium iron phosphate positive electrode plate, the composite solid electrolyte membrane and the metal lithium negative electrode plate in a CR2032 button battery shell to obtain the all-solid lithium metal battery.

Performance testing

The following performance tests were performed on the composite solid state electrolyte and the all solid state lithium metal battery provided in examples and comparative examples:

(1) Ion conductivity: the positive and negative plates in the preparation method of the all-solid-state lithium metal battery are replaced by two stainless steel foils to be used as blocking electrodes, an alternating current impedance test of a Shanghai Chenhua electrochemical workstation is used, the frequency range is set to be 0.1-1MHz, the amplitude is set to be 10mV, and an ion conductivity test at room temperature (26 ℃) is carried out;

(2) Test of mechanical strength: the tensile strength of the composite solid electrolyte membrane is tested through a tensile experiment, the environment where an instrument is positioned is dehumidified before the test, the environment temperature is controlled at 25 ℃, the composite solid electrolyte membrane to be tested is cut into a size of 50mm long and 10mm wide, the tensile speed is set to be 5mm/min, and the clamping distance is set to be 20mm;

(3) Specific capacity and capacity retention test: and (3) performing constant-current charge and discharge on the all-solid-state lithium metal battery at the current density of 0.2C and the temperature of 26 ℃ within 2.8-4.0V, testing the initial discharge specific capacity and the discharge specific capacity after 150 circles of circulation, and calculating the capacity retention rate.

The specific test results are shown in table 1.

TABLE 1

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In table 1 "-" represents that the result was not tested.

As can be seen from the test results of Table 1, the ionic conductivities of the composite solid electrolytes provided in examples 1 to 15 and 17 were 1.1 to 8.3X10 ^-4 S/cm, the tensile strength reaches 35-50 MPa, the initial discharge specific capacity of the all-solid-state lithium metal battery comprising the composite solid-state electrolyte is 140.98-158.43 mAh/g, the specific capacity after 150 circles is 114.19-155.26 mAh/g, and the capacity retention rate is 81-98%; examples 18 to 20 provide composite solid electrolytes having an ionic conductivity of 0.8 to 1.0X10 ^-4 S/cm, the tensile strength reaches 30-32 MPa, the initial discharge specific capacity of the all-solid-state lithium metal battery comprising the composite solid-state electrolyte is 137.46-140.46 mAh/g, the specific capacity after 150 circles is 105.84-119.39mAh/g, the capacity retention rate is 77-80%, and as shown in figure 1, the composite solid-state electrolyte forms a rapid lithium ion migration channel in one-dimensional direction.

Compared with the embodiment 1, in the preparation method of the modified matrix with vertical pore channels, if the water bath stirring time and the temperature in the step (1) are too long and too high (embodiment 4) or the water bath stirring time and the temperature are too short and too low (embodiment 5), the ionic conductivity and the tensile strength are reduced, and the modified matrix with vertical pore channels prepared by adopting the specific temperature and time in the water bath stirring in the step (1) is proved to be used for preparing the composite solid electrolyte, so that the performance is better. Compared with the embodiment 1, in the preparation process of the modified matrix with vertical pore channels, if the soaking time in the step (2) is too short (embodiment 6), the ionic conductivity and the tensile strength are both reduced, and if the soaking time is too long (embodiment 7), the ionic conductivity and the tensile strength are slightly reduced, so that the modified matrix with vertical pore channels prepared by adopting the specific time in the soaking in the step (2) is proved to be used for preparing the composite solid electrolyte, and the performance is better.

In comparison with example 1, if the mass ratio of polymer to monomer is too low (example 8) or if the mass ratio of polymer to monomer is too high (example 9), both the ionic conductivity and tensile strength are reduced, demonstrating better performance of the composite solid electrolyte made with a specific mass ratio of polymer to monomer.

Examples 10-13 are compared with example 1, and it is shown that the molar ratio of the two monomers has a larger effect on the ionic conductivity and mechanical strength of the solid electrolyte and the electrochemical performance of the all-solid lithium metal battery, and the composite solid electrolyte prepared by adopting the two monomers with specific molar fractions has better performance.

In comparison with example 1, if the molar ratio of the ether oxygen structural unit of the polymer to the lithium salt is too low, the polymer addition amount is low (example 14) or if the molar ratio of the ether oxygen structural unit of the polymer to the lithium salt is too high, the polymer addition amount is high (example 15), both the ionic conductivity and the tensile strength are reduced, and it is proved that the composite solid electrolyte prepared by using the polymer and the monomer in a specific mass ratio has better performance.

In contrast to example 1, in the preparation method of the composite solid electrolyte, if the solid electrolyte precursor liquid in step (S2) is less (example 16), the vertical channel matrix cannot be completely soaked, so that the lithium ion transmission between the positive electrode and the negative electrode is interrupted, and the battery performance cannot be obtained; if the solid electrolyte precursor liquid in the step (S2) is more (embodiment 17), the thickness of the composite solid electrolyte is increased, the lithium ion migration path is prolonged, and the rapid migration of lithium ions is not facilitated, so that the ionic conductivity of the solid electrolyte and the cycle performance of the all-solid lithium metal battery are both reduced; the step (S2) is proved to be better in performance when the solid electrolyte precursor liquid with specific volume is added to prepare the composite solid electrolyte.

If the AAO film having vertical cells is replaced with any one of the PC film having vertical cells (example 18), the PET film having vertical cells (example 19) or the PI film having vertical cells (example 20), the decrease in ion conductivity is reduced, but the tensile strength is 30MPa or more, as compared with example 1. This is because the organic matrix having vertical pores has a limited aperture ratio or pore size, and cannot be immersed in more solid electrolyte precursor liquid, resulting in a decrease in ion conductivity, as compared to the AAO film having vertical pores.

Compared with example 1, if the preparation raw materials of the composite solid electrolyte do not comprise a monomer (comparative example 1), the ionic conductivity and tensile strength of the composite solid electrolyte, and the initial specific capacity, the specific capacity after 150 circles and the capacity retention rate of the all-solid lithium metal battery are all reduced, because the existence of the monomer can provide more sites for lithium ion migration, and meanwhile, attract lithium salt anions and increase the content of free lithium ions, so that high ionic conductivity is obtained; on the other hand, the monomer can be cross-linked with the polymer, and the crystallinity of the polymer is reduced, and meanwhile, the cross-linked network strength is improved, so that high tensile strength is obtained, and therefore, the monomer is important to realizing excellent electrochemical performance and mechanical strength of the composite solid electrolyte.

Compared with the embodiment 1, if the preparation raw material of the composite solid electrolyte does not comprise a matrix with vertical pore channels (comparative example 2), the ion conductivity and tensile strength of the composite solid electrolyte, the initial specific capacity of the all-solid lithium metal battery, the specific capacity after 150 circles and the capacity retention rate are all reduced, because the modified matrix with vertical pore channels can provide a one-dimensional lithium ion transmission channel for lithium ion migration and accelerate the transmission of lithium ions between the anode and the cathode on the one hand; on the other hand, the lithium ion composite solid electrolyte can interact with the polymer and the monomer, the crystallinity of the polymer is reduced, the migration rate of lithium ions in a polymer system is improved, and meanwhile, the strong mechanical strength of the lithium ion composite solid electrolyte provides guarantee for the good mechanical strength of the composite solid electrolyte, so that the composite solid electrolyte after the matrix is lost shows poor electrochemical performance and mechanical strength.

In summary, the composite solid electrolyte with vertical pore canal provided by the invention has the advantages that the vertical pore canal matrix is modified, the advantages of the vertical pore canal matrix containing the vertical pore canal matrix and strong mechanical strength are exerted, and meanwhile, the composite solid electrolyte can cooperate with components such as polymers and monomers in a cavity, on one hand, a one-dimensional lithium ion fast migration channel can be constructed between the anode and the cathode, on the other hand, the migration rate of lithium ions in a polymer system can be improved through the cooperation, the formation of a crosslinked network is promoted, the composite solid electrolyte has good mechanical strength, lithium dendrites are restrained, and a stable solid electrolyte interfacial film is constructed, so that the all-solid lithium metal battery with excellent electrochemical performance is obtained.

The applicant states that the process of the invention is illustrated by the above examples, but the invention is not limited to, i.e. does not mean that the invention must be carried out in dependence on the above process steps. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of selected raw materials, addition of auxiliary components, selection of specific modes, etc. fall within the scope of the present invention and the scope of disclosure.

Claims

1. A composite solid electrolyte, characterized in that the preparation raw materials of the composite solid electrolyte comprise a modified matrix with vertical pore channels, a polymer, a monomer, a lithium salt and an initiator;

the modified matrix with the vertical pore canal comprises an inorganic group or an organic matrix with carbon-carbon double bonds on the inner wall of the pore canal;

2. The composite solid state electrolyte of claim 1 wherein the modified matrix with vertical channels comprises a silane coupling agent modified matrix with vertical channels;

Preferably, the silane coupling agent includes a double bond-containing silane coupling agent;

preferably, the silane coupling agent comprises 3- (methacryloyloxy) propyl trimethoxysilane;

preferably, the substrate having vertical channels includes any one of an anodic aluminum oxide film having vertical channels, a polycarbonate film having vertical channels, a polyethylene terephthalate film having vertical channels, or a polyimide film having vertical channels, and further preferably an anodic aluminum oxide film having vertical channels;

(1) Mixing a silane coupling agent with a solvent, adding acid to adjust the pH, and stirring to obtain a hydrolysis solution; mixing a matrix with vertical pore channels with hydrogen peroxide solution to obtain a hydroxylated matrix;

(2) Mixing the hydrolysis solution obtained in the step (1) with the matrix subjected to hydroxylation treatment to obtain a modified matrix with vertical pore channels;

preferably, the solvent in the step (1) comprises methanol and water, more preferably methanol and deionized water, the acid comprises acetic acid, and the pH is adjusted by adding acid to 3-4;

Preferably, the temperature of the stirring in the step (1) is 40-80 ℃, more preferably 50-60 ℃, and the stirring time is 8-12 h, more preferably 10-11 h;

preferably, the volume ratio of the silane coupling agent to the methanol to the water is 1:2-7:1;

preferably, the substrate with the vertical pore channels and the hydrogen peroxide solution are mixed, the substrate with the vertical pore channels is immersed in the hydrogen peroxide solution, and the mass percentage of hydrogen peroxide in the hydrogen peroxide solution is 25-35%;

preferably, the mixing time of the substrate with the vertical pore canal and the hydrogen peroxide solution is 20-40 min;

preferably, the mixing of the substrate with vertical channels and the hydrogen peroxide solution further comprises washing and drying;

preferably, the mixing in the step (2) is that the hydroxylation-treated substrate obtained in the step (1) is immersed in a hydrolysis solution;

preferably, the mixing time in the step (2) is 10 to 120min, more preferably 30 to 60min;

preferably, the mixing further comprises a vacuum drying treatment;

preferably, the temperature of the vacuum drying is 50 to 100 ℃, more preferably 60 to 80 ℃, and the time of the vacuum drying is 1 to 4 hours, more preferably 1.5 to 2 hours.

3. The composite solid electrolyte according to claim 1 or 2, wherein the polymer comprises any one or a combination of at least two of polyethylene glycol diacrylate, polyethylene glycol dimethacrylate or acrylate polymer composed of ethoxylated trimethylolpropane triacrylate monomer, further preferably polyethylene glycol diacrylate.

4. A composite solid state electrolyte according to any one of claims 1-3, wherein the monomer comprises any two or a combination of at least three of N, N-methylenebisacrylamide, acetoacetoxyethyl methacrylate, acrylamide or N, N-vinylbisacrylamide, further preferably a combination of N, N-methylenebisacrylamide and acetoacetoxyethyl methacrylate;

preferably, the acetoacetoxy ethyl methacrylate is used in a total mole fraction of 1 and the N, N-methylenebisacrylamide, and the acetoacetoxy ethyl methacrylate is used in a mole fraction of 0.5 to 0.9, more preferably 0.6 to 0.7.

5. The composite solid state electrolyte according to any one of claims 1 to 4, wherein the lithium salt comprises any one or a combination of at least two of lithium perchlorate, lithium hexafluorophosphate, lithium difluorooxalato borate, lithium trifluoromethane sulfonate, lithium bistrifluoromethane sulfonyl imide, lithium tetrafluoroborate or lithium bisoxalato borate, further preferably lithium bistrifluoromethane sulfonyl imide;

Preferably, the initiator comprises a photoinitiator and/or a thermal initiator, more preferably a thermal initiator;

6. The composite solid state electrolyte of any one of claims 1-5, wherein the mass ratio of polymer to monomer is 0.5-5:1, further preferably 1-1.5:1;

preferably, the molar ratio of ether oxygen structural units to lithium salt in the polymer is 10-20:1, more preferably 12-16:1;

preferably, the mass of the initiator is 0.5 to 2.5% of the total mass of the polymer and the monomer.

7. A method of preparing the composite solid electrolyte of any one of claims 1-6, comprising the steps of:

(S1) mixing a polymer, a monomer, lithium salt and an initiator to obtain a solid electrolyte precursor solution;

(S2) mixing the modified matrix with the vertical pore canal with the solid electrolyte precursor liquid obtained in the step (S1) for reaction to obtain a composite solid electrolyte;

preferably, the temperature of the mixing in the step (S1) is room temperature, and the mixing time is 6-24 hours, more preferably 10-12 hours;

Preferably, the mixing in step (S2) is performed by adding solid electrolyte precursor droplets to the modified substrate surface with vertical channels, and scraping off superfluous surface liquid;

preferably, the volume of the solid electrolyte precursor solution in the step (S2) is 40 to 100 μl, and more preferably 60 to 80 μl;

preferably, the temperature of the reaction in step (S2) is 55 to 75 ℃, more preferably 65 to 70 ℃, and the reaction time is 2 to 6 hours, more preferably 3 to 4 hours.

8. The all-solid-state lithium metal battery is characterized by comprising a positive electrode plate, a solid electrolyte and a negative electrode plate which are sequentially stacked; the solid electrolyte comprising the composite solid electrolyte according to any one of claims 1 to 6;

9. A method of making an all-solid-state lithium metal battery according to claim 8, comprising the steps of:

sequentially stacking an anode plate, a modified matrix with vertical pore channels and a cathode plate, wherein the modified matrix with vertical pore channels is immersed with solid electrolyte precursor liquid prepared from polymer, monomer, lithium salt and initiator, and then assembling and heating the solid electrolyte precursor liquid to obtain an all-solid lithium metal battery;

Preferably, the volume of the solid electrolyte precursor solution is 40 to 100. Mu.L, more preferably 60 to 80. Mu.L;

preferably, the diameter of the negative electrode plate is 12-14 mm, the diameter of the modified matrix with vertical pore channels is 13-16 mm, and the diameter of the positive electrode plate is 10-12 mm.

10. A power plant comprising a composite solid state electrolyte as claimed in any one of claims 1 to 6 and/or an all solid state lithium metal battery as claimed in claim 8.