11650results about "Negative electrodes" patented technology

The invention relates to the technical field of batteries, in particular to a battery. The battery comprises a diaphragm and an electrolyte, the diaphragm comprises a carrier layer and a coating, the coating comprises first particles, the components of the first particles comprise an ester group-containing polymer, and within the area of 100 [mu] m * 100 [mu] m of the surface of the coating, the number of primary particles of the first particles with the particle size smaller than or equal to 0.3 [mu] m accounts for 0.01%-4% of the number of the primary particles of the first particles; the electrolyte comprises cyclic carbonate and fluoroethylene carbonate, the weight ratio of the fluoroethylene carbonate in the electrolyte is 13%-50%, and the weight ratio of the cyclic carbonate to the fluoroethylene carbonate is (0.2-1.5): 1. According to the battery disclosed by the invention, a relatively stable and flexible SEI film is formed on the surface of the negative plate through synergistic cooperation of the diaphragm and the electrolyte, so that the interface stability between the diaphragm and the negative plate is improved, and the high-temperature long-cycle performance of the battery is improved.

The invention discloses a preparation method of a composite high-entropy hard carbon negative electrode material and a sodium ion battery, and relates to the technical field of electrochemical energy storage materials. Existing doping limit is broken through through'high entropy design ', atomic-scale mixing of five elements and more than five elements is realized, strong structural stability which cannot be realized by traditional binary / ternary doping is achieved, 'molecular anchoring' and'entropy locking 'are completed by combining a pre-assembly technology with stepped carbonization, the problem of pain point of multi-element segregation is solved, and the method is suitable for large-scale industrial production. Sodium storage dynamic and thermodynamic properties of a high-entropy hard carbon precursor and an intermediate are synchronously improved through elaborate combination design of multiple elements and subsequent carbonization process parameter optimization, 'defect-interlayer spacing-pore structure 'triple regulation is realized, and the defect degree of high-entropy hard carbon is reduced through design of a coating process; the prepared composite high-entropy hard carbon negative electrode material shows excellent comprehensive performance in a sodium-ion battery, and especially has obvious advantages in high initial coulombic efficiency, high rate capability and long stability.

The invention relates to the technical field of batteries, in particular to a lithium ion secondary battery. The lithium ion secondary battery comprises a negative plate and electrolyte, the negative plate comprises a negative current collector and a negative active layer located on at least one side surface of the negative current collector, the negative active layer comprises a first coating and a second coating which are arranged in the thickness direction of the negative plate, and the first coating is located between the negative current collector and the second coating; the second coating comprises first silicon carbon, and the sphericity degree of the first silicon carbon is 0.8-1; the silicon content of the first silicon carbon is 30%-60%; the average particle size of the first silicon carbon is R1, and R1 is more than 6 microns and less than or equal to 15 microns; the electrolyte comprises a fluorine-containing solvent and a nitrile compound, the fluorine-containing solvent comprises fluoroethylene carbonate and / or ethyl difluoroacetate, based on the total weight of the electrolyte, the content of the fluorine-containing solvent is w1, and w1 is larger than or equal to 30% and smaller than or equal to 70%; the content of the nitrile compound is w2, and 0.4% < = w2 < = 7%. The lithium ion secondary battery provided by the invention has good cycling stability and dynamic performance at high voltage and high temperature.

The invention relates to a silicon-carbon composite material capable of improving the cycling stability of a battery, a preparation method of the silicon-carbon composite material, a negative pole piece and a lithium ion battery. The carbon-silicon composite particle comprises a silicon-carbon inner core and a carbon coating layer, nano-silicon is attached in holes and / or on the surface of a porous carbon matrix to form the silicon-carbon inner core, and the carbon coating layer is coated on at least part of the surface of the inner core; the porous carbon matrix and the carbon coating layer are both doped with halogen. According to the silicon-carbon composite material, the electron conductivity of the silicon-carbon composite material is improved by doping the halogen in the porous carbon matrix inside the silicon-carbon composite material and the carbon coating layer outside the silicon-carbon composite material; and meanwhile, the porous carbon matrix, the inner core composed of the nano silicon and the carbon coating layer are mutually matched and have synergistic interaction, so that the volume expansibility and defects of the silicon-carbon composite material are reduced, and the cycle stability is improved.

The invention discloses a biomass asphalt composite derivative hard carbon material and a preparation method and application thereof, and the preparation method comprises the following steps: step (1), placing biomass raw material powder in an acid pickling solvent for acid pickling, washing to be neutral after acid pickling, and drying to obtain a biomass precursor; (2) mixing the biomass precursor with asphalt to obtain a precursor mixture; and (3) carrying out low-temperature pre-oxidation on the precursor mixture, and then carrying out high-temperature carbonization, so as to obtain the biomass asphalt composite derivative hard carbon material after the high-temperature carbonization is finished. The prepared biomass asphalt composite derivative hard carbon material is used for preparing a sodium ion battery negative electrode. The technical problems that an existing biomass hard carbon material is low in capacity and tap density, difficult in impurity removal and the like can be solved, the biomass hard carbon material can be used for a sodium-ion battery negative electrode, and the sodium storage performance of a sodium-ion battery is improved.

The invention provides a functional graded porous carbon microsphere and a preparation method and application thereof, the preparation method comprises the following steps: S1, mixing a soft template, a phenolic compound, a cross-linking agent and a basic catalyst, and reacting to obtain a thermosetting phenolic resin microsphere; s2, carrying out pre-carbonization treatment on the thermosetting phenolic resin microspheres to obtain a carbonized material; s3, performing physical activation on the carbonized material to obtain graded porous carbon microspheres; s4, performing heat treatment on the graded porous carbon microspheres to obtain functionalized graded porous carbon microspheres; the preparation method has the characteristics of simple process, environmental protection and economical efficiency, the functionalized porous carbon microspheres prepared by the method are uniform in morphology, and the pore volume, pore diameter and pore structure of the functionalized graded porous carbon microspheres can be accurately regulated and controlled, so that the functionalized graded porous carbon microspheres meeting application requirements are obtained.

The invention relates to a solid electrolyte coated silicon-carbon negative electrode material and a preparation method thereof, an all-solid-state battery and an electric device, and belongs to the technical field of methods or devices for directly converting chemical energy into electric energy. The solid electrolyte coated silicon-carbon negative electrode material comprises a silicon-carbon negative electrode material and a solid electrolyte coating layer arranged on the surface of the silicon-carbon negative electrode material, the solid electrolyte coating layer comprises at least one of sulfide electrolyte and halide electrolyte; the silicon-carbon negative electrode material comprises an inner core and a carbon coating layer arranged on the surface of the inner core, the inner core comprises a porous carbon matrix and a silicon-based material positioned in pores of the porous carbon matrix. The solid-state electrolyte coated silicon-carbon negative electrode material enables an all-solid-state battery to have high ionic conductivity and first efficiency and excellent cycling stability.

The invention provides a sodium ion battery, an energy storage device and an energy storage system. The sodium ion battery comprises a positive pole piece, a diaphragm, a negative pole piece and an electrolyte, the negative pole piece comprises a carbon material, the specific surface area of the carbon material is x, the carbon material comprises mesopores, the number percentage of the mesopores in the carbon material is y, and the electrolyte comprises an organic solvent, an electrolyte salt, an organic additive and a sodium salt additive, the organic solvent comprises cyclic carbonate and chain carbonate, the mass fraction of the cyclic carbonate in the electrolyte is a, the mass fraction of the chain carbonate in the electrolyte is b, the mass fraction of the organic additive in the electrolyte is c, and the mass fraction of the sodium salt additive in the electrolyte is d; the sodium ion battery meets the relational expression of 0.4 < = a / y < = 0.8; 0.5 < = a / b < = 1.3; 0.4 < = c / x < = 1.2; and 0.1 < = d / c < = 0.5.

The invention relates to an integrated carbonaceous honeycomb framework lithium metal composite negative electrode and a preparation method thereof, and belongs to the technical field of lithium metal batteries, the integrated carbonaceous honeycomb framework lithium metal composite negative electrode is formed by depositing lithium metal in an integrated carbonaceous honeycomb framework host, and the host is constructed by adopting metal salt-colloidal crystal microsphere template precursor preparation, compression molding and controllable carbonization processes. The structure has a highly ordered three-dimensional integrated macroporous skeleton, and can realize rapid transmission and uniform electric field distribution of lithium ions and electrons, so that dendrite-free homogeneous lithium deposition under ultrahigh capacity is realized, volume expansion is remarkably inhibited, and the reversible stability of lithium metal deposition / stripping is improved. The invention provides an efficient and stable negative electrode solution for a high-energy-density lithium battery, and has an important application prospect.

The invention discloses a preparation method of a phosphorus / silicon composite negative electrode material, and belongs to the technical field of lithium battery negative electrode materials. The method comprises the following steps: putting porous carbon into a CVD (Chemical Vapor Deposition) furnace, vacuumizing, heating to 180-230 DEG C, and keeping the temperature for 50-70 minutes; the temperature is increased to 600-800 DEG C, SiH4 silane gas is introduced, cracking deposition is carried out, and the deposition time is 2-3 h; cooling to 300-500 DEG C, introducing a phosphorus source, and permeating into mesopores of 2-50 nm; and cooling the CVD furnace to 260-350 DEG C, and keeping the temperature for 24-72 hours, so that the simple substance is phosphatized into the amorphous red phosphorus nanoparticles. Nanocrystallized phosphorus and silicon are compounded into porous carbon channels, and the characteristic that the lithiation potential of a phosphorus negative electrode is high is utilized, so that the negative electrode is far away from the lithium precipitation potential; meanwhile, the lithiation gram volume of the phosphorus negative electrode is also very high, and the gram volume of the material is not reduced. Silicon is deposited firstly, then phosphorus is deposited, and the silicon is deposited on the innermost side of a pore channel; and expansion in the phosphorus / silicon lithiation process is inhibited by utilizing the confinement of the porous carbon, so that circulation is guaranteed.

The invention discloses a LiAlO2 fast ion conductor coated silicon-carbon composite material as well as a preparation method and application thereof, and belongs to the technical field of lithium ion battery materials. The LiAlO2 fast ion conductor coated silicon carbon composite material has a core-shell structure; an inner core of the composite material is a silicon-carbon composite material, the silicon-carbon composite material is formed by coating a three-dimensional carbon material with an amorphous carbon layer and loading a nano silicon compound, a shell of the composite material is a LiAlO2 fast ion conductor layer, and the silicon-carbon composite material with a three-dimensional network structure is constructed, and the surface of the silicon-carbon composite material is coated with the LiAlO2 fast ion conductor layer, so that the composite material is obtained. According to the present invention, with the LiAlO2, the volume expansion of the nanometer silicon during the charge-discharge process can be effectively relieved, the stability of the silicon-carbon composite material structure can be improved so as to significantly improve the cycle performance of the battery, and the LiAlO2 can provide the rapid channel for the transmission of the lithium ion during the charge-discharge process so as to improve the rate performance of the battery;

The invention relates to the technical field of batteries, in particular to a composite negative electrode material as well as a preparation method and application thereof. The composite negative electrode material comprises a negative electrode base material and a fast ion conductor layer located on the surface of the negative electrode base material, the negative electrode base material comprises a silicon nanosheet and a carbon coating layer located on the surface of the silicon nanosheet, and the surface of the carbon coating layer is doped with element nitrogen; and the fast ion conductor layer comprises Li3PO4. According to the composite negative electrode material disclosed by the invention, through coordination and cooperation of all the layers, the problem of capacity fading of a pure silicon negative electrode in a circulation process can be relieved, stable long-cycle performance is realized, and a high capacity retention ratio is obtained.

Provided in the present application are a battery cell and a preparation method therefor, and a battery device and an electric device. The battery cell comprises a negative electrode sheet, the negative electrode sheet comprising a first layer and a non-metallic layer located on the surface on at least one side of the first layer, wherein the nucleation overpotential of Li on the non-metallic layer is V1, and the nucleation overpotential of Li on the first layer is V2, and V1>V2. The negative electrode sheet in the present application can induce the deposition of lithium metal on the surface of a first layer, mitigate dendrite growth and improve the uniformity of lithium metal deposition, thereby improving the cycling performance of battery cells.

The invention belongs to the technical field of sodium-ion batteries, and particularly relates to a preparation method of a coal-based hard carbon material and application of the coal-based hard carbon material in a sodium-ion battery negative electrode. The preparation method of the hard carbon material comprises the following steps: carrying out acid-base chemical heat treatment on a coal-based material to obtain an ash-removed and dried precursor material, and activating the material by water vapor to obtain a target sample with etched micropore inner gaps, and in the subsequent carbonization process, the carbon layer is twisted to form a closed pore structure to obtain the electrode material. According to the invention, the application of the rich-resource coal precursor and the high carbon conversion rate in the sodium ion battery is realized, and the storage capacity of sodium and the cycling stability of the material are effectively improved. The coal-based hard carbon material can be used for preparing a sodium ion battery and has important application value.

The invention discloses a negative electrode interface modification material, a negative electrode plate, a positive electrode interface functional layer, a positive electrode plate, a solid-state battery and a power utilization device, and relates to the technical field of batteries, the negative electrode interface modification material comprises a first polymer matrix, a reinforcing filler, a conductive agent and a lithium salt, the modulus of the reinforcing filler is greater than 50 GPa. The tensile strength of the negative electrode interface modification material can be improved through the first polymer matrix, breakage of a negative electrode interface modification layer is reduced, interface impedance is reduced, meanwhile, the first polymer matrix can be matched with the expansion coefficient of a silicon-based material, and bulging of a negative electrode plate is reduced. The modulus of the reinforcing filler is greater than 50GPa, so that the modulus of the negative electrode interface modification layer can be improved, the expansion of the silicon-based active material is further inhibited, the conductive agent can relieve the problem that the flexible substrate interface of the copper foil and the negative electrode interface modification layer possibly causes unsmooth electron transmission, and the lithium salt can improve the ion conduction capability and reduce the interface impedance.

The embodiment of the invention relates to the field of energy storage, and provides a secondary battery and a preparation method thereof, an energy storage system and electric equipment. The negative electrode active material comprises a silicon-based material, honeycomb porous graphite and a polypyrrole layer, the surface of the honeycomb porous graphite is coated with the polypyrrole layer, the silicon-based material is embedded in pores of the honeycomb porous graphite, and the silicon-based material comprises silicon particles, a poly N-isopropylacrylamide layer and a disulfide bond-containing polyaniline layer. The poly (N-isopropylacrylamide) layer and the disulfide bond-containing polyaniline layer are coated on the surfaces of the silicon particles, the poly (N-isopropylacrylamide) layer is positioned between the silicon particles and the disulfide bond-containing polyaniline layer, and the honeycomb porous graphite comprises a graphite flake and a carbon layer which is positioned on the surface of the graphite flake and is of a honeycomb pore structure. The secondary battery formed by assembling the negative electrode active material disclosed by the invention has relatively high cycling stability, high temperature resistance, rate capability, gram volume and safety.

The invention relates to a silicon-carbon composite material with a porous structure and a preparation method thereof, and the silicon-carbon composite material with the porous structure comprises an N / P co-doped porous carbon skeleton with micropore, mesopore and macropore channel networks, and amorphous or low-crystalline nanometer silicon particles which are uniformly loaded in the porous carbon skeleton and have the average particle size of 15-40nm, the mass percent of silicon in the composite material is 40-60%, and good interface bonding is formed between silicon and carbon. The preparation method mainly comprises the following steps: firstly, preparing an N / P co-doped porous carbon skeleton through a template method in combination with high-temperature carbonization and N / P source co-pyrolysis; and hydrolyzing an organic silicon source in the carbon skeleton to form silicon dioxide, and performing low-temperature metal thermal in-situ reduction to obtain the nano-silicon loaded composite material. Through a unique porous carbon skeleton design and a precise in-situ composite strategy of nano silicon, the prepared material shows high specific capacity, high initial coulombic efficiency and excellent cycling stability and rate capability when being used as a negative electrode of a lithium ion battery.

The invention belongs to the technical field of sodium ion batteries, and discloses a multi-coal composite sodium battery hard carbon negative electrode material, a preparation method and an application, three coal raw materials with different characteristics are used as a basis, and the hard carbon material with excellent structure and good performance is prepared by using respective component characteristics, pyrolysis characteristics and structural characteristics of the coal raw materials. The whole preparation method is simple, the large-scale production difficulty is low, no high-pollution chemical reagent is used, the reversible specific capacity reaches up to 350mAh / g when the material is used as a sodium-ion battery negative electrode material, and the material shows ultrahigh rate capability.

The invention discloses a biomass-based sodium ion battery hard carbon material and a preparation method and application thereof, and the preparation method comprises the following steps: uniformly mixing a biomass raw material, an oxidation pore-forming reagent and water to obtain a precursor dispersion liquid, standing and drying the precursor dispersion liquid to obtain a hard carbon precursor, pre-carbonizing the hard carbon precursor at 650-900 DEG C for 1-5 h, and cooling to room temperature to obtain the biomass-based sodium ion battery hard carbon material. And carrying out acid pickling to remove impurities so as to obtain an oxidation pore-forming activated material, carrying out deep carbonization on the oxidation pore-forming activated material at 1150-1450 DEG C for 1-8 hours, and cooling to room temperature, so as to obtain the biomass-based sodium ion battery hard carbon material. The biomass-based sodium-ion battery hard carbon material obtained by the invention has the advantages of high first-circle charge specific capacity, high first-circle discharge specific capacity, high slope capacity, high first-circle coulombic efficiency and high cycle stability.

The invention provides coal-based porous carbon for preparing a silicon-carbon negative electrode material as well as a preparation method and application of the coal-based porous carbon, coal-based porous graphite is used as a matrix carbon material, polymer resin is used as a rigid bonding and coating material, heterogeneous elements such as B, N and P are used as doping materials, a carbon nanotube is used as a flexible conductive buffer material, and the materials are dispersed in a solvent to form slurry; through atomization granulation and high-temperature carbonization, heterogeneous element doped resin hard carbon is bridged with carbon nanotubes to construct a three-dimensional rigid-flexible conductive network to cooperatively coat the surface of the porous coal-based graphite, and doped heterogeneous elements are utilized to induce chemical-physical auxiliary activation to perform micro-mesoporous precise regulation and control pore forming on an inner core and a shell. The prepared novel coal-based porous carbon is high in porous framework particle strength and reasonable in pore distribution and has a three-dimensional rigid-flexible conductive network core-shell structure. The invention aims to solve the problems of unreasonable pore distribution of porous carbon, poor matrix strength and the like in the preparation process of a novel vapor deposition silicon-carbon negative electrode material.

The invention belongs to the technical field of sodium ion battery hard carbon negative electrode materials, and particularly relates to a phenolic resin asphalt super-crosslinking hard carbon composite active material and a preparation method and application thereof.The preparation method comprises the steps of phenolic resin precursor synthesis, oxidized asphalt precursor synthesis, super-crosslinking reaction and stepped carbonization; the preparation method comprises the following steps: reacting phenol with formaldehyde under the action of a catalyst to obtain a phenolic resin precursor; pre-oxidizing the coated asphalt in an air atmosphere to generate an asphalt precursor; the preparation method comprises the following steps: mixing a phenolic resin precursor with an asphalt precursor, adding an acid catalyst into an organic solvent, and performing reflux heating to form a chemically bonded three-dimensional cross-linked network structure; and sequentially carrying out low-temperature pre-carbonization and high-temperature carbonization in an inert gas atmosphere to obtain a target product, namely the hard carbon composite material. The target product provided by the invention has rich closed pore and multistage through pore structure hard carbon, and the sodium storage capacity of the hard carbon material is effectively improved.

The invention relates to the field of battery materials, in particular to a preparation method and application of a high-rate silicon-carbon negative electrode material. The preparation method of the high-rate silicon-carbon negative electrode material comprises the steps of silicon powder pretreatment, silicon-carbon powder composite ball milling, phosphoric acid treatment, high-temperature carbonization and the like. The preparation method of the high-magnification silicon-carbon negative electrode material is simple in process and high in success rate, the cycle stability of a negative electrode is effectively improved, the silicon-carbon negative electrode material has the characteristics of low expansion volume and long cycle life, the phenomenon that a surface oxide layer hinders lithium ion diffusion is avoided, and the service life of the silicon-carbon negative electrode material is prolonged. The comprehensive performance requirement of the existing lithium ion battery on the negative electrode material is met, and the application potential is very wide.

The invention belongs to the technical field of battery material preparation, and particularly relates to a coated negative electrode material as well as a preparation method and application thereof. The coated negative electrode material comprises a porous carbon skeleton and a carbon coating layer coating the porous carbon skeleton, the porous carbon skeleton is provided with a plurality of holes; a silicon layer and a functional layer are attached to the surfaces of part of the holes; the silicon layer comprises silicon, the functional layer comprises a functional material, and the functional material comprises lithium aluminum fluoride. The coated negative electrode material provided by the invention has the properties of low expansion, high lithium ion conduction, few byproducts and the like, and is suitable for a solid battery; the battery energy density is ensured, and the problems that an effective lithium ion path cannot be formed due to contact failure of an active substance caused by high volume expansion of a silicon-based material in the circulation process and contact failure of the active material and a solid electrolyte in a solid-state battery, and performance degradation is caused by negative electrode side polarization increase in the circulation process are solved.

The invention relates to the technical field of lithium ion batteries, in particular to a lithium-doped silicon-carbon composite material, a preparation method thereof, a negative plate and a lithium ion battery. The preparation method of the lithium-doped silicon-carbon composite material comprises the following steps: carrying out reduction reaction and activated pore-forming on a mixed material containing a carbon source, an organic pore-forming agent, a lithium supplement agent and a reducing agent to obtain lithium-doped porous carbon; performing first deposition on the lithium-doped porous carbon and mixed gas containing an inorganic lithium compound and an organic lithium compound; carrying out second deposition on the material obtained after the first deposition and silane gas to obtain a lithium compound doped silicon carbon precursor material; and mixing the lithium compound doped silicon carbon precursor material, an organic metal compound, asphalt and an organic solvent, performing spray drying, and then performing carbonization. According to the preparation method, the initial efficiency and the power performance of the silicon-carbon composite material can be improved.

In one aspect, non-invasive methods are described in which combinations of certain battery parameter values are used to identify whether metal plating (e.g., lithium plating) has occurred during charging of a battery. In response to the detection of metal plating and / or conditions associated with metal plating, one or more characteristics of a charge process may be adjusted or adapted to maintain battery parameter values within a specified range. In some cases, after detection of metal plating, a battery charge process may be adjusted or adapted to remove metal plating from a battery's anode by a discharge pulse.

The invention relates to a graphite silicon carbon composite negative electrode material, a negative electrode plate and a lithium ion battery, and belongs to the technical field of battery negative electrode materials. The graphite silicon carbon composite negative electrode material comprises a graphite inner core and a composite shell layer, the composite shell layer coats the surface of the inner core, the composite shell layer comprises a continuous carbon layer, the carbon layer is of a porous structure, and the porous structure is filled with nano silicon particles. According to the core-shell structure, through a three-stage synergistic mechanism of graphite inner core conductive supporting, porous carbon layer expansion buffering and nanometer silicon capacity contribution, the cycling stability of the negative electrode material is remarkably improved while the high specific capacity is maintained.

The invention relates to the technical field of sodium-ion batteries, and discloses a super-crosslinked asphalt-based hard carbon material, a preparation method and application thereof, and a sodium-ion battery. Asphalt is subjected to super-crosslinking by adopting a mechanochemical method, and the asphalt, a crosslinking agent and a catalyst realize fracture and recombination of chemical bonds under the action of mechanical shearing force of grinding balls, so that the super-crosslinked asphalt-based hard carbon material is obtained. According to the present invention, the asphalt is subjected to segmented ball milling and super-crosslinking, and then carbonization sintering is performed, such that the asphalt cannot be subjected to molecular rearrangement so as to finally form the hard carbon material with the more suitable microporous structure and the more suitable interlayer spacing, such that the negative electrode ion embedding requirement of the sodium ion battery is met, the excellent sodium storage performance is represented, and the capacity and the first coulombic efficiency of the assembled battery are improved; the performance improvement of the sodium ion battery is integrally promoted. The method is low in energy consumption, short in time consumption, simple in parameter control and suitable for large-scale application and popularization.

The invention discloses a silicon-carbon material as well as a preparation method and application thereof. The silicon-carbon material comprises nitrogen-doped porous carbon and an amorphous carbon layer coating the nitrogen-doped porous carbon, and pores of the nitrogen-doped porous carbon are filled with boron-doped nano silicon. The nitrogen-doped porous carbon improves the affinity of silane gas while improving the electron conductivity, a high-conductivity and high-density silicon-carbon composite structure is realized, the boron-doped nano silicon and the nitrogen-doped porous carbon form a nano heterojunction site, and the migration rate of lithium ions is improved, so that electrochemical reaction kinetics is improved, and the electrochemical performance of the lithium ion battery is improved. The material has the advantages of high rate and long cycle performance.

The application discloses a high-energy-density lithium ion battery, which comprises a positive electrode sheet and a negative electrode sheet, the positive electrode sheet comprises a positive electrode active material, the positive electrode active material comprises a lithium iron phosphate material and a lithium-rich material, the mass ratio of the lithium-rich material in the positive electrode active material is 0.2%-8%, and the chemical formula of the lithium iron phosphate material is Li 1+x Fe 1‑ y M y (PO4) 1+z , 0<=x<0.1, 0<=y<0.01, 0<=z<0.04, M comprises at least one of Ti, V, Zr, Nb, Mg, Mo, W and Al, the lithium-rich material comprises at least one of LFO and LNO, the chemical formula of the LFO is Li 5+a Fe 1‑b Z b O 4+c , 0<=a<0.5, 0<=b<0.01, 0<=c<0.03, Z comprises at least one of Ti, V, Zr, Nb, Mg, Mo, W and Al, and the chemical formula of the LNO is Li 2+d Ni 1‑ e Y e O 2+f , -0.5<=d<=0.5, e>=0, -0.5<=f<=0.5, Y comprises at least one of Ti, V, Al, Mg, Mn and Fe, and the negative electrode active material comprises a silicon negative electrode material, the mass ratio of the silicon negative electrode material in the negative electrode active material is 1%-50%. The application has the advantages of improving the energy density, rate performance and cycle performance of the lithium battery.

The invention discloses a method for preparing a lithium-copper composite negative electrode by utilizing lithium slag and application, and the preparation method of the negative electrode comprises the following steps: adding the lithium slag with certain concentration after removing impurities such as Ca < 2 + >, Mg < 2 + > and Fe < 3 + > through acid treatment into metal lithium in a molten state, and fully stirring until the reaction is complete; and coating the molten metal lithium obtained after the reaction on a current collector to obtain the modified lithium metal negative electrode plate. The prepared lithium-copper composite negative electrode has a lithium-loving 3D frame structure, volume expansion in the circulation process can be inhibited, lithium oxide, lithium aluminum alloy and lithium silicon alloy existing on the 3D frame structure can serve as lithium-loving sites for uniform lithium ion deposition, lithium dendrite growth is inhibited, and long-term stable circulation of the lithium metal negative electrode is promoted.