57 results about "Lithium ion intercalation" patented technology

The invention discloses a solid-state battery and a positive electrode material thereof. The solid-state battery consists of a lithium storage positive electrode, a battery electrolyte and a lithium-rich negative electrode. Wherein the lithium-storing positive electrode comprises an embedded lithium-storing transition metal chalcogenide and a composite material of the embedded lithium-storing transition metal chalcogenide. The positive electrode material has ionic conductivity and electronic conductivity at the same time, a three-dimensional ionic and electronic conductive network structure is formed in the positive electrode, and the network structure is beneficial to intercalation and deintercalation of lithium ions. The crystal structure of the transition metal chalcogenide can be a layered structure or a SiFerel phase, and transition metal contained in the transition metal chalcogenide can be at least one of IVB, VB, VIB and VIIB group metal elements. In the lithium ion intercalation and deintercalation process, the transition metal is subjected to valence change reaction. By introducing the positive electrode material, the weight ratio of inactive substances in the battery is effectively reduced, and the energy density of the solid electrolyte is further improved.

The invention provides a pole piece of a lithium ion battery and a preparation method of the pole piece, the pole piece of the lithium ion battery comprises a current collector and an active material coated on the current collector, and by arranging the active material and an adhesive, the active material can be conveniently and rapidly fixed when being extruded and arranged on the current collector along an angle; the assembly state of the active material on the current collector is stabilized, the active material is placed in the slit die cavity to be extruded, the active material moves and deforms towards the single side direction, so that the structure becomes long and narrow, and the end part of the long and narrow active material is connected with the current collector to be rolled, so that the tortuosity of the lithium ion battery pole piece is reduced, and the service life of the lithium ion battery pole piece is prolonged. And the migration rate of lithium ions in the pole piece and the embedding rate of the lithium ions in the active material are accelerated, meanwhile, the problem that the pole piece is expanded and increased due to lithium ion embedding in the thickness direction of the pole piece is solved, and the probability of deformation of the lithium ion battery is reduced.

The present application relates to the technical field of battery, in particular to a kind of graphite material and its preparation method and application.The present application provides a kind of graphite material, the graphite material includes graphite body, the graphite body has multiple through-hole structures, the hole diameter R of each through-hole structure is 0.07~1.81 μm;The particle size Dv50 of the graphite material and the hole diameter R of the through-hole structure satisfy:3.9≤Dv50 / R≤107.1.The graphite material of the present application has abundant through-hole structure, provides more channels for lithium ion deintercalation, and shortens the solid-phase diffusion path of lithium ion intercalation, so as to improve the rate performance of graphite negative electrode material, and the through-hole channel structure can improve the wettability and liquid retention of electrolyte, thereby improving the cycle performance of battery.

The utility model provides a battery cell and a battery, the battery cell comprises a roll core structure formed by sequentially laminating and winding a positive pole piece, a diaphragm and a negative pole piece, the negative pole piece further comprises an insulating coating, the insulating coating is coated on a second surface, at least part of the insulating coating is located on the outermost ring of the roll core structure, and the insulating coating is located on the outer ring of the roll core structure in the length direction of the negative pole piece. A first interval exists between the head end of the insulating coating and the tail end of the second negative active material layer; the roll core structure comprises a straight area and bending areas located at the two ends of the straight area, and at least part of the first interval is located in the bending areas. Therefore, the insulating coating can be prevented from covering the negative electrode active material layer and extending between the negative electrode active material layer and the negative electrode current collector, so that the poor conductivity of the region is avoided, the lithium ion embedding speed is reduced in the charging process, and the lithium precipitation of the region is slowed down or even avoided, and the safety performance of the battery in use is further improved; and the reduction of the energy density of the battery formed by the roll core structure due to the increase of the thickness of the region of the roll core structure can be avoided.

The application belongs to the technical field of electrochemical energy storage, and particularly relates to a pre-sodium-embedded hard carbon negative electrode sheet and a preparation method and application thereof. The pre-sodium-embedded hard carbon negative electrode sheet comprises the following raw materials in parts by weight: pre-sodium-embedded hard carbon 70-90 parts, conductive agent 5-15 parts, and binder 5-15 parts; and the pre-embedded amount of sodium in the pre-sodium-embedded hard carbon is 5%-30% of the theoretical sodium storage capacity of the hard carbon. The pre-sodium-embedded hard carbon negative electrode sheet has the following beneficial effects: when assembled into a secondary battery, sodium ions in the negative electrode sheet will preferentially react with an electrolyte to form a stable and dense SEI film mainly composed of sodium-containing compounds on the surface of the hard carbon. When assembled into a full battery for the first time, lithium ions are embedded into the negative electrode from the positive electrode, and a large amount of additional lithium is no longer needed to build the SEI film, thereby effectively improving the first coulomb efficiency of the full battery and improving the initial energy density of the battery.

This application discloses a method and apparatus for electrochemical extraction to obtain low-impurity lithium ions, relating to the field of capacitive deionization technology. The apparatus includes a positive current collector and a negative current collector with a working surface coated with mesoporous activated carbon material and a chemically de-intercalated lithium ion sieve. A lithium-ion-containing solution circulates between the working surfaces of the positive and negative current collectors. A voltage is applied to insert lithium ions into the chemically de-intercalated lithium ion sieve. After the power is turned off, the cations adsorbed by the mesoporous activated carbon material are re-desorbed. The resulting lithium-ion-intercalated sieve electrode is placed in an electrolyte solution and a voltage is applied to remove lithium. This application uses mesoporous activated carbon material as the negative electrode to adsorb impurity cations in the salt solution. The impurity cations are enriched on the surface of the activated carbon and do not accumulate on the surface of the ion sieve, hindering the absorption of lithium. + By placing the lithium ion extraction device closer to the chemical deintercalation sieve, the content of impurity cations intercalating into the sieve lattice can be reduced, thereby improving the lithium extraction efficiency and purity of the sieve.

This invention discloses a superlattice structure all-solid-state thin-film battery cathode material, its preparation method, and its applications. The cathode material consists of a substrate and a stacked structure deposited on the substrate surface. The stacked structure is formed by alternating deposition of a first transition metal oxide layer and a second transition metal oxide layer from bottom to top. The first and second transition metal oxides of this invention have different work functions and lithium-ion intercalation potentials. An integrated electric field is induced through interface bandgap engineering, synergistically enhancing electron / ion transport dynamics. Simultaneously, lattice pinning and lattice pre-strain are used to suppress structural degradation during cycling. The cathode material provided by this invention exhibits high specific capacity, excellent rate performance, long cycle life, and low preparation temperature, is compatible with semiconductor processes, and is suitable for microelectronic integrated systems.

The invention belongs to the technical field of secondary batteries, and particularly relates to a nickel cobalt manganese oxide precursor and a preparation method and application thereof. According to the nickel cobalt manganese oxide precursor provided by the invention, the specific surface area of the nickel cobalt manganese oxide precursor is 50-150m < 2 > / g, and the pore volume of the nickel cobalt manganese oxide precursor is 0.1-0.5 cm < 3 > / g. Researches find that the specific surface area and the pore volume of the nickel cobalt manganese oxide precursor are limited in a specific range, a more favorable lithium intercalation path can be provided, the reaction activity of a lithium source and the nickel cobalt manganese oxide precursor in the subsequent calcination reaction process is improved, more lithium ions are intercalated into the nickel cobalt lithium manganate material, and the lithium ion battery performance is improved. And the nickel cobalt lithium manganate material with low residual alkali on the surface and excellent electrical performance can be prepared.

The utility model provides a solid-state battery and an electric device. The solid-state battery comprises an electrode assembly, the electrode assembly comprises a positive electrode layer, a negative electrode current collector and a solid-state electrolyte layer, and the solid-state electrolyte layer is located between the positive electrode layer and the negative electrode current collector; at least one surface of the negative current collector is provided with a blind hole, and the opening of the blind hole faces the solid electrolyte layer. According to the solid-state battery, the blind holes are formed in the negative current collector, so that lithium ions can be embedded into the blind holes, the embedding amount of the lithium ions in the surface of the negative current collector is reduced, and the influence of volume expansion caused by lithium ion embedding on a contact interface between the surface of a negative pole piece and a solid-state electrolyte layer is reduced; the improvement of the cycle performance of the solid-state battery is promoted.

The invention belongs to the field of batteries, and particularly discloses a positive pole piece, a preparation method of the positive pole piece, a battery, a battery pack and electric equipment. The positive electrode active material layer is arranged on at least one side of the positive electrode current collector, the positive electrode active material layer comprises ternary positive electrode material particles and a binder, and the binder is located between the different ternary positive electrode material particles and exposes part of the surfaces of the ternary positive electrode material particles; and 0.05 < = ANCM / G < = 0.58. The lithium ion intercalation and deintercalation efficiency is effectively improved, meanwhile, the ion transmission path can be optimized, the stripping force and the electrochemical activity specific surface of the positive pole piece are effectively improved, the resistivity of the positive pole piece is effectively reduced, and the service life of the positive pole piece is prolonged. Therefore, the direct current internal resistance (DCIR) of the battery using the positive pole piece can be effectively reduced, and the mixed material gram volume and the cycle performance of the battery can be effectively improved.

The application relates to the technical field of batteries and discloses a formation method of a battery and the battery. The application controls the voltage and the current of each formation process in a segmented formation mode, reduces the intensity of side reactions under high potential, effectively discharges reaction gas, avoids continuous gas production of residual active substances in a high-temperature aging stage, eliminates swelling and black spot lithium precipitation defects, and improves long-term stability of the battery; the voltage is further increased to 35%-50% of the nominal capacity, which is beneficial to battery exhaust and can control polarization of the battery to prevent capacity loss and super-thickness risk of the battery under high temperature. In addition, the application controls the current rate of the third charging to be less than the current rate of the second charging, the current rate of the second charging is less than or equal to 0.2C, increases the reaction time of the lithium supplement agent, promotes complete reaction of the lithium supplement agent, simultaneously, lithium ions are embedded into the negative electrode more slowly and uniformly in small-current charging, the risk of lithium precipitation is greatly reduced, swelling and black spot lithium precipitation defects are eliminated, and the long-term stability of the lithium ion battery is improved.

The invention provides an embedded lithium / tungsten carbide nanowire composite material as well as a preparation method and application thereof. The structure of the intercalated lithium / tungsten carbide nanowire composite material is as follows: lithium ions are intercalated into internal crystal lattices of tungsten carbide nanowires. The preparation method comprises the following steps: firstly, growing a tungsten oxide nanowire precursor on the surface of the substrate through a hydrothermal reaction; then, ethidene diamine is adopted as a carbonizer, and the tungsten oxide nanowire is converted into a tungsten carbide nanowire structure; and finally, placing the obtained tungsten carbide nanowire in an electrolyte containing lithium hexafluorophosphate, and realizing embedding of lithium ions by using an electrochemical lithium tuning technology, thereby obtaining the intercalated lithium / tungsten carbide nanowire composite structure material. The preparation method is simple in technological process, high in safety, convenient to operate and low in cost; the prepared composite structure is excellent in electro-catalytic performance and has potential wide application value.

The invention discloses a negative plate, a secondary battery and electric equipment. The negative plate comprises a current collector layer which is arranged in sequence, the first active material layer comprises a first graphite material, and the OI1 value of the first graphite material is 8-15; and the second active substance layer comprises a second graphite material and a silicon-based material, and the OI2 value is 0-8. The included angle between the first active material layer and the current collector is small, and the contact area with the current collector is increased, so that the bonding force between the active material and the current collector is enhanced, extension is reduced, and the problems of pole piece demolding and breakage are solved. Meanwhile, the included angle between the second active material layer and the current collector is increased, and the active material is approximately vertically arranged, so that a lithium ion channel is optimized, lithium deintercalation and lithium intercalation are easier, the charge-discharge performance is enhanced, and the overall expansion of lithium ion intercalation is converted into the direction parallel to the current collector from the direction perpendicular to the current collector; and meanwhile, the transverse expansion is limited by the arrangement of the graphite at the bottom layer, so that a synergistic effect is generated.

The present disclosure relates to a negative active material for a lithium secondary battery, a lithium secondary battery comprising the same, and a method of preparing the same. The negative active material comprises a coating layer self-bound to the surface of a carbonaceous material and containing porous carbon particles, thereby exhibiting reduced electrical resistance during intercalation of lithium ions on the surface of the carbonaceous material and providing improved surface reactivity and structural stability, thereby providing improved high-rate charge characteristics without causing deterioration of charge / discharge efficiency and life characteristics when used as a negative active material for a lithium secondary battery. The negative active material comprises a carbonaceous material and a carbon coating layer self-bound to the surface of the carbonaceous material. Here, the self-bound amorphous carbon coating layer can optionally have a controlled pore structure by chemical etching.

A negative electrode material, including graphite, where the negative electrode material has an I-order lithium intercalation plateau potential P1 of 30 mV to 75 mV and an II-order lithium intercalation plateau potential P2 of 90 mV to 110 mV. The use of the negative electrode material of this application can significantly improve the cycling performance of the electrochemical apparatus using the negative electrode material under high voltage and high temperature, enhance the gram capacity of the negative electrode material, while maintaining the initial efficiency of the negative electrode material.

The application belongs to the technical field of battery preparation, and particularly relates to a battery and a device. The battery comprises a negative electrode sheet, the negative electrode sheet comprises a current collector and a negative electrode active material layer arranged on at least one surface of the current collector, the negative electrode active material layer comprises a negative electrode active material, and the negative electrode active material comprises a silicon-containing material. The silicon content in the negative electrode active material layer and the elongation at break of the negative electrode current collector satisfy a specific relationship, which not only can ensure the lithium ion embedding capacity of the negative electrode while reducing the risk of negative electrode foil cracking caused by negative electrode expansion, but also can avoid the risk of positive and negative electrode short circuit caused by the negative electrode foil cracking process, thereby improving the capacity density, cycle performance and safety performance of the battery.

This invention discloses a continuous electrochemical lithium extraction device and process from salt lakes, belonging to the field of lithium extraction technology. The device employs a two-chamber structure, separated into a brine chamber and a recovery chamber by a membrane electrode assembly (MEA). By applying voltage to both the brine chamber and the recovery chamber on either side of the MEA, lithium ions are inserted into the MEA in the brine chamber and extracted from the MEA in the recovery chamber. Simultaneously, an oxygen evolution reaction occurs at the electrode in the brine chamber, and a hydrogen evolution reaction occurs at the electrode in the recovery chamber. The MEA, the two-chamber structure, and the liquid path remain fixed throughout the process, eliminating the need to move electrodes, switch chambers, or change liquid paths, thus achieving continuous operation. Furthermore, OH- is generated at the hydrogen evolution electrode in the recovery chamber. ‑ Li released from the membrane electrode + This combination forms a high-value-added lithium hydroxide solution. The device of this invention has a simple structure, is easy to operate, has a recyclable membrane electrode, high lithium-ion selectivity, no acid or alkali consumption, and is environmentally friendly. It is suitable for lithium extraction from high magnesium-to-lithium ratio salt lake brines.

The invention discloses a graphite negative electrode material and a preparation method and application thereof, and belongs to the technical field of negative electrode materials. The graphite negative electrode material comprises a plurality of composite particles, and each composite particle comprises graphite and a barium titanate coating layer located on the surface of the graphite; the relative distribution ratio average value gt of the barium titanate coating layer on the end surface of the graphite; and 50%. In the lithium ion charging and discharging process, graphite can generate volume change and generate stress, barium titanate is used as a piezoelectric material and can generate electric charges and change a lithium intercalation electric field when being stressed, so that intercalation of lithium ions is promoted, the fast charging performance of a graphite negative electrode is improved, and meanwhile, lithium deposition and lithium loss can be reduced. The barium titanate coating layer is mainly formed on the end surface of the graphite, so that the barium titanate can play a role, and unnecessary coating is reduced, thereby avoiding reduction of specific capacity and hindering of lithium ion embedding caused by excessive barium titanate. The graphite negative electrode material provided by the invention is beneficial to improving the rate capability and cycling stability of the battery.

The application belongs to the technical field of lithium ion battery negative electrode materials, and particularly relates to a high-sulfur coke-based fast-charging artificial graphite negative electrode material and a preparation method and application thereof. The application selects high-sulfur coke with a sulfur content of 3-8 wt% as a raw material, and simultaneously selects a heat treatment process with segmented temperature rising for desulfurization treatment, so as to cooperatively remove harmful sulfur in the high-sulfur coke and realize C-axis pore formation of graphite. By controlling the volatilization speed of sulfur, the collapse of the structure of the high-sulfur coke is avoided, and the reconstructed porous desulfurized coke can ensure the order degree of the C-axis pore formation graphite, which is beneficial to the acquisition of pore structures, active sites for lithium ion intercalation and deintercalation and transmission, and thus the rate performance of the prepared fast-charging artificial graphite negative electrode material is effectively improved.

The invention provides a graphene-coated lithium titanate composite material and a preparation method thereof, and relates to the technical field of battery materials, the graphene-coated lithium titanate composite material comprises the following components by mass: 80-95 parts of a lithium titanate matrix, 1-10 parts of a graphene layer, and 0.5-5 parts of a dispersant; the surface of the lithium titanate matrix is coated with the graphene layer, and the dispersing agent is used for dispersing graphene in the graphene layer; the graphene layer is of a continuous and compact structure; by accurately controlling the number of graphene layers, the thickness of the coating layer and the use amount of the dispersing agent, the graphene forms a continuous and compact nano armor coating layer on the surface of the lithium titanate, so that the defect of low electronic conductivity of the lithium titanate is overcome, and the problem of conductive path breakage caused by graphene agglomeration is avoided; the two-dimensional flexible structure of graphene and the zero-strain characteristic of lithium titanate generate a synergistic effect, so that agglomeration and corrosion of lithium titanate particles in the circulation process can be effectively inhibited, and the volume micro-change during lithium ion intercalation and deintercalation is buffered.

The present application solves the problem of high resistance to lithium ion intercalation and deintercalation in a single-sided region of an electrode sheet, which seriously affects the energy density of a battery cell. The present application provides a positive electrode sheet, a secondary battery, and an electric device. The positive electrode sheet comprises a current collector, and a lithium compensation layer and a positive electrode active material layer arranged in a stacked configuration on a surface of at least one side of the current collector, wherein the lithium compensation layer is arranged close to the current collector, and the positive electrode active material layer is arranged on a surface of a side of the lithium compensation layer facing away from the current collector; the lithium compensation layer comprises a pre-lithiation agent and a first positive electrode active material, and the positive electrode active material layer comprises a second positive electrode active material and does not contain the pre-lithiation agent; and a mass of the pre-lithiation agent accounts for 3.5%-10% of a total mass of the lithium compensation layer. The positive electrode sheet not only has a lithium compensating effect, but also exhibits good structural stability during charging and discharging cycles, thereby simultaneously improving the energy density and cycle performance of the battery.

This application relates to the field of energy storage technology, providing a battery cell and its preparation method, battery device, power consumption device, and energy storage device. The battery cell includes: a cell assembly comprising a negative electrode, a separator, and a positive electrode stacked together; a casing containing the cell assembly; and an electrolyte containing the electrolyte within the casing. The negative electrode comprises a negative electrode active material, which includes a modified graphite material having a core-shell structure. The core-shell structure includes a shell and a core located within the shell. The core comprises graphite and a buffer sheet located between at least some layers of the graphite. The lithium intercalation potential of the buffer sheet is greater than that of the graphite, and the lithium intercalation potential of the shell is greater than that of the buffer sheet. This application at least facilitates precise control of the lithium-ion intercalation process and interfacial reactions from the interior to the surface of the material.

The application provides a negative electrode applied to a lithium-hydrogen battery and a preparation method of the negative electrode, and the lithium-hydrogen battery, and belongs to the technical field of electrochemical energy storage. The application provides a preparation method of a negative electrode applied to a lithium-hydrogen battery, which comprises the following steps: preparing a silicon nanomaterial slurry; uniformly coating the silicon nanomaterial slurry on one surface of a metal foil current collector, drying and rolling to form a silicon nanomaterial coating on the metal foil current collector, thereby forming a negative electrode precursor; and assembling the negative electrode precursor and an electrolyte containing lithium ions into a lithium-hydrogen battery to perform first charging, so that lithium ions are embedded into the negative electrode precursor to form a lithiumophilic interface, thereby forming the negative electrode. The application further provides a negative electrode and a lithium-hydrogen battery applying the negative electrode.

A lithium-ion battery component and method of manufacture are presented. An active material layer with a lithiophilic nitrate compound is mixed with graphite particles and coated onto a current collector. Upon polarization, lithiophilic nanoparticles form on the graphite surfaces, while nitrate anions remain in the electrode structure. The lithiophilic nanoparticles inhibit lithium plating during charging and increase electronic conductivity. The nitrate anions weaken lithium ion solvation in the electrolyte, facilitating faster lithium ion intercalation into the graphite.

The invention provides a fullerene polymer material, a negative electrode material, a negative electrode plate, a lithium ion battery and a preparation method of the lithium ion battery. The fullerene polymer material provided by the invention comprises a fullerene polymer and alkaline earth metal ions doped in the fullerene polymer, the molar ratio of the alkaline earth metal ions to the fullerene molecules is (0.01-1): 1. Alkaline-earth metal is adopted to induce fullerene molecules to be covalently connected, then an acidic reagent is adopted to remove part of alkaline-earth metal ions, the fullerene polymer material of a three-dimensional layered network structure is obtained, the fullerene polymer material is good in stability and large in interlayer gap, has more adsorption sites, and has a good adsorption effect when being used as a negative electrode material. The lithium ion intercalation and deintercalation efficiency is high, and the specific capacity, the rate capability and the cycle performance of the lithium ion battery can be improved.

The present application relates to the field of lithium ion batteries, and provides a lithium supplement electrolyte, a lithium supplement electrode and a lithium ion battery, all of which comprise a lithium supplement additive; the oxidation of the lithium supplement additive nitrite in the charging process can make lithium ions in the battery insert into the negative electrode, supplement the lithium ions lost in the lithium ion battery due to the formation of a solid electrolyte interface film, and improve the cycle life and capacity of the battery; in addition, the nitrate produced by the decomposition of the nitrite can improve the structure of the solid electrolyte interface film generated subsequently, which is beneficial to improve the cycle life and stability of the battery; in addition, the nitrite of the present application can be produced on a large scale and is cheap, and therefore can be applied to industrial production. Compared with the prior art, the present application has the advantages of improving the cycle life and capacity of the battery and being applicable to industrial production.

The invention discloses a low-temperature preparation method and device of aluminum-lithium alloy powder, and belongs to the technical field of metal powder preparation, a pretreated aluminum foil and a lithium sheet are assembled into an electrochemical lithium intercalation unit through a diaphragm, electrolyte is injected into a closed cavity, and lithium ion intercalation is realized through short circuit or external circuit discharge under the condition of-100 DEG C to 200 DEG C. According to the method, a traditional smelting process is avoided, aluminum-lithium alloy powder with controllable components is directly generated in a low-temperature environment, and the lithium atom proportion is 0-69.2%. A fluorine / sulfur-containing passivation film is formed on the surface of the product, and the product has high chemical purity and designable electrochemical characteristics. And the process energy consumption is obviously reduced, and the method is suitable for preparing aerospace light structure materials and high-energy-density battery negative electrode materials.

This utility model discloses a stacked battery, belonging to the field of battery technology. The stacked battery includes a positive electrode, a positive tab, a negative electrode, a first tab, and a second tab. The positive tab protrudes from the top side of the positive electrode and is coated with a first coating near the bottom of the positive electrode. The first and second tabs are spaced apart and protruding from the top side of the negative electrode. The positive electrode is stacked on one side of the negative electrode. The second tab is coated with a second coating, which is positioned opposite to the first coating. Along the thickness direction of the stacked battery, the projection of the first coating falls on the projection of the second coating. This stacked battery allows the second coating to completely cover the first coating, enabling the second coating to provide lithium-ion intercalation sites corresponding to the first coating. This avoids lithium plating problems caused by the lack of corresponding lithium-ion intercalation sites in the first coating and improves the overall capacity of the stacked battery.

This invention relates to a microporous copper foil current collector with in-situ grown carbon nanotubes (CNTs), its preparation method, and its applications. The microporous copper foil current collector with in-situ grown CNTs comprises: a microporous copper foil substrate, the microporous copper foil substrate including a through-hole structure; and a carbon nanotube layer formed by carbon nanotubes in-situ grown on the surface of the microporous copper foil substrate and inside the pore structure; the carbon nanotube layer forms a three-dimensional conductive network structure on the surface of the microporous copper foil substrate and the pore walls. This invention, by in-situ growing CNTs on the surface and pore walls of the microporous copper foil substrate, forms a stable three-dimensional conductive network, improves the adhesion between the active material and the current collector, improves interfacial contact, inhibits the shedding of the negative electrode material, reduces internal resistance and polarization, and simultaneously improves lithium-ion intercalation efficiency, achieving a comprehensive improvement in cycle performance and energy density.

The invention discloses a double-layer coated graphite negative electrode material, a preparation method thereof and a lithium ion battery. The graphite negative electrode material comprises an inner core and a coating layer, the inner core is graphite, and the coating layer is sequentially provided with a soft carbon coating layer and an organic polymer coating layer. The preparation method comprises the following steps: firstly, dynamically coating the surface of graphite to form a soft carbon coating layer, then growing on the soft carbon coating layer by an in-situ polymerization method to form an organic polymer coating layer, and finally performing high-temperature carbonization treatment to obtain the double-layer coated graphite negative electrode material. The preparation method solves the problems of non-uniform coating of single-layer soft carbon, poor conductivity and insufficient lithium ion embedding channels. The material provided by the invention has high specific capacity and excellent rate capability, is suitable for a lithium ion battery negative electrode, and is especially suitable for a high-power charge-discharge scene.