872 results about "Manganese phosphate" patented technology

The invention provides a method for preparing a high-performance lithium manganese iron phosphate positive electrode material based on a manganese iron phosphate precursor, and relates to the technical field of batteries. A method for preparing a high-performance lithium manganese iron phosphate positive electrode material based on a manganese iron phosphate precursor comprises the following steps: S1, mixing a phosphorus source, an iron source and a manganese source in a water medium, adding a surfactant, and carrying out ball milling, drying and sintering to obtain the manganese iron phosphate precursor; and S2, mixing the manganese iron phosphate precursor, a lithium source, a carbon source, a doping agent, an auxiliary agent and deionized water, and carrying out ball milling, drying and sintering to obtain the lithium manganese iron phosphate positive electrode material. The method can improve the surface / interface stability while improving the surface conductivity of the material, thereby prolonging the cycle life of the battery and improving the charge-discharge capacity of the battery.

The invention relates to the field of positive electrode materials, in particular to a lithium manganese iron phosphate / carbon fiber composite positive electrode material and a preparation method thereof, which are used for solving the problems of poor electronic conductivity of lithium manganese iron phosphate and the like. The preparation method comprises the following steps: firstly, carrying out graft modification and ZrO2 film coating on carbon fibers, and then compounding the modified carbon fibers with lithium iron manganese phosphate to obtain the lithium iron manganese phosphate / carbon fiber composite positive electrode material. The lithium manganese iron phosphate / carbon fiber composite positive electrode material can greatly improve the electronic conductivity and improve the rate capability; active substance dissolution and side reaction can be inhibited, and the cycling stability is improved; a lithium ion diffusion channel can be optimized, and the ion conduction efficiency is improved; the electrode mechanical performance can be enhanced, and the structural reliability is improved. Meanwhile, the advantages of all the components are exerted, and finally the electrochemical performance and structural stability of the composite positive electrode are remarkably improved.

The invention belongs to the technical field of batteries, and discloses a carbon-coated modified lithium manganese iron phosphate positive electrode material and a preparation method and application thereof, and the carbon-coated modified lithium manganese iron phosphate positive electrode material comprises carbon-coated modified lithium manganese iron phosphate positive electrode material particles, the carbon-coated modified lithium manganese iron phosphate positive electrode material particle comprises a lithium manganese iron phosphate core, a first carbon coating layer and a second carbon coating layer, wherein the first carbon coating layer is positioned between the lithium manganese iron phosphate and the second carbon coating layer; the graphitization degree of the first carbon coating layer is greater than that of the second carbon coating layer. The carbon-coated modified lithium manganese iron phosphate positive electrode material has relatively high conductivity, compaction density and the like, and a battery using the carbon-coated modified lithium manganese iron phosphate positive electrode material has relatively high charge-discharge rate, excellent energy density, excellent capacity and the like.

The invention discloses a lithium manganese iron phosphate material prepared by taking lithium iron phosphate as a template agent as well as a preparation method and application of the lithium manganese iron phosphate material. Specifically, lithium iron phosphate is taken as a template agent, other iron sources, manganese sources, lithium sources, phosphorus sources and carbon sources are added, high-energy ball milling mixing is carried out in water or an organic solvent, rheological phase reaction is carried out, and the surface of the lithium iron phosphate is uniformly coated with the raw materials. And then drying, pre-calcining, secondary carbon coating and high-temperature calcining are carried out, and bulk phase diffusion and epitaxial growth of the raw materials are synchronously carried out on the surface of the lithium iron phosphate by utilizing a solid phase diffusion-epitaxial growth coupling mechanism, so that the lithium iron manganese phosphate material is finally obtained. The lithium iron manganese phosphate prepared by taking lithium iron phosphate as a template agent and matching with other iron sources has the characteristic of manganese element concentration gradient distribution, and meanwhile, nanoscale particle refinement is realized. The secondary battery prepared by taking the lithium manganese iron phosphate as the positive electrode material has excellent electrochemical performance and cycling stability.

The application provides a lithium ion battery and an electric device, the lithium ion battery comprising a positive electrode sheet and an electrolyte, an active substance in the positive electrode sheet comprising a phosphate lithium positive electrode material and a lithium nickel cobalt manganese oxide, the electrolyte comprising a positive electrode film former, a negative electrode film former and a lithium salt, the lithium salt comprising lithium hexafluorophosphate and a lithium bisfluorosulfonylimide salt, the lithium ion battery satisfying the following formula: wherein NL is a mass ratio of the lithium nickel cobalt manganese oxide and the phosphate lithium positive electrode material, S alt is a value of a molar concentration of the lithium hexafluorophosphate and the lithium bisfluorosulfonylimide salt in the electrolyte in mol / L, and A dd is a mass ratio of the positive electrode film former and the negative electrode film former. The application can adjust the ratio of the positive electrode film former and the negative electrode film former and the ratio of the high-heat-resistance lithium salt according to the mixing ratio of the ternary material doped in the lithium manganese iron phosphate or the lithium iron phosphate, so that the cycle performance of the battery is improved.

The invention discloses a manganese iron oxalate precursor, a lithium manganese iron phosphate material and a preparation method and application of the manganese iron oxalate precursor and the lithium manganese iron phosphate material, and belongs to the technical field of battery materials. The lithium manganese iron phosphate material core layer is prepared by taking the oxalate manganese iron precursor with a specific particle size range, particle size distribution uniformity and a specific structure as a raw material, and meanwhile, the shell layer comprising the ionic conductive agent and carbon is introduced outside the core layer, so that the comprehensive performance of the lithium manganese iron phosphate material can be effectively improved; and thus, the capacity, the cycle performance and the first charge-discharge efficiency of the prepared corresponding secondary battery are improved.

The invention discloses a lithium manganese iron phosphate positive electrode material and a preparation method thereof, a positive electrode plate and a lithium ion battery, and relates to the technical field of lithium ion batteries. The lithium manganese iron phosphate positive electrode material comprises a lithium manganese iron phosphate inner core and a coating shell layer, the surface of the lithium manganese iron phosphate inner core is coated with the coating shell layer; the coating shell layer comprises lithium iron phosphate; the positive electrode material can solve the problem of poor high-temperature storage performance of the lithium manganese iron phosphate material, so that the lithium manganese iron phosphate material has high capacity and high-temperature storage stability.

The invention provides a lithium manganese iron phosphate material, a preparation method thereof, a positive pole piece and a lithium ion battery. The preparation method of the lithium manganese iron phosphate material comprises the following steps: sequentially mixing and sintering a manganese iron phosphate precursor, a manganese iron pyrophosphate precursor, a lithium source, a carbon source and an organic additive to obtain the lithium manganese iron phosphate material, the ferromanganese phosphate precursor is in an amorphous state; the crystal structure of the ferromanganese pyrophosphate precursor is a monoclinic system; the organic additive is a polymer of which the molecular structure carries an anionic functional group; sintering comprises first-stage sintering, second-stage sintering, third-stage sintering, fourth-stage sintering and fifth-stage sintering which are performed in sequence. According to the invention, the unique properties of the amorphous ferromanganese phosphate precursor and the monoclinic system ferromanganese pyrophosphate precursor are utilized, and the special organic additive and the five-stage sintering process are combined, so that the particle filling effect in the sintering process is enhanced, and the purpose of optimizing the particle gradation and the element distribution uniformity is achieved.

The invention relates to the technical field of lithium ion batteries, in particular to a lithium iron manganese phosphate battery and a preparation method thereof, and the lithium iron manganese phosphate battery comprises a positive pole piece and a negative pole piece; the positive pole piece comprises a positive current collector and a positive active material layer arranged on the surface of the positive current collector; the positive electrode active material layer comprises lithium manganese iron phosphate; the lithium manganese iron phosphate comprises LiMnxFe1-xPO4, and x is more than or equal to 0.4 and less than or equal to 0.9; the surface density of the positive electrode active material layer is 493.4-584.3 g / m < 2 >; the negative electrode plate comprises a negative electrode current collector, a first negative electrode active material layer arranged on the surface of the negative electrode current collector and a second negative electrode active material layer arranged on the surface of the first negative electrode active material layer; the first negative electrode active material layer comprises first graphite; in a Raman spectrogram of the first graphite, ID / IG is 0.05 to 0.15; the second negative electrode active material layer comprises second graphite; and in the Raman spectrogram of the second graphite, ID / IG is 0.4-0.65. The lithium manganese iron phosphate battery provided by the invention has significantly improved energy density and charge.

The invention discloses a lithium manganese iron phosphate positive electrode material and a preparation method thereof.The lithium manganese iron phosphate positive electrode material comprises large-particle lithium manganese iron phosphate of a core-shell structure and small-particle lithium manganese iron phosphate, and the large-particle lithium manganese iron phosphate of the core-shell structure comprises a manganese-rich lithium manganese iron phosphate inner core and an iron-rich lithium manganese iron phosphate outer shell; the core content of manganese is larger than that of the shell, and the core content of iron is smaller than that of the shell. The inner-layer manganese-rich lithium manganese iron phosphate in the core-shell structure maintains a high-voltage platform and improves the energy density, and the outer-layer iron-rich lithium manganese iron phosphate reduces the dissolution of manganese and improves the stability of the material; the large particles with the core-shell structure and the iron-rich lithium manganese iron phosphate small particles are mutually filled to form the spherical lithium manganese iron phosphate with the graded large and small particles, so that the compaction density of the lithium manganese iron phosphate and the stability in the long cycle process are improved; the proper molar ratio difference of elements in the inner layer and the outer layer is adopted, lattice mismatch caused by component mutation is reduced, and the steps of drying, coating, thermal decomposition, particle self-assembly and the like are completed in one step through a spray drying process.

The invention provides a lithium manganese iron phosphate material and a preparation method and application thereof, and belongs to the technical field of lithium batteries, the lithium manganese iron phosphate material comprises a gradient manganese-doped core, a magnesium-doped layer, a carbon coating layer and an Al2O3 coating layer; the gradient manganese-doped inner core sequentially comprises a manganese-containing core layer, a manganese-containing transition layer and a manganese-containing shell from inside to outside, and the manganese ion concentration of the manganese-containing core layer is from high to low. According to the lithium manganese iron phosphate material disclosed by the invention, the gradient manganese-doped core is designed, so that the concentration gradient distribution of manganese ions is realized, and the electrochemical performance of the material is optimized. Meanwhile, due to the introduction of the magnesium doping layer, the cycling stability and the thermal stability of the material are further improved, and the manganese ion dissolution phenomenon in a high-temperature environment is reduced; in addition, the use of the carbon coating layer significantly improves the conductivity of the material and improves the charge and discharge performance of the material, and the Al2O3 coating layer can improve the structural stability of the material and reduce the dissolution of manganese ions, and also can improve the cycling stability and thermal stability of the material.

The invention discloses a long-life lithium manganese iron phosphate positive electrode material and a preparation method thereof, and relates to the technical field of lithium ion battery positive electrode materials. The long-life lithium manganese iron phosphate positive electrode material comprises lithium manganese iron phosphate, a middle coating layer and a carbon coating layer, the surface of the lithium manganese iron phosphate is coated with the middle coating layer, the surface of the middle coating layer is coated with the carbon coating layer, the middle coating layer contains metal fluoride and aluminum-containing sinter, and the aluminum-containing sinter comprises aluminum oxide and lithium metaaluminate. The synergistic coating of the middle coating layer and the carbon coating layer can effectively reduce the contact between the positive electrode material and an electrolyte, inhibit the generation of surface side reactions, improve the stability of the electrode material structure, and have low manganese dissolution and excellent cycle life.

The invention provides carbon-coated nitrogen-doped lithium manganese iron phosphate, a preparation method thereof and a lithium ion battery, and relates to the technical field of lithium ion battery positive electrode materials. The preparation method comprises the following steps: preparing lithium manganese iron phosphate, reduced graphene oxide and azone into uniform slurry; and carrying out spray drying on the slurry, sintering and cooling to obtain the carbon-coated nitrogen-doped lithium manganese iron phosphate. A reduced graphene oxide (rGO) / azone co-modification strategy is adopted to prepare the lithium manganese iron phosphate positive electrode material, an rGO tight coating and N-doped carbon bridging dual-network conductive system is structurally constructed, N-doped carbon generated by azone cracking is combined with the surface of LMFP through a C-O-P covalent bond, and interface stripping is inhibited; the physical barrier effect of rGO and the chemical anchoring effect of N-doped carbon cooperate to reduce the dissolution amount of manganese and improve the dynamic performance of the material.

The invention provides a lithium manganese iron phosphate composite positive electrode material and a preparation method thereof, and relates to the technical field of lithium batteries. The lithium manganese iron phosphate composite positive electrode material is of a core-shell composite structure; wherein the core is lithium manganese iron phosphate; the first coating layer and the second coating layer are sequentially arranged on the outer surface of the core; the first coating layer is made of Cu-Ti alloy; the second coating layer is a boron-doped carbon material; a B-Ti chemical bond is arranged between the Ti element in the first coating layer and the B element in the second coating layer. According to the unique double-layer core-shell structure of the material, through the conductive and firm Cu-Ti alloy and the boron-doped carbon coating layer, the rate capability is improved, and meanwhile, the volume change of the core material is effectively inhibited, so that the cycling stability and safety are enhanced. The key B-Ti chemical bond ensures the tight combination and integrity of the coating layer, and is the basis for realizing long-acting stable protection.

The invention provides an amorphous carbon coated lithium manganese iron phosphate positive electrode material and a preparation method and application thereof, the preparation method comprises the following steps: mixing a lithium source, a ferrous source, a manganese source, a phosphorus source, a carbon source and a solvent to obtain mixed slurry; carrying out spray drying treatment on the mixed slurry, and carrying out plasma treatment on the obtained dried material to obtain a precursor material; and mixing the precursor material with a boron source, and sintering to obtain the amorphous carbon coated lithium iron manganese phosphate positive electrode material. The surface of the lithium manganese iron phosphate positive electrode material is coated with the amorphous carbon layer, the bonding strength of the amorphous carbon coating layer and the positive electrode material is high, the problem of electronic conductivity of the lithium manganese iron phosphate positive electrode material is solved, and meanwhile, the ionic conductivity of the material is improved through boron doping.

The invention provides a positive plate, a battery and electronic equipment. The positive plate comprises a positive current collector and a positive active layer positioned on at least one surface of the positive current collector; the positive electrode active layer comprises a first positive electrode active layer and a second positive electrode active layer which are sequentially stacked in a direction far away from the positive electrode current collector; the first positive electrode active layer comprises a first positive electrode active material, and the first positive electrode active material comprises lithium manganese iron phosphate and a lithium oxide compound; the second positive electrode active layer comprises a second positive electrode active material, and the second positive electrode active material comprises a lithium oxide compound and nickel cobalt lithium manganate. When the positive plate is applied to the battery, the battery is not easy to generate gas during high-temperature storage, so that the safety performance of the battery is improved.

The invention belongs to the field of positive electrode materials, and particularly relates to a core-shell ferromanganese phosphate precursor, a modified lithium ferric manganese phosphate material, a preparation method and application of the modified lithium ferric manganese phosphate material and a lithium ion battery. The core-shell ferromanganese phosphate precursor comprises a core and a shell wrapping the core, and the core is Fe3 (PO4) 2; the shell is MnxFe1-x (PO4) y (ferromanganese phosphate), x is more than or equal to 0.1 and less than or equal to 0.9, and y is more than or equal to 0.67 and less than or equal to 0.75. The invention provides a core-shell ferromanganese phosphate precursor which takes Fe3 (PO4) 2 as a core and MnxFe1-x (PO4) y as a shell, and when the core-shell ferromanganese phosphate precursor is used for preparing lithium ferromanganese phosphate, the problem of component segregation is solved, and the Jahn-Teller effect of manganese is reduced; especially for subsequent doping and coating, doping segregation is expected to be reduced, coating interface impedance is reduced, and rapid charging of the prepared material and cycling stability under large current can be remarkably enhanced.

The invention provides an electrolyte and a lithium iron manganese phosphate battery, and relates to the technical field of lithium batteries. The electrolyte comprises a lithium salt, an organic solvent and an additive, the additive is a phenylboronic acid pinacol ester compound, and the phenylboronic acid pinacol ester compound has a structure as shown in a formula I. The electrolyte provided by the invention is helpful for improving the cycling stability of the lithium manganese iron phosphate battery under a high-temperature condition.

The invention belongs to the field of batteries, and particularly relates to a positive plate, a lithium battery and a preparation method thereof. Comprising a positive current collector and an active coating coated on the surface of the positive current collector, the active coating comprises a first coating close to the current collector and a second coating far away from the current collector; the first positive electrode active material is a mixture of monocrystal lithium manganese iron phosphate and a lithium-rich manganese-based material, and the second positive electrode active material is aggregate lithium manganese iron phosphate. The positive plate adopts a double-layer coating design, the first coating close to one side of the current collector is made of high-manganese lithium manganese iron phosphate in a nano small particle form, the second coating far away from the current collector is made of a low-manganese lithium manganese iron phosphate material in an aggregate form, and a gradient manganese distribution design with high manganese in the inner layer and low manganese in the outer layer is constructed; the manganese dissolution risk can be effectively reduced, and the cycle performance is improved. And meanwhile, the energy density of the battery can also be improved by using the high-manganese-content lithium manganese iron phosphate.

The invention provides a lithium manganese iron phosphate positive electrode material, a preparation method thereof and a lithium ion battery. The lithium manganese iron phosphate positive electrode material comprises an inner core, and a first shell and a second shell which sequentially coat the surface of the inner core, wherein the inner core comprises a boron-doped lithium manganese iron phosphate material, the first shell is a boron-doped aluminum oxide layer, and the second shell is a lithium niobium tantalate layer; the doping amount of boron in the lithium manganese iron phosphate positive electrode material is gradually reduced from the inner core to the second shell layer. According to the invention, a plurality of shell layers are constructed for collaborative protection, and gradient boron doping is carried out on the inner core and the first shell, so that the intrinsic electron / ionic conductivity of lithium manganese iron phosphate is improved, the interface stress caused by element distribution mutation between different material layers is avoided, and the balance of bulk phase high conductivity-interface low impedance is realized; and the comprehensive electrochemical performance is improved.

The invention discloses a polymeric dispersant for lithium iron phosphate and lithium iron manganese phosphate positive electrode slurry and a preparation method, and relates to the technical field of preparation of lithium ion battery positive electrode materials. The dispersing agent is a segmented copolymer obtained by synchronously dropwise adding free radicals to polymerize a nitrogen heterocyclic ring-containing monomer and a carboxylic acid group-containing monomer, the number-average molecular weight is 10000-50000, and the molecular weight distribution is 1.5-3.0. The dispersing agent is adaptive to an LFP / LMFP dual system, has excellent dispersing performance, can reduce the viscosity of LMFP slurry to 3800 mPa.s or below, can increase the solid content of the LFP slurry to 75% or above, and has the 24-hour sedimentation rate lt; 1.5% by weight; the 3C / 0.2 C discharge ratio of the battery using the dispersing agent is greater than or equal to 88% and 2000, the selected monomers are low in cost, expensive synergists are not needed, and the dispersing agent has remarkable industrial advantages.

The invention belongs to the technical field of cellular immunity, and particularly relates to calcium-doped manganese phosphate engineered red blood cells based on a biomimetic mineralization technology and application of the calcium-doped manganese phosphate engineered red blood cells in immunotherapy. Calcium ions, manganese phosphate, acidic polypeptide and a carboxyl activator are deposited on the surfaces of red blood cells, the acidic polypeptide provides a negative electricity environment, the concentration of calcium and manganese on red blood cell membranes is increased, and a mineralization layer of calcium ions and manganese ions is formed; the carboxyl activator can activate carboxyl of amino acid on acidic polypeptide and is covalently bound with other molecules; calcium can improve the stability of the manganese phosphate crystal, optimize the release of manganese ions and activate a cGAS-STING pathway in the DC; the natural half-life period of red blood cells reaches 120 days, rapid clearing of the liver can be avoided, the aged red blood cells are swallowed by spleen DC, and cross presentation of antigens is promoted. The calcium-doped manganese phosphate engineered erythrocyte provided by the invention can promote the maturation, migration, homing and antigen presentation functions of dendritic cells, and enhance the ability of the dendritic cells to activate CD8 + T cells.

The present application discloses a lithium iron manganese phosphate composite material, a preparation method therefor as well as a secondary battery. The lithium iron manganese phosphate composite material sequentially comprises a core, a first coating layer and a second coating layer, wherein the core comprises LixMnyFe1-y-zDzPO4 material, 1≤x≤1.05, 0<y<1, 0≤z<1, and D is a metal element; the first coating layer comprises LiaAlbMcOd material, 0<a≤1, 0<b<1, 0<c<1, 0<d<3, M comprises at least one of Y element, Zr element and Mg element, and the second coating layer comprises carbon. The method for preparing the lithium manganese iron phosphate composite material comprises: providing a core, which comprises a material having a chemical general formula LixMnyFe1-y-zDzPO4; preparing a first coating layer on the outer surface of the core utilizing an atomic layer deposition technology, the first coating layer comprises a material having a chemical general formula LiaAlbMcOd; and preparing a second coating layer on the outer surface of the first coating layer, the second coating layer comprises carbon.

The invention discloses a preparation method and application of a ferromanganese phosphate hydrate based on sulfate free radicals, and provides the preparation method and application of the ferromanganese phosphate hydrate based on the sulfate free radicals in order to solve the technical problems existing in preparation of the ferromanganese phosphate hydrate (Mn1-xFexPO4.H2O) in an aqueous solution system in the prior art. The invention innovatively provides a technology for preparing a precursor ferromanganese phosphate hydrate of a lithium ion battery positive electrode material based on a three-step synergistic strategy of oxidation, locking and release of sulfate free radicals, and the sulfate free radicals (SO4 <.->) with strong oxidizability are generated in situ through thermal activation of persulfate; the high-quality ferromanganese phosphate hydrate Mn1-xFexPO4.H2O (01t, 01t) which is pure in phase, uniform in composition and controllable in structure is accurately prepared by combining subsequent formation and'locking 'of an intermediate-state complex and final regulation and control'release' and homogeneous precipitation steps; and x < = 0.5). The Mn < 1-x > FexPO4.H2O (0 lt; x is greater than or equal to 1 and less than or equal to 0.5) is used as a precursor for preparing a lithium battery positive electrode material, and the prepared LiMn1-xFexPO4 / C positive electrode material shows excellent electrochemical performance.

The invention discloses carbon-coated lithium manganese iron phosphate as well as a preparation method and application thereof, and belongs to the technical field of battery positive electrode materials. A preparation method of carbon-coated lithium manganese iron phosphate comprises the following steps: S1, mixing and dispersing a manganese source, an iron source, a lithium source, a phosphorus source and a carbon source, grinding, spray-drying and sintering to prepare carbon-coated lithium manganese iron phosphate; and S2, ammonium fluoride and the carbon-coated lithium manganese iron phosphate obtained in the step S1 are sequentially subjected to low-temperature fluorination sintering treatment and high-temperature defluorination sintering treatment. According to the preparation method, the carbon coating layer is modified through fluorine doping subjected to low-temperature fluorination sintering treatment in the step S2, so that the electronic structure distribution and the conductivity of the material are regulated and controlled, and the doped fluorine atoms leave the system in a fluorine gas form through fluorine-doped defluorination sintering treatment at a high temperature; and then proper sintering is performed to accelerate polymerization and heal excessive defect sites, so that the specific surface area of the material is reduced, and controllable adjustment of the specific surface area of the material is realized.

The invention provides a composite positive electrode material and a preparation method and application thereof. The composite positive electrode material comprises a lithium manganese iron phosphate inner core, and an inorganic coating layer and an organic coating layer which sequentially coat the surface of the lithium manganese iron phosphate inner core, wherein the inorganic coating layer comprises a lithium niobate tantalate material, and the organic coating layer comprises polypyrrole and polyolefin. By adopting an inorganic-organic composite coating strategy, on one hand, the high stability of the lithium niobate tantalate material is taken as a core support, the volume expansion of the positive electrode material in the charging and discharging process is inhibited, the structural stability of the material in a high-temperature and high-voltage environment is enhanced, and the potential safety hazard is reduced; on the other hand, by means of high conductivity of polypyrrole, the problem that the intrinsic conductivity of the positive electrode material is low is solved, the rate capability of the battery is effectively improved, meanwhile, the interface protection effect of polyolefin is utilized, the interface side reaction and dissolution of metal ions such as Mn and Fe are inhibited, and the cycle life of the battery is prolonged.

Provided in the present disclosure is a positive electrode material, containing a positive electrode active material, a conductive agent and a binder, the positive electrode active material consisting of a positive electrode main material and a lithium supplementing agent, the positive electrode main material being selected from at least one of lithium iron phosphate and lithium manganese iron phosphate, and the lithium supplementing agent being selected from at least one of lithium manganate and a lithium-rich manganese-based material. On the basis of the total weight of the positive electrode active material, the mixing weight ratio of the positive electrode main material to the lithium supplementing agent is: 70:30≤positive electrode main material: lithium supplementing agent≤99.9:0.1. A positive electrode coating is formed by means of a double-layer synchronous coating process, the content of the lithium supplementing agent in the surface layer being a wt %, the content thereof in the bottom layer being b wt %, and the total content of the lithium supplementing agent in the positive electrode active material being within the range of 0.1-30%. Correspondingly, further disclosed in the present disclosure is a positive electrode pre-lithiated battery comprising the positive electrode material. The pre-lithiation technology for positive electrode materials of lithium-ion batteries provided by the present disclosure significantly improves the usable cycle capacity, rate capability and cycle stability of batteries, and has important application value and promotion prospects.

The invention belongs to the field of lithium ion battery positive electrode materials, and particularly relates to a low-cost preparation method of a lithium ion battery positive electrode material lithium manganese iron phosphate. The preparation method comprises the following steps: firstly, reacting manganese oxide with phosphoric acid and hydrogen peroxide in advance to obtain manganese phosphate slurry; adding an iron source and a carboxylic acid-based carbon source into the reaction system, uniformly stirring and mixing, ball-milling for a period of time, adding lithium phosphate and an organic carbon source into the reaction container, fully and uniformly mixing the raw materials, and refining particles; and finally, carrying out spray drying and high-temperature sintering on the obtained slurry to prepare the lithium iron manganese phosphate positive electrode material. The method has the advantages of low slurry viscosity in the preparation process, high solid content, simple preparation process, low cost, easiness in batch and large-scale expansion and the like, and the prepared lithium manganese iron phosphate positive electrode material product has excellent electrochemical performance.

The invention provides a lithium manganese iron phosphate / titanium carbide heterojunction positive electrode material, a preparation method thereof, a positive plate and a lithium ion battery. The chemical structural formula of the lithium manganese iron phosphate / titanium carbide heterojunction positive electrode material is LiMn1-xFexPO4 / Ti3C2, wherein x is more than or equal to 0.1 and less than or equal to 0.9. In the lithium manganese iron phosphate / titanium carbide heterojunction positive electrode material, a part of titanium ions occupy an M site in lithium manganese iron phosphate to form a metal-hole pair, so that the Jahn-Teller effect can be reduced, the dissolution of manganese ions caused by lattice distortion in the circulation process can be reduced, and the service life of the lithium manganese iron phosphate / titanium carbide heterojunction positive electrode material is prolonged. Further, the structural stability and the cycle performance of the lithium manganese iron phosphate / titanium carbide heterojunction positive electrode material can be improved. Besides, reversible high capacity is realized by constructing a heterostructure and titanium carbide absorbing and utilizing lattice oxygen, and a stable positive electrode / electrolyte interface is obtained, so that a positive electrode system is favorably stabilized, and stable output of electrochemical performance is favorably promoted.

The invention relates to a lithium manganese iron phosphate (LFMP) electrode material, an LFMP-solid electrolyte positive plate with a gradient structure design, a preparation method of the LFMP-solid electrolyte positive plate and an all-solid-state battery. The lithium manganese iron phosphate (LFMP) electrode material comprises a lithium manganese iron phosphate material, a composite binder and a solid electrolyte, the lithium manganese iron phosphate material comprises lithium manganese iron phosphate particles and a coating layer located on at least part of the surface of the lithium manganese iron phosphate, and the coating layer comprises lithium phosphate (Li3PO4); the composite binder comprises a polymer matrix and a conductive agent, the polymer matrix comprises polytetrafluoroethylene and a PEO / LiTFSI compound, and the PEO / LiTFSI compound is a compound composed of polyethylene oxide and lithium bis (trifluoromethylsulfonyl) imide. According to an electrode plate containing the lithium manganese iron phosphate (LFMP) electrode material, migration or dissolution of manganese ions is not prone to occurring in the charge-discharge cycle process, and the service life of a battery can be prolonged.