121 results about "Lithium ferrite" patented technology

The invention provides a lithium-rich lithium ferrite material and a preparation method and application thereof, the lithium-rich lithium ferrite material comprises a core layer and a carbon coating layer, the core layer is doped lithium-rich lithium ferrite, the chemical formula of the doped lithium-rich lithium ferrite is Li < 5 > Fe < 1-x > Al < x > O < 4 >, and x is 0.003-0.030. The lithium-rich lithium ferrite material is high in structural stability and excellent in conductivity; as a lithium supplement additive of a positive electrode active material, the composite material can improve electrochemical performance such as high-temperature storage performance and normal-temperature cycle performance of a lithium ion battery.

The invention belongs to the technical field of batteries, and particularly relates to a lithium ferrite lithium supplement agent and a preparation method and application thereof. Compared with the prior art, a solid electrolyte coating layer is formed on the surface of the carbon-doped lithium iron oxide material through a low-temperature molten salt method, so that air can be effectively isolated, the air stability of the material is improved, the lithium removal phenomenon is reduced, and the structural integrity and lithium supplement performance of the material are kept; and the lithium ferrite lithium supplement agent combines the high theoretical lithium supplement capacity of Li5FeO4 and the excellent ionic conductivity of the solid electrolyte, so that the electrochemical performance of the material can be improved while the high lithium supplement capacity is maintained, and a new technical scheme is provided for commercial application of the high-energy-density lithium ion battery.

The invention belongs to the technical field of battery materials, and provides a lithium-rich lithium ferrite lithium supplement agent and a synthesis method and application thereof.The synthesis method comprises the steps that solid electrolyte, conductive carbon and elemental sulfur are mixed and subjected to low-temperature heat treatment to form a composite mixture, then the composite mixture and lithium-rich lithium ferrite are subjected to secondary mixing and low-temperature heat treatment, and the lithium-rich lithium ferrite lithium supplement agent is obtained. And enabling the composite mixture to form a mixed coating layer to obtain the lithium-rich lithium ferrite lithium supplement agent. Sulfur in the mixed coating layer can absorb surface released oxygen in the charging process of the lithium-rich lithium ferrite, so that gas production is reduced, the solid electrolyte and conductive carbon can form an ion and electron conductive network, and the problems that Li < + > is difficult to separate and the lithium supplementing capacity is reduced due to too thick sulfur coating are avoided. Meanwhile, the elemental sulfur is melted through low-temperature heat treatment, so that the dispersing and bonding effects can be achieved, uniform dispersion of the solid electrolyte and the conductive carbon and effective coating of the composite mixture are achieved, the binding property and compatibility can be improved, and the air stability of the lithium supplementing agent can be effectively improved through the obtained mixed coating layer.

The invention discloses a battery and a preparation method thereof. The battery comprises a positive electrode lithium supplementing material and an electrolyte, the positive electrode lithium supplementing material comprises at least one of lithium nickelate, lithium ferrite and lithium oxide; the electrolyte comprises a silicon-based fluorophosphate compound as shown in a formula I: # imgabs0 #, wherein R1, R2 and R3 are independently H, F, alkyl of C1-C4, fluoroalkyl of C1-C4, alkenyl of C2-C4, fluoroalkenyl of C2-C4, alkynyl of C2-C4, fluoroalkynyl of C2-C4, cycloalkane of C5-C7, phenyl substituted by R4 or benzyl substituted by R5; r1, R2, R3, R4 and R5 are independently alkyl groups of C1-C4, alkylene groups of C2-C4, alkyne groups of C2-C4, fluoro alkyl groups of C1-C4, fluoro alkylene groups of C2-C4 or fluoro alkyne groups of C2-C4. The compound shown in the formula I is added into the electrolyte, so that the problems of gas expansion and lithium precipitation caused by a positive electrode lithium supplementing material can be solved, and the battery performance is improved.

The invention discloses a lithium supplementing material and a preparation method thereof, and belongs to the technical field of lithium ion battery lithium supplementing materials. The lithium supplementing material has a spherical core-shell structure; the spherical core-shell structure sequentially comprises a lithium iron phosphate layer and a lithium-rich lithium ferrite layer from outside to inside. The lithium supplementing material is prepared by two steps: firstly, carrying out surface coating in a similar sol-gel mode to obtain a material precursor, and then carrying out heat treatment on the precursor to obtain the lithium iron phosphate coated lithium-rich lithium ferrite material; in the preparation process, tannic acid is introduced for modified coating, so that the lithium iron phosphate coated lithium-rich lithium ferrite material which is uniformly coated and has high lithium supplement efficiency, high stability and relatively high reversible capacity is obtained, and the prepared lithium supplement agent material shows excellent lithium supplement performance and charge-discharge performance in a lithium ion battery performance test. Meanwhile, the preparation method is simple to operate and beneficial to actual production.

The invention provides a positive electrode lithium supplementing material and a preparation method thereof, a positive electrode plate and a lithium ion battery. The positive electrode lithium supplementing material comprises a lithium supplementing base material and a coating layer coating the surface of the lithium supplementing base material, the lithium supplementing matrix material comprises an anion-doped lithium ferrite material, and the coating layer comprises a fast ion conductor material. According to the positive electrode lithium supplementing material provided by the invention, through the synergistic cooperation of anion doping and fast ion conductor coating, the lithium supplementing effect is good, the influence caused by gas production of the lithium supplementing material can be reduced, and meanwhile, the charge-discharge capacity, the rate capability and the cycle stability of a battery can be improved.

The invention provides carbon-lithium aluminate double-layer coated lithium-rich lithium ferrite, which is characterized in that an aluminum source is used for reacting on the surface of lithium-rich lithium ferrite to coat a layer of lithium aluminate, and then a carbon source is used for coating to form the carbon-lithium aluminate double-coating layer coated lithium-rich lithium ferrite. The carbon-lithium aluminate double-layer coated lithium-rich lithium ferrite disclosed by the invention has relatively good lithium supplement performance, and can be used as a lithium supplement agent for a positive electrode of a lithium ion battery, so that the service life of the lithium ion battery is prolonged, and the long cycle performance of the lithium ion battery is improved. In addition, the invention also provides a preparation method and application of the carbon-lithium aluminate double-layer coated lithium-rich lithium ferrite.

The invention discloses a preparation method of a composite lithium-rich and lithium-supplement additive, which comprises the following steps: taking lithium ferrite as a core, preparing NiO (at) lithium salt by adopting an ALD atomic deposition method, fully and uniformly mixing carbon-coated lithium ferrite and the NiO (at) lithium salt, and sintering to prepare the composite lithium-rich and lithium-supplement additive. According to the invention, the advantages of high lithium supplement capacity of lithium ferrite, less gas production of lithium nickelate and good environmental adaptability are fully exerted, and the lithium supplement agent with high capacity and good stability is obtained; the nanometer nickel protoxide is in full contact with a lithium salt coating layer prepared by an ALD method, subsequent sintering is facilitated, preparation can be performed at a lower temperature, cost reduction is facilitated, meanwhile, the nickel protoxide and the peripheral lithium salt coating layer are subjected to a solid solution reaction, and residual lithium on the surface of lithium ferrite of a nuclear body can be obtained. The'two-channel lithium acquisition mode 'can reduce the overall residual alkali amount of the material, and is beneficial to improving the processing performance of subsequent battery slurry.

The invention discloses a preparation method and application of a positive electrode lithium supplement agent, the positive electrode lithium supplement agent is of a core-shell structure, and a core layer comprises lithium-rich metal materials such as lithium-rich lithium ferrite, lithium-rich lithium nickelate and lithium-rich lithium manganate; and a shell layer comprises organic lithium salt materials such as lithium bis (oxalato) borate, lithium bis (fluorosulfonyl) imide, lithium difluorophosphate and lithium difluorobis (oxalato) phosphate. The lithium-rich metal material lithium supplementing agent is coated with the organic lithium salt lithium supplementing agent which is also used as the lithium supplementing agent, so that the lithium-rich metal material is prevented from being in contact with air, and the environmental stability of the lithium-rich metal material is improved; through chelation of specific groups and transition metal ions, the structural stability of the lithium-rich metal material is improved, a lithium ion transmission path is fixed, the capacity of the lithium supplement agent for the lithium-rich metal material can be exerted to the maximum extent, and the organic lithium salt also has a lithium supplement effect, so that the migration rate of lithium ions can be further improved, and the lithium supplement effect is improved. The lithium supplementing effect of the two lithium supplementing agents greatly improves the energy density and the cycling stability of the battery.

The invention provides a lithium supplement agent, and belongs to the technical field of energy storage, the lithium supplement agent comprises a lithium-rich lithium ferrite material and a coating layer coating the surface of the lithium-rich lithium ferrite material, and the material of the coating layer comprises lithium pyrophosphate. According to the invention, the technical problems of poor air stability, relatively poor safety and the like of the lithium-rich positive electrode material in the related technology can be solved, so that lithium can be effectively supplemented.

The invention provides a carbon-coated metal element-doped lithium ferrite material and a preparation method and application thereof.The material is of a core-shell structure, the core-shell structure comprises an inner core and a coating layer, and the coating layer is arranged on at least part of the outer surface of the inner core; the inner core comprises lithium ferrite doped with an element L; the element L is selected from at least one of Co, Ni, Cu, Ga, Pb, Sn, Zn and Rh; and the coating layer comprises a carbon elementary substance. The carbon-coated metal element doped lithium ferrite material provided by the invention has the characteristic of relatively high discharge gram capacity.

This invention belongs to the technical field of waste lithium iron phosphate recycling, and discloses a method for preparing lithium-rich lithium ferrite from waste lithium iron phosphate, as well as lithium-rich lithium ferrite, lithium replenishment materials, and modified lithium-ion battery cathode materials. The preparation method of lithium-rich lithium ferrite includes sequentially subjecting waste lithium iron phosphate to impurity removal, hydrochloric acid solution purification, mixed extractant extraction, organic phase washing and back-extraction, lithium iron precipitation, drying and calcination, and sintering. The mixed extractant comprises 50-80 wt% tributyl phosphate, 10-40 wt% light petroleum, and 1-10 wt% calcium chloride solution. Through the synergistic effect of each processing step, effective separation of lithium, iron, and lithium elements is achieved from waste lithium iron phosphate, yielding high-purity lithium-rich lithium ferrite. This lithium-rich lithium ferrite has high irreversible capacity, is an excellent lithium replenishment material, has high added value, and has broad application prospects.

The invention provides a positive electrode lithium supplementing material and a preparation method thereof, a positive electrode plate and a lithium ion battery. The positive electrode lithium supplementing material comprises an inner core and a carbon coating layer coating the surface of the inner core, the inner core comprises a titanium-doped lithium ferrite material, and carbon in the carbon coating layer is obtained by deriving and carbonizing an MOFs material. According to the positive electrode lithium supplementing material provided by the invention, through the synergistic cooperation of titanium doping and the carbon coating layer derived and carbonized by the MOFs material, the stability is good, and the lithium supplementing effect is excellent, so that the charge-discharge capacity, the rate capability and the cycling stability of a battery are improved.

The present invention belongs to the technical field of battery materials, and provides a lithium-rich lithium ferrite lithium supplementing agent, a synthesis method and a use thereof. In the synthesis method, a solid electrolyte, conductive carbon and elemental sulfur are mixed and subjected to low-temperature heat treatment to form a composite mixture, and then the composite mixture is secondarily mixed with lithium-rich lithium ferrite and subjected to low-temperature heat treatment to form a mixed coating layer on the lithium-rich lithium ferrite, thereby obtaining the lithium-rich lithium ferrite lithium supplementing agent. Sulfur in the mixed coating layer can absorb the surface oxygen released during the charging process of the lithium-rich lithium ferrite, thereby reducing gas generation. The solid electrolyte and the conductive carbon can form an ionic and electronic conductive network, avoiding the difficulty of Li+ extraction and the decrease of lithium supplementing capacity caused by too thick sulfur coating. At the same time, the low-temperature heat treatment causes the elemental sulfur to melt, which can play a role in dispersion and adhesion, realizing the uniform dispersion of the solid electrolyte and the conductive carbon and the effective coating of the composite mixture, which is beneficial to improving the binding property and compatibility. The obtained mixed coating layer can effectively improve the air stability of the lithium supplementing agent.

The invention belongs to the technical field of lithium ion battery materials, and discloses a positive electrode lithium supplement agent and a preparation method and application thereof. The positive electrode lithium supplement agent comprises a lithium-rich lithium ferrite matrix and an organic lithium supplement coating layer, wherein the organic lithium supplement coating layer coats at least part of the surface of the lithium-rich lithium ferrite matrix; and the organic lithium-supplementing coating layer is any one or two of lithium oxalate and lithium squarate. The organic lithium supplement coating layer provided by the invention can prevent the lithium-rich lithium ferrite from being in contact with air, the stability of the lithium-rich lithium ferrite is improved while the residual alkali is reduced, the lithium ion transmission effect of the lithium-rich lithium ferrite is improved, and the lithium supplement effects of the lithium-rich lithium ferrite and the organic lithium supplement agent can be utilized to improve the capacity and the cycling stability of the battery.

The present disclosure relates to the technical field of secondary batteries. Disclosed are a composite lithium-supplementing agent and a use thereof, a positive electrode material, a positive electrode sheet, a lithium battery, a battery module, and an electrical apparatus. A lithium-supplementing agent containing Ni2+ or Ni3+ is added on the basis of a lithium-rich-based transition metal oxide (such as lithium iron oxide LFO), the lithium-supplementing agent can have some of Ni3+ / Ni4+ ions in a reaction system, and under an electrochemical action, the Ni3+ / Ni4+ ions react with a small number of O2- ions subsequently generated by LFO, so as to produce NiO / NiO2 and other substances, thereby reducing the ring-opening reaction between O2- ions and an electrolyte, and further reducing gas production and being conducive to improving the cycle performance of a battery.

The invention provides an electrochemical device and an electronic device.The electrochemical device comprises a positive pole piece, the positive pole piece comprises a positive current collector, a first coating and a positive material layer, the first coating is arranged on the surface of the positive current collector, and the positive material layer is arranged on the surface, away from the positive current collector, of the first coating; the first coating comprises a first main material and a first binder, the first main material comprises a lithium supplementing material, and the lithium supplementing material comprises at least one of lithium iron phosphate, lithium iron manganese phosphate, lithium orthosilicate or lithium ferrite; the infrared spectrum of the first coating has a characteristic peak between 3200 cm <-1 > and 3400 cm <-1 >. The electrochemical device provided by the invention can give consideration to the safety performance, the capacity and the volume energy density of the cotter pin.

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 invention relates to the technical field of lithium batteries, and provides a secondary battery and a preparation method thereof, which are at least beneficial to improving the performance of the secondary battery. The preparation method comprises the following steps: carrying out winding treatment or lamination treatment on a positive plate, a diaphragm and a negative plate, then putting the positive plate, the diaphragm and the negative plate into a shell, and injecting an electrolyte into the shell to obtain the secondary battery, the preparation method of the positive plate comprises the following steps: preparing lithium ferrite, lithium nickelate, lithiated carbon nanotubes and a spinning auxiliary agent into a precursor solution; depositing the precursor solution on the surface of a positive electrode current collector through electrostatic spinning so as to form an initial fiber membrane on the surface of the positive electrode current collector; the positive electrode current collector with the initial fiber membrane is pre-sintered in air and then calcined in inert gas, so that the initial fiber membrane is converted into a fiber lithium supplementing layer, and the fiber lithium supplementing layer is of a fiber network structure; and coating a positive electrode material layer on the surface of the fiber lithium supplementing layer, and drying to obtain the positive plate.

The invention discloses a lithium supplement agent and a preparation method and application thereof, and belongs to the technical field of lithium supplement agents. The lithium supplement agent comprises a core-shell structure, a material forming an inner core comprises at least one of a lithium ferrite material and a lithium silicate material, and a material forming a shell comprises at least one of lithium-rich lithium nickelate, a nickel-cobalt-manganese ternary material and a nickel-cobalt binary material; and at least part of the material forming the shell coats the surface of the inner core. The shell material can have part of Ni < 3 + > and / or Ni < 4 + > ions in a reaction system, and in the circulation and storage process after the battery cell is prepared, the shell material reacts with oxygen released by a very small amount of the core material which is not completely decomposed and various oxygen ions dissolved in the electrolyte, so that the ring-opening reaction of ethylene carbonate in the electrolyte is reduced, and the gas production is reduced. The preparation method comprises the step of preparing the shell on the surface of the core. The method is simple, easy to operate and suitable for industrial production. The lithium supplement agent can be used for preparing a battery, especially a battery with a graphite system as a negative electrode material.

The invention provides composite coated high-stability lithium-rich lithium ferrite and a preparation method thereof, and belongs to the field of lithium ion battery positive electrode lithium supplements.The preparation method of the composite coated high-stability lithium-rich lithium ferrite comprises the steps that an iron source and a lithium source are mixed, and a first mixture is obtained; performing first calcining treatment on the first mixture to obtain a calcined product; mixing and dispersing the calcined product and a metal compound to obtain a second mixture; carrying out second calcining treatment on the second mixture to obtain composite coated high-stability lithium-rich lithium ferrite; wherein the ratio of the amount of substance of the lithium element in the lithium source to the amount of substance of the iron element in the iron source is greater than 5. According to the method, excessive lithium sources are introduced, so that a large amount of residual lithium on the surface of Li5FeO4 forms a residual alkali layer, the residual alkali layer is converted into a compact and complete metal lithium oxide coating layer under the action of the metal compound and the second calcination treatment, and the air stability of Li5FeO4 is effectively improved.

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 belongs to the technical field of lithium battery materials, and provides a spherical composite carbon-coated positive electrode lithium supplementing material and a preparation method and application thereof. The preparation method comprises the following steps: mixing a lithium source, an iron source, an organic composite carbon source, an organic solvent and a dispersing agent, and performing solvothermal reaction to obtain an intermediate product; and performing high-temperature annealing on the intermediate product to obtain the spherical composite carbon-coated anode lithium supplementing material. The preparation process is simple and efficient, and the spherical composite carbon-coated positive electrode lithium supplementing material prepared by the preparation process has a spherical core-shell structure and comprises a lithium-rich lithium ferrite core and a composite carbon-coated layer shell, so that the stability of the positive electrode lithium supplementing material in air and the conductivity of the positive electrode lithium supplementing material are greatly improved, and meanwhile, the stability of the positive electrode lithium supplementing material is greatly improved. The spherical composite carbon-coated positive electrode lithium supplement material also has the characteristics of high purity, controllable morphology and good electrochemical performance.

The invention discloses lithium-rich lithium ferrite slurry and a preparation method and application thereof.The lithium-rich lithium ferrite slurry is composed of lithium-rich lithium ferrite, a thickening agent and a solvent, in a dry environment, lithium-rich lithium ferrite powder, the thickening agent and the solvent are weighed, the thickening agent is mechanically stirred and dissolved in the solvent, then the lithium-rich lithium ferrite is added, stirring is conducted under the vacuum condition, and a uniform suspension is obtained; according to the lithium-rich lithium ferrite slurry prepared by the method, the sensitivity of lithium-rich lithium ferrite to air and moisture is effectively reduced, and the problem that the lithium-rich lithium ferrite is easy to lose efficacy is solved. When in use, the lithium-rich lithium ferrite is added after the raw materials of the positive electrode material are dispersed and before the step of adjusting the viscosity, so that the problem of slurry gel during positive electrode slurrying caused by premature reaction between the lithium-rich lithium ferrite and the binder PVDF in the positive electrode slurry is avoided.

The invention provides a multi-element lithium supplement agent and a preparation method thereof, a positive pole piece and a lithium ion battery, the multi-element lithium supplement agent comprises an inner core, a first coating layer and a second coating layer, the inner core comprises lithium-rich lithium aluminum ferrite, the first coating layer comprises lithium-rich lithium manganate, and the second coating layer comprises lithium-rich lithium nickelate; the chemical general formula of the multi-element lithium supplement agent is LixFeaAlbMncNidOy, 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 < = 5.5 a + 5.5 b + 2.1 c + 2.1 d, and y = (x + 3a + 3b + 4c + 2d) / 2. Iron and aluminum are adopted as main elements, and lithium-rich lithium manganate and lithium-rich lithium nickelate are coated at the same time, so that the stability of the lithium supplementing agent can be improved, gas production can be reduced, the ionic conductivity can be improved, and the capacity exertion of the lithium supplementing agent can be promoted.

The invention provides a lithium ion battery, a lithium supplementing method thereof and electronic equipment, and particularly relates to the technical field of lithium ion batteries. The lithium ion battery comprises a negative pole piece and a positive pole piece, and the positive pole piece comprises a positive current collector and a positive active material layer arranged on at least one side of the positive current collector; the positive electrode active material layer comprises a positive electrode active material and a positive electrode lithium supplement agent, the positive electrode active material comprises lithium-containing phosphate, the positive electrode lithium supplement agent at least comprises a first lithium supplement agent lithium ferrite and a second lithium supplement agent, and the mass percentage of the lithium ferrite to the total mass of the positive electrode active material and the positive electrode lithium supplement agent is a, 0 < a < = 3%. According to the invention, at least two lithium supplementing agents are introduced into the positive pole piece, and the addition proportion of the lithium supplementing agents is controlled, so that a synergistic effect is achieved, the advantages of various lithium supplementing agents are exerted, and the cycle life of the battery is prolonged.

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 non-gas-production type lithium-rich lithium ferrite positive electrode lithium supplement material and a preparation method and application thereof.The preparation method comprises the steps that common lithium-rich lithium ferrite is used as a raw material, the lithium-rich lithium ferrite, elemental sulfur or phosphorus and a conductive agent are subjected to ball milling and then heated at the high temperature, the elemental sulfur or phosphorus and the conductive agent are mixed to be uniform, the surface of the lithium-rich lithium ferrite is coated with the mixture, and the surface of the lithium-rich lithium ferrite is coated with the conductive agent to obtain the non-gas-production type lithium-rich lithium ferrite positive electrode lithium supplement material; and finally obtaining the composite material. Compared with the prior art, the lithium supplementing material disclosed by the invention is added into positive electrode slurry, so that the purpose of positive electrode pre-lithiation can be achieved, and the problem of oxygen release of a lithium-rich lithium ferrite lithium supplementing agent in a charging process can be inhibited.

The invention provides a carbon coating method of lithium-rich lithium ferrite, an obtained material and a lithium ion battery, and belongs to the technical field of lithium ion battery materials. According to the method, a physical vapor deposition method is adopted for carrying out carbon film deposition treatment on lithium ferrite particles which circularly flow in a physical vapor deposition coating device; and after deposition is completed, turning off a device power supply, and cooling to room temperature to obtain the carbon-coated lithium ferrite material. The obtained carbon-coated lithium ferrite material can effectively make up for active lithium lost in the first charging and discharging process of a lithium battery, the energy density of the lithium battery is improved, and the carbon-coated lithium ferrite material has good storage stability and conductivity in air.