86results about How to "Buffer volume expansion" patented technology

The invention discloses a silicon-carbon composite material and a preparation method thereof, a pole piece and a battery. The silicon-carbon composite material comprises a cluster structure and a third carbon layer coating the cluster structure, wherein the cluster structure comprises a plurality of silicon-carbon composite particles, pores are distributed among the plurality of silicon-carbon composite particles, each silicon-carbon composite particle has a core-shell structure, each silicon-carbon composite particle comprises an inner core and an outer shell coating the inner core, each outer shell sequentially comprises a first carbon layer and a second carbon layer in the direction far away from the inner core, the first carbon layer comprises a conductive carbon material with a three-dimensional structure, an annular gap exists between the second carbon layer and the first carbon layer, and the inner core comprises porous silicon nanoparticles. The battery prepared from the silicon-carbon composite material has excellent electrochemical performance.

The invention provides a porous carbon skeleton silicon-based negative electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: (1) modifying nano silicon on the surface of low-softening-point asphalt: stirring and dispersing nano silicon and low-softening-point asphalt into an organic solvent, uniformly mixing, distilling to remove the solvent, drying, and carrying out pre-oxidation treatment to obtain lipophilic nano silicon; (2) fully blending the obtained lipophilic nano silicon, fused salt and high-softening-point mesophase pitch at a high temperature, and performing crushing granulation, primary carbonization, washing and drying to obtain a primary silicon-carbon precursor of which the nano silicon is embedded in a porous carbon matrix; and (3) performing high-temperature solid-phase coating on the primary silicon-carbon precursor by using high-softening-point coating asphalt powder to obtain a secondary silicon-carbon precursor, and performing secondary carbonization to obtain the porous carbon skeleton silicon-based negative electrode material with multi-level buffering, the inner core is a porous carbon skeleton, and the outer layer is a compact carbon coating. The silicon-based negative electrode material with a porous carbon skeleton is ingeniously designed from three kinds of asphalt derived carbon, a silicon volume expansion space, an ion electron channel and expansion stress intensity are provided, the specific capacity, the conductivity and the mechanical stability of the silicon-carbon negative electrode material can be improved, and the silicon-carbon negative electrode material has excellent electrochemical performance when being used for a lithium ion battery.

The invention relates to a low-temperature graphite negative electrode material and a preparation method thereof, and belongs to the technical field of high polymer materials. According to the prepared low-temperature graphite negative electrode material, firstly, the surface of graphite is pre-oxidized through potassium persulfate, phosphorus pentoxide and concentrated sulfuric acid, and then under the action of sodium nitrate, potassium permanganate and hydrogen peroxide, graphite oxide is prepared; then, ammonium molybdate hydrate and thioacetamide are used as a molybdenum source and a sulfur source, graphite oxide is used as a supporting material, a molybdenum disulfide-graphite compound is synthesized, and the conductivity and the cycling stability are improved; secondly, the surface of the negative electrode is coated with amorphous resin carbon / nickel oxide, so that the ion diffusion efficiency of the low-temperature graphite negative electrode material is enhanced, and the electrochemical lithium storage performance is improved in a low-temperature environment; and finally, the surface of the amorphous resin carbon / nickel oxide is coated with a layer of polythiophene film, so that the rate capability of the negative electrode material is improved due to large surface area and high pores.

The invention relates to the technical field of building materials, and particularly discloses a steel slag-based composite cementing material as well as a preparation method and application thereof. The steel slag-based composite cementing material comprises 60-70 parts of modified steel slag powder, 15-25 parts of water-quenched blast furnace slag powder, 2-8 parts of gypsum, 2-8 parts of silica fume and 4-6 parts of a stabilizer, the preparation method comprises the steps of grinding and mixing. The steel slag-based composite cementing material can be used for concrete, and has the advantage of reducing the adverse effect on the stability of the concrete.

The invention relates to a double-layer coated silicon-carbon composite material, a preparation method thereof and a lithium ion battery. The preparation method comprises the following steps: adding a porous carbon precursor with a particle size D50 of 5-10 [mu] m into a chemical vapor deposition furnace, and introducing monosilane for 100-800 min for silicon deposition to obtain a silicon-carbon composite material; introducing acetylene gas, and reacting for 50 to 500 minutes to obtain a primary carbon-coated silicon carbon composite material; dissolving lithium nitrate in absolute ethyl alcohol, adding the primary carbon-coated porous silicon-carbon composite material, stirring and dispersing, dropwise adding an ammonium dihydrogen phosphate solution into the solution, and reacting at 60-80 DEG C for 1-3 hours; and carrying out suction filtration, cleaning and drying on the reacted material to obtain the porous silicon-carbon composite material with the double-layer coating structure. Through the double-layer coating structure, the electrochemical stability and mechanical stability of the material are improved, and meanwhile, the application scene of the silicon-carbon negative electrode material at low temperature is expanded.

The invention discloses a battery negative electrode material and a preparation method thereof, and relates to the technical field of batteries. The battery negative electrode material comprises an inner core, a titanium dioxide coating layer coated on the surface of the inner core, a lithium titanate coating layer coated on the surface of the titanium dioxide coating layer, a carbon coating layer coated on the surface of the lithium titanate coating layer and a polymer coating layer coated on the surface of the carbon coating layer, the inner core comprises a silicon-based negative electrode material; the polymer coating layer comprises at least one of polyaniline, polythiophene and polypyrrole. Under the action of the four coating layers, the integrity of the silicon-based negative electrode material can be kept, direct contact between the silicon-based negative electrode material and an electrolyte is avoided, side reactions are reduced, the capacity fading of the battery in the charge-discharge cycle process is reduced, and the rate capability and the cycle stability of the battery are improved.

The invention relates to the technical field of lithium ion battery materials, in particular to a coated lithium cobalt oxide positive electrode material and a positive electrode plate prepared from the coated lithium cobalt oxide positive electrode material. A binder with dynamic reversible bonds such as a hydrogen bond and a disulfide bond is synthesized through free radical polymerization among acrylamide, acrylic acid and a double-bond-terminated disulfide bond-containing compound; the preparation method comprises the following steps: doping lithium cobalt oxide with Mg, coating the surface of the lithium cobalt oxide with a conductive polymer polypyrrole, and coating the surface of the lithium cobalt oxide with an organic porous polymer prepared from a quaternary connector 5, 10, 15, 20-tetra (4-aminophenyl) porphyrin and pyromellitic dianhydride by using a large pi bond of the polypyrrole; the conductive agent is modified, (3-mercaptopropyl) trimethoxysilane is firstly used for sulfhydrylation, then sulfydryl-double bond light click is utilized, and a double-bond end-capped disulfide bond-containing compound with a reversible bond is grafted, so that the stability and the safety of the battery performance are improved.

The invention belongs to the technical field of lithium ion batteries, and relates to a high-load positive pole piece, a preparation method and a high-specific-energy battery. The positive pole piece is an electrode of a double-layer structure and comprises a current collector, a first electrode layer and a second electrode layer, wherein the first electrode layer and the second electrode layer are far away from the current collector. The specific gravity of the active substance small-particle single crystal ternary material of the first electrode layer is smaller than that of the large-particle polycrystalline ternary material, and the specific gravity of the active substance small-particle single crystal ternary material of the second electrode layer is larger than that of the large-particle polycrystalline ternary material. According to the dual-structure electrode plate, Li < + > migration paths are distributed in a tortuous gradient mode, large and small particles have a synergistic effect, a rapid electrolyte diffusion channel and a rapid lithium ion diffusion channel are achieved, the first electrode layer serves as a rapid transmission layer, the second electrode layer serves as a reaction balance layer, the concentration polarization problem in a thick electrode is effectively solved, the positive electrode capacity can be brought into play, and the service life of the electrode plate is prolonged. The battery energy density is improved. Meanwhile, the prepared positive electrode slurry is heated, high solid content is achieved, the use amount of a solvent is reduced, cracking of a high-load pole piece during coating is prevented, simultaneous coating and integrated preparation of the first electrode layer and the second electrode layer are achieved through the double-layer coating die head, and the interface internal resistance is reduced.

The invention relates to a negative electrode material and a preparation method thereof, and a lithium ion battery, the negative electrode material comprises a porous carbonaceous material and a silicon material, the negative electrode material has a first region located in the central region in the porous carbonaceous material, a second region distributed on the surface of the first region, and a third region distributed on the surface of the second region, the porous carbonaceous material located in the first area has first pores, the porous carbonaceous material located in the second area has second pores, the porous carbonaceous material located in the third area has third pores, at least part of the first pores are communicated with the second pores, at least part of the second pores are communicated with the third pores, and the third pores are communicated with the third pores. At least part of the third pores are communicated with the surface of the negative electrode material, the silicon material is distributed in at least one of the first pores, the second pores and the third pores, the pore diameter of the first pores is 0.1-2.2 nm, the pore diameter of the second pores is 1.8-5 nm, the pore diameter of the third pores is 3-60 nm, and the probability entropy H of the pores in the porous carbonaceous material meets 0.96 gt; hgt; and 0.70%.

The present invention discloses a SnO2-H2Ti2O5 coaxial fiber and a preparation method and application thereof. In the SnO2-H2Ti2O5 coaxial fiber, SnO2 is used as a core axis, H2Ti2O5 is used as an outer shell, the diameter distribution of the inner axis is 100-200 nm, the diameter distribution of the outer axis is 300-500 nm, and the specific surface area is 100 m 2 g ‑1 ~300 m 2 g ‑1 The present invention combines electrospinning technology and room temperature alkaline heating method to form a core-shell coaxial structure in situ, breaking through the traditional secondary coating preparation method. The overall process is simple and has strong controllability. The SnO2-H2Ti2O5 coaxial fiber prepared by the present invention has a stable nano-scale multi-level structure, which can effectively alleviate the volume expansion effect during lithium insertion, has stable cyclic lithium storage performance, and can be used as a high-performance lithium-ion battery negative electrode material.

The present invention relates to a metal organic framework material coated silicon ball lithium ion battery negative electrode material and a preparation method thereof. The present invention adopts a one-step method to prepare a Si&ZIF‑8 lithium ion battery negative electrode material with high performance and special structure. A core-shell structure with a thickness of about 2nm is coated on the surface of a nano silicon ball with a particle size of 10nm‑100nm, and the material shows a morphology in which nano silicon balls and rhombus polyhedron ZIF‑8 coexist. The structure has a large specific surface area, ionic conductivity and electrochemical stability. The ZIF‑8 coating layer on the surface of the nano silicon ball can effectively buffer the huge volume expansion of silicon during lithium insertion and extraction, shortening the transmission path of lithium ions. The Si&ZIF‑8 negative electrode material with a core-shell structure prepared by the present invention has a good morphology and also has excellent electrochemical properties.

The invention discloses a silicon-oxygen-carbon-based negative electrode material and a preparation method thereof, and belongs to the technical field of lithium battery negative electrode materials, and the preparation method comprises the following steps: (1) mixing alcohol, water and acid to prepare an acid solution with the pH value of 2-4, adding organosiloxane into the acid solution, and stirring in a water bath to obtain a siloxane hydrolysate; (2) adding a pyrene compound into the siloxane hydrolysate, and carrying out ultrasonic treatment; (3) adding alkali, stirring in a water bath at 20-50 DEG C for 1-3 hours, and then freeze-drying to obtain a precursor of SiOC; and (4) placing the precursor in an atmosphere furnace, sintering in an argon atmosphere, and naturally cooling to obtain the modified negative electrode material SiOC. The amorphous carbon content of the prepared SiOC is increased, on one hand, the electronic conductivity of the SiOC can be improved, and on the other hand, volume expansion in the charging and discharging process can be relieved.

This invention relates to a Ni-doped cobalt sulfide three-dimensional graphene anode material for sodium-ion batteries and its preparation method, belonging to the field of electrochemical energy storage. A NiCoCN precursor is obtained by grinding and mixing nickel nitrate, cobalt nitrate, and urea uniformly, followed by air annealing. The precursor is then mixed with a commercial graphene oxide solution, stirred, centrifuged, washed, and dried to obtain a NiCoCN / graphene oxide precursor. High-temperature sulfidation using thiourea as a sulfur source via vapor deposition yields the NiCoSCN@three-dimensional graphene anode material. When this anode material is applied to sodium-ion battery anodes, nickel doping improves the rate performance and long-cycle stability of the material. (5 A g) ‑1 After 400 cycles, the capacity retention is ≥80% at 10 A g. ‑1 After 1000 cycles, the capacity retention rate can still reach over 65%. This method has a simple preparation process and broad application prospects in the energy field.

The present application provides a low-expansion silicon negative electrode material, including porous carbon, nano-silicon, conductive carbon and ion conductor material, wherein the pores of the porous carbon include open pores and closed pores; taking the total number of the open pores and the closed pores as 100%, the number of the open pores accounts for 80-99.9%. The porous carbon provides a continuous conductive channel, the closed pores can buffer part of the volume expansion, and the open pores are used to accommodate the nano-silicon material, and some pores are reserved to further alleviate the volume expansion and ensure the low expansion rate of the material; the nano-silicon ensures the high specific capacity of the material, the conductive carbon further improves the electronic conductivity of the material, and the ion conductor can provide more ion-conducting channels, while isolating the electrolyte and preventing the occurrence of side reactions. The silicon negative electrode material provided in the present application has a low expansion rate and excellent cycle and rate performance.

The application relates to a silicon-carbon composite material and a preparation method thereof, a negative active material, a negative electrode sheet, a secondary battery and an electric device. The silicon-carbon composite material comprises porous carbon and a zinc silicate-silicon-oxygen-carbon composite material; at least part of the zinc silicate-silicon-oxygen-carbon composite material is filled in the pores of the porous carbon; the zinc silicate-silicon-oxygen-carbon composite material is of a porous structure; the pore diameter of the zinc silicate-silicon-oxygen-carbon composite material is 1-5 nm; and the mass content of zinc elements in the zinc silicate-silicon-oxygen-carbon composite material is 1-6%. The zinc silicate-silicon-oxygen-carbon composite material has proper pore diameter and zinc element content, is good in structural stability, and has low volume expansion rate and good conductivity. Since part of the zinc silicate-silicon-oxygen-carbon composite material is filled in the pores of the porous carbon, the volume expansion of the silicon-carbon composite material is further buffered. In the electrochemical cycle process, the silicon-carbon composite material has low volume expansion, and the cycle stability of the secondary battery can be improved.

The invention discloses a preparation method of a graphene oxide coated natural graphite negative electrode material, and belongs to the technical field of lithium ion batteries. According to the method, graphene oxide is used as a coating agent, natural graphite is used as a raw material, and a spray drying method is used for preparing the high-performance lithium ion battery negative electrode material. The preparation method comprises the following steps: firstly, preparing graphene powder and a solvent into dispersion liquid according to a certain proportion, then uniformly mixing the dispersion liquid with natural graphite according to a certain proportion, and finally, controlling spray drying parameters to obtain the graphene-coated natural graphite negative electrode material. The graphene is adopted as a coating agent, the natural graphite negative electrode material is coated to form a core-shell structure, the core-shell structure is good in compatibility with an electrolyte, stripping of a graphite layer caused by co-intercalation of solvated lithium ions is avoided, meanwhile, volume expansion of natural graphite electrode particles in the charging and discharging process is buffered, and the performance of the lithium ion battery is improved. And the cycle performance and the high-current charge-discharge performance of the natural graphite are greatly improved. The method has the advantages of simple process, low cost and good product coating effect.

This invention relates to the field of lithium-ion battery technology, specifically to a composite electrode material and its preparation method. The preparation method includes the following steps: using tin, red phosphorus, and lithium salt in a molar ratio of 3.5–3.9:3:0.5–0.1 as raw materials, ball milling is performed in an inert gas to obtain lithium-doped tin phosphide material; the lithium-doped tin phosphide material and carbon nanotube material are mixed uniformly, and calcined under a protective atmosphere to construct a carbon conductive network on the surface of the lithium-doped tin phosphide material to obtain modified tin phosphide material; the modified tin phosphide material is mixed uniformly with additives to obtain the composite electrode material. This invention achieves multi-dimensional modification of tin phosphide anode material through stepwise synergistic processing, solving the technical problem of decreased electrochemical performance of existing tin phosphide anode materials due to volume expansion and lithium loss.

The application provides a positive electrode material and a preparation method and application thereof. The positive electrode material is indicated by a gas generation index of the positive electrode material obtained based on a cumulative particle size distribution change rate of the positive electrode material after being pressed under different pressures. The positive electrode material has good structural stability and particle pressure strength, is not easy to break, can reduce the volume expansion of a battery, and improves the performance of the battery.

This invention discloses a method for preparing a graphene / silicon-carbon composite anode material. The method includes: firstly, preparing a carbon-coated silicon dioxide precursor via a hydrothermal reaction; then, converting it into a carbon-coated silicon material using a magnesothermic reduction method in the presence of sodium chloride, effectively inhibiting the aggregation and growth of silicon particles; finally, combining graphene with the carbon-coated silicon material through a secondary hydrothermal and calcination treatment to construct a conductive network. This invention, through a multi-level structural design, utilizes the synergistic buffering effect of the internal carbon layer and the external graphene to effectively alleviate the volume expansion of silicon during charging and discharging, significantly improving the conductivity and structural stability of the material. The prepared composite anode material exhibits high specific capacity and excellent cycle performance, making it suitable for lithium-ion battery applications.

The present application provides a silicon negative electrode material with a porous coating layer, including a silicon-based material, a conductive carbon layer and a fast ion conductor layer, characterized in that the conductive carbon layer is coated on the surface of the silicon-based material, and the fast ion conductor layer is coated on the surface of the conductive carbon layer; the fast ion conductor layer is a porous structure. The physical position of the porous fast ion conductor layer is an excellent conductor of lithium ions and stabilizes the SEI film, thereby improving the cycle performance of the material; the pore position exposes the inner carbon layer, increasing the electronic conductivity; at the same time, the pore position reserves expansion space, which is conducive to buffering the expansion of the silicon-based core. The above-mentioned negative electrode material can be used to prepare lithium-ion batteries with high energy density and rapid charge and discharge.

The present invention relates to a novel electrolyte additive, a non-aqueous electrolyte for a lithium secondary battery comprising the novel electrolyte additive, and a lithium secondary battery comprising the non-aqueous electrolyte. In more detail, the present invention relates to a non-aqueous electrolyte for a lithium secondary battery, which comprises an additive capable of forming a stable coating on the surface of an electrode. The present invention also relates to a lithium secondary battery with improved performance, which comprises the above-mentioned non-aqueous electrolyte, so that the high temperature life of the lithium secondary battery will not deteriorate, and the resistance will not increase when the lithium secondary battery is stored at high temperature. In addition, when the lithium secondary battery is stored at high temperature, the volume (thickness) expansion of the secondary battery can be suppressed.

This application relates to the technical field of lithium-ion battery materials, specifically disclosing a high-efficiency silicon-oxygen composite anode material, its preparation method, and its application. The preparation method of this anode material includes the following steps: mixing a siloxane with a fatty acid at a mass ratio of 1:(5~35), and ball milling under inert gas protection to obtain a pre-coated mixture; heating the pre-coated mixture to 50~1500℃ under an inert atmosphere and holding for 1~20h to obtain a carbon-coated silicon-oxygen material; immersing the carbon-coated silicon-oxygen material in a lithium-rich organic composite solution, holding at -5~25℃ under inert gas protection for 5~180 minutes, and drying to obtain a pre-lithiation product; mixing the pre-lithiation product with a nitride at a mass ratio of 1:(0.1~5), and ball milling under inert gas protection to obtain the high-efficiency silicon-oxygen composite anode material. This application can synergistically improve the stability and initial efficiency of the silicon-oxygen composite anode material.

The invention belongs to the field of lithium-sulfur secondary batteries, and relates to a high-performance lithium-sulfur battery, the high-performance lithium-sulfur battery comprises a sulfur-carbon positive electrode, a lithium negative electrode, an electrolyte and a diaphragm, the diaphragm comprises a base membrane and a functional coating coated on one or two surfaces of the base membrane, and the functional coating comprises molybdenum disulfide particles coated with metal molybdenum nanoparticles. The application of molybdenum disulfide particles coated with metal molybdenum nanoparticles to the functional layer of the lithium-sulfur battery diaphragm is proposed for the first time, so that the shuttle effect of polysulfide can be effectively inhibited, the redox reaction of the polysulfide can be accelerated, the polysulfide is promoted to be quickly converted into solid Li2S, the utilization rate of sulfur is increased, the accumulation of intermediate products is reduced, and the service life of the lithium-sulfur battery diaphragm is prolonged. The coulombic efficiency and the cycling stability of the battery are improved; and the two are combined to form an efficient conductive network, so that the conductivity is remarkably improved, rapid transmission of electrons in the conductive network is promoted, and the rate capability of the battery is improved.

This application provides a dynamic ion transport binder and its preparation method, a silicon-based anode, and an all-solid-state lithium-ion battery, relating to the field of solid-state batteries. The raw materials of the dynamic ion transport binder, by mass (100%), include: 60-80% nitrile compounds, 10-30% ether-based ion compounds, and 5-10% borate compounds. The dynamic ion transport binder employs a low-polarity elastic main structure, avoiding the introduction of a large number of highly active groups such as carboxyl and hydroxyl groups, thus effectively inhibiting the decomposition of sulfide electrolytes. The borate ester dynamic bonds formed by the borate compounds undergo reversible breakage and reconstruction under stress, thereby mitigating volume changes during silicon anode cycling. This dynamic ion transport binder can effectively improve the structural integrity of the silicon-based anode after cycling, reducing interfacial delamination and crack formation.

The invention relates to a preparation method of a lithium-sulfur battery positive electrode material, in particular to a preparation method of a boric acid etched flower-like bimetallic loaded porous carbon material for a lithium-sulfur battery. The invention aims to solve the problems of slow oxidation-reduction reaction rate and shuttle effect of a sulfur positive electrode in a lithium-sulfur battery. The method disclosed by the invention comprises the following steps: 1, preparing a nickel-cobalt bimetal organic framework compound (NiCo-ZIF8); (2) preparation of nitrogen-doped porous carbon (NiCo / NPC) with nickel and cobalt double atoms fixed thereon; and 3, preparing the nickel-cobalt diatom-based composite positive electrode material (S / NiCo / NPC). According to the preparation method, cobalt nitrate hexahydrate and nickel nitrate hexahydrate are taken as metal salts, 2-methylimidazole is taken as an organic ligand, boric acid is taken as a pore-forming agent, and the nickel-cobalt-doped flower-shaped porous carbon is prepared through a one-step pyrolysis method, so that the problems of low oxidation reduction rate, positive electrode volume expansion and shuttle effect of a sulfur positive electrode in a lithium-sulfur battery are effectively solved. Meanwhile, the invention provides a new strategy for promoting bidirectional catalysis of a lithium-sulfur system by manipulating the spin delocalization electron effect. The adopted raw materials are rich and low in cost, and the preparation process is simple, convenient and feasible, so that the preparation method has great commercial application potential.

The application discloses a silicon-based negative electrode material, which comprises, from inside to outside, a core carbon layer, a gradient silicon-carbon composite layer, an intermediate silicon layer, a dispersed silicon layer and a boundary carbon layer; the core carbon layer is a dense carbon layer; the gradient silicon-carbon composite layer comprises a gradient porous carbon layer with gradually increasing porosity from inside to outside; silicon is deposited in the pores of the gradient porous carbon layer, and the content of the silicon gradually increases from inside to outside; the intermediate silicon layer and the dispersed silicon layer are sequentially coated on the outside of the gradient silicon-carbon composite layer; the boundary carbon layer is coated on the outside of the dispersed silicon layer; and part of the silicon particles in the dispersed silicon layer are embedded in the boundary carbon layer. The application further discloses a preparation method of the silicon-based negative electrode material and a lithium ion battery prepared from the silicon-based negative electrode material. The silicon-based negative electrode material can reduce the volume expansion of the electrode during the charging and discharging process, and improve the cycle life of the battery.

The application relates to the field of secondary batteries, in particular to a kind of antimony negative material and its preparation method, lithium ion battery and terminal, organic ligand containing carboxyl and mercapto, antimony source and polyethylene glycol are mixed to obtain solution A; Sodium borohydride and selenium source are added into ethanol, and then polyethyleneimine is added to obtain solution B; Solution A and solution B are mixed to carry out solvothermal reaction; The solvothermal reaction product is collected, washed and dried, and the lithium ion battery assembled by the antimony-based negative material of the application shows excellent electrochemical performance and can be used in various terminals.

This invention discloses a lithium metal anode based on a gradient solid-state electrolyte, its preparation method, and its application. The lithium metal anode sequentially comprises: a current collector, a porous lithium-zinc alloy interface layer, a lithium metal layer, and a gradient solid-state electrolyte layer. The gradient solid-state electrolyte layer includes a polymer matrix and a high-dielectric filler layer distributed in a gradient within the polymer matrix. In this invention, the porous lithium-zinc alloy interface layer and the gradient high-dielectric filler polymer layer work synergistically to effectively guide uniform lithium-ion deposition, suppress dendrite growth, and reduce tip effects, thereby improving cycle life, reducing interface impedance and polarization voltage, and minimizing volume expansion.

A negative electrode material, a preparation method thereof, a negative electrode sheet and a battery. The negative electrode material comprises a negative electrode active material and a coating layer existing on the surface of the negative electrode active material, wherein the coating layer comprises piezoelectric polymer fibers; the piezoelectric polymer fibers have a diameter of 500 nm to 2000 nm and a length of 100 mu m to 500 mu m. The negative electrode material provided by the application can effectively buffer the volume expansion of a silicon-based active material, reduce the interface transmission impedance, and help improve the capacity, rate performance and cycle life of the battery.

The invention discloses a silicon-based negative electrode material and a preparation method and application thereof. A main body material of the negative electrode material is a tin-doped pre-magnesium silicon oxide material, and the surface of the main body material is sequentially coated with a carbon layer and a molybdenum disulfide-doped polyphenylene sulfide coating layer; the preparation method comprises the following steps: S1, crushing silicon, silicon dioxide and tin, mixing, and tabletting; s2, sintering the tabletting material obtained in the step S1 to obtain a tin-doped silicon monoxide material; s3, crushing and grading the product in S2, and controlling the particle size distribution; s4, placing the product in S3 in a rotary kiln in an inert atmosphere, raising the temperature to a sintering temperature, placing dimethyl cyclopentadienyl magnesium in a gas reactor, sintering, and discharging at room temperature to obtain an intermediate product A; and S5, dispersing the product A and molybdenum disulfide in acetylacetone, adding diphenyl disulfide, introducing oxygen for reaction, and performing secondary heating reaction in a nitrogen atmosphere to obtain the molybdenum disulfide doped polyphenylene sulfide coated silicon-based negative electrode material.