145 results about "Lithium ion conduction" patented technology

The application discloses a modified polyvinylidene fluoride lithium-sulfur battery positive electrode binder and a preparation method thereof, and belongs to the technical field of lithium-sulfur batteries. In the method, a modifier is connected to a polyvinylidene fluoride molecular chain through hydrogen bonds, cross-linking of the polyvinylidene fluoride molecular chain is realized, and the mechanical property of the polyvinylidene fluoride binder is improved. The introduction of the modifier reduces the crystallinity of the polyvinylidene fluoride, increases the porosity, promotes the swelling of the polyvinylidene fluoride binder in electrolyte, and increases the lithium ion conductivity. Meanwhile, the metallocycle connected to the iron atom in the modifier not only provides an adsorption site for lithium polysulfide, but also promotes the conversion of the lithium polysulfide. The modified polyvinylidene fluoride binder obtained by the method has the advantages of simple synthesis process and low cost, can significantly reduce sulfur positive electrode polarization when applied in a lithium-sulfur battery positive electrode, improves the cycle stability and rate performance of the battery, is suitable for traditional lithium battery electrode preparation processes, and is suitable for large-scale commercial application.

The present invention provides a method for producing a sulfide solid electrolyte capable of continuously and stably producing a sulfide solid electrolyte exhibiting high lithium-ion conductivity. The present invention relates to a method for producing a sulfide solid electrolyte, the method comprising: preparing a sulfide solid electrolyte raw material based on stoichiometric ratio; supplying 0.1-20 mass% of a sulfur source relative to the total amount of the sulfide solid electrolyte raw material; heating and melting the sulfide solid electrolyte raw material; and cooling the obtained melt by contact with a cooling structure. The present invention also relates to a method for producing a sulfide solid electrolyte, the method comprising: preparing a sulfide solid electrolyte raw material based on stoichiometric ratio; heating and melting the sulfide solid electrolyte raw material; cooling the obtained melt by contact with a cooling structure; and obtaining a sulfide solid electrolyte in which the excess proportion of sulfur compared to the stoichiometric composition is 0.0-5.0 mass%.

A negative electrode active material for a secondary battery includes a silicon-containing material. The silicon-containing material includes a lithium-ion conductive phase, silicon particles dispersed in the lithium-ion conductive phase, and particles containing vanadium dispersed in the lithium-ion conductive phase.

The invention discloses a high-flux interface modification method of an oxide-based all-solid-state battery and a lithium ion battery, and belongs to the technical field of solid-state lithium ion batteries. The method comprises the following steps: mixing LTFSI, PVDF-HFP, m-fluorobenzamide and LLZO powder, and adding dimethylformamide to obtain a mixed raw material; adding an organic wet grinding solvent into the mixed raw material, and carrying out ball milling to obtain interface modification slurry; and coating one side of an LLZO electrolyte sheet with the interface modification slurry, and drying to complete interface modification. According to the interface modification method disclosed by the invention, the solid electrolyte has a lithium-loving property, can be in good contact with a metal lithium negative electrode, and can generate LiFamp through an in-situ reaction; and Li3N fills up interface defects and pores, and meanwhile, lithium dendrite growth and electron permeation can be inhibited, so that the interface structure of the obtained modified layer is stable. In addition, the lithium ion conductivity at the interface is further improved, the lithium ion flux at the interface is enhanced, the cycle life of the lithium battery is prolonged, and the preparation method is simple and suitable for industrial large-scale production.

A secondary battery comprises a positive electrode layer (14), a negative electrode layer (12), and an electrolyte layer (15) for conducting lithium ions between the positive and negative electrode layers. The positive electrode layer contains a positive electrode active material (14a) containing Mn and an oxide-based ion conductor (14b) with lithium ion conductivity. The electrolyte layer contains a fluorinated lithium salt containing fluorine atoms and a solvent capable of dissolving the fluorinated lithium salt. The ion conductor is a dielectric that promotes the dissociation of lithium ions from the fluorinated lithium salt.

Provided is a lithium metal secondary battery having a novel structure in which an intermediate layer is provided between a negative electrode layer and a solid electrolyte layer, lithium metal can be uniformly deposited on the intermediate layer-side surface of the negative electrode layer, and dendrites are not easily generated. This lithium metal secondary battery is provided with a positive electrode layer, a negative electrode layer, a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, and an intermediate layer disposed between the negative electrode layer and the solid electrolyte layer, and is characterized in that: a lithium metal layer is disposed on the surface of the negative electrode layer on the intermediate layer side; and an intermediate layer insulating material that covers the outer peripheral surface of the intermediate layer, the intermediate layer insulating material not having lithium ion conductivity.

The application discloses a high lithium ion conductivity flame-retardant interface modifier and a preparation method thereof. The material is synthesized by one-pot one-step reaction of phosphorus oxychloride, diamine and alcohol ether compound, and is used in combination with lithium salt to form a flame-retardant interface modifier with high lithium ion conduction function. The molecular structure is rich in ether bonds, which can effectively coordinate with lithium ions, promote the efficient migration of lithium ions at the electrode interface, and significantly improve the cycle stability and rate performance of the solid-state battery. At the same time, the nitrogen and phosphorus elements introduced in the material endow it with excellent flame-retardant properties, which helps to improve the safety of the battery system. In addition, the modifier has good flowability and wettability, which can enhance the interface compatibility between the components in the solid-state battery. The preparation process of the application is simple, controllable, reproducible and low in cost, and is suitable for interface modification of solid-state lithium ion batteries, and has important prospects for promoting the development of high-safety, high-energy-density and low-cost solid-state batteries.

The application relates to the technical field of lithium batteries, and particularly discloses a metal lithium alloy negative electrode material and a preparation method thereof. The negative electrode material comprises a three-dimensional porous alloy framework, a porous carbon layer compounded on the surface of the three-dimensional porous alloy framework, and metal lithium at least partially filled in the pores of the three-dimensional porous alloy framework; wherein the three-dimensional porous alloy framework is a porous structure formed by metal lithium and alloy metal, and a fast ion conduction phase LiC6 is formed at the interface between the porous carbon layer and the three-dimensional porous alloy framework; and the preparation method comprises the steps of smelting, ultrasonic treatment, casting forming, rolling into a strip, corona surface treatment, composite rolling, porous carbon compounding, secondary rolling, heat treatment and the like. By constructing the three-dimensional alloy framework with the super-ion conductor characteristics and the LiC6 fast ion conduction interface layer, the lithium dendrite growth is effectively inhibited, the volume expansion is buffered, and the lithium ion conduction rate and the cycle stability are improved.

This invention provides a lithium-sulfur silver-germanium ore-based multiphase solid-state electrolyte material, its preparation method, and its application, relating to the field of solid-state battery technology. The multiphase solid-state electrolyte material comprises a metal / oxygen co-doped lithium-sulfur silver-germanium ore phase as a matrix, with heterogeneous disulfide nanoparticles dispersed at the grain boundaries of this matrix. This invention utilizes a lithium-sulfur silver-germanium ore-type solid-state electrolyte with high ionic conductivity as the matrix material and introduces high-valence metals and oxygen elements for co-doping, promoting the formation of sulfur vacancies and reducing the lithium-ion diffusion barrier. Simultaneously, the interfacial effect of the heterogeneous disulfide nanoparticles at the grain boundaries helps reduce the internal interfacial resistance of the electrolyte, further improving lithium-ion conduction efficiency. Furthermore, the high electronegativity of the high-valence metals and oxygen elements, along with the in-situ passivation effect of the heterogeneous disulfide, significantly enhances the stability of the electrolyte under high-voltage conditions, reduces side reactions between the electrolyte and the cathode material, and improves the overall cycle performance of the battery.

Provided are: a negative electrode for an all-solid-state secondary battery, which has a low resistance value; a method for producing the negative electrode; and an all-solid-state secondary battery. The present invention relates to targets 12, 3, 7, 11 of sustainable development targets (SDGs). This negative electrode for an all-solid-state secondary battery is characterized by comprising a molded body of a negative electrode mixture containing a solid electrolyte and a negative electrode material containing a negative electrode active material, the negative electrode material containing, as the negative electrode active material, a carbon material having, on the surface thereof, a layer containing an oxide having lithium ion conductivity. The carbon material contains hard carbon, the oxide contains a lithium titanium oxide, the amount of the oxide is 1 part by mass or more with respect to 100 parts by mass of the carbon material, a sulfide-based solid electrolyte is contained as the solid electrolyte, and the thickness of a molded article of the negative electrode mixture is 200 [mu] m or more and 3000 [mu] m or less.

The invention discloses a high-ionic-conductivity halide solid electrolyte material and a preparation method thereof, and belongs to the technical field of all-solid-state batteries. The chemical general formula of the solid electrolyte is Li2ZrxMyCl6. Wherein x ranges from 0.1 to 0.99, y ranges from 0.01 to 0.99 and follows the equation of 4x + 5y = 4 or 4x + 6y = 4 or 4x + 5y1 + 6y2 = 4; m is at least one of positive pentavalent or positive hexavalent metal elements. According to the invention, high-valence metal ions are used as an initiator to regulate and control the vacancy concentration of non-lithium cations in the matrix electrolyte Li2ZrCl6, and more vacancies reduce energy barriers required to be overcome by lithium ion conduction, so that the ionic conductivity is remarkably improved. The ionic conductivity of the finally obtained Zr-based halide solid electrolyte is more than 2 mS / cm. The electrolyte obtained by the method not only has high ionic conductivity, but also has a wide electrochemical window, and is suitable for manufacturing a high-performance and high-rate solid-state battery.

The invention relates to a solid-state battery with a composite interface and a preparation method of the solid-state battery. The solid-state battery comprises a positive plate, a negative plate, SEI protection layers coated on the positive plate and the negative plate, and a lithium ion conduction agent coating layer between the SEI protection layers. The SEI protective layer is formed by compounding a polymer matrix and an ion conduction lithium salt through a dip-coating method, the lithium ion conduction agent coating layer comprises an electrolyte lithium salt, a tackifier and an oxide solid electrolyte, and the lithium ion conduction agent coating layer is formed by mixing to prepare a lithium ion conduction agent and coating the lithium ion conduction agent. The problems that a traditional battery is lack of flexibility and poor in safety and an existing solid-state battery is high in interface impedance and short in cycle life are solved, cooperation of flexible protection and efficient ion conduction is achieved, the 200-circle cycle capacity retention rate reaches 90% or above, the preparation process is simple and controllable, material compatibility is good, an existing production line does not need to be transformed, industrial popularization is facilitated, and the method is suitable for industrial production. The method is suitable for energy storage scenes such as flexible electronic equipment and electric automobiles.

The invention discloses a coated and modified high-nickel polycrystalline positive electrode material and a preparation method and application thereof, the coated and modified high-nickel polycrystalline positive electrode material provided by the invention comprises secondary polycrystalline particles composed of primary particles, the primary particles are arranged along the radial direction and are in contact with each other to form a grain boundary; a first coating layer is arranged at the grain boundary of the primary particle and the surface of the secondary polycrystalline particle, and the first coating layer comprises a fast ion conductor; and a second coating layer is also arranged on the first coating layer on the surface of the secondary polycrystalline particle. According to the coated and modified high-nickel polycrystalline positive electrode material, the lithium ion diffusion coefficient of the first coating layer is high, the diffusion impedance of lithium ions at the grain boundary can be reduced, and the interface lithium ion conduction is improved; the lithium ion diffusion coefficient of the second coating layer is lower than that of the first coating layer, and the second coating layer is used as a protective layer and can prevent the interface side reaction of the high-nickel polycrystalline positive electrode material and electrolyte, so that the electrochemical performance of the high-nickel polycrystalline positive electrode material is greatly improved.

Provided are: a negative electrode for an all-solid-state secondary battery, which has a low resistance value; a method for producing the negative electrode; and an all-solid-state secondary battery. The present invention relates to targets 12, 3, 7, 11 of sustainable development targets. The negative electrode for an all-solid-state secondary battery is characterized by comprising a molded body of a negative electrode mixture containing a solid electrolyte and a negative electrode material containing a negative electrode active material, the negative electrode material containing, as the negative electrode active material, a carbon material having, on the surface thereof, a layer containing an oxide having lithium ion conductivity. The carbon material contains at least one of graphite and hard carbon, the oxide contains at least one of lithium niobium oxide, lithium titanium oxide and lithium phosphorus oxide, the amount of the oxide is 1 part by mass or more with respect to 100 parts by mass of the carbon material, and a sulfide-based solid electrolyte is contained as the solid electrolyte. The thickness of the molded body of the negative electrode mixture is 200 [mu] m or more and 3000 [mu] m or less.

The application provides a lithium manganese iron phosphate positive electrode material and a surface lithiumation compensation process thereof, and belongs to the technical field of new energy batteries. The compensation process comprises the following steps: providing a lithium manganese iron phosphate base material; constructing an interface stabilization layer on the surface of the base material, wherein the interface stabilization layer is a rare earth oxide layer; and constructing a composite functional layer on the interface stabilization layer, wherein the composite functional layer comprises carbon material and composite fluoride, and the composite functional layer simultaneously provides stress buffering and lithium ion conduction functions. The lithium ion battery prepared from the lithium manganese iron phosphate positive electrode material has a significant improvement in cycle life and rate performance, can meet the demand of new energy vehicles and energy storage for high-performance batteries, and has a wide market application prospect.

The invention relates to an all-solid-state battery, a preparation method thereof and electronic equipment in the technical field of lithium battery production. The all-solid-state battery comprises a positive electrode, a negative electrode, a solid electrolyte membrane and a flexible thin film buffer layer, the flexible thin film buffer layer is arranged between the negative electrode and the solid electrolyte membrane; the flexible film buffer layer is provided with a through hole. According to the invention, the perforated flexible film buffer layer is arranged between the negative electrode and the solid electrolyte, so that the problems of breakage and short circuit of the negative plate in the isostatic pressing process are solved. The all-solid-state battery can effectively absorb stress in the isostatic pressing process, stress concentration is avoided, and therefore the negative plate is prevented from being broken. The perforated flexible film not only plays a buffering role, but also ensures the smoothness of a lithium ion conduction path, and the electrochemical performance is improved.

The present invention provides an electrolyte, an electrode additive, and an electrode for a lithium ion secondary battery, which can improve input / output characteristics, can suppress an increase in resistance at the interface between a metal lithium negative electrode and an electrolyte after charge / discharge cycles, and can also suppress deterioration of the metal lithium negative electrode. The electrolyte according to the present invention is characterized by comprising a lithium ion conductive material selected from a glass ceramic powder having a main crystal phase represented by the following formula (1) and an average particle diameter of 5 μm or less, a garnet-type oxide powder represented by the following formula (2), and a perovskite-type oxide powder represented by the following formula (3), and an electrolyte solution containing a mixed solvent having a relative dielectric constant of 50.0 or less, wherein Li 1+x+2y+z A x Ca y T 2‑（x+y） Si z P 3‑z O 12 (1) (in formula (1), A is at least one selected from the group consisting of Al, Ga, and Y, T is at least one selected from the group consisting of Ti, Ge, and Zr, 0≤x≤1, 0≤y≤1, 0≤z≤1, 0≤x+y≤1, 0≤x+2y+z≤2), Li 5+X La3(Zr X ,A 2‑X )O 12 (2) (in formula (2), A is at least one selected from the group consisting of Sc, Ti, V, Y, Nb, Hf, Ta, Bi, Al, Si, Ga, and Ge, 1.4≤X<2), Li x La y TiO3 (3) (in formula (3), 0

The invention discloses an all-solid-state battery, a preparation method of the all-solid-state battery and a power utilization device. The all-solid-state battery comprises a positive pole piece with a high-voltage positive active material, a negative pole piece with a lithium metal negative active material and a solid electrolyte membrane, the solid-state electrolyte membrane comprises a first solid-state electrolyte layer in contact with the negative pole piece, an interface modification layer and a second solid-state electrolyte layer in contact with the positive pole piece, and the thickness of the first solid-state electrolyte layer is greater than or equal to that of the second solid-state electrolyte layer; the interface modification layer is an interface buffer layer with electronic insulation and lithium ion conduction, and the thermal expansion coefficient of the interface modification layer is between the thermal expansion coefficient of the first solid electrolyte layer and the thermal expansion coefficient of the second solid electrolyte layer. According to the solid electrolyte membrane with the layered structure, the problem of interface compatibility is solved, so that the safety of a battery is improved, and the cycle life of the battery is prolonged.

This application relates to a cathode material, comprising: a cathode active material; a first coating layer, the first coating layer coating the cathode active material, the first coating layer having an electrochemical window of 6.0V or higher; and a second coating layer, the second coating layer coating the first coating layer, the second coating layer having a lithium-ion conductivity of 10. ‑3 The positive electrode material of this application, with its double-layer coating, exhibits high electrochemical stability and lithium-ion conductivity at high charging voltages. Furthermore, this application also relates to methods for preparing the aforementioned positive electrode material, secondary batteries, battery modules, battery packs, and power-consuming devices.

This application relates to the field of lithium-ion battery technology, and particularly to functional binders and their preparation methods, and lithium-ion batteries. The functional binder has a three-dimensional network structure and comprises the following raw material components: a main binder, a functional polyurethane, and a crosslinking agent. The functional polyurethane contains heterocyclic groups and functional groups. The heterocyclic groups contain hydrogen bond acceptors and hydrogen bond donors, and the functional groups include ion-conducting groups and / or electron-conducting groups. The crosslinking agent contains hydrogen bond donors, hydrogen bond acceptors, and positively charged groups. The main binder possesses basic adhesive properties; the functional polyurethane exhibits flexibility and elasticity. The functional polyurethane also forms a complementary hydrogen bond pairing mode with the crosslinking agent, enabling the crosslinking agent to accurately identify the heterocyclic groups on the functional polyurethane, resulting in high bonding strength. The crosslinking agent and the main binder generate electrostatic adsorption. Therefore, the functional binder possesses high flexibility, elasticity, adhesive properties, lithium-ion conductivity, and / or electronic conductivity.

The present invention relates to an electrolyte composition for a lithium secondary battery. The electrolyte composition for a lithium secondary battery comprises a fluorinated linear ester solvent and a fluorinated acrylic acid-based additive as a non-aqueous organic solvent and an electrolyte additive, respectively, thus, a solid electrolyte interface layer (SEI layer) having high lithium ion conductivity and excellent heat resistance can be uniformly formed on the surface of the negative electrode during activation of the lithium secondary battery. Accordingly, since the reactivity between the negative electrode active material and the electrolyte composition is significantly reduced, the temperature (heat generation initiation temperature) at which the negative electrode active material and the electrolyte composition begin to generate heat increases, thereby suppressing heat generation due to degradation of the negative electrode, etc. In addition, the lithium secondary battery containing the electrolyte composition has the advantage of excellent high-temperature safety because it can minimize side reactions of the electrolyte composition occurring on the surface of the negative electrode when exposed to high temperatures.

The invention relates to a lithium negative electrode interface layer with micro-area temperature intelligent sensing and ion transmission dynamic regulation and control functions and a preparation method of the lithium negative electrode interface layer, and belongs to the technical field of lithium negative electrodes of secondary batteries. The thickness of the interface layer is 0.5-5 [mu] m, and a three-dimensional interpenetrating network is formed in the temperature-sensitive polymer matrix by two-dimensional bismuth telluride nanosheets; wherein the mass fraction of the two-dimensional bismuth telluride nanosheets is 20-60%, and the two-dimensional bismuth telluride nanosheets have remarkable Seebeck effect and excellent lithium ion conductivity, and can directly convert local temperature gradient into counter potential for inhibiting dendritic crystal growth; and the temperature-sensitive polymer dynamically regulates and controls an ion transmission channel through temperature-sensitive phase change. The invention further provides a preparation method of the interface layer, the intelligent interface layer is constructed on the surface of lithium metal by adopting a solvent evaporation method, self-driven thermal safety management of'sensing-response 'integration is realized, and the safety and the cycling stability of the lithium metal battery are remarkably improved.

The invention provides an amorphous substance coated positive electrode active material as well as a preparation method and application thereof. In the invention, the amorphous substance is selected from one or more of transition metal silicide, boride, phosphide, sulfide, selenide, carbide, amorphous carbon or amorphous silicon materials. The amorphous substance coating in the invention can form a compact self-healing passivation layer at the interface of the positive electrode material, not only can inhibit oxygen precipitation under high voltage in dynamics, but also can be combined with Li alkali metal to become a mixed conductor of ions and electrons, so that the conduction performance of the electrons and lithium ions is improved, and the interface impedance is reduced. Meanwhile, the surface of the positive electrode material can be uniformly coated by a special coating mode of the amorphous substance, so that side reaction between the positive electrode material and electrolyte is effectively inhibited, a solid electrolyte membrane on the surface of the positive electrode material is stabilized, formation of microcracks in the material is reduced, and the cycling stability is improved.

The invention aims to improve the low lithium ion conductivity of a conventional all-solid-state battery and to improve the performance and stability of the conventional all-solid-state battery. The present invention relates to a compound comprising a repeating unit represented by Formula 1 described herein or a lithium salt thereof, a complex comprising the compound and a lithium compound, a solid electrolyte comprising the same, and an all-solid-state battery.

The invention provides a lithium ion battery positive pole piece, a lithium ion battery comprising the lithium ion battery positive pole piece and electric equipment, and relates to the technical field of batteries. An active material coating of the positive pole piece is of a double-layer structure, the D50 particle size of a positive active material in the first active material coating is 5.0-9.5 [mu] m, and the D50 particle size of a positive active material in the second active material coating is 7.0-15.0 [mu] m; the mass ratio of the conductive agent in the first active material coating is 2-4%, and the mass ratio of the conductive agent in the second active material coating is 1-3%. Meanwhile, the sulfonated PVDF copolymer is adopted as an active substance coating adhesive, and the adhesive can remarkably improve the lithium ion conduction efficiency in the pole piece and reduce the polarization phenomenon in the charging and discharging process; in addition, the conductivity of sulfonate radicals in the binder can also cooperate with the conductive agent to optimize a pole piece electronic network, so that the rate output and cycling stability of the battery are enhanced.

This invention discloses an electrolyte and a lithium-ion battery. The electrolyte comprises a lithium salt, an organic solvent, a first additive, a second additive, and a conventional electrolyte. The first additive is a polysubstituted ethylene sulfate, the chemical structure of which is shown in Formula I. The second additive is fluoroethylene carbonate. The mass percentages a of the first additive and b of the second additive in the electrolyte satisfy: 2≤a≤4, 3≤b≤5, and 5≤|(a+b)×(a-b)|≤20. This invention, through the synergistic regulation of specific additives and their contents, can form a gradient structure SEI film with both high lithium-ion conductivity and high stability on the negative electrode surface, effectively suppressing electrolyte decomposition and side reactions under high temperature and high pressure conditions, reducing active lithium loss and interfacial impedance growth. Applying the electrolyte of this invention to lithium-ion batteries can significantly improve the cycle life, storage stability, safety performance, and rate performance of the battery under high temperature and high pressure conditions.

The invention discloses a high-load composite sulfur positive electrode, a preparation method thereof and a lithium-sulfur battery, and belongs to the technical field of lithium batteries. The high-load composite sulfur positive electrode comprises a current collector; a carbon / sulfur positive electrode layer on the current collector, wherein the carbon / sulfur positive electrode layer comprises a carbon-sulfur composite material; and a functional polymer layer on the carbon / sulfur positive electrode layer, the functional polymer layer being formed from a polymer containing an electron-deficient group. A polymer with a strong electron-deficient group is used as a positive electrode protective coating, and the inherent electron-deficient center of the polymer is utilized to adsorb anions and repel cations. The anion adsorption effect can prevent the active substance from penetrating through the polymer layer and shuttling back and forth to the negative electrode to cause capacity loss. On the other hand, dissociation of lithium ions and anions in the polymer layer can be promoted through the cation repelling effect, and lithium ion conduction is facilitated. Compared with the prior art, the method has the advantages that the problem of cracking of the high-load composite sulfur positive electrode is solved, and relatively good ion conductivity and battery capacity are still kept.

A functionalized coated separator and lithium-ion battery, by grafting and modifying the polymer backbone PVDF of the coating layer with single-ion conductor lithium salt, effectively constructs a single-lithium-ion conduction ion transport layer at the electrode / electrolyte interface without changing the original function of the coating layer. In lithium-ion battery systems, only lithium ions actually participate in the electrochemical reaction and energy conversion process. The movement of anions in the electrolyte will cause their accumulation on the electrode surface, leading to increased battery polarization and interfacial side reactions. The PVDF coating layer itself can effectively improve the adhesion between the separator and the electrode and the wettability with the electrolyte. By introducing immobilized anionic groups on the PVDF backbone, the functionalization of interfacial single-lithium-ion transport provided by this invention can further optimize the performance of the coating layer, the separator, and the liquid lithium-ion battery.

The application relates to the technical field of lithium ion batteries, and discloses a negative electrode material and a preparation method and application thereof, wherein the negative electrode material is a core-shell structure, the inner core is a silicon-based particle, and the shell comprises a first coating layer and a second coating layer; the first coating layer is attached outside the inner core, and the second coating layer is attached outside the first coating layer; the first coating layer comprises a carbon-nitrogen compound, and the second coating layer comprises a phosphate salt. The negative electrode material provided by the application takes a silicon-based particle as the inner core, and the carbon-nitrogen coating layer and the phosphate coating layer are attached outside the inner core in sequence; under the action of the double coating layers, the lithium ion conduction capacity and the electrochemical performance of the negative electrode material are effectively improved.

The invention provides a negative plate as well as a preparation method and application thereof. The negative plate comprises a negative current collector and a negative active coating coated on at least one surface of the negative current collector, the negative electrode active coating comprises composite active particles, sulfide electrolyte and a conductive agent; wherein the composite active particle comprises a core and a coating layer, the core comprises a negative electrode active material, and the coating layer comprises an elastic composite electrolyte; the negative active material comprises a silicon element; the elastic composite electrolyte comprises a nano inorganic electrolyte and a polymer electrolyte. The coating layer of the elastic composite electrolyte is formed on the surface of the negative electrode active material, so that the volume expansion of silicon can be inhibited, the reduction decomposition of sulfide electrolyte is improved, the adhesive strength of the negative electrode active coating can be enhanced, and the lithium ion conduction performance of the negative electrode plate can be enhanced.