90 results about "Lithium ferrite" patented technology

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 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 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 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 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 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 lithium-rich lithium ferrite lithium supplement agent and a preparation method thereof, and belongs to the technical field of lithium ion batteries, the lithium-rich lithium ferrite lithium supplement agent comprises an intermediate and a composite carbon coating layer coating at least part of the surface of the intermediate, the intermediate comprises an inner core and a solid electrolyte coating layer coating at least part of the surface of the inner core; the inner core comprises lithium-rich lithium ferrite, and the solid electrolyte coating layer comprises LLZAO. According to the application, the LLZAO and the composite carbon are sequentially coated on the surface of the lithium-rich lithium ferrite, so that the contact between the lithium-rich lithium ferrite and external air and electrolyte can be effectively isolated by utilizing two formed coating layers, the air stability of the lithium-rich lithium ferrite is improved, meanwhile, the problem of continuous gas production in the charging and discharging process is avoided, and the service life of the lithium-rich lithium ferrite is prolonged. Further, the comprehensive performance of the lithium-rich lithium ferrite lithium supplement agent is effectively improved.

Described is an intrinsically multiplexed magnetostatic surface wave (MSSW) device comprising of a pair of transducers that couple to one or more plurality of ferrite films. In embodiments, the ferrite films may be provided as one or more of a YIG, Nickle Zinc Ferrite, Lithium Ferrite configured to simultaneously provide the MSSW device having an associated plurality of MSSW operational bandwidths. The concepts, structure and technique described herein may be used to provide broadband magnetostatic surface wave devices that employ intrinsic multiplexing techniques which enable customizable frequency responses over broad bandwidths.

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 present invention relates to the technical field of lithium-ion batteries, and particularly relates to a lithium ferrite lithium supplement and a preparation method thereof. The lithium ferrite lithium supplement comprises the following components: an iron salt, an organic ligand, a lithium salt, a regulator, and a biomass graphene quantum dot; first, defective Fe-MOFs are synthesized as a template, which is mixed with the lithium salt, the iron salt, and the biomass graphene quantum dot, and then calcined in a nitrogen atmosphere to obtain the lithium ferrite lithium supplement. As a synthesis template, Fe-MOFs can make the distribution of lithium ions uniform, reduce the local stress and volume change inside the battery. At the same time, the introduction of the biomass graphene quantum dot can improve the conductivity of the lithium supplement, and can synergistically act with Fe-MOFs to improve the overall performance of the lithium supplement, providing an efficient and green solution for the optimization of lithium-ion batteries.

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.

The present application discloses an electrode material for assisting in the degradation of organic pollutants and a method for degrading organic pollutants. The electrode material has an iron matrix with a lithium ferrite oxide layer coated on the surface. Among them, the chemical formula of lithium ferrite is LiFe5O8 (LFO). In the present invention, the degradation of organic pollutants is assisted by using this electrode material. This electrode material can not only directly electrolyze and degrade organic pollutants in wastewater, but also electrochemically activate persulfate as the anode and cathode respectively to assist in the degradation of organic pollutants in wastewater. When electrochemically activating persulfate as the anode and cathode to degrade organic pollutants, there is an obvious synergistic effect, which can efficiently degrade organic pollutants. At the same time, this electrode material is inexpensive, has high stability and strong cycle performance, will not cause secondary pollution, and has good practical application prospects.

The application relates to a double-coated positive electrode material and a preparation method thereof, and the preparation steps are as follows: a soluble ferrous salt solution is heated and stirred, a phosphorus source is added, heating and stirring are continuously carried out, a lithium source, an additive and water are added, a first mixed material is obtained after ball milling, sand milling and spraying; the first mixed material is calcined under an inert gas atmosphere and then crushed to obtain a first material; the first material is dispersed in a citric acid solution and continuously stirred, a soluble iron salt solution and a lithium carbonate solution are added, continuous stirring is carried out, and finally a carbon source is added, a second mixed material is obtained after sand milling and spraying; the second mixed material is calcined to obtain a double-coated lithium iron phosphate composite material. Through coating lithium ferrite on the surface of lithium iron phosphate and then carrying out carbon coating treatment, the double-coated lithium iron phosphate positive electrode material is formed, and the cycle performance, processing performance and safety performance of the material can be effectively improved.

The invention belongs to the technical field of batteries, and provides a double-layer coated lithium supplement material and a preparation method thereof, a positive pole piece and a battery, the double-layer coated lithium supplement material comprises an inner core, a silicon nitride coating layer and a carbon coating layer; the silicon nitride coating layer is located on the surface of the inner core, and the carbon coating layer is located on the surface of the side, away from the inner core, of the silicon nitride coating layer; the inner core comprises lithium-rich lithium ferrite and / or lithium-rich lithium nickelate. According to the lithium supplementing material, the silicon nitride layer is firstly coated and then the carbon layer is coated, so that carbon is prevented from reacting with an inner core substance, meanwhile, the carbon coating layer is utilized to enhance the electronic conductivity of the lithium supplementing material, the reaction of the lithium supplementing material with environmental moisture is inhibited, and the processing performance of positive electrode slurry is improved; therefore, the problems of poor conductivity and low environmental stability of the lithium supplement material and poor stability of the positive electrode slurry added with the lithium supplement material are solved.

The present application belongs to the field of positive electrode materials, and provides a lithium-rich lithium iron oxide material, and a preparation method therefor and the use thereof. The lithium-rich lithium iron oxide material comprises a particle of a core-shell structure, wherein the particle of a core-shell structure comprises a core, a first coating layer that coats the core, and a second coating layer that coats the first coating layer; the core is Li5FeO4, the first coating layer is a carbon layer, and the second coating layer is a mixed layer comprising polyoxyethylene and a lithium salt; and the mass ratio of the first coating layer to the core is (2:100) to (10:100), and the mass ratio of the second coating layer to the core is (3:100) to (13:100). The present application is conducive to improving the air stability of the lithium iron oxide material, and can also enhance the overall ionic conductivity of an electrode.

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 belongs to the technical field of battery materials, and particularly relates to a double-layer coated lithium-rich lithium ferrite material as well as a preparation method and application thereof. The double-layer coated lithium-rich lithium ferrite material comprises a Li5FeO4 inner core, a sulfide solid electrolyte layer coated on the surface of the inner core and a polydimethylsiloxane hydrophobic layer coated outside the sulfide solid electrolyte layer. According to the material, the migration path of lithium ions is optimized through electrolyte coating in double-layer coating, the discharge capacity of Li5FeO4 is improved, erosion of moisture and carbon dioxide in air can be effectively isolated through the hydrophobic layer, side reaction of active lithium in lithium-rich lithium ferrite and the external environment is inhibited, and the air stability of the material is improved.

The invention discloses a composite material containing lithium-rich lithium ferrite and a layered positive electrode material as well as a preparation method and application of the composite material. The composite material contains lithium-rich lithium ferrite and a main active substance layered positive electrode material, can contain or does not contain a carbon coating layer, and can contain or does not contain a coating layer of other elements except carbon. Wherein the lithium-rich lithium ferrite is mainly used for improving the first efficiency and the cycle performance of the battery cell; the carbon layer which can be contained or not contained is mainly used for improving the electronic conductivity and air stability of the material; the coating layer can contain or does not contain other elements and is mainly used for improving the electrical property and improving the air stability to a certain degree; in addition, the air stability of the LFO is further improved due to the layered material, particularly, when the composite material is applied to a high-nickel ternary material system, the compatibility of the composite material and the high-nickel ternary material can be further improved, and the problems of side reaction and gas production are solved.