467 results about "Lithium ion conduction" patented technology

A Li ion conducting sheet of sulfide glass has a vitreous sheet of Li ion conducting sulfide glass having a first major surface and composite material interlayer on the first major surface of the vitreous sheet. The Li ion conducting sheet may be for use as an interlayer in a battery cell, the composite material layer having a first material component that is an electronically conductive non-metal, typically a carbonaceous material, such as carbon black, and a second material component that is a metal or semi-metal. In a particular embodiment, the second material component may be a transition metal, such as a precious metal, for example silver. The composite material interlayer may be a silver carbon composite.

A lithium ion-conductive solid electrolyte including a freestanding inorganic vitreous sheet of sulfide-based lithium ion conducting glass is capable of high performance in a lithium metal battery by providing a high degree of lithium ion conductivity while being highly resistant to the initiation and / or propagation of lithium dendrites. Such an electrolyte is also itself manufacturable, and readily adaptable for battery cell and cell component manufacture, in a cost-effective, scalable manner.

The invention discloses a double-layer coated lithium supplement agent as well as a preparation method and application thereof. The double-layer coated lithium supplement agent comprises a lithium supplement agent inner core and a first layer coated on the surface of the lithium supplement agent inner core, and the surface of the first layer is coated with a second layer; the first layer comprises a polymer and a lithium salt, the polymer has a polar group, the second layer comprises a hydrophobic material, a hydrogen bond and / or a coordinate bond is formed between the lithium salt and the polymer, and a coordinate bond is formed between the lithium salt and the hydrophobic material. According to the lithium supplement agent disclosed by the invention, through double-layer coating, the first layer has a lithium ion conduction enhancement function and the second layer has a hydrophobic protection function, and the two layers have a synergistic effect, so that the lithium ion conduction efficiency of the lithium supplement agent is improved, the air stability of the lithium supplement agent is improved, and the service life of the lithium supplement agent is prolonged. And good compatibility between the electrolyte and the first layer is also ensured, so that the problems that the safety of the battery is reduced and the cycle life of the battery is shortened due to side reaction are avoided.

The invention belongs to the technical field of solid-state electrolytes, and particularly discloses a modified PEO-based composite solid-state electrolyte, a preparation method thereof and a solid-state battery. The modified PEO-based composite solid electrolyte comprises the following components: lithium-doped indium gallium phosphate, PEO and a lithium-based electrolyte, wherein the chemical formula of the lithium-doped indium gallium phosphate is InxGa (1-x) PO4: Li, and x is more than or equal to 0.3 and less than or equal to 0.8. The indium gallium phosphate has an amorphous structure and shows excellent lithium ion transmission performance and conductivity; after lithium ions are further embedded into the indium gallium phosphate with the amorphous structure, the lithium ion conductivity of the indium gallium phosphate can be further improved, and more active sites are provided for transmission of the lithium ions; the lithium-doped indium gallium phosphate is added into the PEO-based solid electrolyte as an inorganic filler, so that the mechanical strength, the ion transmission capability and the conductivity of the PEO-based solid electrolyte can be effectively improved.

Preparation of anhydrous lithium sulfide (Li2S) purified suitably for applications in advanced batteries, and, in particular, for synthesis of solid electrolytes based on Li2S, including sulfide solid electrolytes of the type that may be described as crystalline (e.g., polycrystalline), amorphous (e.g., glass) and combinations thereof, such as sulfide glass-ceramic solid electrolyte materials.

A glassy electroactive prepreg made by generating submicron particles of lithium-ion conducting sulfide glass by providing lithium-ion conducting sulfide glass feedstock material, and subjecting the feedstock material to subzero processing to transform the material into submicron particles can avoid plastic deformation of sulfide glass particles during grinding and produce submicron powders. The prepreg is formed by providing a porous electroactive layer comprising electroactive material, and infiltrating the porous electroactive layer with the submicron particles of lithium-ion conducting sulfide glass. The subzero processing can include cryogenic processing. The prepreg can be used to form glassy embedded electrodes.

The invention relates to the technical field of batteries, in particular to a negative plate and a lithium ion secondary battery. The negative plate comprises a negative current collector and a negative active material layer positioned on at least one side surface of the negative current collector; the negative electrode active material layer comprises a first coating close to the negative electrode current collector and a second coating deviating from the negative electrode current collector; the thickness of the negative plate is 30-1000 [mu] m; the first coating comprises a first negative electrode active substance, the second coating comprises a second negative electrode active substance, and the second negative electrode active substance comprises a second graphite material and hard carbon; the ratio of the average particle size of the second negative electrode active material to the average particle size of the first negative electrode active material is L, 1lt; l < = 2.5; the outer surface of the negative electrode active material layer has a recess. The negative plate disclosed by the invention has excellent lithium ion conduction capability and capacity exertion, and the lithium ion secondary battery comprising the negative plate disclosed by the invention has relatively high energy density and rapid charging capability.

The invention provides a positive active material and a preparation method thereof, a positive plate and a battery. The positive electrode active material satisfies the following condition: # imgabs0 #, wherein I (111), I (222), I (400) and I (440) are all not 0. According to the positive electrode active material provided by the invention, the exposure degrees of the crystal face (222) and the crystal face (111) relative to the crystal face (110) and the crystal face (100) are limited by the formula 1, so that the lithium ion conduction rate and the dynamic performance of lithium nickel manganese oxide can be improved, and the rate capability and the discharge capacity of a corresponding battery can be remarkably improved.

The invention provides a positive active material and a preparation method thereof, a positive plate and a battery. The positive electrode active material satisfies the following conditions: I1 + I2 + I3 < = 10.20; wherein I1 is I (111) / I (311) in an XRD (X-Ray Diffraction) pattern of the positive electrode active material, I2 is I (111) / I (400) in the XRD pattern of the positive electrode active material, I3 is I (111) / I (440) in the XRD pattern of the positive electrode active material, and I1, I2 and I3 are all not 0. According to the positive electrode active material provided by the invention, the exposure degrees of the (110) surface, the (100) surface and the (311) surface are limited by the formula 1, so that the lithium ion conduction rate can be improved, the manganese dissolution phenomenon can be reduced, and the rate capability and the cycling stability of a corresponding battery can be remarkably improved.

The invention provides a solid electrolyte film and a preparation method thereof, a diaphragm-free solid-state battery, a solid-state battery and a mechanical device. The method comprises the following steps: (1) mixing and modifying a lithium salt, an ionic liquid and a cross-linking agent to obtain a modified active component; (2) mixing the modified active component, a polymer monomer and an initiator to obtain a precursor solution, wherein the polymer monomer comprises at least one of a boron-containing monomer, a sulfate monomer, a carbonate monomer, an amide monomer, an ether monomer and a fluorine-containing monomer; and (3) applying the precursor solution to a base material for polymerization to obtain the solid electrolyte film. Therefore, the solid-state electrolyte film has high lithium ion conductivity and excellent mechanical strength and stability, a solid-state battery prepared from the solid-state electrolyte film has high ionic conductivity, a diaphragm can be replaced, a diaphragm-free battery can be prepared, the cycle life of the battery is prolonged, and the safety of the battery is improved.

The invention relates to the technical field of lithium ion batteries, and discloses a negative electrode material and a preparation method and application thereof.The negative electrode material is of a core-shell structure, an inner core is silicon-based particles, and a shell comprises a first coating layer and a second coating layer; the first coating layer is attached to the outside of the inner core, and the second coating layer is attached to the outside of the first coating layer; the first coating layer comprises a carbon nitrogen compound, and the second coating layer comprises phosphate. The negative electrode material provided by the invention takes the silicon-based particles as the inner core, the carbon-nitrogen coating layer and the phosphate coating layer are sequentially attached outside the inner core, and under the action of the double coating layers, the lithium ion conductivity and the electrochemical performance of the negative electrode material are effectively improved.

The invention belongs to the technical field of battery material preparation, and particularly relates to a coated negative electrode material as well as a preparation method and application thereof. The coated negative electrode material comprises a porous carbon skeleton and a carbon coating layer coating the porous carbon skeleton, the porous carbon skeleton is provided with a plurality of holes; a silicon layer and a functional layer are attached to the surfaces of part of the holes; the silicon layer comprises silicon, the functional layer comprises a functional material, and the functional material comprises lithium aluminum fluoride. The coated negative electrode material provided by the invention has the properties of low expansion, high lithium ion conduction, few byproducts and the like, and is suitable for a solid battery; the battery energy density is ensured, and the problems that an effective lithium ion path cannot be formed due to contact failure of an active substance caused by high volume expansion of a silicon-based material in the circulation process and contact failure of the active material and a solid electrolyte in a solid-state battery, and performance degradation is caused by negative electrode side polarization increase in the circulation process are solved.

The present exemplary embodiments relate to a lithium metal electrode, a method of manufacturing the same, and a lithium secondary battery including the same. According to an exemplary embodiment, a lithium metal electrode including: a current collector and a metal layer which is disposed on at least one surface of the current collector and includes a lithium component, in which a protective layer including amorphous carbon and lithium-ion conduction promoting ceramic particles is formed on a surface of the metal layer, may be provided.

The invention relates to the technical field of batteries, in particular to a porous composite diaphragm, a preparation method thereof and a secondary battery. The porous composite diaphragm comprises a base membrane, a first coating and a second coating, the first coating and the second coating are oppositely arranged on the two surfaces of the base film; the first coating layer and the second coating layer comprise a copolymer containing a first monomer unit and a second monomer unit; the first monomer unit contains a cyano group on a side chain, and the second monomer unit contains a carbonyl group on a side chain; in the copolymer, the molar ratio of the second monomer unit is 1-20%; the first coating and the second coating comprise skeleton structures and first-class pore structures formed between the skeleton structures, and second-class pore structures are formed on bodies of the skeleton structures; and the average pore diameter of the first-type pore structure is greater than that of the second-type pore structure. According to the porous composite diaphragm, the lithium ion conductivity can be improved while the bonding performance with a pole piece is improved.

The invention provides a composite negative electrode, a preparation method thereof and an all-solid-state lithium battery, and belongs to the technical field of all-solid-state lithium ion batteries. The composite negative electrode provided by the invention comprises a negative electrode material and a nano silicon coating arranged on the surface of the negative electrode material, and the negative electrode material is one or more of Al, Sn, Ge, In, Mg and Ag. The negative electrode material in the composite negative electrode provided by the invention can avoid serious side reaction between the negative electrode and a sulfide solid electrolyte interface, reduce the risk of lithium dendrites at the interface, and ensure the electrochemical performance of the all-solid-state lithium battery; the nano-silicon coating forms a Li-Si alloy layer after the first lithiation, and has high lithium ion conduction characteristic and lower Young modulus, so that good interface contact is formed between the composite negative electrode and a solid electrolyte, a high-diffusivity transmission channel and stable dynamic guarantee are provided for the reversible lithiation / lithium removal process of the composite negative electrode, and the composite negative electrode can be applied to the lithium ion battery. And the electrochemical performance of the all-solid-state lithium battery is further improved.

The invention relates to a novel electrolytic copper foil and a preparation method thereof, a negative pole piece and a secondary battery. The novel electrolytic copper foil comprises at least one copper layer, at least part of the surface of the copper layer is provided with a through hole array, the through hole array is formed by arranging M * N through holes in M rows and N columns, the through holes in each row in the through hole array are arranged in the x direction, the through holes in each column in the through hole array are arranged in the y direction, the x direction and the y direction intersect and are located on the same plane, and the x direction and the y direction are perpendicular to each other. The surface area, covered by the through hole array, of the copper layer is an array area, the surface area, not covered by the through hole array, of the copper layer is a non-array area, and the weight of the array area per square meter meets a certain relational expression. The electrolytic copper foil can effectively solve the problem of lithium ion conduction of the traditional copper foil in a solid-state battery, and can effectively improve the performance of the battery, especially the solid-state battery as a battery cathode current collector.

This lithium recovery device 10C is provided with a processing tank 1 that is partitioned into a supply tank 11 and a recovery tank 13 by a lithium ion-conducting electrolyte membrane 2. In order to selectively move Li+ to an aqueous solution RS in the recovery tank 13 from an aqueous solution SW in the supply tank 11, the aqueous solution SW containing Li+ and other metal ions Mn+, this lithium recovery device 10C is also provided with: a first power supply 51 which is connected between a first electrode 31 that has a porous structure and is arranged so as to be in contact with a supply tank 11-side surface of the electrolyte membrane 2 and a second electrode 32A that is arranged within the recovery tank 13, in such a manner that the first electrode 31 functions as the positive electrode; and a sub power supply 53 which is connected in series to the positive electrode of the first power supply 51, while having the positive electrode thereof connected to a sub electrode 41 that is arranged within the supply tank 11 at a distance from the electrolyte membrane 2.

A separator of a lithium-ion battery cell includes a porous separator film, an inner layer disposed against the separator film and including ceramic filler, and an outer layer disposed against the inner layer and including ferroelectric material configured to facilitate lithium-ionic conductivity between the separator and an electrode.

Dielectric thin film for a solid-state or semi-solid-state lithium battery, wherein the lithium battery comprises a negative electrode and a positive electrode; the dielectric thin film is connected between the negative electrode and the positive electrode; the negative electrode comprises a negative electrode slurry, which is used as a binder, and a plurality of negative electrode particles dispersed in the negative electrode slurry; the positive electrode comprises a positive electrode slurry, which is used as a binder, and a plurality of positive electrode particles dispersed in the positive electrode slurry; the dielectric thin film comprises: a first, a second and a third film layer; wherein the first film layer is connected to the positive electrode and the third film layer to the negative electrode; wherein the second film layer is connected between the first film layer and the third film layer; the first film layer comprises the following: a first polymer material which is used as the base material of the first film layer; wherein the first polymer material is a mixture of PVDF-HFP (polyvinylidene fluoride hexafluoropropylene copolymer), ADN (adiponitrile), GLN (glutaronitrile) and SN (succinonitrile); wherein each of the ADN, GLN and SN is used as a plasticizer in the first polymer material and is dispersed in the PVDF-HFP to disperse a structure of the first polymer material itself; a first lithium salt dispersed in the first polymer material; wherein the first lithium salt is a mixture of LiBOB (LiB(C2O4)2, lithium bis(oxalate)borate), LiTFSI (LiN(CF3SO2)2, lithium bis(trifluoromethanesulfonyl)imide) and LiFSI (F2LiNO4S2, lithium bis(fluorosulfonyl)imide); where ADN, GLN and SN in the first polymer material serve to reduce crystal precipitation of the first polymer material and to support dissociation of the first lithium salt in the first film layer, which increases lithium ion conductivity and malleability of the first film layer; the second film layer comprises the following: a second polymer material used as the base material of the second film layer; wherein the second polymer material is a mixture of PVDF-HFP, PAN (polyacrylonitrile) and SN; wherein PAN and SN are each used as plasticizers in the second polymer material and are dispersed in the PVDF-HFP; a second lithium salt dispersed in the second polymer material; wherein the second lithium salt is a mixture of LiFSI and LiTFSI; wherein PAN and SN in the second polymer material serve to reduce crystal precipitation of the second polymer material and to promote dissociation of the second lithium salt in order to increase lithium ion conductivity of the second film layer; a second inorganic ceramic structure consisting of a plurality of first LLZO particles dispersed in the second polymer material; an outer surface of each of the first LLZO particles is coated with a first dopamine layer (DA, 3,4-dihydroxyphenethylamine); each of the first LLZO particles consists of LLZO (lithium lanthanum zirconium oxide, Li7La3Zr2O) 12 ) or from LLZO doped with at least one metal; and the third film layer comprises the following: a third polymer material, which is used as the base material of the third film layer; the third polymer material is a mixture of PEO (poly(ethylene oxide), polyethylene oxide) and PAN; the PAN in the third polymer material is used as a plasticizer and is dispersed in the PEO; a third lithium salt formed from LiTFSI and dispersed in the third polymer material; a third inorganic ceramic structure formed from a plurality of second LLZO particles dispersed in the third polymer material; an outer surface of each of the second LLZO particles is coated with a second dopamine layer; each of the second LLZO particles is formed from LLZO or doped with at least one metal; and the third inorganic ceramic structure serves to increase the lithium ion conductivity of the negative electrode.

The invention provides a preparation method and application of a high-nickel ternary positive electrode material flexibly coated with a polymer, and aims to improve the cycling stability and interface compatibility of a battery. According to the technology, a liquid phase method is adopted for preparation, and a uniform and stable coating layer is formed on the surface of the high-nickel positive electrode material, so that the interface characteristic between the positive electrode and sulfide solid electrolyte is effectively improved. The coating layer is formed by compounding a polymer and a lithium salt, and has both electronic insulativity and excellent ionic conductivity. On one hand, the coating layer can prevent electron leakage, inhibit side reaction of a positive electrode-electrolyte interface and improve the interface stability; and on the other hand, the excellent lithium ion conductivity can reduce the interface impedance, accelerate the diffusion of lithium ions, improve the rate capability of the battery and prolong the long-term cycle life of the battery. Besides, by optimizing the components and the thickness of the coating layer and the interface structure of the coating layer and the electrode material, the performance of the battery is improved, and meanwhile, good process feasibility and cost effectiveness are ensured.

The present application provides modified polyvinylidene fluoride and a preparation method therefor, an active material composition, a positive electrode sheet, and an energy storage device. The modified polyvinylidene fluoride provided by the present application is a copolymer of vinylidene fluoride and 4-vinyl-4'-substituent-bis-benzenesulfonimide lithium, and the mass fraction of the 4-vinyl-4'-substituent-bis-benzenesulfonimide lithium in the modified vinylidene fluoride ranges from 2% to 10%. The modified vinylidene fluoride not only has good binding power, but also has relatively strong lithium ion conduction capability, thereby improving the rate performance of the energy storage device.

The invention relates to an all-solid-state battery cell with a three-dimensional staggered lithium ion conduction network as well as a preparation method and application of the all-solid-state battery cell. The method comprises the following steps: uniformly and electrostatically spraying positive electrode powder A, B and C with different particle sizes and compositions into a grinding tool in sequence; spraying a layer of sulfide electrolyte on the composite positive electrode layer; then uniformly and electrostatically spraying composite negative electrode powder D and E which are uniformly mixed and have different particle sizes and compositions on the surface of an electrolyte layer in sequence; and finally, integrally pressing the powder by adopting warm isostatic pressing to prepare an all-solid-state battery cell, and assembling the all-solid-state battery cell into a solid-state battery. The invention provides a brand new battery structure design, a three-dimensional staggered lithium ion conduction network is constructed by introducing a low-viscosity thermoplastic and an electrostatic dry spraying technology, the lithium ion migration efficiency is remarkably improved, and meanwhile, the interface stability between an electrode and a solid electrolyte is enhanced; therefore, the interface impedance of the sulfide solid-state battery is reduced so as to realize better capacity retention ratio, longer cycle life and better safety performance.

Lithium manganese iron phosphate composite positive electrode particles with high strength conductive carbon are provided. [Solution] A composite positive electrode particle 200 includes an LMFP particle 121 and a conductive layer 122 that covers the outer surface of the LMFP particle. The conductive layer includes a plurality of carbon aggregates 123 and a plurality of lithium ion conductor particles 10. The plurality of carbon aggregates are formed by dehydrating carbohydrates, water-soluble fibers, or amino acid polymers. The plurality of lithium ion conductor particles are distributed inside the conductive layer, adjacent to the outside of the conductive layer, or adjacent to the outer surface of the LMFP particle. The lithium ion conductor particles are oxides or carbonates having lithium ion conducting ability, or oxides having a garnet or perovskite structure. The conductive layer further includes a plurality of conductive carbons 124.

A secondary battery includes a positive electrode, a negative electrode, an electrolyte layer, and a shut layer. The electrolyte layer is made of an electrolyte material having lithium ion conductivity. The shut layer contains a lithium ion conductive solid material having lithium ion conductivity. The electrolyte layer is interposed between the negative electrode and the shut layer. The shut layer is made of only a lithium ion conductive solid material or a mixture of the lithium ion conductive solid material. The lithium ion conductive solid material is at least one of a pyrochlore solid electrolyte, a NASICON solid electrolyte, and a perovskite solid electrolyte. The lithium ion conductive solid material has a larger decrease in lithium ion conductivity when in contact with lithium metal than the electrolyte material.

The present invention belongs to the field of battery technology. The present invention provides a lithium supplement material, a lithium supplement diaphragm and a preparation method thereof. The lithium supplement material uses a lithium supplement agent as a core and a ternary or quaternary active material (such as NCM and NCA, etc.) as a coating layer, so that the coating layer can conduct electricity and ions, which not only enhances the conductivity of the lithium supplement material, but also provides active Li ions and has a sufficient amount of lithium supplement, so that an excellent and stable lithium supplement effect can be achieved. When the obtained lithium supplement material is applied to a diaphragm to form a coating diaphragm, the risk of increasing short circuits by introducing inactive conductive carbon substances can be avoided, and the basic functions of the diaphragm can be ensured to function normally, and the effects of lithium supplementation and lithium ion conduction can effectively improve the performance of the battery.

The present invention provides a positive electrode composite active substance and a lithium ion secondary battery in which a coating layer covers a surface of an oxide active substance, and a resistance loss due to the coating layer can be suppressed while generation of gas due to decomposition of a nonaqueous electrolyte solution is suppressed as compared with a conventional case. A positive electrode composite active substance constituting a part of a positive electrode of a lithium ion secondary battery using a nonaqueous electrolyte solution as an electrolyte, the positive electrode composite active substance including: an oxide active substance; and a coating layer covering a surface of the oxide active substance, in which the coating layer has lithium ion conductivity, and a grain boundary resistance of the coating layer is 3 times or more and 20 times or less larger than a charge transfer resistance of the oxide active substance.

The invention discloses a Sn-doped high-voltage lithium nickel manganese oxide positive electrode material as well as a preparation method and application thereof, and belongs to a lithium ion battery positive electrode material. The preparation method comprises the following steps: 1) dissolving a lithium source, a nickel source, a manganese source and a tin source which are acetate in water, then adding a complexing agent citric acid, and stirring for reaction; 2) drying and spraying the obtained mixed solution to obtain solid powder; and 3) pre-sintering, grinding, re-sintering and grinding the obtained solid powder to obtain the Sn-doped high-voltage lithium nickel manganese oxide positive electrode material. The obtained high-voltage lithium nickel manganese oxide positive electrode material is high in purity, has excellent uniform granularity and a good truncated octahedral crystal structure, has excellent lithium ion conduction and electron conduction performance and shows high specific capacity and cycling stability, and the structural stability is effectively improved by Sn doping; and the preparation process is simple to operate, few in procedures, high in production efficiency, cheap and easily available in raw materials and beneficial to industrial production.

The invention relates to a lithium ion conductive dense membrane and a preparation method and application thereof. The lithium ion conductive dense membrane comprises a polymer base membrane, ion conductive inorganic particles and a polymer solid electrolyte, the polymer base membrane is of a net structure; the Gurley value of the lithium ion conductive dense film is larger than or equal to 1000, and the porosity is smaller than or equal to 5%. The lithium ion conductive dense membrane provided by the invention has the advantages of high lithium ion conductivity, high transport efficiency and high lithium ion selectivity, and can be applied to electrodialysis lithium extraction. And under the action of external voltage, lithium ions are directionally migrated to the air negative electrode subjected to oxygen reduction reaction through the lithium ion conductive dense membrane to form a lithium hydroxide solution, and other metal hetero-ions are isolated on the positive electrode side by the lithium ion conductive dense membrane, so that lithium enrichment is realized. And meanwhile, transportation of the membrane to lithium ions does not depend on pores in the conductive membrane, so that the service life can be prolonged while the lithium ion separability and the transportation efficiency of the salt lake lithium extraction method are improved.

The invention relates to the technical field of batteries, in particular to a high-temperature-resistant lithium cobalt oxide positive electrode material and a preparation method and application thereof.The high-temperature-resistant lithium cobalt oxide positive electrode material comprises a lithium cobalt oxide matrix and a coating layer coating the surface of the lithium cobalt oxide matrix, the lithium cobalt oxide matrix is doped with Mg, Ti and La, and the coating layer is a fast ion coating layer of a Li-Gd-Ti-O4 spinel phase. Bulk phase doping is carried out through a high-temperature solid-phase method, Mg, Ti and La are doped in a lithium cobalt oxide matrix, and the lattice structure thermal stability of lithium cobalt oxide under high voltage (4.4 V) is improved; a fast ion coating layer of a Li-Gd-Ti-O4 spinel phase is formed on the surface of a lithium cobalt oxide matrix by adopting a solid phase method, and the comprehensive performance of the lithium cobalt oxide positive electrode material is improved through multiple mechanisms such as the lattice stabilization effect of rare earth ions, the interface barrier effect of composite oxide and lithium ion conductivity regulation and control; particularly, the capacity, the cycling stability, the thermal stability, the high-voltage tolerance and the like are realized.

The invention provides a secondary particle lithium manganese iron phosphate positive electrode material, a preparation method thereof and a battery, and particularly relates to the secondary particle lithium manganese iron phosphate positive electrode material, the preparation method thereof and the battery. Comprising the following steps: mixing a lithium source, an iron source, a manganese source, a phosphorus source and a dispersing agent to obtain first mixed slurry, mixing the first mixed slurry with a conductive material and a fast ion conductor, adding water, grinding, and performing spray drying to obtain a spherical precursor; the lithium manganese iron phosphate positive electrode material disclosed by the invention is spherical secondary particles, and the added lamellar or tube-rod-shaped conductive material can establish a conductive network in the spherical particles, so that the secondary particle lithium manganese iron phosphate positive electrode material is obtained. And the filled fast ion conductor material can effectively establish a lithium ion transmission channel, so that the electron and lithium ion conduction rate of secondary particles is integrally improved, and the electrochemical performance of lithium manganese iron phosphate is fully exerted.