540 results about "Composite cathode" patented technology

The invention discloses a composite positive electrode material and a preparation method thereof, a positive plate and a lithium ion battery. The composite positive electrode material comprises lithium iron phosphate and a carbon coating layer coating the surface of the lithium iron phosphate, wherein the integral intensity ratio ID / IG of a D peak to a G peak of the carbon coating layer in a Raman spectrum is 0.2-0.9, and the resistivity of the composite positive electrode material is 0.1-10 omega.cm. According to the preparation method, the graphitization degree of the carbon coating layer is controlled within a proper range (ID / IG is 0.2-0.9), so that good conductivity is ensured, and structural instability caused by excessive graphitization is avoided. The moderate graphitization degree is beneficial to formation of an ordered carbon layer structure, provides more electron transport channels and reduces the potential barrier of electron migration, so that the conductivity of the composite material is greatly improved, and the resistivity is reduced to an excellent level of 0.1-10 omega.cm.

The invention discloses a lithium manganese iron phosphate positive electrode material with a core-shell structure, which is prepared by the following steps: mixing a manganese source, an iron source, a phosphorus source, lithium carbonate and a carbon source, grinding and drying to prepare a pre-sintered material; then carrying out gas crushing on the pre-sintered material to obtain a pre-gas crushed material, and carrying out heat preservation at the temperature of 200-600 DEG C; putting the pre-gas crushed material subjected to heat preservation into an iron salt solution for quenching reaction to obtain iron compound coated lithium manganese iron phosphate; and finally, mixing the lithium iron manganese phosphate coated with the iron compound, a lithium source, a phosphorus source and a carbon source, grinding, drying, and carrying out secondary calcination to obtain the lithium iron manganese phosphate material with the core-shell structure. During preparation of the lithium manganese iron phosphate positive electrode material, a lithium manganese iron phosphate pre-sintered body and an iron salt solution are subjected to a quenching reaction to form an iron compound coated lithium manganese iron phosphate pre-sintered body, and then the iron compound coated lithium manganese iron phosphate pre-sintered body and other raw materials of lithium iron phosphate are subjected to a secondary calcination reaction to generate the composite positive electrode material with a core-shell structure. A coating structure is formed, the reaction between manganese and electrolyte is reduced, the dissolution of manganese is inhibited, the Gingtaler effect of manganese is relieved, and the stability of the material is improved; and the material has the advantages of high energy density, high power density, excellent cycle performance and strong core-shell interface bonding force.

The invention provides a manganese-based composite positive electrode material and a preparation method and application thereof. The manganese-based composite positive electrode material has a core-shell structure; the core of the core-shell structure is made of a lithium manganate material, and the shell is made of a lithium-rich manganese-based positive electrode material. Compared with the prior art, a manganese-based composite positive electrode material precursor with the inner core mainly comprising manganese and the outer shell mainly comprising nickel, cobalt and manganese is prepared in situ by adopting a coprecipitation method, and then pre-oxidation, lithium mixing and sintering modification are performed; the high-capacity, high-safety, long-circulation and high-compaction manganese-based composite positive electrode material of which the core is the lithium manganate material and the shell is the lithium-rich manganese-based positive electrode material is obtained, so that the problems of cycling stability and high-temperature storage of the manganese-based positive electrode material are solved; furthermore, the manganese-based composite positive electrode material is used as the positive electrode material of the lithium ion battery, so that the lithium ion battery with high energy density, long service life and high safety can be prepared.

The disclosed subject matter relates to solid state batteries, such as pseudo solid state and all solid state batteries, and methods of making and use thereof. The solid state batteries comprise: an interfacial layer; a halide solid state electrolyte layer; and a composite cathode. The halide solid state electrolyte layer is sandwiched between and in contact with the interfacial layer and the composite cathode. The interfacial layer, the halide solid state electrolyte layer, and the composite cathode each has an electrochemical stability window, and the electrochemical stability window of the interfacial layer overlaps with that of the halide solid state electrolyte layer. In some examples, the solid state batteries further comprise an anode disposed on the interfacial layer, wherein the electrochemical stability window of the interfacial layer overlaps with that of the halide solid state electrolyte layer and the anode.

The invention relates to the field of lithium ion battery materials, and particularly discloses a composite positive electrode material as well as a preparation method and application thereof. The composite positive electrode material comprises a positive electrode active material and a coating material coated on the surface of the positive electrode active material, lithium iron phosphate is used as a basic raw material, and the positive electrode active material is prepared by doping rare earth elements and non-metallic elements; the surface of the positive active matter is coated with a layer of mixture which takes sulfide solid electrolyte, a conductive agent and lithium salt as raw materials, interface impedance is effectively reduced through element doping and surface coating, the interlayer spacing of the material is increased, and the diffusion rate of lithium ions is improved, so that the lithium ion battery also has good electrical properties in a wide temperature range. According to the technical scheme, the problems that in the prior art, the charging and discharging efficiency of a lithium battery is reduced in a high / low-temperature environment, the battery capacity is attenuated, and the cycle performance and the service life of the battery are affected are effectively solved.

A composite cathode active material for an all-solid-state battery including a sulfide solid electrolyte, a preparation method thereof, a cathode layer for an all-solid-state battery, and an all-solid-state battery including the cathode layer, the composite cathode active material including a secondary particle including a plurality of primary particles; and a buffer layer on a surface of the secondary particle, wherein the secondary particle includes a nickel lithium transition metal oxide represented by Formula 1 (LiaNi1-bMbO2), the buffer layer includes a first buffer layer adjacent to a surface of the secondary particle and including an oxide represented by Formula 2 (LixAyOz); and a second buffer layer including an oxide represented by Formula 3 (LixEyOz).

The invention discloses a low-porosity and low-impedance dry positive electrode of a solid-state battery and a preparation method of the low-porosity and low-impedance dry positive electrode. The dry positive electrode of the solid-state battery comprises a large-particle positive electrode active material, a small-particle positive electrode active material, a first conductive agent, a second conductive agent, a third conductive agent, a small-size sulfide solid electrolyte, a large-size sulfide solid electrolyte and a binder. All the components are mixed in a manner of size matching and step-by-step embedding. Size matching among multi-stage particles is introduced, so that the size of gaps among different components is reduced, and the porosity is reduced; the binding agent and part of the conductive agent are premixed to form a'binding-conductive double network ', and then the active material and the electrolyte are gradually embedded, so that the purpose of low impedance of the composite positive electrode is achieved. And finally, the rate capability and the cycling stability of the solid-state battery are improved.

The invention discloses a composite positive electrode material applied to an all-solid-state lithium-sulfur battery. The composite positive electrode material comprises elemental sulfur as an active substance, and a high-temperature and high-ionic-conductivity sulfide solid electrolyte as an ionic conductive agent for conducting lithium ions; and the conductive carbon material is used as an electronic conductive agent for conducting electrons. The mass ratio of the elemental sulfur to the conductive carbon material to the sulfide solid electrolyte can be 1: 1: 2. The volume expansion of the active substance sulfur in the obtained composite positive electrode is small, the ion / electron path in the composite positive electrode is excellent, and the assembled all-solid-state battery is high in safety, good in cycle stability and high in energy density and power density.

The invention relates to a 3D printing composite positive pole piece, a preparation method thereof and a solid-state battery, the 3D printing composite positive pole piece comprises 90-97wt% of a positive active material, 10-15wt% of a conductive agent, 10-15wt% of a binder, 10-15wt% of a plasticizer and 10-15wt% of a polymer monomer; the proportion of the conductive agent is 1 to 3.5 weight percent; the plasticizer accounts for 0 to 1.5 wt%; the binder accounts for 1 to 5 weight percent; the proportion of the polymer monomer is 1 to 5 weight percent. The method has the advantages that the raw materials are printed on the positive electrode current collector in a 3D printing mode, the printed electrode has high integration and high material utilization rate, compared with a coating mode, the battery manufacturing time and cost can be effectively reduced, monomers in the electrode and an electrolyte precursor solution are polymerized, the combination degree between the solid electrolyte and the electrode is improved, and the battery performance is improved. And electrode / solid electrolyte integration is realized, so that the interface impedance between the electrolyte and the electrode is reduced, the lithium ion interface transmission is accelerated, and the capacity exertion and rate capability of the positive electrode material are improved.

The invention discloses a positive electrode material formed by compounding polyanionic sodium ferric sulfate and a layered transition metal oxide, and a preparation method and application thereof, and the preparation method comprises the following steps: preparing a sodium ferric sulfate positive electrode material, preparing a layered transition metal oxide positive electrode material, and mechanically mixing the sodium ferric sulfate and the layered transition metal oxide material, the composite material is obtained. The production process of the two materials is easy for large-scale production, has high similarity with the existing battery industrial equipment, is simple in method for compounding the two materials, and has large-scale industrial application value. The composite material has the stability of a polyanionic material and the high energy density of a layered oxide material, and has more excellent comprehensive electrochemical performance.

A solid secondary battery and a method of manufacturing the same are provided. The solid secondary battery includes a cathode layer, an anode layer, a solid electrolyte layer provided between the cathode layer and the anode layer, wherein the cathode layer includes a cathode current collector and a cathode active material layer provided on one surface or two surfaces of the cathode current collector. The cathode active material layer includes a composite cathode active material, and the composite cathode active material includes a composite of M2S, an alkali metal salt, and an inorganic electronic-conductive structure, wherein M is an alkali metal, and the alkali metal is Li or Na. The inorganic electronic-conductive structure has an electronic conductivity of 11×10−3 S / cm or more, and the composite includes a solid solution of the M2S and the alkali metal salt.

The invention belongs to the technical field of all-solid-state lithium batteries, and particularly relates to a densified sulfide all-solid-state battery composite positive electrode material and a preparation method and application thereof. The preparation method of the composite positive electrode material comprises the following steps: (1) raw material pretreatment: mixing a positive electrode active substance, a sulfide solid electrolyte and an additive according to a predetermined mass ratio under the protection of an inert atmosphere, and carrying out mechanical grinding to obtain composite positive electrode powder; the additive is Li3PO4 (lithium phosphate); (2) isostatic pressing pretreatment: performing hot isostatic pressing treatment on the composite positive electrode powder, and then controlling the cooling rate to cool to room temperature to obtain a densified composite positive electrode blank; (3) adding a conductive agent and a binder into the densified composite positive electrode blank, and mixing; the composite positive electrode material is obtained; the binder is formed by compounding nano-scale polytetrafluoroethylene and micron-scale polytetrafluoroethylene according to a mass ratio of 1: 2-1: 4.

The invention discloses a composite positive electrode lithium supplement agent and a preparation method thereof, a positive plate and a lithium ion battery, and belongs to the technical field of lithium ion batteries. The composite positive electrode lithium supplement agent is of a core-shell structure, an internal core body is one of Li2NiO2, Li5FeO4 and Li6CoO4, and an external shell layer is C-coated Li7 / 4Ti5 / 4O3. The preparation method comprises the following steps: co-doping, ball-milling and mixing an internal core material with a lithium source, a titanium source and a carbon source, and calcining in an inert atmosphere to obtain the composite positive electrode lithium supplement agent. The composite positive electrode lithium supplement agent has multiple technical advantages: both the internal core and the external shell have a lithium supplement effect; the external shell layer can effectively isolate the direct contact between the internal main body material and air and inhibit the generation of residual alkali on the surface; and the electronic conductivity of the internal main body material is improved. When the composite positive electrode lithium supplement agent is used for preparing an electrode plate as a lithium ion battery positive electrode, the gas production rate can be reduced, and the energy density, the cycle life and the safety performance of the battery are improved.

The invention relates to a niobium-based solid electrolyte and a preparation method and application thereof, the niobium-based solid electrolyte has the following chemical general formula: xLia Ab-yNbCl5-(1-y) McBd, 0.1 < = x < = 3, 0 < y < 1, 0 < a < = 3, 0 < b < = 1, 0 < c < = 3 and 0 < d < = 8, and M comprises at least one of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, W, Ce and Eu. The niobium-based solid electrolyte can effectively reduce the influence of inactive components such as electrolyte in a composite positive electrode of a solid-state battery on the energy density of the solid-state electrolyte, effectively improves the energy density and power density of the solid-state lithium battery, has good room-temperature ionic conductivity, and has a good application prospect in the field of lithium batteries.

A composite cathode active material and a cathode and a lithium battery including the composite cathode active material. The composite cathode active material has a core including a plurality of primary particles including a nickel-containing first lithium transition metal oxide having a layered crystal structure; a grain boundary disposed between adjacent primary particles of the plurality of primary particles; and a shell on the core, the shell including a second lithium transition metal oxide having a spinel crystal structure, wherein the grain boundary includes a first composition having a spinel crystal structure.

According to the cobalt-doped molybdenum disulfide lithium-sulfur battery composite positive electrode material, the preparation method and the application, a cobalt-doped stable molybdenum disulfide defect structure composite nitrogen-doped graphene material is prepared by combining a solvothermal method and an annealing technology, and the process is mature; the method is simple, and the composite positive electrode material with high sulfur content is easy to obtain. According to the lithium-sulfur battery composite sulfur positive electrode material disclosed by the invention, the strong chemical adsorption effect and catalytic conversion effect of the cobalt-doped stable molybdenum disulfide defect structure composite nitrogen-doped graphene carrier on polar lithium polysulfide are utilized, so that the diffusion of the lithium polysulfide in an ether electrolyte is inhibited, and the electrochemical reaction kinetics is improved; therefore, the shuttling effect is slowed down, and the lithium-sulfur battery has the characteristics of high capacity and long service life.

The invention relates to a sodium ion battery composite positive electrode, a preparation method and a prepared secondary sodium ion battery. The composite positive electrode of the sodium ion battery sequentially comprises a collector electrode, a layered oxide layer and an MOF layer, when the sodium ion battery composite positive electrode is prepared, the layered oxide layer and the MOF layer are respectively formed by adopting a dry method. The surface of the manganese-based layered oxide layer is directly coated with the MOF layer, so that the stability of the layered oxide in air is improved, the layered oxide is prevented from being corroded by electrolyte, proper sodium ion conductors and electronic conductors are added into the MOF layer, transmission of sodium ions is promoted, meanwhile, gas products and solid by-products of side reaction of the battery are adsorbed, and the service life of the battery is prolonged. And a sodium ion conductor and an electronic conductor in the MOF layer can ensure rapid transmission of sodium ions and electrons, and the activity of the positive electrode is improved, so that higher capacity, more excellent rate capability and longer cycle life of the battery are realized.

The invention provides a sodium ferric sulfate composite positive electrode material and a preparation method and application thereof. The porosity of the sodium ferric sulfate composite positive electrode material is 0.1%-10%, the compaction density is 2.1-3g / cm < 3 >, the specific surface area of the sodium ferric sulfate composite positive electrode material is 5-12m < 2 > / g, and the mass percentage of a sodium-rich impure phase in the sodium ferric sulfate composite positive electrode material is 0.1%-1%. According to the invention, the charge-discharge capacity, the first coulombic efficiency and other performances of the battery can be improved.

The invention particularly relates to a sulfur-loaded carbon microsphere with a hierarchical pore structure as well as a preparation method and application of the sulfur-loaded carbon microsphere. The invention provides a NiX (X = Se, Te) selenium and tellurium porous carbon microsphere sulfur-loaded positive electrode material prepared based on a spray drying technology. According to the material, gamma-cyclodextrin is used as a carbon source, NaCl is used as a template, and three-dimensional porous carbon microspheres with the particle size of 10-20 microns are formed through a spray drying method. Then, the carbonized particles are activated by KOH, and rich micropores are introduced on the basis of an original macroporous structure; and finally, loading sulfur into the porous carbon structure through a melt permeation method to prepare the sulfur composite positive electrode material suitable for the room-temperature sodium-sulfur battery. The three-dimensional porous carbon skeleton of the material can effectively buffer the volume change of sulfur in the sodium ion intercalation / deintercalation process, the electronic conductivity of an electrode is also remarkably improved, and the construction of a room-temperature sodium-sulfur battery positive electrode material with high specific capacity and high stability is facilitated.

The invention provides a composite positive electrode material and a preparation method and application thereof, the composite positive electrode material comprises a matrix and a carbon coating layer on the surface of the matrix, and the matrix comprises a porous LMFP material; the porous LMFP material comprises doped metal elements, and holes of the porous LMFP material comprise a lithium supplement agent. Doping elements in the composite positive electrode material can improve the stability of a crystal structure and reduce high-temperature storage and cyclic gas production, and the lithium supplement agent in the porous LMFP material can prolong the cycle life of the material and can be decomposed to form pores again after first-time charging, so that an electrolyte can enter the interior of material particles, and the service life of the material is prolonged. And the carbon coating layer can improve the conductivity of the material and reduce the polarization impedance of the material, and meanwhile, the processing problems that residual alkali on the surface of the lithium supplementing agent reacts with a glue solution, so that slurry is gelled and the like can be avoided.

The utility model provides a device suitable for preparing lithium sulfide by a continuous double decomposition method. The device mainly comprises a material stirring reaction kettle, a solvent storage tank, continuous solid-liquid separation equipment, continuous solvent evaporation equipment, a first condensing tower and continuous dynamic vacuum calcination equipment, the device disclosed by the utility model can smoothly realize continuous production and preparation of lithium sulfide, and is simple in operation process and free from harmful gas pollution; in the preparation process, a single solvent is used and the solvent is recycled, so that the preparation method has the advantages of energy conservation and low cost, and cross contamination of multiple solvents is avoided; in addition, during continuous production of lithium sulfide, only one-time high-temperature calcination operation is carried out, and a lithium sulfide product with high purity and small particle size is successfully prepared; the composite cathode material can be directly used for preparing a sulfide solid electrolyte and a lithium-sulfur battery. The method has high industrial application value.

The invention provides a preparation method of a composite positive electrode, which comprises the following steps: (a) a positive electrode material, a solid electrolyte, conductive carbon and an alcohol solvent are provided, the positive electrode material comprises a plurality of first particles, and the composition of the positive electrode material is Li [NiaCobMncAld] O2, a + b + c + d = 1, 0.8 lt; a < = 1, 0 < = blt; 1, 0 < = clt; 1, 0 < = dlt; the composition of the solid electrolyte is Li3InClxFy, x + y is less than or equal to 6, x is more than or equal to 0 and less than or equal to 6, and y is more than or equal to 0 and less than or equal to 3; (b) mixing the positive electrode material, a solid electrolyte, conductive carbon and an alcohol solvent to form a first slurry; (c) mixing the first slurry and a binder to form a second slurry; and (d) heat treating the second slurry, removing the alcohol solvent, and forming a composite positive electrode, the composite positive electrode comprising a plurality of second particles, each of the plurality of second particles comprising one of the plurality of first particles and a solid electrolyte, and the solid electrolyte coating the first particles.

The invention discloses a layered structure solid oxide fuel cell composite cathode catalyst as well as a preparation method and application thereof, and belongs to the field of solid oxide fuel cells. The invention aims to solve the problem that the electro-catalytic performance and low-oxygen reduction reaction activation energy of the existing medium-temperature solid oxide fuel cell are poor. The Sr2. 9Ca0. 1Fe2O7-CuO composite cathode catalyst is prepared by adopting a sol-gel method and a solid phase method, the components in a sol-gel system are in a nanometer range, the reaction is easier to carry out, the reaction temperature is low, the prepared materials are uniformly mixed, and the sol-gel method is carried out in a solution, so that even if the content of doped elements is very low, the doping can be easily realized; the material is prepared by adopting a solid phase method, and the method has the advantages of convenience in operation, simple synthesis process, uniform particle size, no agglomeration of powder particles, good filling property, low cost, high yield and the like, so that the electrochemical performance of the cathode catalyst is improved, and the method is convenient to operate and suitable for industrial production.

The invention discloses a composite positive electrode material for realizing sodium ion internal compensation based on electrochemical potential difference as well as a preparation method and application thereof, relates to a sodium ion battery composite positive electrode material as well as a preparation method and application thereof, and aims at solving the problems of polarization increase, capacity reduction and poor rate capability of the existing sodium ion battery positive electrode material at the discharge end and in a low-temperature environment. The composite positive electrode material is formed by compounding a main phase material A and an auxiliary phase material B with the electrochemical potential higher than that of the main phase material A in a physical mode; at the final stage of discharge or at low temperature and high rate, the auxiliary phase spontaneously releases sodium ions to the main phase based on the electrochemical potential difference of the two phases without the action of an external electric field, and the available capacity of the main phase is improved through internal compensation. The specific discharge capacity of the sodium vanadium fluorophosphate and sodium vanadium phosphate composite material is 119.2 mAh g <-1 >, the specific discharge capacities of the sodium vanadium fluorophosphate and sodium vanadium phosphate composite material are 76.4 mAh g <-1 > and 107.4 mAh g <-1 > at the multiplying power of 30 C and the multiplying power of-20 DEG C and the multiplying power of 0.1 C, and the sodium vanadium fluorophosphate and sodium vanadium phosphate composite material can be applied to the field of sodium ion batteries.

The invention relates to the technical field of solid-state batteries, and discloses a positive electrode material which comprises a positive electrode active material, a first coating layer, a second coating layer and an additive. A positive electrode active material including a ternary oxide; the first coating layer comprises lithium phosphate and is coated on the positive electrode active material; the second coating layer comprises lithium phosphorus sulfur chlorine and is coated on the first coating layer to form a composite positive electrode material; the additive comprises lithium difluorophosphate and lithium bis (fluorosulfonyl) imide which are dissolved in an acetonitrile solution; wherein the additive is uniformly dispersed on the surface of the composite positive electrode material through a spray drying method. Therefore, the side reaction of the positive electrode and the solid electrolyte interface can be effectively inhibited, and the interface impedance is reduced. And meanwhile, the stability of circulation and the structure can be improved. The invention also discloses a preparation method of the positive electrode material, a positive plate and a solid-state battery.

The present application relates to field of cathode material, and a cathode material and a method for preparing the same, a lithium ion battery provided, where the cathode material includes an active material having a chemical formula Lia(NixCoyRz)1-bMbO2, where 0.9≤a≤1.10, x+y+z=1, 0.8≤x≤0.99, 0≤y≤0.15, 0≤z≤0.1, 0≤b≤0.1; R includes Al and / or Mn, M includes a metal element; and a coating layer on surface of the active material, where the coating layer includes a phosphate compound; the cathode material has a particle hardness of Cs≥50 Mpa and satisfies the following: Cs10 / Cs50≥0.7; where Cs10 is hardness of particles with a particle size D10, and Cs50 is hardness of particles with a particle size D50. The cathode material and method for preparing the same, lithium ion battery provided, which improve coating uniformity, precisely control coating amount, improve rate and cycling performance of lithium ion battery, and reduce production costs.

The invention relates to the technical field of electrochemical wastewater treatment, and discloses a method for treating industrial wastewater through electrochemical enhanced hydrolytic acidification. Pollutant degradation is achieved by constructing a reaction system containing a heterojunction anode, a composite cathode and a charcoal particle electrode, the heterojunction anode forms a gradient conductive structure through a titanium matrix composite metal oxide and a conductive polymer, and the bioelectrochemical activity is enhanced by fixing a symbiotic flora of sulfur reducing bacteria and electroactive bacteria; modifying the composite cathode based on the activated carbon felt; the biochar particle electrode is subjected to iron doping modification to form a porous interface. The method utilizes electrochemical redox to destroy sulfur bonds and cyclic structures of biotin, couples microbial metabolism to realize deep mineralization, has efficient electron migration and biological membrane stability, significantly improves the conversion efficiency of organic matters, reduces sludge byproducts, and is suitable for efficient treatment of biotin-containing wastewater in the fields of medicine and chemical industry.

The invention discloses a hydrogenated butadiene-acrylonitrile rubber (HNBA)-polyacrylic acid (PAA) composite positive electrode binder for a secondary battery as well as a preparation method and application of the hydrogenated butadiene-acrylonitrile rubber-polyacrylic acid composite positive electrode binder. The composite positive electrode binder comprises the following raw materials: HNBA and PAA in a mass ratio of (1-10): (1-10); the content of residual hydrogen bonds in the HNBR is 1-10%, and the content of ACN is 10-40%; the molecular weight of the PAA is 3 * 10 < 5 >-1 * 10 < 6 >. The adhesive is compounded through a solution blending method, and based on the synergistic effect between HNBR and PAA, the viscosity of the material is greatly improved on the premise that it is guaranteed that the adhesive has excellent corrosion resistance. When the binder is used for preparing the positive pole piece of the secondary battery, not only can the bonding strength and the mechanical property among the components of the positive pole be effectively improved, but also the interfacial compatibility of the material can be effectively improved, the ion transmission efficiency can be improved, and the comprehensive performance of the battery can be effectively improved.

A lithium iron phosphate / carbon / lithium-rich lithium iron oxide composite cathode material and a preparation method and an application thereof are provided. The preparation method includes the following steps: mixing iron salt, lithium compound, orthophosphate and an organic salt with water, to obtain a mixed slurry; performing a spray granulation on the mixed slurry, to obtain a precursor powder; and performing a heat preservation on the precursor powder in a protective atmosphere, to obtain a lithium iron phosphate / carbon / lithium-rich lithium iron oxide composite cathode material. The preparation method is based on the characteristics that electric double layer physical energy storage of porous carbon can enhance the rate, and lithium-rich lithium iron oxide additive can increase the system lithium source and prolong the service life, combined with the synthesis process of lithium iron phosphate and lithium-rich lithium iron oxide, a lithium iron phosphate / carbon / lithium-rich lithium iron oxide composite cathode material is synthesized by one-step method.

The invention discloses a molybdenum-modified nickel-manganese-iron-based ternary composite positive electrode material and a preparation method and application thereof, the positive electrode material comprises a molybdenum-doped nickel-manganese-iron-based oxide and a coating layer coating the surface of the nickel-manganese-iron-based oxide, and the molecular formula of the positive electrode material is NaNi < x > Mn < y > Fe < z > Mo O < 2 > (at) (Na2MoO < 4 >) b. The preparation method comprises the following steps: mixing a precursor containing nickel, manganese and iron, a modifier containing molybdenum and a sodium source to obtain a raw material mixture, adding an organic solvent, then carrying out wet ball milling to obtain raw material powder, and sintering the raw material powder in an air atmosphere at 800-880 DEG C; according to the positive electrode material provided by the invention, the molybdenum element is subjected to bulk phase doping to replace part of iron sites, so that a crystal structure can be effectively stabilized, primary grain refinement is promoted, stress accumulation is relieved, and the structural stability is improved; the coating layer Na2MoO4 can effectively inhibit the interface side reaction between the electrode and the electrolyte, relieve the surface and interface phase change and transition metal dissolution, and improve the surface and interface stability; when being used as a positive electrode material, the material has excellent electrochemical performance.