Abstract: A preparation method includes the following steps: S1, preparing an aqueous solution of a metal salt and an aqueous solution of a precipitant, where the precipitant includes one or more selected from oxalic acid and a water-soluble oxalate; S2, mixing the aqueous solution of the precipitant and the aqueous solution of the metal salt at a shear speed of 10000 r/min or more for co-precipitation reaction; and S3, after the reaction is completed, obtaining the positive electrode active material precursor via washing and drying.

Abstract: A method for preparing the ammonium manganese iron phosphate precursor includes mixing and grinding metal source powder and phosphorus source powder to enable a low-heating-temperature solid-state reaction of each component, and then washing and drying the obtained product to obtain the ammonium manganese iron phosphate precursor, where the metal source includes an iron source, a manganese source and an optional source of a doping element M which represents doping elements at manganese and iron sites, and the phosphorus source includes triammonium phosphate.

Abstract: A composite positive electrode active material, a method for preparing the same, and an electric device are described. The method includes: providing positive electrode active material particles; providing a solid aluminum salt to make the solid aluminum salt cover a surface of the positive electrode active material particles; and providing a solid base to the positive electrode active material particles covered by the solid aluminum salt to make the solid aluminum salt and the solid base undergo an in situ solid-phase chemical reaction and generate a cladding layer covering the surface of the positive electrode active material particles, to obtain the composite positive electrode active material, wherein the cladding layer has alumina nanoparticles. The prepared alumina can uniformly cover the surface of the positive electrode active material particles, protect the positive electrode active material, and ensure the electrochemical performance of the positive electrode active material.

Abstract: The present application provides a continuous reaction system, a ferromanganese phosphate precursor, a lithium iron manganese phosphate, a preparation method, and a secondary battery. A method for preparing a ferromanganese phosphate precursor provided in the present application is a continuous preparation method, thereby improving the production efficiency, and obtaining the ferromanganese phosphate precursor with small particle size, narrow particle size distribution, high crystallinity, monocrystal phase, regular appearance, high tap density, high batch stability, and high batch consistency.

Abstract: A continuous reaction system for preparing a ferromanganese oxalate precursor may comprise a first dissolution reactor, a second dissolution reactor, a first reactor, a second reactor, a material storage tank, and an ultrasonic reactor; the first dissolution reactor may be configured to accommodate a metal salt solution required for preparing the ferromanganese oxalate precursor, and the second dissolution reactor may be configured to accommodate a precipitant solution required for preparing the ferromanganese oxalate precursor; the first reactor may include a first feed port and a first overflow port, and the first feed port of the first reactor may be interconnected to a first discharge port of the first dissolution reactor and a second discharge port of the second dissolution reactor respectively through two pipelines.

Abstract: A lithium manganese iron phosphate positive electrode active material, preparation method, a positive electrode plate, a secondary battery and an electrical apparatus are disclosed. The method comprises: mixing and grinding an iron source, a solid base and optionally a source of doping element M After grinding, impurities are removed to obtain a nanoscale iron-containing oxide; mixing the obtained nanoscale iron-containing oxide with a solvent, a lithium source, a manganese source, a phosphorus source, optionally a source of doping element N, optionally a source of doping element Q and optionally a source of doping element R in a predetermined ratio and then grinding. After grinding, granulating to obtain a powder; and sintering the powder to obtain the lithium manganese iron phosphate positive electrode active material. A lithium manganese iron phosphate positive electrode active material having both good electrochemical performance and high tap density can be obtained.