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CN119050482B - A curing additive, a low-impedance composite electrolyte containing the curing additive, and a safe semi-solid battery - Google Patents

A curing additive, a low-impedance composite electrolyte containing the curing additive, and a safe semi-solid battery Download PDF

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Publication number
CN119050482B
CN119050482B CN202411519170.0A CN202411519170A CN119050482B CN 119050482 B CN119050482 B CN 119050482B CN 202411519170 A CN202411519170 A CN 202411519170A CN 119050482 B CN119050482 B CN 119050482B
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battery
low
semi
composite electrolyte
polymer monomer
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CN119050482A (en
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盖建丽
佘馨瑶
姚远
宗若奇
王彦艳
刘峻溢
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Tianmu Lake Institute of Advanced Energy Storage Technologies Co Ltd
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Tianmu Lake Institute of Advanced Energy Storage Technologies Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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Abstract

The invention discloses a curing additive containing a polymer monomer I, II, a low-impedance composite electrolyte containing the curing additive and a safe semi-solid battery containing the low-impedance composite electrolyte, wherein the polymer monomer I has a structure of formula 1: The polymer monomer II has a structure of formula 2: wherein R 1-R3 is selected from alkyl, alkoxy, haloalkyl or haloalkoxy of C 1-C4, R 4 is selected from alkylene or haloalkyl of C 1-C6, R 5 is selected from alkyl or haloalkyl of C 1-C2, and R 6、R7、R8 is selected from alkylene or haloalkyl of C 1-C4. According to the invention, the polymer monomer I, II is introduced into the curing additive, and the safety semi-solid battery impedance is reduced while the safety is ensured by utilizing the compounding effect between the polymer monomers I, II, so that the low-impedance composite electrolyte and the semi-solid battery with high safety and low impedance are obtained.

Description

Curing additive, low-impedance composite electrolyte containing curing additive and safe semi-solid battery
Technical Field
The invention relates to the technical field of batteries, in particular to a curing additive, a low-impedance composite electrolyte containing the curing additive and a safe semi-solid battery.
Background
With the continuous enhancement of global pursuit of sustainable energy solutions and the continuous growth of high-performance battery demands for portable electronic devices and electric automobiles, research and application of solid-state electrolytes have received unprecedented attention. The use of solid electrolytes provides higher safety standards and better electrochemical performance than conventional liquid electrolytes. The material can not only prevent battery leakage and fire risk, but also expand the working temperature range of the battery, thereby greatly improving the overall performance and service life of the battery. Therefore, the development of solid-state electrolytes is not only the key to battery technology innovation, but also an important step in the forward development of modern electronic technology.
However, the polymer monomers raise the safety of the battery while also providing some problems compared to conventional liquid batteries. The solid-state battery adopting the polymer monomer as the electrolyte eliminates the liquid organic electrolyte to cause the increase of the ion movement difficulty, and simultaneously, the solid-liquid interface replaced by the solid-solid interface further increases the interface impedance, so that the problem of high internal resistance of the solid-state battery is serious, and the wide popularization and the use of the solid-state battery in practical application are limited.
Therefore, how to optimize the resistance of the solid-state battery while maintaining the safety of the solid-state electrolyte becomes a great difficulty in the current research, and it is very difficult to obtain a solid-state electrolyte having both low resistance and high safety.
Disclosure of Invention
Aiming at the problems existing in the prior art, the invention constructs a cross-linked framework in electrolyte to form semi-solid electrolyte through the mutual compounding action of the polymer monomer I and the polymer monomer II of the curing additive, constructs an ion-conducting channel and reduces the internal resistance of the battery through the introduction of an aromatic triazine ring and a carbonyl group, solves the problems of higher safety but higher impedance when the polymer monomer is taken as a raw material to prepare the battery electrolyte, and obtains the low-impedance composite electrolyte with low impedance and high safety and the safe semi-solid battery using the electrolyte.
The invention provides a curing additive, which comprises a polymer monomer I and a polymer monomer II, wherein the structural formula of the polymer monomer I is as follows,
Wherein R 1-R3 is selected from alkyl, alkoxy, haloalkyl or haloalkoxy of C 1-C4, R 4 is selected from alkylene or halocarbyl of C 1-C6, and R 5 is selected from alkylene or halocarbyl of C 1-C2;
the structural formula of the polymer monomer II is as follows:
Wherein R 6、R7、R8 is selected from alkyl or haloalkyl of C 1-C4.
The invention also provides a low-impedance composite electrolyte comprising a curing additive dispersed in a solvent.
The invention also provides a high-safety semi-solid secondary battery, which comprises a semi-solid electrolyte constructed by polymer monomers dispersed in the low-impedance composite electrolyte.
As some exemplary preferred embodiments, the polymer monomer I has a structure wherein the number of alkoxy groups in R 1-R3 is less than 3, R 1-R3 is selected from alkyl, alkoxy, haloalkyl or haloalkoxy groups of C 1-C2, R 4 is selected from alkylene or halocarbon groups of C 1-C3, R 5 is selected from alkyl or haloalkyl groups of C 1-C2, and R 6、R7、R8 is selected from alkylene or halocarbon groups of C 1-C2.
As a further scheme, the ratio of the polymer monomer I to the polymer monomer II is selected from 3:1-30:1.
As a further scheme, the ratio of the polymer monomer I to the polymer monomer II is selected from 6:1-15:1.
As a further scheme, the mass content of the curing additive in the low-impedance composite electrolyte is 0.1% -8%.
As still further scheme, the mass content of the curing additive in the low-impedance composite electrolyte is 1% -6%.
As a further scheme, the low-impedance composite electrolyte also comprises a solvent, an additive, an inorganic electrolyte salt and an initiator.
As still further schemes, the solvent is selected from one or more of carbonate compounds, carboxylate compounds, fluoro compounds, ethers and epoxy compounds.
As still further schemes, the carbonate compounds are selected from any one or more of cyclic carbonate compounds and chain carbonate compounds.
As still further schemes, the fluoro compound is selected from any one or more of fluorinated carboxylic ester compounds, fluorinated ether compounds and fluorinated aromatic compounds.
In still a further embodiment, the low-impedance composite electrolyte according to the present invention is characterized in that the additive is at least one selected from the group consisting of lithium salt compounds, nitrile compounds, organic silicon compounds, sultone compounds, and sulfate compounds.
In still a further aspect, in the low-impedance composite electrolyte according to the present invention, the inorganic electrolyte salt is at least one selected from the group consisting of borates, phosphates, sulfates, nitrides, antimonates, arsenates, and chlorates.
As a further aspect, the inorganic electrolyte salt is substituted with fluorine.
As still further aspects, the initiator is selected from one or more of ammonium persulfate, sodium persulfate, potassium persulfate, hydrogen peroxide, t-butyl peroxide, dibenzoyl peroxide, and azobisisobutyronitrile.
The safe semi-solid battery also comprises a positive plate, a negative plate and a separation film.
As a further aspect, the positive electrode sheet includes a positive electrode active material, a positive electrode binder, and a positive electrode conductive agent, and a positive electrode current collector.
As still further embodiments, the positive electrode active material is at least one selected from the group consisting of transition metal composite oxides and transition metal phosphate compounds.
As a still further scheme, the chemical general formula of the transition metal composite oxide is any one selected from (A)xM11-pB1pO2、r(A)2Mn1-qB2qO3·(1-r)AM21-sB3sB3O2、(A)y(M32-hB4h)2O4, x is more than or equal to 0.05 and less than or equal to 0.4, p is more than or equal to 0 and less than or equal to 0.4, q is more than or equal to 0 and less than or equal to 0.4, s is more than or equal to 0 and less than or equal to 1, Y is more than or equal to 1.2 and h is more than or equal to 0 and less than or equal to 0.8, wherein A is a removable active metal ion, specifically comprises any one or more of Li+, na+, K+, mg2+ and Ca2+, M1 and M2 、 M3 are one or more transition metal elements, specifically scandium (Sc), yttrium (Y), lanthanoid (from lanthanum (La) to lutetium (Lu)), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), B1, B2, B3, B4 are doping elements, specifically aluminum (Al), cobalt (Co), magnesium (Mg), tantalum (Ta), tungsten (W), niobium (Nb), zirconium (Zr), calcium (Ca), one or more of vanadium (V), molybdenum (Mo), chromium (Cr), lanthanum (La), scandium (Sc), lutetium (Lu), yttrium (Y), and boron (B).
As a still further scheme, the chemical general formula of the transition metal phosphate compound is (C) z(M41-vB5v)PO4, 0<z is less than or equal to 1,0 is less than or equal to V is less than or equal to 0.4, C represents a removable active metal ion and specifically comprises any one or more of Li+, na+, K+, mg2+ and Ca2+, M4 represents one or more transition metal elements, specifically including scandium (Sc), yttrium (Y), lanthanoid (from lanthanum (La) to lutetium (Lu)), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), B5 is a doping element, specifically including aluminum (Al), cobalt (Co), magnesium (Mg), tantalum (Ta), tungsten (W), niobium (Nb), zirconium (Zr), calcium (Ca), vanadium (V), molybdenum (Mo), chromium (Cr), lanthanum (La), zirconium (Zr), scandium (Sc), lutetium (Lu), yttrium (Y), and boron (B).
As still further aspects, the positive electrode binder is selected from at least one of thermoplastic resin, acrylic resin, sodium carboxymethyl cellulose, and styrene butadiene rubber.
As still further aspects, the positive electrode conductive agent is selected from a carbon material, a metal material, or a material prepared by conductive in situ curing.
As a still further aspect, the positive electrode current collector is a metal foil layer selected from any one of aluminum, zinc, magnesium, titanium, nickel, and copper
As a further aspect, the negative electrode sheet includes a negative electrode active material, a negative electrode binder, a negative electrode conductive agent, and a negative electrode current collector.
As still further aspects, the anode active material may be provided with a coating layer on the surface thereof, or may be mixed with another compound having a coating layer.
As still further aspects, the coating is at least one of an oxide of a coating element, a hydroxide of a coating element, a oxyhydroxide of a coating element, a carbonate or nitrate or phosphate or borate of a coating element, and a hydroxycarbonate of a coating element.
As a still further aspect, the coating element compound is amorphous or/and crystalline.
As a still further aspect, the separator is provided with a porous layer of at least one surface.
As a still further aspect, the porous layer includes inorganic particles and a porous layer binder.
As a further scheme, the thickness of the diaphragm layer is selected from 12-20 mu m.
As a further aspect, a safe semi-solid battery is prepared by the method of:
The battery is prepared by a conventional method, and after the battery is formed, a secondary liquid injection mode is adopted to inject the low-impedance composite electrolyte into the battery, and the safe semi-solid battery is obtained by polymerization and solidification for 2-20 hours at 45-75 ℃.
As a further scheme, the battery prepared by the conventional method contains a primary injection electrolyte.
As a further scheme, the primary injected electrolyte can be understood as an electrolyte conventionally adopted in the prior art, and the type of the primary injected electrolyte is not limited in the invention.
As a further scheme, for the purpose of convenient operation, the primary injection electrolyte can be the same as the types and the content proportions of the solvent, the additive and the inorganic electrolyte salt in the low-impedance composite electrolyte.
As a further scheme, the mass ratio of the primary injection electrolyte to the low-impedance composite electrolyte is 1:0.24-1:0.35.
As a further scheme, the curing temperature is selected from 50-70 ℃ and the curing time is selected from 3-10 h.
Compared with the prior art, the invention has at least the following beneficial effects:
According to the low-impedance composite electrolyte and the safe semi-solid battery, the polymer monomer I and the polymer monomer II are introduced into the electrolyte, a uniform, stable and strong-expansion-resistance three-dimensional network structure is built by using the polymer monomer I and the polymer monomer II, meanwhile, the cross-linking and activation sites are optimized through the adjacent-C=C and-COO-groups in the polymer monomer I, the occurrence of side reaction is avoided, the-Si-O is further introduced on the basis, the HF content is reduced, the stability and the flexibility of the electrolyte are further improved, the battery impedance is further reduced by introducing carbonyl and triazine rings in the polymer monomer II, and the problem of high impedance of the battery when the polymer monomer is used as an electrolyte material is solved.
The safety semi-solid battery containing the low-impedance composite electrolyte has excellent safety, has ultrahigh passing rate and lower explosion pressure in a 10-hour overcharge test, inhibits the expansion of the battery, improves the cycle performance of the battery, and simultaneously endows the safety semi-solid battery with ultralow impedance through a unique polymer monomer structure, and the low-impedance composite electrolyte and the safety semi-solid battery with high safety and electrochemical capacity are obtained.
Detailed Description
The battery electrolyte of the present invention will be more fully described below for ease of understanding, and examples of the present invention are given, but the scope of the present invention is not limited thereby.
The invention provides a safe semi-solid battery, which comprises a semi-solid electrolyte constructed by polymer monomers dispersed in low-impedance composite electrolyte, wherein the polymer monomers comprise a polymer monomer I and a polymer monomer II, the structural formula of the polymer monomer I is as follows,
Wherein R 1-R3 is selected from alkyl, alkoxy, haloalkyl or haloalkoxy of C 1-C4, R 4 is selected from alkylene or halocarbyl of C 1-C6, R 5 is selected from alkyl or haloalkyl of C 1-C2;
the structural formula of the polymer monomer II is
Wherein R 6、R7、R8 is selected from the group consisting of alkylene or halogenated hydrocarbon groups of C 1-C4.
In the development of the low-impedance composite electrolyte of the safe semi-solid battery, by introducing adjacent-C=C and-COO-groups into the polymer monomer I and the polymer monomer II, the ionic conductivity of the battery is further improved, the internal impedance is effectively reduced, and the decomposition and side reaction of the electrolyte are reduced on the basis of realizing the crosslinking and curing of the electrolyte. Furthermore, the introduction of the adjacent-c=c and-COO-groups also optimizes the cross-linking structure and the active sites, further enhancing the electrochemical performance of the battery. In the polymer monomer I, a-Si-O group is further introduced, so that the ion conductivity can be effectively improved, the HF content can be reduced, and the stability and flexibility of the electrolyte after solidification can be enhanced. And for the polymer monomer II, the introduction of carbonyl groups on the basis of adjacent-C=C and-COO-can effectively identify and guide the transmission and transportation of ions, and a high-efficiency ion transmission channel which only passes through the ions is constructed.
In the present invention we propose a polymer monomer I comprising both-c=c, -Si-O and-COO-groups. The polymer monomer I with the coexistence of three functional groups is beneficial to optimizing the crosslinking site to the greatest extent, improves the compounding effect among the three, effectively avoids side reactions possibly generated due to the dispersion of the functional groups among different substances by the design of the monomer I, further improves the safety performance of the safe semi-solid battery, further introduces the polymer monomer II based on the curing monomer I, further builds a stable, uniform and strong-expansion-resistant three-dimensional network structure through the compounding of the polymer monomer II and the curing monomer I, and further introduces carbonyl and triazine rings on the basis of-C=C, -Si-O and-COO-groups, thereby greatly reducing the impedance of the safe semi-solid battery and obtaining the safe semi-solid battery with high safety and low resistance.
According to the safe semi-solid battery containing the low-impedance composite electrolyte, the invention also provides the low-impedance composite electrolyte which comprises a polymer monomer I and a polymer monomer II for constructing the semi-solid electrolyte in situ.
According to the low-impedance composite electrolyte, the invention also provides a curing additive, namely a polymer monomer I and a polymer monomer II.
As some exemplary preferred embodiments, the polymer monomer I has a structure wherein the number of alkoxy groups in R 1-R3 is less than 3, R 1-R3 is selected from alkyl, alkoxy, haloalkyl or haloalkoxy groups of C 1-C2, R 4 is selected from alkylene or halocarbon groups of C 1-C3, R 5 is selected from alkyl or haloalkyl groups of C 1-C2, and R 6、R7、R8 is selected from alkylene or halocarbon groups of C 1-C2.
As a further aspect, the present invention also provides that the polymer monomer I is selected from
The polymer monomer II is selected from tris (2-acryloyloxyethyl) isocyanurate.
As a further scheme, the ratio of the polymer monomer I to the polymer monomer II is selected from 3:1-30:1, when the ratio of the polymer monomer I to the polymer monomer II is more than 30:1, the higher polymer monomer I may cause insufficient three-dimensional network structure, so that the battery is difficult to inhibit the expansion phenomenon in the cycle process and reduce the cycle stability of the battery, and when the ratio of the polymer monomer I to the polymer monomer II is less than 6:1, the integrity of the three-dimensional network structure is improved, but the impedance is increased due to the reduction of the content of the polymer monomer I, and the retention rate and the rate capability of the battery at normal temperature cycle capacity are affected. Therefore, the reasonable and vital proportion of the polymer monomer I and the polymer monomer II is ensured, so that the battery has good expansion inhibition capability and long-term cycling stability, and the optimization of the electrochemical performance of the battery is considered.
As a further scheme, in order to consider the battery multiplying power performance, the cycle performance and the safety in the use process, the proportion range of the polymer monomer I and the polymer monomer II is preferably 6:1-15:1, when the proportion range of the polymer monomer I and the polymer monomer II is selected from 6:1-15:1, the compounding effect of the polymer monomer I and the polymer monomer II can be exerted to the greatest extent, a stable and uniform three-dimensional network frame can be constructed, network crosslinking sites can be further improved, an ion transmission path is optimized, the internal resistance is reduced, and when the proportion range of the polymer monomer I and the polymer monomer II is preferably 6:1-15:1, the safe semi-solid battery with high cycle capacity, high safety and low resistance is obtained.
As a further scheme, the mass content of the curing additive in the low-impedance composite electrolyte is 0.1% -8%, the mass content of the curing additive in the low-impedance composite electrolyte is critical, when the mass content of the curing additive is higher than 8%, excessive curing additive can cause excessive crosslinking of the three-dimensional frame, on one hand, the ion transmission path is prolonged, the transmission path is complicated, on the other hand, the interface resistance is improved, the electrochemical performance of the battery is influenced, and when the mass content of the curing additive is lower than 0.1%, the construction of the three-dimensional frame cannot be realized, so that the battery is difficult to inhibit the swelling phenomenon in circulation, the circulation performance and the safety performance are poor, and meanwhile, the electrochemical performance of the battery is influenced because the too low content of the curing additive cannot contribute to the ion-conducting capacity, so that in order to further improve the electrochemical performance and the safety performance of the battery, a reasonable content balance must be found on the premise of keeping the electrolyte performance and the battery efficiency.
As a still further scheme, the content of the curing additive in the low-impedance composite electrolyte is preferably 1% -6%, when the content is 0.1% -8%, the increase of the content of the curing additive is accompanied by the gradual stabilization and uniformity of the three-dimensional framework, so that the volume stability of the battery is synchronously improved, the explosion pressure is gradually reduced, meanwhile, the improvement of the content of the solid-state additive is also beneficial to optimizing the interface impedance and improving the electrochemical performance of the battery, when the content of the solid-state additive is controlled within 1% -6%, a safe semi-solid battery with balanced safety and multiplying power performance can be obtained, when the content of the solid-state additive is controlled within 1% -6%, and when the content of the solid-state additive is higher than 6%, the interface impedance can be improved, and when the content of the solid-state additive is lower than 1%, the three-dimensional framework with higher stability and ion conducting capacity can not be obtained, so that the content of the solid-state additive in the low-impedance composite electrolyte is preferably 1% -6%.
As a further scheme, the low-impedance composite electrolyte also comprises a solvent, an additive, an inorganic electrolyte salt and an initiator.
As still further schemes, the solvent is selected from one or more of carbonate compounds, carboxylate compounds, fluoro compounds, ethers and epoxy compounds.
As still further schemes, the carbonate compounds are selected from any one or more of cyclic carbonate compounds and chain carbonate compounds.
As still further scheme, the cyclic carbonate compound is selected from any one or more of ethyl carbonate, ethylene carbonate, propylene carbonate, methyl ethylene carbonate, fluoroethylene carbonate, chloroethylene carbonate, vinylene carbonate, ethylene carbonate, fluoroethylene carbonate, trifluoromethyl ethylene carbonate and difluoro ethylene carbonate.
As a still further scheme, the chain carbonate compound is selected from any one or more of dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, ethylene propyl carbonate, dipropyl carbonate and methyl ethyl carbonate.
As still further schemes, the carboxylic ester compounds are selected from any one or more of ethyl propionate, propyl propionate, ethyl butyrate, propyl acetate, butyl acetate, methyl acetate and ethyl acetate.
As still further schemes, the fluoro compound is selected from any one or more of fluorinated carboxylic ester compounds, fluorinated ether compounds and fluorinated aromatic compounds.
As still further scheme, the fluorinated carboxylic ester compound is selected from any one or more of ethyl difluoroacetate, ethyl trifluoroacetate, ethyl trifluoropropionate, methyl trifluoropropionate, ethyl tetrafluoroacetate, methyl trifluoroacetate and ethyl difluoropropionate.
As still further schemes, the fluorinated ether compounds are selected from any one or more of fluoroether, methyl (2, 2-trifluoroethoxy) diethyl ether, trifluoroethyl (2, 2-trifluoroethoxy) diethyl ether, trifluoromethyl (2, 2-trifluoroethoxy) diethyl ether, fluorodi (trifluoromethyl) oxyethane, 2- (2, 2-trifluoroethoxy) -1, 1-trifluoroethane, fluorotriethyl ether, perfluoro-2-butoxyethanol, pentafluoro-1-propyldiethyl ether.
As still further scheme, the fluorinated aromatic hydrocarbon compound is selected from any one or more of fluorobenzene, difluorobenzene, trifluorobenzene, perfluoromethylbenzene, tetrafluorobenzene, pentafluorobenzene, perfluorobenzene, fluorotoluene and fluoroterphenyl.
As still further scheme, the ether compound is selected from any one or more of 1, 2-dimethoxyethane, diglyme, triglyme, tetrahydrofuran, 1, 3-dioxolane, dimethoxymethane, 1, 2-dimethoxypropane, diethoxymethane, polyoxyethylene dimethyl ether, methoxypropoxypropane and ethylene glycol dimethyl ether.
As still further embodiments, the epoxy compound is selected from any one or more of ethylene oxide, propylene oxide, butylene oxide, cyclohexane oxide, benzene epoxide, 1, 2-epoxyheptane, 1, 2-epoxyoctane, 1,3 dioxolane, 1,3 dioxane, 1,4 dioxane.
In still a further embodiment, the low-impedance composite electrolyte according to the present invention is characterized in that the additive is at least one selected from the group consisting of lithium salt compounds, nitrile compounds, organic silicon compounds, sultone compounds, and sulfate compounds.
As still further aspects, the lithium salt compound is at least one selected from the group consisting of lithium difluorophosphate, lithium difluorooxalato borate, lithium bisoxalato borate, lithium tetrafluoroborate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethylsulfonate imide, lithium nitrate, lithium hexafluorophosphate, lithium difluorosulfonyl imide, lithium bistrifluoromethylsulfonyl imide, lithium fluoride, and lithium chloride.
As still further embodiments, the nitrile compound is at least one selected from adiponitrile, succinonitrile, hexanetrinitrile, propionitrile, benzonitrile, acetonitrile, isobutyronitrile.
As still further embodiments, the organosilicon compound is selected from at least one of tris (trimethylsilane) phosphate, tris (trimethylsilane) phosphite, tris (trimethylsilane) borate, polydimethylsiloxane, trimethylchlorosilane.
As still further embodiments, the sultone compound is at least one selected from the group consisting of 1,3 propane sultone, 1,3 propene sultone, benzene sultone, cyclohexene sultone, cyclopentene sultone, vinyl sultone, octyl sultone, and phenyl sultone.
As still further embodiments, the sulfate compound is at least one selected from the group consisting of vinyl sulfate, dimethyl sulfate, ethyl sulfate, propylene sulfate, dimethoxyethane sulfate, and methoxy sulfate.
In still a further aspect, in the low-impedance composite electrolyte according to the present invention, the inorganic electrolyte salt is at least one selected from the group consisting of borates, phosphates, sulfates, nitrides, antimonates, arsenates, and chlorates.
As a further aspect, the inorganic electrolyte salt is substituted with fluorine.
As still further aspects, the inorganic electrolyte salt is selected from LiPF 6、NaPF6.
As still further aspects, the initiator is selected from one or more of ammonium persulfate, sodium persulfate, potassium persulfate, hydrogen peroxide, t-butyl peroxide, dibenzoyl peroxide, and azobisisobutyronitrile.
The safe semi-solid battery also comprises a positive plate, a negative plate and a separation film.
As a further aspect, the positive electrode sheet includes a positive electrode active material, a positive electrode binder, and a positive electrode conductive agent, and a positive electrode current collector.
As still further embodiments, the positive electrode active material is at least one selected from the group consisting of transition metal composite oxides and transition metal phosphate compounds.
As a still further scheme, the chemical general formula of the transition metal composite oxide is any one selected from (A)xM11-pB1pO2、r(A)2Mn1-qB2qO3·(1-r)AM21-sB3sB3O2、(A)y(M32-hB4h)2O4, x is more than or equal to 0.05 and less than or equal to 0.4, p is more than or equal to 0 and less than or equal to 0.4, q is more than or equal to 0 and less than or equal to 0.4, s is more than or equal to 0 and less than or equal to 1, Y is more than or equal to 1.2 and h is more than or equal to 0 and less than or equal to 0.8, wherein A is a removable active metal ion, specifically comprises any one or more of Li+, na+, K+, mg2+ and Ca2+, M1 and M2 、 M3 are one or more transition metal elements, specifically scandium (Sc), yttrium (Y), lanthanoid (from lanthanum (La) to lutetium (Lu)), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), B1, B2, B3, B4 are doping elements, specifically aluminum (Al), cobalt (Co), magnesium (Mg), tantalum (Ta), tungsten (W), niobium (Nb), zirconium (Zr), calcium (Ca), one or more of vanadium (V), molybdenum (Mo), chromium (Cr), lanthanum (La), scandium (Sc), lutetium (Lu), yttrium (Y), and boron (B).
As a still further scheme, the chemical general formula of the transition metal phosphate compound is (C) z(M41-vB5v)PO4, 0<z is less than or equal to 1,0 is less than or equal to V is less than or equal to 0.4, C represents a removable active metal ion and specifically comprises any one or more of Li+, na+, K+, mg2+ and Ca2+, M4 represents one or more transition metal elements, specifically including scandium (Sc), yttrium (Y), lanthanoid (from lanthanum (La) to lutetium (Lu)), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), B5 is a doping element, specifically including aluminum (Al), cobalt (Co), magnesium (Mg), tantalum (Ta), tungsten (W), niobium (Nb), zirconium (Zr), calcium (Ca), vanadium (V), molybdenum (Mo), chromium (Cr), lanthanum (La), zirconium (Zr), scandium (Sc), lutetium (Lu), yttrium (Y), and boron (B).
As still further aspects, the positive electrode binder is selected from at least one of thermoplastic resin, acrylic resin, sodium carboxymethyl cellulose, and styrene butadiene rubber.
As still further aspects, the thermoplastic resin includes at least one of polyvinylidene fluoride, a copolymer of vinylidene fluoride, polytetrafluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene, a copolymer of tetrafluoroethylene-perfluoroalkyl vinyl ether, a copolymer of ethylene-tetrafluoroethylene, a copolymer of vinylidene fluoride-trifluoroethylene, a copolymer of vinylidene fluoride-trichloroethylene, a copolymer of vinylidene fluoride-fluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene, thermoplastic polyimide, polyethylene, and polypropylene.
As a further aspect, the acrylic resin includes at least one of vinyl acrylate resin, methyl acrylate resin, butyl acrylate resin, styrene acrylate resin, acrylate copolymer resin, acrylic resin, and acrylic emulsion resin.
As still further aspects, the positive electrode conductive agent is selected from a carbon material, a metal material, or a material prepared by conductive in situ curing.
As still further aspects, the carbon material is selected from any one of carbon nanotubes, graphite, graphene, carbon fibers, activated carbon, super P.
As a still further aspect, the metal material is selected from simple substance or oxide of any one element of silver, copper, nickel, cobalt, aluminum, titanium, rhodium, gold.
As a still further aspect, the positive electrode current collector is a metal foil layer selected from any one of aluminum, zinc, magnesium, titanium, nickel, and copper.
As a further aspect, the negative electrode sheet includes a negative electrode active material, a negative electrode binder, a negative electrode conductive agent, and a negative electrode current collector.
As still further aspects, the negative electrode active material is selected from at least one of natural graphite, artificial graphite, mesophase micro carbon spheres, hard carbon, soft carbon, silicon (oxygen) -carbon composite, alloy compound, sn, snO, snO 2.
As still further aspects, the anode active material may be provided with a coating layer on the surface thereof, or may be mixed with another compound having a coating layer.
As still further aspects, the coating is at least one of an oxide of a coating element, a hydroxide of a coating element, a oxyhydroxide of a coating element, a carbonate or nitrate or phosphate or borate of a coating element, and a hydroxycarbonate of a coating element.
As a still further aspect, the coating element compound is amorphous or/and crystalline.
In still a further scheme, the coating element is any one or more of magnesium (Mg), aluminum (Al), cobalt (Co), K, na, calcium (Ca), silicon (Si), titanium (Ti), vanadium (V), tin (Sn), germanium (Ge), gallium (Ga), boron (B), arsenic (As), zirconium (Zr), tantalum (Ta), niobium (Nb), lanthanum (La).
As still further aspects, the kind of the negative electrode binder is not limited, and the skilled person may select at least one of styrene-butadiene rubber, aqueous acrylic resin, carboxymethyl cellulose, sodium carboxymethyl cellulose, and polyacrylate according to actual needs.
As still further aspects, the kind of the negative electrode conductive agent is not limited, and a skilled person may select according to actual needs, and the negative electrode conductive agent includes at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, multi-arm carbon nanotubes, single-wall carbon nanotubes, graphene, conductive carbon black, and carbon nanofibers.
As a further scheme, the negative electrode current collector is selected from metal materials, including any one metal foil layer of copper, aluminum, nickel and tin.
As a further aspect, the separator is selected from at least one of polyethylene, polypropylene, polyethylene terephthalate, polyimide, and aramid.
As a still further aspect, the separator is provided with a porous layer of at least one surface.
As a still further aspect, the porous layer includes inorganic particles and a porous layer binder.
As still further aspects, the inorganic particles are selected from at least one of alumina, silica, magnesia, titania, hafnia, tin oxide, ceria, nickel oxide, zinc oxide, calcium oxide, zirconia, yttria, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, and barium sulfate.
As still further aspects, the porous layer is adhered to at least one selected from polyvinylidene fluoride-hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, and polyhexafluoropropylene
As a further scheme, the thickness of the diaphragm layer is selected from 12-20 mu m.
As a further aspect, a safe semi-solid battery is prepared by the method of:
The battery is prepared by a conventional method, and after the battery is formed, a secondary liquid injection mode is adopted to inject the low-impedance composite electrolyte into the battery, and the safe semi-solid battery is obtained by polymerization and solidification for 2-20 hours at 45-75 ℃.
By the secondary liquid injection method, adverse effects possibly caused by subsequent operation of primary liquid injection on the low-impedance composite electrolyte are effectively avoided, and key parameters in the polymerization curing process are controlled, so that the electrolyte is cured under the optimized condition, and the consistency and the repeatability of the battery performance are improved.
As a further scheme, the battery prepared by the conventional method contains a primary injection electrolyte.
As a further scheme, the primary injected electrolyte can be understood as an electrolyte conventionally adopted in the prior art, and the type of the primary injected electrolyte is not limited in the invention.
As a further scheme, for the purpose of convenient operation, the primary injection electrolyte can be the same as the types and the content proportions of the solvent, the additive and the inorganic electrolyte salt in the low-impedance composite electrolyte.
As a further scheme, the mass ratio of the primary injection electrolyte to the low-impedance composite electrolyte is 1:0.24-1:0.35.
As a further scheme, the curing temperature is selected from 50-70 ℃ and the curing time is selected from 3-10 h, the in-situ curing effect can be optimized by the higher curing temperature and the longer curing time, and a more stable safe semi-solid battery is obtained, so that the capacity retention rate is gradually increased by 200 circles of normal temperature circulation along with the gradual increase of time and temperature, the explosion pressure is gradually reduced, and the safety is gradually increased, however, the rate performance and the battery impedance are influenced while the crosslinking degree of the polymer monomer is increased by the temperature, and the slight fluctuation is shown, so that the optimal balance of the battery performance is ensured, the curing temperature is preferably 50-70 ℃ and the curing time is preferably 3-10 h.
The technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The chemical raw materials referred to in the following examples and comparative examples are all prior art and are all commercially available. The experimental apparatus, test apparatus, etc. referred to in the following examples and comparative examples are conventional in the art, and are not particularly required or limited.
Example 1
Preparation of lithium ion safe semi-solid battery
Mixing positive active materials of lithium cobaltate, a conductive agent Super P, polyvinylidene fluoride and carbon nano tubes according to the weight ratio of 95:2:2.5:0.5, adding N-methyl pyrrolidone, and uniformly stirring under the action of a vacuum stirrer to obtain positive slurry, wherein the solid content of the positive slurry is 70wt%. And uniformly coating the obtained anode slurry on an anode current collector aluminum foil, drying the aluminum foil coated with the anode slurry at 90 ℃, and then carrying out cold pressing, cutting and slitting to obtain the anode plate.
Mixing negative electrode active material graphite, silicon (oxygen), carboxymethyl cellulose, binder styrene-butadiene rubber, polyacrylate, multi-arm carbon nano tube and single-wall carbon nano tube according to the weight ratio of 85.5:10:0.6:1.3:2:0.5:0.1, adding deionized water, and obtaining negative electrode slurry under the action of a vacuum stirrer. And (3) uniformly coating the negative electrode slurry on a negative electrode current collector copper foil, drying the copper foil at 80 ℃, and then carrying out cold pressing, cutting and slitting to obtain the negative electrode plate.
In a dry argon atmosphere glove box, the EC/EMC (1:9, wt.) solvent, 0.5% vinyl sulfate and 8% fluoroethylene carbonate were dissolved and stirred well, and then 1.1M LiPF 6 was added and mixed well to obtain a primary injected electrolyte. And uniformly mixing 20% of electrolyte with the polymer monomer and ammonium persulfate to obtain the low-impedance composite electrolyte (the polymer monomer, the addition amount and the types are shown in table 1).
The isolating film is 16 μm thick polyethylene isolating film.
Sequentially stacking the positive plate, the isolating film and the negative plate, enabling the isolating film to be positioned between the positive plate and the negative plate, playing a role of isolation, placing the positive plate, the isolating film and the negative plate in an outer packaging foil aluminum plastic film after welding the electrode lugs, drying, injecting the primary liquid injection electrolyte, vacuum packaging, standing, forming, adding the low-impedance composite electrolyte, fully standing, heating, polymerizing and solidifying (heating temperature and polymerization time are shown in table 1), and obtaining the safe semi-solid battery after capacity test.
Examples 2 to 15
Some of the parameters in example 1 were changed, and the rest was used to prepare a safe semi-solid battery in the same manner as in example 1, with the parameter change shown in table 1.
EXAMPLE 16 preparation of sodium-ion safe semi-solid Battery
Mixing Na 0.44MnO2, a conductive agent Super P, polyvinylidene fluoride and a carbon nano tube according to a weight ratio of 95:2:2.5:0.5, adding N-methyl pyrrolidone to prepare positive electrode slurry, coating the positive electrode slurry on a positive electrode current collector aluminum foil, drying the aluminum foil coated with the positive electrode slurry at a temperature of 90 o ℃, and then carrying out cold pressing, cutting and slitting to obtain the positive electrode plate.
Mixing the anode active material hard carbon, carboxymethyl cellulose, a binder styrene-butadiene rubber, polyacrylate, multi-arm carbon nanotubes and single-wall carbon nanotubes according to the weight ratio of 85.5:0.6:1.3:2:0.5:0.1, adding deionized water, and obtaining anode slurry under the action of a vacuum stirrer. And (3) uniformly coating the negative electrode slurry on a negative electrode current collector copper foil, drying the copper foil at 80 o ℃, and then carrying out cold pressing, cutting and slitting to obtain the negative electrode plate.
In a dry argon atmosphere glove box, the EC/EMC (1:9, wt.) solvent, 0.5% vinyl sulfate, 8% fluoroethylene carbonate were dissolved and stirred well, and then 1.1M NaPF 6 was added and mixed well to obtain a primary injected electrolyte. And uniformly mixing 20% of electrolyte with the polymer monomer and ammonium persulfate to obtain the low-impedance composite electrolyte (the polymer monomer, the addition amount and the types are shown in table 1).
The isolating film is 16 μm thick polyethylene isolating film.
Sequentially stacking the positive plate, the isolating film and the negative plate, enabling the isolating film to be positioned between the positive plate and the negative plate, playing a role of isolation, placing the positive plate, the isolating film and the negative plate in an outer packaging foil aluminum plastic film after welding the electrode lugs, drying, injecting the primary liquid injection electrolyte, vacuum packaging, standing, forming, adding the low-impedance composite electrolyte, fully standing, heating, polymerizing and solidifying (heating temperature and polymerization time are shown in table 1), and obtaining the safe semi-solid battery after capacity test.
Comparative examples 1 to 6,8
Some of the parameters in comparative examples 1 to 6,8 were changed, and the rest was used to prepare a safe semi-solid battery in the same manner as in example 1, with the parameter change shown in Table 1.
Comparative example 7
Prepared in the same manner as in example 1 except that the low-impedance composite electrolyte was injected simultaneously with the injection of the one-shot electrolyte.
Comparative example 9
Some of the parameters in example 16 were changed, and the rest was used to prepare a safe semi-solid battery in the same manner as in example 16, with the parameter change shown in table 1.
The testing method comprises the following steps:
(1) Lithium/sodium ion battery cycle performance test
The battery was placed in a 25 o C incubator for 2 hours to reach constant temperature. The battery having reached the constant temperature was charged to a voltage of 4.45V (lithium battery) or 4V (sodium battery) at a constant current of 0.5C (25 o C), and then discharged to a voltage of 3V (lithium battery) or 1.5V (sodium battery) at a constant current of 0.5C, so that it was one cycle, and the discharge capacity was recorded. Cyclic capacity retention = discharge capacity of nth turn/discharge capacity of first turn 100%. The first-turn discharge capacity was recorded as C0.
(2) Battery rate performance test
After the battery cell is fully charged, discharging is carried out at 2C multiplying power, and discharge capacity C1, C1/C0= (C1-C0)/C0 is 100%.
(3) Battery impedance testing
And after the battery core is fully charged at 25 ℃, clamping two lugs of the battery core by using a BK-300A battery internal resistance tester, wherein the reading is the internal resistance.
(4) Overcharge test
Cell 1C was charged to 6V and then maintained for 10 hours without ignition and explosion, and the test was considered to pass, 10 replicates per formulation, overcharge test pass = battery amount passed/10.
(5) Explosion pressure test
Under the full charge condition, the battery is heated in a closed furnace chamber until the battery explodes, and the gas pressure in the furnace chamber is tested when the battery explodes.
Test results
Examples 1-16, comparative examples 1-9, test results are shown in Table 2.
TABLE 1
Note that polymer monomer 1 is of formula I-2, polymer monomer 2 is of formula I-6, polymer monomer 3 is of formula I-8, polymer monomer 4 is of formula I-5, polymer monomer 5 is tris (2-acryloyloxyethyl) isocyanurate, polymer monomer 6 is allyl-2-cyanoacrylate, polymer monomer 7 is butadiene, polymer monomer 8 is polymethyl methacrylate, and polymer monomer 9 is polydimethylsiloxane.
TABLE 2
Examples 1-16 overall exhibited 200-cycle capacity retention, 2C capacity retention, and safer explosion pressure than comparative examples 1-9.
From examples 1 and 16, and comparative examples 1 and 9, it is apparent that the addition of the polymer monomer I and the polymer monomer II significantly enhances the electrochemical performance and the cycle stability of the lithium ion safety semi-solid battery and the sodium ion safety semi-solid battery, probably because the polymer monomer I having-c=c, -Si-O and-COO-groups and the polymer monomer II having-c=c, -COO-, carbonyl and triazine rings can effectively improve the three-dimensional crosslinked structure of the solid electrolyte, improve the flexibility of the crosslinked structure, reduce the battery impedance, inhibit side reactions such as oxidation reduction, reduce the HF content, and reduce the decomposition of the electrolyte, thereby obtaining the safety semi-solid battery with high electrochemical capacity and high safety.
Whereas from example 2, comparative examples 2,3, it can be observed that the simultaneous presence of-c=c, -Si-O and-COO-functional groups is important for improving the electrochemical capacity and safety of the safe semi-solid battery, both comparative example 2 containing only-c=c and comparative example 3 containing no-Si-O exhibit poorer cycling capacity, capacity retention and safety than example 2 under the same test conditions, probably because the complexation of-c=c, -Si-O and-COO-is of great importance for reducing the explosion pressure in order to improve the electrochemical capacity of the safe semi-solid battery.
In example 2, comparative example 4 shows another case, in comparative example 4, -c=c, -Si-O and-COO-are respectively located on different monomer polymers, and when the cyclic capacity retention and the 2C capacity retention are tested, comparative example 4 shows much lower performance than example 2, and the explosion pressure is much higher than that of example 2, which may be because, -c=c and-COO-located at ortho positions in the polymer monomer I can effectively optimize the three-dimensional frame cross-linking structure, optimize the active site, and simultaneously improve the ion conducting performance, and further, when-c=c, -Si-O and-COO-are located in the same monomer polymer, not only the ion conducting performance is further improved, but also the occurrence of harmful side reactions between the multi-monomer polymers is avoided, and the stability and safety performance of the battery are improved.
Comparative examples 5 and 6 show the case when the polymer monomer I and the polymer monomer II are added separately, and as can be seen from comparison of example 2 and comparative examples 5 and 6, the effect of compounding the polymer monomer I and the polymer monomer II is particularly important for improving the electrochemical performance and the safety performance of the battery. When only polymer monomer I is present (comparative example 5), the three-dimensional crosslinked skeleton formed by polymer monomer I may not be uniform and complete enough to inhibit battery swelling and improve cycle performance, thus comparative example 5 shows significantly lower electrochemical performance and safety than example 2, and when only polymer monomer II is added (comparative example 6), the pressure at explosion is slightly better than that of comparative example 5 but still much lower than that of example 2 due to the lack of doping of polymer monomer I, and at the same time, electrochemical performance is significantly lower, which suggests that the use of polymer monomer II alone does not meet our overall requirements for battery performance. Therefore, reasonable compounding of the polymer monomers I and II is not only the key for improving the battery performance, but also provides a new method and thought for developing high-efficiency and safe energy storage equipment, and through reasonable compounding, the electrochemical performance of the battery is cooperatively improved, the internal network structure is optimized, the electrochemical performance and stability are improved, the battery impedance and explosion pressure are reduced, and the safety performance is improved.
Example 2 and comparative example 8 show the effect of polymer monomer II, and example 2 shows much better impedance than comparative example 8, because the introduction of carbonyl group can effectively construct a high-efficiency ion transmission channel through which only ions pass, promote the formation of stable interface layer, reduce interface impedance, and on the basis that the existence of pi-electron rich aromatic triazine ring significantly reduces internal impedance, thereby obtaining a safe semi-solid battery with high safety and low impedance.
Different priming methods can also affect the electrochemical capacity and safety of a safe semi-solid battery. As can be seen from the comparison of example 2 and comparative example 7, comparative example 7 shows a capacity retention rate and a 2C battery rate much lower than that of example 2 at normal temperature cycle 200 cycles when the primary injection method is adopted, and at the same time, the explosion pressure is much higher than that of example 2, since the low-resistance composite electrolyte in the battery may be affected by the subsequent operation steps after the primary injection of the battery is completed, and the low-resistance composite electrolyte contained in the battery prepared by the secondary injection method effectively avoids these problems. Therefore, the secondary priming method is favorable for improving the consistency and the repeatability in the development process of the battery and improving the electrochemical performance and the safety.
It can be observed from comparison of examples 2 and 13 that the cyclic capacity retention rate of example 2 shows a certain improvement with gradual decrease of the siloxane group content in the structural formulas of the in-situ curing monomer I and the in-situ curing monomer II, while the results of comparison of examples 13 and 14 show that the explosion pressure is optimized when the length of the carbon chain in the silane is shortened, which indicates that the silane group with short carbon chain can effectively improve the safety of the battery, and that the reduction of the number of carbon atoms between the siloxane group and the carboxylate group can optimize the explosion pressure to a certain extent by observing examples 2 and 15.
As can be seen from comparison of examples 2, 8 and 9, when the mass ratio of the polymer monomer I to the polymer monomer II is in the range of 6:1-15:1, the safe semi-solid battery with uniform and stable structure, lower impedance, excellent cycle life and good safety performance is advantageously obtained, and therefore, according to examples 2, 8 and 9, the ratio of the polymer monomer I to the polymer monomer II is preferably 6:1-15:1.
It can be observed from comparison of examples 2 and 10-12 that, on the basis of the mass content of the curing additive in the low-impedance composite electrolyte being 0.1% -8%, the capacity retention rate of 200 cycles of normal temperature circulation shows an increasing trend to a certain extent along with the gradual increase of the total content of the polymer monomers, and the explosion pressure is also optimized, which is probably because the increase of the content of the polymer monomers in the low-impedance composite electrolyte helps to construct a more stable solid electrolyte, but at the same time, a slight decrease of the 2C multiplying power is also possible, so that the total content of the polymer monomers in the low-impedance composite electrolyte is 1% -6% according to examples 2 and 10-12 in consideration of the change of the electrochemical performance and the safety of the battery.
It can be observed from examples 1-7 that the curing time and temperature will affect the curing of the polymer monomer in the low-impedance composite electrolyte, that the higher curing temperature and longer curing time can optimize the in-situ curing effect under the reaction conditions of 45-75 ℃ and 2-20 hours to obtain a more stable safe semi-solid battery, that the capacity retention rate after 200 times of normal temperature circulation is gradually increased, that the explosion pressure is reduced and that the safety is gradually increased along with the gradual increase of the time and temperature, however, the increase of the temperature has a certain influence on the rate performance and the impedance although the crosslinking degree of the polymer monomer is increased, so that the optimal balance of the battery performance is ensured, the curing temperature is selected to be 50-70 ℃ and the curing time is 3-10 hours according to examples 1-7.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description. While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that alterations, modifications, substitutions and variations may be made in the above embodiments by those skilled in the art without departing from the scope of the invention. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

Claims (30)

1. A low-impedance composite electrolyte is characterized by comprising a curing additive, wherein the curing additive comprises a polymer monomer I and a polymer monomer II, the structural formula of the polymer monomer I is as follows,
;
Wherein R 1-R3 is selected from alkyl, alkoxy, haloalkyl or haloalkoxy of C 1-C4, R 4 is selected from alkylene or halocarbyl of C 1-C6, R 5 is selected from alkyl or haloalkyl of C 1-C2, and polymer monomer I has a-Si-O group;
the structural formula of the polymer monomer II is
;
Wherein R 6、R7、R8 is selected from alkylene or halogenated hydrocarbon groups of C 1-C4, the mass content of the curing additive in the low-impedance composite electrolyte is 0.1% -8%, and the ratio range of the polymer monomer I to the polymer monomer II is selected from 6:1-15:1.
2. The low impedance composite electrolyte according to claim 1, wherein the number of alkoxy groups in R 1-R3 is less than 3, R 1-R3 is selected from alkyl, alkoxy, haloalkyl or haloalkoxy groups of C 1-C2, R 4 is selected from alkylene or haloalkoxy groups of C 1-C3, R 5 is selected from alkyl or haloalkyl groups of C 1-C2, and R 6、R7、R8 is selected from alkylene or haloalkoxy groups of C 1-C2 in the formula of polymer monomer I.
3. The low-impedance composite electrolyte according to claim 1, wherein the content of the curing additive in the low-impedance composite electrolyte is 1% -6%.
4. The low impedance composite electrolyte of claim 1 further comprising a solvent, an additive, an inorganic electrolyte salt, and an initiator.
5. The low-impedance composite electrolyte according to claim 4, wherein the solvent is one or more selected from the group consisting of carbonate compounds, carboxylate compounds, fluoro compounds, ethers, and epoxy compounds.
6. The low-impedance composite electrolyte according to claim 5, wherein the carbonate compound is one or more selected from the group consisting of a cyclic carbonate compound and a chain carbonate compound.
7. The low-impedance composite electrolyte according to claim 5, wherein the fluorinated compound is selected from any one or more of fluorinated carboxylic acid ester compounds, fluorinated ether compounds and fluorinated aromatic compounds.
8. The low-impedance composite electrolyte according to claim 4, wherein the additive is at least one selected from the group consisting of lithium salt compounds, nitrile compounds, organic silicon compounds, sultone compounds, and sulfate compounds.
9. The low-impedance composite electrolyte according to claim 4, wherein the inorganic electrolyte salt is at least one selected from the group consisting of borates, phosphates, sulfates, nitrides, antimonates, arsenates, and chlorates.
10. The low impedance composite electrolyte according to claim 4, wherein the inorganic electrolyte salt is substituted with fluorine.
11. The low impedance composite electrolyte according to claim 4, wherein the initiator is selected from one or more of ammonium persulfate, sodium persulfate, potassium persulfate, hydrogen peroxide, t-butyl peroxide, dibenzoyl peroxide, azobisisobutyronitrile.
12. A safe semi-solid battery comprising an electrolyte constructed from the low-impedance composite electrolyte of any one of claims 1-11.
13. The safety semi-solid battery of claim 12, further comprising a positive electrode tab, a negative electrode tab, and a separator.
14. The safe semi-solid state battery of claim 13, wherein the positive electrode sheet comprises a positive electrode active material, a positive electrode binder, and a positive electrode conductive agent, a positive electrode current collector.
15. The safe semi-solid battery of claim 14, wherein the positive electrode active material is selected from at least one of a transition metal composite oxide, a transition metal phosphate compound.
16. The safe semi-solid battery according to claim 15, wherein the chemical general formula of the transition metal composite oxide is any one selected from (A)xM11-pB1pO2、r(A)2Mn1-qB2qO3·(1-r)AM21-sB3sB3O2、(A)y(M32-hB4h)2O4, x is 0.05-0.4, p is 0-0.4, q is 0-0.4, s is 0-0.4, r is 0-1, Y is 1.2, h is 0-0.8, wherein A is a removable active metal ion, specifically comprising any one or more of Li+, na+, K+, mg2+, ca2+, M1, M2 、 M3 is one or more transition metal elements, specifically scandium (Sc), yttrium (Y), lanthanoid (from lanthanum (La) to lutetium (Lu)), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), B1, B2, B3, B4 are doping elements, specifically aluminum (Al), cobalt (Co), magnesium (Mg), tantalum (Ta), tungsten (W), niobium (Nb), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), one or more of zirconium (Zr), calcium (Ca), vanadium (V), molybdenum (Mo), chromium (Cr), lanthanum (La), scandium (Sc), lutetium (Lu), yttrium (Y), and boron (B).
17. The safe semi-solid battery according to claim 15, wherein the chemical formula of the transition metal phosphate compound is (C) z(M41-vB5v)PO4, 0<z is less than or equal to 1, V is less than or equal to 0.4, C represents a removable active metal ion, specifically comprises any one or more of Li+, na+, K+, mg2+ and Ca2+, M4 represents one or more transition metal elements, specifically including scandium (Sc), yttrium (Y), lanthanoid (from lanthanum (La) to lutetium (Lu)), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), B5 is a doping element, specifically including aluminum (Al), cobalt (Co), magnesium (Mg), tantalum (Ta), tungsten (W), niobium (Nb), zirconium (Zr), calcium (Ca), vanadium (V), molybdenum (Mo), one or more of chromium (Cr), lanthanum (La), scandium (Sc), lutetium (Lu), yttrium (Y), and boron (B).
18. The safe semi-solid state battery of claim 14, wherein the positive electrode conductive agent is selected from a carbon material, a metal material, or a material prepared by conductive in situ solidification.
19. The safe semi-solid state battery of claim 14, wherein the positive current collector is selected from a metal foil layer of any one of aluminum, zinc, magnesium, titanium, nickel, copper.
20. The safety semi-solid battery of claim 13, wherein the negative electrode sheet comprises a negative electrode active material, a negative electrode binder, a negative electrode conductive agent, a negative electrode current collector.
21. The safe semi-solid battery as claimed in claim 20, wherein the negative active material has a coating layer provided on a surface thereof, or is mixed with another compound having a coating layer.
22. The safe semi-solid battery of claim 21, wherein the coating is at least one of an oxide of a coating element, a hydroxide of a coating element, a oxyhydroxide of a coating element, a carbonate or nitrate or phosphate or borate of a coating element, a hydroxycarbonate of a coating element.
23. The safe semi-solid battery of claim 22, wherein the coating element compound is amorphous or/and crystalline.
24. The safe semi-solid state battery of claim 13, wherein the separator is provided with a porous layer of at least one surface.
25. The safe semi-solid state battery of claim 24, wherein the porous layer comprises inorganic particles and a porous layer binder.
26. The safe semi-solid state battery of claim 13, wherein the separator film layer thickness is selected from 12 μιη to 20 μιη.
27. The safety semi-solid battery of claim 13, wherein the safety semi-solid battery is prepared by the method of:
The battery is prepared by a conventional method, and after the battery is formed, a secondary liquid injection mode is adopted to inject the low-impedance composite electrolyte into the battery, and the safe semi-solid battery is obtained by polymerization and solidification for 2-20 hours at 45-75 ℃.
28. The safe semi-solid battery of claim 27, wherein the battery prepared by the conventional method comprises a single-shot electrolyte.
29. The safe semi-solid battery of claim 28, wherein the mass ratio of the primary injected electrolyte to the low-impedance composite electrolyte is 1:0.24-1:0.35.
30. The safe semi-solid battery of claim 27, wherein the curing temperature is selected from 50 ℃ to 70 ℃ and the curing time is selected from 3h to 10h.
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