685results about How to "Uniform deposition" patented technology

The preparation method of the silicon-carbon composite material comprises the following steps: uniformly mixing a carbon source, a pore forming agent and a cross-linking agent, and introducing peroxide gas into a tubular furnace for sintering to obtain porous carbon; uniformly mixing the porous carbon with liquid silane and a surfactant, and transferring the mixture into a high-pressure reaction kettle for reaction to obtain a silicon-carbon precursor; and introducing the obtained material into a carbon source gas containing a heteroatom gas for deposition to obtain the silicon-carbon composite material. The obtained material generates porous carbon with high strength and high pore volume by utilizing the cross-linking agent and the pore-forming agent thereof, so that the expansion is reduced; and the liquid silane has the characteristics of low decomposition temperature, low cost and high safety performance, so that the specific capacity is improved, and the cost is reduced.

The invention discloses a modified zinc electrode material as well as a preparation method and application thereof, 3, 4-ethylenedioxythiophene, lauryl sodium sulfate and potassium perchlorate are taken as electrolyte, and the surface of a zinc electrode is coated with an organic polymer coating in an electrochemical polymerization manner, so that the problems of dendritic crystal growth, side reaction, corrosion and the like of the zinc electrode are solved; the cycling stability and reversibility of the zinc electrode are improved; meanwhile, the coating has hydrophilicity and better electrolyte wetting capacity, zinc ions are helped to be rapidly diffused on an electrode, and the polarization influence caused by concentration difference in the cycle process of the battery is relieved. Besides, by controlling the electrochemical polymerization time, the thickness of the coating is controlled, and the method has the advantages of simplicity, rapidness and the like and is suitable for large-scale popularization and application.

The invention relates to the technical field of batteries, in particular to a negative electrode, a preparation method thereof and a solid-state battery. The negative electrode comprises a composite current collector and a negative electrode protection layer, the composite current collector comprises a current collector substrate and a negative electrode material, the current collector substrate has a three-dimensional network structure, the negative electrode material is distributed in the three-dimensional network structure, and the negative electrode material comprises a lithium-loving carbon-based material and a lithium-loving metal material; the negative electrode protection layer is arranged on at least one side surface of the composite current collector, and the negative electrode protection layer comprises a solid electrolyte and a lithium-phobic carbon-based material. The solid-state battery comprises the negative electrode. The problem of dendritic crystal growth short circuit caused by non-uniform deposition of metal lithium can be relieved, the problem of volume expansion of a full-charge battery can be reduced, and the cycle stability of a solid-state battery can be improved.

The invention discloses a zinc negative electrode protective layer material of an aqueous zinc ion battery as well as a preparation method and application of the zinc negative electrode protective layer material. The method comprises the following steps: dispersing a carbon material in an acidic liquid, stirring at room temperature, and fully mixing to obtain a uniform suspension; adding manganese salt into the mixed solution, stirring at room temperature, and then performing constant-temperature water bath; washing, centrifuging, drying and calcining a product obtained by the reaction to obtain expanded graphite; uniformly dispersing expanded graphite in a solvent, and stirring to obtain a dispersion liquid; adding a titanium-containing organic compound into the dispersion liquid and stirring; adding deionized water into the dispersion liquid and refluxing; and centrifuging, washing, drying and calcining to obtain the protective layer. According to the composite material, expanded graphite is prepared firstly, and then titanium dioxide quantum dots are anchored on the expanded graphite. Due to excellent zinc ion rate, compared with the prior art, the material has lower interface resistance and good cycling stability and rate capability, and the problems of interface dendritic crystal growth and the like are solved.

The invention provides a preparation method of a silicon substrate and a heterojunction solar cell, and the preparation method of the silicon substrate comprises the steps: an initial silicon substrate comprises a first surface and a second surface, a first mask layer is formed on the first surface, and a second mask layer is formed on the second surface; performing first dot matrix laser etching treatment on the first mask layer to form a first intermediate mask layer; the second surface is provided with a target area, the target area is used for arranging a grid line, and second dot matrix laser etching processing is carried out on the second mask layer corresponding to the target area to form a second middle mask layer; performing alkali etching treatment on the first surface through the first intermediate mask layer, and performing alkali etching treatment on the target area through the second intermediate mask layer; and removing the first intermediate mask layer to obtain a first suede, and removing the second intermediate mask layer to obtain the silicon substrate with the target area as the second suede. The silicon substrate with excellent adhesiveness between the second surface and the grid lines and ultralow reflectivity on the first surface is prepared by using the method.

The invention relates to a preparation method of composite porous carbon beneficial to silicon deposition and a silicon-carbon composite negative electrode. The method comprises the following steps: (P1) carrying out surface oxidation treatment on porous carbon fine powder to obtain oxidized porous carbon fine powder; (P2) adding the oxidized porous carbon fine powder and ether polycarboxylic acid silanol into a solvent to obtain ether polycarboxylic acid silanol modified porous carbon fine powder; the ether polycarboxylic acid silanol is prepared by copolymerizing a polyether macromonomer, an acrylic monomer and an alkenyl silane coupling agent in water; (P3) soaking the ether polycarboxylic acid silanol modified porous carbon fine powder in a salt aqueous solution to obtain catalyst-loaded porous carbon; (P4) mixing the porous carbon loaded with the catalyst with a carbon source precursor solution, and performing spray drying to obtain a composite carbon precursor; and (P5) carbonizing and activating the composite carbon precursor to obtain the composite porous carbon beneficial to silicon deposition. The composite porous carbon prepared by the invention is beneficial to more uniform deposition of silicon in pores of the core porous carbon fine powder.

The invention provides an electrolyte for improving the interface stability of a four-electron aqueous zinc-iodine battery, and belongs to the technical field of zinc-iodine battery electrolyte additives, the electrolyte comprises N, N-dihydroxyethyl glycine, zinc sulfate, an additive and water; in the electrolyte, the concentration of the N, N-dihydroxyethyl glycine is 0.5 + / -0.2 mol / L; the molar ratio of the additive to the zinc sulfate is 1: 3; the additive comprises any one of methyl triethyl ammonium chloride, betaine hydrochloride and triethylamine hydrobromide. The electrolyte can enhance the interface stability of the electrode electrolyte, improve the cycling stability and electrochemical performance of the aqueous zinc-iodine battery, inhibit side reactions, and improve the safety and reliability of the battery. The invention also provides a high-capacity aqueous zinc-iodine battery.

The invention discloses a numerical analysis method for predicting speed distribution of downwash airflow of an unmanned aerial vehicle in a rice canopy based on a fluid-solid coupling method. The numerical analysis method comprises the following steps: measuring physical parameters of rice plants based on physiological characteristics of rice; establishing a three-dimensional rice plant model based on three-dimensional geometric modeling software; dividing a three-dimensional rice plant canopy grid based on grid division software; establishing a fluid-solid coupling model of the lower washing flow field of the unmanned aerial vehicle and the rice canopy; setting an initial boundary condition and performing spatial discretization; full-coupling finite element numerical simulation of the fluid-solid coupling model is carried out; performing post-processing on the numerical simulation result based on flow field post-processing software to obtain an evolution process and spatial distribution of the downward washing flow field of the unmanned aerial vehicle and dynamic behaviors of rice plants; and analyzing the influence of the dynamic behavior of the rice plant on the downwash airflow of the unmanned aerial vehicle, and determining the distribution rule of the downwash airflow speed in the rice canopy. The problems of high time consumption, influence of external conditions, difficulty in copying, limitation and the like are effectively solved.

The invention relates to a method for automatically generating a track of a ceramic bathroom surface glazing robot based on 3D vision. The method comprises the following steps: acquiring a surface point cloud model of a target ceramic bathroom; inputting the surface point cloud model into a pre-trained point cloud segmentation model, and outputting S1 and S2 type curved surfaces; generating a preliminary fitting path curve based on the S1 and S2 curved surfaces; performing interpolation processing on the preliminary fitting path curve to obtain path scatter points on the path curve after interpolation; performing path attitude estimation based on path scatter points on the interpolated path curve to obtain a path attitude estimation result; and generating the track of the glazing robot based on the path attitude estimation result. According to the method, a personalized path generation scheme can be intelligently formulated according to different types of glazing curved surfaces on the surface of the ceramic bathroom workpiece. The key influence of the position and posture of the spray gun on the glazing effect is also considered, and the uniformity and high quality of the glazing process are ensured through fine position and posture control and path optimization.

The invention belongs to the technical field of negative-electrode-free sodium metal batteries, and particularly discloses a negative-electrode-free sodium battery modified current collector and a preparation method and application thereof.The preparation method includes the steps that on the basis of polypyrrole preparation, transition metal salt is added, and the nitrogen doping type in polypyrrole-derived nitrogen-doped nano carbon particles is regulated and controlled. The negative-electrode-free sodium battery modified current collector prepared by the preparation method disclosed by the invention is high in relative content of N-6 and N-5 type doped nitrogen, so that the sodium affinity of a nitrogen-doped coating is improved, the nucleation over-point location of sodium metal is reduced, the reversibility of a sodium deposition / stripping reaction is improved, and the electrochemical performance of a negative-electrode-free sodium battery is further improved.

The invention relates to an electrolyte for an aqueous zinc ion battery and the zinc ion battery. The electrolyte consists of soluble zinc salt, an electrolyte additive and solvent water, and the electrolyte additive is a thiazole derivative containing functional groups such as sulfydryl, amino, sulfonic acid group and formic acid group. According to the electrolyte provided by the invention, the electrolyte additive can regulate and control the coordination environment through coordination with zinc ions so as to realize uniform deposition of zinc, meanwhile, the electrolyte additive can also be grafted to the surface of zinc through functional groups such as sulfydryl, amino, sulfonic acid group and formic acid group so as to form a layer of stable protective film, and the protective film has good zinc affinity; direct contact between an electrolyte and the zinc negative electrode can be effectively blocked, chemical corrosion and hydrogen evolution reaction of the zinc negative electrode can be reduced, interface ion transmission can be regulated and controlled, zinc dendrite growth is effectively inhibited, the cycling stability of the zinc negative electrode is improved, the cycle life of the battery is prolonged, the rate performance of the battery is improved, and the method is easy and convenient to prepare, low in cost, high in safety and suitable for industrial production. The large-scale production is easy to realize.

The invention provides a silicon carbon material with a multilayer coating structure and a preparation method and application thereof, and relates to the technical field of battery materials. The silicon-carbon material with the multi-layer coating structure comprises a porous carbon core body, and a first carbon layer and a second carbon layer which sequentially coat the porous carbon core body from inside to outside, and the porous carbon core body comprises porous carbon and nano silicon particles deposited on the surface and in pore channels of the porous carbon; and a conductive nano carbon filler is dispersed in the second carbon layer. The silicon carbon material with the multilayer coating structure provided by the invention is used as a lithium ion battery negative electrode material, and has excellent specific capacity, coulombic efficiency and cycle performance. The result of the embodiment shows that when the silicon carbon material with the multi-layer coating structure is applied to the lithium ion battery, the first reversible capacity is 1882-2071 mAh / g, the first coulombic efficiency is 92.6-94.1%, and the capacity retention ratio of 100 cycles is 95.3-97.7%.

The invention provides a current collector, a preparation method thereof and a battery. The current collector includes: a polymer layer; the metal layers are located on the surfaces of the two sides of the polymer layer; the through hole structure penetrates through the polymer layer and the metal layer along the thickness direction of the current collector; holes of the through hole structure are filled with a first lithium-philic polymer material. According to the current collector provided by the invention, the purpose of reducing weight is achieved through the synergistic cooperation of the structure and the material, the energy density of the current collector is improved, the uniform deposition of lithium is also realized, and the generation of lithium dendrites is avoided; meanwhile, the effect of reducing the occurrence probability of thermal runaway is also achieved, and the electrochemical performance of the battery is improved.

The invention provides a preparation method of a high interface strain polymer electrolyte for a lithium metal battery, and belongs to the technical field of lithium metal batteries, and the preparation method specifically comprises the following steps: firstly preparing a precursor solution A containing a lithium salt and an organic solvent, then preparing a precursor solution B obtained by mixing a polymer monomer, an initiator, a cross-linking agent and the lithium salt, mixing the precursor solution A and the precursor solution B, and carrying out vacuum drying to obtain the high interface strain polymer electrolyte for the lithium metal battery. And assembling a lithium metal battery by using the polymer as an electrolyte, and drying to obtain the high interface strain polymer electrolyte which is formed in situ in the positive and negative electrode interfaces of the lithium metal battery. By designing the proportion of fluorine element and oxygen element in a polymer electrolyte chain segment, the coordination strength of Li-O in a polymer electrolyte body phase is reduced, and the interface volume deformation during polymer lithium ion removal is improved, so that the potential difference of an electrolyte / lithium metal interface is reduced, the interface lithium deposition is homogenized, and the lithium dendrite growth is inhibited; and the cycling stability of the lithium metal battery is finally improved.

The invention discloses a method for preparing a flexible electrode layer by using laser-induced graphene and the flexible electrode layer. The method comprises the following steps: preparing a laser-induced graphene pattern on the surface of a polymer by using a carbon dioxide laser; and coating flexible photosensitive resin on the surface of the polymer with the laser-induced graphene pattern, carrying out ultraviolet curing, and peeling off the cured flexible photosensitive resin and the laser-induced graphene pattern from the polymer film to obtain the LIGG and flexible photosensitive resin double-layer structure. The graphene pattern induced by laser is quickly, simply and conveniently transferred to the flexible photosensitive resin substrate by adopting an ultraviolet curing method, and the flexible electrode layer which can be bent, can be patterned, has excellent conductivity and is provided with the LIGG and flexible photosensitive resin layer structure is obtained.

The invention belongs to the field of secondary batteries, and particularly relates to an aqueous zinc ion battery electrolyte additive and an electrolyte. The additive is a beta-diketone organic reagent. When the additive is added into the zinc salt-containing electrolyte, dendritic crystal growth and hydrogen evolution corrosion of zinc can be remarkably inhibited, so that the cycle performance and coulombic efficiency of the zinc ion battery are improved. According to the invention, the zinc ion battery has good cycle performance, is easy for industrial production, and has an application prospect in the technical field of energy storage.

The invention relates to a preparation method and application of an organic-inorganic artificial composite solid electrolyte interface layer, and belongs to the technical field of lithium metal batteries. The organic polymer, the black phosphorene, the conductive carbon black and other inorganic substances are uniformly mixed to construct the organic-inorganic artificial composite interface layer, and the organic-inorganic artificial composite interface layer can induce uniform lithium deposition, reduce the local current density caused by nonuniformity and roughness of the surface of the copper current collector, reduce the lithium nucleation barrier, and improve the lithium ion battery performance. Meanwhile, the affinity of deposited lithium and a current collector is enhanced, the interface impedance of the negative-electrode-free lithium metal battery is remarkably reduced, and the lithium dendrite growth of a lithium metal negative electrode is inhibited; the cathode-free lithium metal battery assembled by adopting the copper current collector modified by the organic-inorganic artificial composite interface layer shows long cycle stability, good rate capability and remarkable safety performance, and has a wide commercial application prospect.

The present invention belongs to the field of batteries, and specifically relates to a modified current collector for a negative electrode-free sodium metal battery, comprising a planar current collector and a single-layer modified layer composited on its surface; and the modified layer is composed of a binder, a conductive agent and a modified material in a weight ratio of 20-80:10-60:10-20; the modified material includes at least one of Y2O3, Gd2O3, yttrium carbonate, lead carbonate, tungsten carbonate, iridium carbonate, hafnium carbonate, molybdenum carbonate, gadolinium carbonate, yttrium titanate, iridium titanate, hafnium titanate, molybdenum titanate and gadolinium titanate. The thickness of the modified layer is 20-100 μm. The present invention also includes the preparation of the modified current collector and the application in a negative electrode-free sodium battery. The innovative research of the present invention shows that the modified current collector containing the modified material can adapt to the application requirements of negative electrode-free sodium batteries, can induce the deposition of sodium metal, can inhibit sodium expansion, and not only that, can also effectively inhibit sodium dendrites. Applying it to negative electrode-free sodium batteries can significantly improve its electrochemical performance.

The present invention discloses a wide temperature range hydrated eutectic electrolyte and its application in aqueous zinc ion batteries. The wide temperature range hydrated eutectic electrolyte comprises a zinc salt, an alcohol organic solvent and an inorganic additive. The zinc salt is zinc perchlorate hexahydrate; the organic solvent is ethylene glycol; and the inorganic additive is an indium trichloride solution. The hydrated eutectic electrolyte prepared by the present invention enables aqueous zinc ion batteries to exhibit excellent electrochemical properties in a wide temperature range, can effectively inhibit the generation of side reactions such as dendrites and corrosion in aqueous zinc ion batteries, and thus prolong the service life of aqueous zinc ions in a wide temperature range.

The invention provides a high-temperature-resistant iron-chromium black pigment as well as a preparation method and application thereof, and belongs to the technical field of pigments. The preparation method comprises the following steps: preparing porous SiO2 / Al2O3 nanospheres, modifying the surfaces of the porous SiO2 / Al2O3 nanospheres by using tannic acid, depositing iron-containing and chromium-containing precipitates in situ, impregnating zirconium, calcining to obtain a precursor, and modifying the surfaces of the porous SiO2 / Al2O3 nanospheres by using polydopamine to obtain the high-temperature-resistant iron-chromium black pigment. The high-temperature-resistant iron-chromium black pigment prepared by the preparation method disclosed by the invention contains an aluminum element, so that the high-temperature-resistant, heat-resistant and flame-retardant properties of a prepared precursor are greatly improved, and the high-temperature-resistant iron-chromium black pigment contains silicon oxide, so that the temperature resistance and the wear resistance are obviously improved, and the high-temperature-resistant iron-chromium black pigment is relatively uniform in black, uniform in particle size, good in weather resistance and light resistance, good in dispersity and wide in application prospect.

The invention discloses an amphoteric self-supporting single-ion polymer electrolyte diaphragm as well as a preparation method and application thereof. The diaphragm is prepared by physically doping a self-supporting single-ion polymer with an amphoteric ionic compound. The polymer electrolyte provided by the invention has a high-molecular polymer structure, negative ions of the polymer electrolyte are relatively fixed in an electrochemical reaction process, and single-ion conduction of lithium ions can be realized, so that uniform deposition of the lithium ions on the surface of a negative electrode is realized, and formation of lithium dendrites is inhibited. Meanwhile, the doped zwitter-ions can increase the dielectric constant of the electrolyte, so that the overall lithium ion conductivity of the electrolyte diaphragm is improved, all the components of the diaphragm are electrolyte components, an additional binder does not need to be added, and the self-supporting electrolyte diaphragm with qualified mechanical properties can be prepared.

The invention discloses a PEO-based solid electrolyte film and a preparation method and application thereof, the PEO-based solid electrolyte film comprises a polymer matrix and a lithium salt, the polymer matrix is selected from PEO, and the lithium salt is selected from LiTFSI; the PEO-based solid electrolyte film also comprises a molecular coordination regulator and a filler, the molecular coordination regulator is selected from DFBOP, and the filler is selected from LLZTO. According to the PEO-based solid electrolyte film disclosed by the invention, the problems of poor lithium stability and high-voltage compatibility of PEO-based solid electrolyte can be remarkably improved, and the cycling stability and rate capability of a PEO-based solid lithium metal battery can be remarkably improved.

The invention discloses a solid-state lithium battery and a preparation method thereof and belongs to the technical field of battery processing. The preparation method of the solid-state lithium battery comprises the following steps: S1, assembling a positive plate, a diaphragm and a negative plate into a dry cell; wherein a composite film layer is cured on a current collector base material of the negative plate, and rubidium nitrate is added into the composite film layer; s2, injecting the gel precursor solution into a dry battery cell, fully standing, and charging the battery cell to 100% SOC; wherein the gel precursor solution contains an electrolyte, a cross-linking agent and an initiator; and S3, heating to initiate a chemical cross-linking reaction of a cross-linking agent in the gel precursor solution, and carrying out in-situ polymerization and curing on the surface of each component of the dry cell and in internal pores thereof to obtain a gel polymer electrolyte, thereby forming the solid-state lithium battery. According to the invention, the interface resistance can be reduced, and the lithium ion transmission capability and efficiency are improved.

The invention discloses a lithium-free negative electrode for a lithium metal battery, a preparation method of the lithium-free negative electrode and the lithium metal battery. The lithium-free negative electrode comprises a current collector, the metal layer is arranged on at least one side of the current collector, and the material of the metal layer is one or more of tin, magnesium, zinc, bismuth, lead, silver and aluminum; and the graphene oxide layer is arranged on one side, far away from the current collector, of the metal layer. According to the invention, the deposition uniformity of lithium at the negative electrode is improved to inhibit the growth of lithium dendrites, and the coulombic efficiency and the capacity retention ratio of the battery are improved.

The invention provides a nickel-tungsten alloy electroplating solution, a preparation method thereof and a preparation method of a solar cell metal electrode, and particularly relates to the technical field of solar cell preparation. The nickel-tungsten alloy electroplating solution provided by the invention comprises nickel salt, tungstate, a complexing agent, a wetting agent and water. In the nickel-tungsten alloy electroplating solution provided by the invention, on the basis of nickel salt and tungstate, a uniform and compact nickel-tungsten alloy layer can be formed on the surface of a plated part, and the layer of alloy combines the electrical conductivity of nickel and the corrosion resistance and high hardness characteristics of tungsten, so that the comprehensive performance of the plated part is remarkably improved. And the complexing agent is added, so that the activity of nickel ions and tungsten ions and the electrodeposition process are effectively controlled, and the quality and the production efficiency of a plating layer are optimized. And the wetting agent is used, so that the wettability of the plating solution on the surface of a plating piece is improved, uniform deposition of an alloy layer is promoted, pores and defects are reduced, and the binding force and durability of a plating layer are enhanced.

The invention relates to the technical field of new energy, in particular to an extensible composite hole transport layer and a perovskite solar cell based on the extensible composite hole transport layer, and a preparation method of the perovskite solar cell comprises the following steps: forming a nickel oxide film on transparent conductive glass through magnetron sputtering; soaking the nickel oxide thin film to form a self-assembled monomolecular layer; forming a perovskite active layer on the self-assembled monomolecular layer; forming an electron transport layer on the perovskite active layer; and forming an electrode on the electron transport layer. According to the method, the preparation size of the hole transport layer can be expanded, and the photoelectric conversion efficiency of the perovskite solar cell can be improved.

The invention discloses zinc ion battery electrolyte as well as a preparation method and application thereof, and belongs to the technical field of ion battery electrolyte. According to the preparation method disclosed by the invention, the coumarin derivative is added into the basic zinc salt solution, so that the uniform deposition of zinc ions can be promoted at a low temperature of-20 DEG C or below, the formation of dendritic crystals is remarkably reduced, and a stable protective layer is formed on the surface of the zinc anode, and the protective layer can maintain high reversibility of the battery at a normal temperature, and also can be used for preparing a lithium ion battery. And the stability can be kept in a low-temperature environment, so that the battery can show excellent electrochemical performance under different temperature conditions, and the technical problem of the electrochemical performance of the water-based zinc ion battery (ZIBs) in the low-temperature environment is solved.

The invention provides an electrolyte, which comprises a lithium salt and an organic solvent, and the organic solvent comprises a cyclic non-coordination solvent represented by the following formula (I) # imgabs0 # (I), in the formula (I), R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 are respectively and independently selected from a hydrogen atom, a chlorine atom, a bromine atom, a fluorine atom, a C1-C3 alkyl group, a C1-C3 alkoxy group, a fluorine-substituted C1-C3 alkyl group or a fluorine-substituted C1-C3 alkoxy group. The electrolyte provided by the invention can be applied to the lithium metal secondary battery, and can significantly improve the cycle stability and safety of the battery and prolong the cycle life of the battery; meanwhile, decomposition of the coordination type solvent can be effectively inhibited, and uniform deposition of metal lithium dendrites is realized, so that the stability of the electrolyte is improved; and moreover, the high-temperature storage gas production inhibition effect is obvious.

The invention provides a preparation method of a wide-temperature-range high-capacity cascade aqueous zinc-iodine battery and the aqueous zinc-iodine battery, and belongs to the technical field of aqueous zinc ion batteries, the preparation method comprises the following steps: dissolving zinc perchlorate, bacterial cellulose, acrylamide, 1-vinyl-3-butylimidazolium bromide, a cross-linking agent and an initiator in water together to obtain a mixed solution; and carrying out polymerization reaction on the mixed solution at 60-80 DEG C to obtain the bromine-rich polycation hydrogel electrolyte, an iodine composite material is used as a positive electrode, metal zinc is used as a negative electrode, the bromine-rich polycation hydrogel electrolyte is used as an electrolyte, and the aqueous zinc-iodine battery is assembled. The aqueous zinc-iodine battery prepared by the method has extremely high specific capacity and excellent cycle performance in a wide temperature range from-50 DEG C to 50 DEG C.

The invention relates to a negative active material and a preparation method thereof, a negative pole piece and a lithium ion battery, and belongs to the technical field of electrochemistry. The negative electrode active material comprises a composite core material and a coating material, the composite core material comprises a substrate material and a first material, the substrate material is provided with a plurality of pores, and the first material is arranged on the pore walls of the pores of the substrate material; the coating material coats at least part of the outer surface of the composite core material; wherein the nucleation overpotential of lithium on the first material is smaller than the nucleation overpotential of lithium on the coating material, so that lithium ions are more prone to nucleation and deposition on the first material, and formation of lithium dendrites is reduced; the coating material further protects the inner core material and prevents the inner core material from being in direct contact with the electrolyte, so that the probability of side reaction between the metal lithium and the electrolyte / electrolyte is reduced, and the cycle performance is improved.