40 results about "Lithium ferrite" patented technology

The invention discloses a composite lithium supplement additive and a preparation method and application thereof, and belongs to the technical field of lithium ion batteries. The composite lithium supplement additive provided by the invention comprises a lithium-rich lithium ferrite core; the conductive carbon coating layer and the pentafluoropropionamide coating layer are sequentially coated outside the lithium-rich lithium ferrite inner core from inside to outside, so as to form a core-shell structure. The composite lithium supplement additive prepared by the invention forms a three-dimensional interpenetrating electron transport network, significantly improves the material conductivity, optimizes the charge transfer dynamics, can effectively isolate lithium-rich lithium ferrite from contacting H2O and CO2 in the air, significantly reduces the generation of surface residual alkali, can adapt to the volume expansion of lithium-rich lithium ferrite in the charge-discharge process, and improves the lithium supplement efficiency. And material structure damage caused by interface stress is reduced, so that the cycling stability of the lithium ion battery is greatly improved, the service life of the lithium ion battery is greatly prolonged, and the material has a wide application prospect in the lithium ion battery.

The application belongs to the technical field of lithium ion batteries, and particularly relates to a carbon-nitrogen double-layer coated positive electrode lithium supplementing agent and a preparation method and application thereof. The preparation method of the carbon-nitrogen double-layer coated positive electrode lithium supplementing agent provided by the application is as follows: a carbon source such as sucrose, a nitrogen source such as melamine, and an iron source such as nano-iron oxide are uniformly mixed, and then one-step sintering is performed to make the mixture dehydrate; then in the second-step sintering, a lithium source such as pitch and lithium oxide (Li2O) is introduced to generate lithium ferrite (Li5FeO4), which effectively avoids water generated by dehydration of the carbon source such as sucrose and impurities generated by the reaction of lithium ferrite, improves the purity and performance of the positive electrode lithium supplementing agent, and meanwhile, the carbon-nitrogen double-layer coating can effectively coat the lithium ferrite and introduce nitrogen, thereby improving the stability, ion diffusivity and conductivity of the positive electrode lithium supplementing agent, so as to solve the technical problem of poor performance of the lithium manganate positive electrode lithium supplementing agent prepared by the existing preparation method.

The invention discloses a difunctional composite lithium supplement additive and a preparation method and application thereof, and belongs to the technical field of lithium ion batteries. The bifunctional composite lithium supplement additive provided by the invention comprises lithium-rich lithium ferrite as a core layer and a lanthanum gallate coating layer coating the outer surface of the core layer. The lithium supplementing additive prepared by the invention realizes dual inhibition on released high-active oxygen species, the released O2 is captured and fixed in the coating layer through oxygen vacancy adsorption and lattice constraint, and a physical barrier is synchronously formed in the coating layer in a deep lithium removal process to block a migration channel of active oxygen to an electrolyte, so that the lithium supplementing effect is improved. Therefore, the cycling stability of the lithium ion battery is greatly improved, the service life of the lithium ion battery is greatly prolonged, and the application prospect in the lithium ion battery is wide.

The invention provides a gradient-doped single-layer coated lithium-rich lithium ferrite material as well as a preparation method and application thereof, and belongs to the technical field of lithium ion battery positive electrode lithium supplementing materials. According to the invention, a lithium source and an iron source are sintered at a low temperature to form an inner core, and then gradient doping and coating are realized through a ball milling process and dynamic CVD (Chemical Vapor Deposition). The material takes Li5FeO4 as an inner core, element distribution is optimized through a gradient doping technology, and a single-layer coating design is adopted, so that the air stability and the ionic conductivity of the material can be remarkably improved, and meanwhile, the loss of active lithium during first charge and discharge of a battery is compensated. When being used as a positive electrode lithium supplementing agent and matched with a silicon-carbon negative electrode, the lithium ion battery positive electrode lithium supplementing agent can improve the initial coulombic efficiency of a lithium ion battery to be greater than or equal to 88% and enhance the cycling stability.

The invention relates to a lithium supplement agent and a preparation method thereof and a battery, the lithium supplement agent is of a core-shell structure, and comprises a lithium ferrite inner core, and a first coating layer, a second coating layer and a carbon coating layer which sequentially coat the lithium ferrite inner core from inside to outside; the first coating layer comprises a porous carbon material, and the porous carbon material comprises one or more of activated carbon, carbon nanotubes, carbon nitride and carbon nitride nanotubes; the second coating layer comprises a metal compound, and metal elements in the metal compound comprise one or more of Al, Zr, Ti, Mg, Nb and Mo. The surface of the lithium ferrite inner core is sequentially coated with the first coating layer, the second coating layer and the carbon coating layer, so that the capacity release of the lithium supplement agent can be effectively improved, the gel problem of the electrode slurry is improved, and the long-cycle stability and the safety performance of the battery can be improved.

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a positive electrode lithium supplementing material, a preparation method and a lithium ion battery, the positive electrode lithium supplementing material is of a core-shell structure, and comprises an inner core, a middle layer and a shell; the inner core is lithium-rich lithium ferrite doped with cations, and the cations are Ti, Mg, Al, Zr or Ta; the shell is a coating layer formed by halogen and Li, and the halogen is one or more of F and Cl; the preparation method of the positive electrode lithium supplementing material comprises the following steps: in an inert atmosphere, heating a precursor, and enabling gas generated by heating to pass through a core material, so as to obtain the positive electrode lithium supplementing material; the precursor is a material capable of generating HF and / or HCl at a high temperature, and the core material is cation-doped lithium-rich lithium ferrite; the gas production rate and the interface impedance can be reduced.

The invention relates to the technical field of batteries, in particular to a battery and a power utilization device, and the battery comprises a positive pole piece, a negative pole piece and electrolyte; the positive pole piece comprises a positive current collector and a positive active layer arranged on at least one surface of the positive current collector, the positive active layer comprises a positive lithium supplement agent, and the positive lithium supplement agent comprises at least one of lithium ferrite and lithium nickelate; the electrolyte comprises a first additive, the first additive comprises a compound with a structure shown in a formula (I), R1, R2 and R3 are respectively and independently selected from one of allyl, divinyl methyl silane, vinyl dimethyl silane or trivinyl silane, and at least one of R1, R2 and R3 is selected from one of divinyl methyl silane group, vinyl dimethyl silane group or trivinyl silane group. By adding the first additive into the electrolyte, dissolution of iron ions or nickel ions in the lithium supplement agent is inhibited, the structural stability of the positive electrode lithium supplement agent is enhanced, and the cycle life of the battery is prolonged.

The invention discloses a carbon-loaded lithium iron metaphosphate positive electrode material as well as a preparation method and application thereof, and belongs to the technical field of electrochemical energy storage and lithium ion battery positive electrode materials. The preparation method of the carbon-loaded lithium iron metaphosphate positive electrode material comprises the following steps: S01, adding lithium ferrite into a first solvent, and carrying out ultrasonic dispersion and uniform mixing to obtain a lithium ferrite dispersion solution; s02, adding organic phosphonic acid and a second solvent into the lithium ferrite dispersion solution, and reacting in a nitrogen environment; after the reaction is finished, cooling to room temperature, and centrifuging the mixed solution to obtain a sample containing impurities; washing, centrifuging and drying to obtain a precursor material; and S03, carbonizing and crystallizing the precursor material in a nitrogen environment to obtain the carbon-loaded lithium iron metaphosphate positive electrode material. The metaphosphoric acid chain structure of the prepared carbon-loaded lithium iron metaphosphate positive electrode material has excellent chemical stability, so that the carbon-loaded lithium iron metaphosphate positive electrode material can be used as a lithium ion battery positive electrode material with safety advantage, cost advantage and structural novelty.

This invention discloses a lithium replenishing agent coated with a metal-organic framework (MOF), its preparation method, and its application, belonging to the field of lithium-ion batteries. The lithium replenishing agent comprises a matrix and a coating layer. The matrix is ​​lithium ferrite, and the coating layer is a MOF with a thickness of 0.5-10 nm. The MOF is prepared using fluorine-containing and carboxyl-containing compounds as ligands and zirconium tetrachloride as the metal source via a solvothermal method. The preparation method includes the following steps: preparing and activating a lithium ferrite intermediate; adding the activated lithium ferrite intermediate to a buffer solution containing dissolved dopamine hydrochloride to prepare lithium ferrite intermediate @PDA; performing in-situ growth of the MOF to construct a hydrophobic MOF-coated precursor; adding a lithium source to the precursor and performing programmed sintering to obtain the lithium replenishing agent. The lithium replenishing agent provided by this invention achieves excellent air stability, low gas production, and excellent conductivity.

This invention provides a method for preparing phosphorus-doped lithium ferrite using waste lithium iron phosphate (LFP) electrode sheets and the resulting product, belonging to the field of materials synthesis technology. This method creatively recycles waste LFP electrode sheets in the form of phosphorus-doped lithium ferrite, greatly improving their utilization value. The method for synthesizing phosphorus-doped lithium ferrite using waste LFP electrode sheets has the following advantages: 1) This method requires no additional oxidant, is environmentally friendly, and solves the problem of difficult treatment of phosphorus-containing waste from the process; 2) Using waste LFP electrode sheets as raw materials not only reduces costs and yields high-value-added products, but also has high atom utilization, introduces no other impurities, and is pollution-free; 3) Phosphorus doping can improve the conductivity of lithium ferrite, reduce polarization, and improve structural and air stability.

The invention discloses a method for detecting the content of ferrous iron impurities in a lithium supplementing material and application of the method, and belongs to the technical field of lithium ion battery pre-lithiation. According to the technical scheme, the method comprises a lithium ferrite pretreatment step and a potassium permanganate titration step, the lithium ferrite pretreatment step comprises the following steps: adding lithium ferrite into concentrated hydrochloric acid for dissolving, carrying out suction filtration after dissolving to obtain a clear yellow green liquid, and then diluting to obtain a to-be-titrated liquid. The invention provides the method for detecting the content of the ferrous iron impurity in the lithium supplementing material, the detection method is simple and rapid to operate, has an important promotion effect on the detection of the purity of lithium ferrite, can also be used for analyzing and guiding the modification of the lithium ferrite material, and has important significance on improving the performance of the material.

The invention relates to the technical field of batteries, in particular to a sodium ion battery which comprises a positive plate and a negative plate, the positive plate comprises a positive current collector and a positive active layer positioned on at least one side surface of the positive current collector; in the thickness direction of the positive plate, the positive active layer comprises a first region and a second region, the first region is located on the outermost layer of the positive active layer, the second region is close to the positive current collector, the positive active layer of the first region contains a first positive active material, and the first positive active material is composed of a first sodium-containing active material and a lithium-rich lithium ferrite material. According to the sodium ion battery, the SEI film with lithium-containing organic matter or inorganic matter as the main component (larger than or equal to 50%) can be formed in the first formation process, continuous consumption of the SEI film on active sodium ions is reduced, the SEI film under the positive and negative electrode system has higher stability, and therefore the cycle life of the sodium ion battery is guaranteed, and the long-life requirement of an energy storage scene is met.

The present disclosure relates to the technical field of lithium-ion batteries, and provides a fast-charging lithium-ion battery, and a preparation method therefor and an application thereof. Specifically, a positive electrode of the lithium-ion battery comprises lithium iron phosphate and a positive electrode additive; the positive electrode additive comprises at least one of lithium ferrite, lithium oxalate, and lithium squarate; an electrolyte of the lithium-ion battery comprises a solvent, a lithium salt, and electrolyte additives; the solvent includes a low-viscosity solvent with a viscosity of ≤0.5 cps; and the electrolyte additives include a carbonate-based additive, a sulfur-containing additive, and a lithium salt additive. The lithium-ion battery of the present disclosure can effectively improve the fast-charging performance and low-temperature performance of lithium iron phosphate batteries, without causing degradation in the cycle performance and high-temperature performance of batteries. That is, the lithium-ion battery takes into account various electrical properties and has a good application prospect.

The application provides an electrochemical device and an electronic device. The electrochemical device comprises a positive electrode sheet, the positive electrode sheet comprises a positive electrode current collector, a first coating layer and a positive electrode material layer, the first coating layer is arranged on the surface of the positive electrode current collector, and the positive electrode material layer is arranged on the surface of the first coating layer away from the positive electrode current collector. The first coating layer comprises a first main material and a first binder, the first main material comprises a lithium supplement material, and the lithium supplement material comprises at least one of lithium iron phosphate, lithium manganese iron phosphate, lithium orthosilicate or lithium ferrite; the infrared spectrum of the first coating layer has a characteristic peak between 3200 cm ‑1 and 3400 cm ‑1 . The electrochemical device provided by the application can balance the nail penetration safety performance, capacity and volume energy density.

The invention discloses a carbon-coated iron defect high-specific-capacity lithium ferrite lithium supplement agent and a preparation method and application thereof, the structural general formula of the lithium ferrite lithium supplement agent is C (at) Li5Fe (1-x) O4, and x is greater than or equal to 0 and less than or equal to 0.1; the coating amount of the carbon is less than or equal to 5% of the weight of the lithium ferrite lithium supplementing agent, and the coating thickness h of the carbon is set to be 0 lt; h < = 50nm. According to the invention, the high-purity phase structure synthesis of the LFO is improved by adjusting iron defects, the lithium supplement agent with less impurity content can be obtained, and the specific capacity of the material is improved. Compared with the prior art, the preparation method has the advantages that better electronic conductivity and air stability are realized synchronously through carbon coating, the electronic conductivity is improved, the specific capacity is further improved and can be up to 747.9 mAh / g, and the problem that the specific capacity is reduced due to poor air stability and easiness in generation of an impurity phase in the existing LFO synthesis technology is well solved.

The invention relates to a lithium supplement additive and a preparation method thereof, a positive plate and a lithium ion battery. The lithium supplement additive comprises an inner core and a shell, the material of the inner core comprises a lithium-rich manganese-based composite material, and the lithium-rich manganese-based composite material comprises a lithium-rich manganese-based material matrix and a first solid electrolyte coating layer coating the surface of the lithium-rich manganese-based material matrix; the shell is made of a lithium-rich lithium ferrite composite material, and the lithium-rich lithium ferrite composite material comprises a lithium-rich lithium ferrite matrix and a second solid electrolyte coating layer coating the surface of the lithium-rich lithium ferrite matrix. The lithium supplement additive is constructed by taking the lithium-rich manganese-based composite material as the inner core and the lithium-rich lithium ferrite composite material as the shell, active lithium consumed by an SEI film formed through first charging is supplemented, lithium can be continuously supplemented in the subsequent charging and discharging process, and the cycle performance of the battery is improved.

The present application belongs to the technical field of batteries, and provides a positive electrode active material, a positive electrode slurry, a positive electrode sheet, and a battery. The positive electrode active material comprises lithium manganese iron phosphate and lithium-rich lithium ferrite; the mass ratio of the lithium-rich lithium ferrite added to the positive electrode active material is 0.5%-5%; the particle size D50 of the lithium manganese iron phosphate is d1, and the particle size D50 of the lithium-rich lithium ferrite is d2, 0.05≤d1 / d2≤0.32.

This invention belongs to the field of secondary battery technology, and particularly relates to a positive electrode lithium replenishment material, a positive electrode sheet, and a secondary battery. The positive electrode lithium replenishment material includes lithium ferrite, a stabilizing layer coated on the outer surface of the lithium ferrite, and a hydrophobic layer coated on the outer surface of the stabilizing layer. In this invention, a positive electrode lithium replenishment material has a stabilizing layer and a hydrophobic layer sequentially coated on the surface of the lithium ferrite. The stabilizing layer can mitigate the generation of oxygen free radicals during the lithium ferrite delithiation process, preventing structural instability of the lithium ferrite. The hydrophobic layer can prevent lithium loss from the lithium ferrite, prevent lithium ion diffusion, ensure material capacity, and improve processing performance.

The invention discloses a lithium iron phosphate / activated carbon / lithium ferrate composite positive electrode material, a lithium iron phosphate battery with an ultra-long cycle life and a preparation method of the lithium iron phosphate / activated carbon / lithium ferrate composite positive electrode material. Meanwhile, the two key problems of positive electrode structure stability and active lithium supplement are solved; lithium loss is accurately compensated by combining an endogenous pre-lithiation technology based on lithium ferrate; and with the assistance of optimized manufacturing processes such as full-tab and high-vacuum drying, the interface stability, the structural integrity and the manufacturing consistency of the battery are systematically improved. And the finally prepared lithium iron phosphate battery shows ultra-long cycle life, excellent rate capability and extremely high safety, and is particularly suitable for long-life demand scenes such as large-scale energy storage and the like.

The present application belongs to the technical field of energy storage, and provides a lithium-replenishing agent. The lithium-replenishing agent comprises: a lithium-rich lithium ferrite material and a coating layer that coats the surface of the lithium-rich lithium ferrite material, wherein the material of the coating layer comprises lithium pyrophosphate. The present application is beneficial for solving the technical problems of the poor air stability, relatively poor safety, etc., of lithium-rich positive electrode materials in the related art, and thus can effectively replenish lithium.

This invention provides a carbon-coated lithium ferrite rich in lithium iron ferrite, its preparation method, a cathode lithium supplement material, and its applications. The preparation method includes: step S1, crystallizing an iron source and a structure inducer in an organic solvent to obtain a crystallized product; step S2, micro-reacting a lithium source and the crystallized product in a microwave reactor to obtain a precursor; and step S3, sintering the precursor to obtain carbon-coated lithium ferrite rich in lithium iron ferrite. The structure inducer includes organic amines and polyphenolic compounds. The lithium ferrite rich in lithium iron ferrite prepared by this invention exhibits higher ionic conductivity and structural stability, higher purity, lower residual alkali content, and reduced average particle size, resulting in superior overall performance.

The invention relates to the technical field of electrochemistry, in particular to a lithium-rich material, a preparation method of the lithium-rich material, a positive pole piece containing the lithium-rich material, a secondary battery and an electric device. The lithium-rich material comprises an internal phase, and the internal phase is coated with a coating phase; the internal phase is doped lithium-rich lithium ferrite, and the coating phase is a mixed layer comprising cobalt disulfide and molybdenum trisulfide. According to the lithium-rich material, the migration rate of lithium ions is increased, the internal resistance of the battery after first charging is directly reduced, the gram volume of the material is remarkably increased, and therefore the overall energy density and rate performance of the battery are effectively improved. The lithium-rich material disclosed by the invention has excellent environmental adaptability and can be kept stable under the condition of relatively high humidity, so that the dependence of a production process on a dry environment is greatly reduced, the production process is simplified, and the control on the manufacturing cost is facilitated.

The invention relates to a composite lithium supplement agent and a preparation method thereof, a positive plate and a lithium ion battery. The composite lithium supplement agent comprises an inner core, and a middle layer and a shell layer which are formed in situ along a direction far away from the center of the inner core, the material of the inner core comprises lithium-rich lithium nickelate; the material of the middle layer comprises lithium-rich lithium ferrite; and the material of the shell layer comprises lithium-rich lithium nickelate. According to the invention, the lithium-rich lithium ferrite intermediate layer is arranged between the lithium-rich lithium nickelate core and the shell, and the concentration gradient of lithium ions is matched with a specific electric field structure formed by a double-heterogeneous interface, so that the improvement of the electronic conductivity and the ionic conductivity in the lithium-rich lithium ferrite is driven; and meanwhile, the lithium-rich lithium nickelate shell improves the air stability of the composite lithium supplementing agent, so that the composite lithium supplementing agent has high lithium supplementing capacity and also has good rate capability and air stability.

The invention belongs to the technical field of lithium supplement agents, and discloses a composite lithium ion battery lithium supplement agent and a preparation method thereof.The preparation method comprises the following steps that ascorbic acid is added into a mixed aqueous dispersion solution of conductive carbon black and carbon nanotubes to obtain a first dispersion solution, and the first dispersion solution reacts for 6-8 h at the temperature of 70-90 DEG C; after the reaction is finished, polyvinyl alcohol, polyacrylic acid-Li and carboxymethyl cellulose-Li are added, ice bath is carried out, stirring is carried out for a set time, and a second dispersion liquid is obtained; then adding lithium ferrite micron particles into the second dispersion liquid, and uniformly stirring; injecting the obtained mixed solution into a mold, and performing freeze drying; and finally, crushing the prepared material, etching with a nitric acid solution, and cleaning to obtain the lithium supplement agent. The lithium ferrite is coated in the flexible conductive aerogel, so that gaps generated after the lithium ferrite is shelled can be well made up, and the lithium ferrite can be in contact with the conductive layer all the time.

The invention discloses a low-gas-yield lithium-rich lithium ferrite material as well as a preparation method and application thereof, and belongs to the technical field of lithium ion battery positive electrode lithium supplementing materials. The low-gas-production lithium-rich lithium ferrite material is of a composite core-shell structure and comprises an inner core and an outer shell, the inner core is lithium-rich lithium ferrite, the outer shell is a fast ion conductor of a Nascon structure, the outer shell can be secondarily crystallized on the surface layer of the lithium-rich lithium ferrite under the induction of electrolyte, and a uniform and compact coating layer continuously coating the surface of the lithium-rich lithium ferrite is formed. The material is applied to the aspect of a lithium ion battery positive electrode lithium supplementing material, the problems of high soft package high-temperature storage gas production and high-temperature capacity attenuation after the lithium-rich lithium ferrite is added are solved, the contact between the lithium ferrite and an electrolyte can be isolated, the high-temperature storage gas production is inhibited, and the high-temperature cycle performance is further improved.

A positive electrode active material, a positive electrode slurry, a positive electrode sheet and a battery are provided herein. The positive electrode active material includes lithium manganese iron phosphate and lithium-rich lithium ferrite; where a mass ratio of the lithium-rich lithium ferrite in the positive electrode active material is 0.5%-5%; a particle size D50 of the lithium manganese iron phosphate is d1, the particle size D50 of the lithium-rich lithium ferrite is d2, and 0.05≤d1 / d2≤0.32.

This application discloses a composite cathode material and its preparation method, a cathode sheet, and a battery and power device. The composite cathode material includes lithium manganese iron phosphate (LMFP) and lithium nickel manganese cobalt oxide (NCM); wherein the composite cathode also includes a lithium replenishing agent, which includes lithium-rich manganese oxide (LMR) and lithium iron phosphate (LFO). This application uses LMFP and NCM to form the main material, and adds LMR and LFO as lithium replenishing agents. Utilizing the synergistic lithium replenishment mechanism of these two agents, the initial coulombic efficiency, cycle life, and rate performance of the battery are significantly improved.

The invention discloses a preparation method of a low-iron-phosphide high-compaction-density lithium iron phosphate material, which comprises the following steps: preparing a mixture containing a lithium source, a carbon source, anhydrous iron phosphate, a titanium source and a phosphorus source, and sanding to prepare mixed slurry; carrying out spray granulation on the mixed slurry to obtain an iron-lithium spray material; sintering the spray material in an inert atmosphere, crushing and screening to obtain lithium iron phosphate A; adding at least one of ammonium metavanadate and lithium ferrite into the obtained lithium iron phosphate A, adding a carbon source, uniformly mixing, and sintering in an inert atmosphere to obtain lithium iron phosphate B; and crushing the lithium iron phosphate B to obtain the lithium iron phosphate material with low iron phosphide and high compaction density. According to the invention, ammonium metavanadate and / or lithium ferrite are / is added to react with iron phosphide, so that the content of iron phosphide is effectively reduced; the compaction of the obtained material can reach 2.6 g / cm < 3 >; the cycle performance is excellent, and the 1C 100-cycle cycle retention rate is 98%.

Provided in the present application are a lithium-supplementing agent and a preparation method therefor, a positive electrode sheet, a separator, a battery and an electric device. The lithium-supplementing agent of the present application comprises Li(5-x)MxFe(1-y)NyO4, wherein M comprises at least one metal element of Al, Mg, Ti, V, Ge, Ga, Rb and Cs, and N comprises at least one metal element of Al, Ti, V, Ge, Cr, Co, Mn, Ni, Cu, Zn, Y, Pd, Ag, Cd, Pt and Au, where 0.01≤x≤1, and 0≤y≤0.5. In the present application, by doping lithium-rich lithium ferrite with a specific element, the phase structure change of the lithium-rich lithium ferrite can be inhibited, and the structural stability of the lithium-rich lithium ferrite positive electrode material is improved, such that the lattice is not prone to deformation, which is beneficial for reducing the generation of residual alkali on the surface of the material, thereby reducing the influence of the residual alkali on the comprehensive performance of a lithium-supplementing battery, and meeting the requirements for a power battery.

The application provides a multi-element lithium supplementing agent, a preparation method thereof, a positive pole piece and a lithium ion battery. The multi-element lithium supplementing agent comprises a core, a first coating layer and a second coating layer. The core comprises lithium-rich lithium aluminum iron oxide. The first coating layer comprises lithium-rich lithium manganese oxide. The second coating layer comprises lithium-rich lithium nickel oxide. The chemical general formula of the multi-element lithium supplementing agent is Li x Fe a Al b Mn c Ni d O y , 0.1≤d / (a+b)≤0.9, 0.62≤a≤0.96, 0.04≤b≤0.38, 0.005≤c / (a+b)≤0.02, 5a+5b+2c+2d≤x≤5.5a+5.5b+2.1c+2.1d, y=(x+3a+3b+4c+2d) / 2. The application adopts iron and aluminum main elements, simultaneously coats lithium-rich lithium manganese oxide and lithium-rich lithium nickel oxide, can improve the stability of the lithium supplementing agent, reduces gas production, improves ion conductivity and promotes capacity development.