Preparation method of iron manganese phosphate

Abstract

The invention discloses a preparation method of iron manganese phosphate. The preparation method comprises the steps of preparing a base solution, and adding a ferromanganese mixed solution and an ammonium hydrogen carbonate solution to the base solution in a stirring condition, and after adding is completed, continuously performing a stirring reaction to obtain carbonate paste; performing solid liquid separation on the carbonate paste, washing the filtering residue by hot pure water, and then adding the product into the pure water to be subjected to slurrying, and next, adding a phosphoric acid solution and hydrogen peroxide into the slurry material at the unfirm speed synchronously, and next, performing heating to obtain iron manganese phosphate paste; performing solid liquid separationon the iron manganese phosphate paste, washing the filtering residue by hot pure water, and then performing vacuum drying, screening and iron removing to obtain iron manganese phosphate; and adding iron manganese phosphate into a mixed solution of anhydrous alcohol and butyl titanate, performing grinding, and next carrying out spray drying on the paste to obtain titanium-coated iron manganese phosphate. The titanium-coated iron manganese phosphate material obtained in the invention has small grain diameter, high tap density, small specific surface, and uniform grain diameter distribution, without causing a ferromanganese segregation phenomenon.

Description

technical field [0001] The invention relates to a preparation method of ferromanganese phosphate, which belongs to the field of lithium battery new energy materials. Background technique [0002] LiMnPO4 (LMP) has the advantages of cheap raw materials, relatively stable structure, high theoretical specific capacity and high discharge voltage platform, and is one of the positive electrode materials for lithium-ion power batteries with great development prospects. However, LMP materials have defects such as low electronic conductivity and ionic conductivity, which limit their large-scale application. Doping Fe in LMP can improve the kinetic performance of the material during charge and discharge. In recent years, methods such as nano-composite carbon coating have been used to greatly improve the electrochemical performance of iron-doped lithium manganese phosphate (LFMP) materials. The latest report shows that PHOSTCH also has the ability to mass produce LFMP, and LFMP materi...

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Problems solved by technology

[0004] The precursor of lithium manganese iron phosphate is generally ferromanganese phosphate, but the conventional preparation process, such as the coprecipitation reaction of phosphate and ferrous salt, manganese salt and oxidant, has the following problems: due to the low pH of ferric phosphate precipitation, and The pH of manganese phosphate precipitation is higher, and at higher pH, ferrous salt reacts with oxidant to get ferric hydroxide, resulting in high content of ferric hydroxide, low purity and low phosphorus content

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