Iron manganese vanadium phosphate precursor, iron manganese vanadium lithium phosphate/carbon anode material and preparation method

Abstract

The invention discloses an iron manganese vanadium phosphate precursor, an iron manganese vanadium lithium phosphate / carbon anode material and a preparation method. The preparation method includes following steps: 1), preparing a mixed solution of ferric iron source, manganous source, pentavalent vanadium source and phosphor source, and preparing an ammonia water solution; 2), mixing the mixed solution with the ammonia water solution according to a set proportion for co-precipitation reaction to obtain a precipitation product; 3), subjecting the precipitation product to washing, drying and pre-sintering to obtain an iron manganese vanadium phosphate precursor material, well mixing the iron manganese vanadium phosphate precursor material with a lithium source and a carbon source, drying, and calcining in an inert atmosphere to obtain the iron manganese vanadium lithium phosphate / carbon anode material. The iron manganese vanadium phosphate precursor is prepared firstly, a ferric iron compound is used as an iron source in the process of preparation, control on valence state changing of iron is unique, ferric iron can be ensured to be reduced into ferrous in the subsequent carbothermic reaction step, and then the LiFe1-xMn2x / 3Vx / 3PO4 material high in both purity and electrochemical performance is obtained.

Description

technical field [0001] The invention belongs to the technical field of energy materials, in particular to an iron manganese vanadium phosphate (Fe 1-x mn 2x / 3 V x / 3 PO 4 ) precursor and lithium iron manganese vanadium phosphate / carbon (LiFe 1-x mn 2x / 3 V x / 3 PO 4 / C) preparation method. Background technique [0002] Lithium-ion battery cathode materials directly determine the performance indicators of the final battery product. At present, the commercialized lithium-ion battery cathode materials include lithium cobaltate, lithium manganese oxide, ternary materials, lithium iron phosphate, etc. Compared with other The positive electrode material has the advantages of high stability, safety, reliability, environmental protection and low price, and has become one of the ideal positive electrode materials for power and energy storage lithium-ion batteries recognized in the industry. However, the low energy density of this material hinders its large-scale application in p...

AI Technical Summary

Problems solved by technology

[0003] Although there is also a preparation method for lithium iron manganese vanadium phosphate in the prior art, generally ferrous iron compounds are used as the iron source to directly react to generate lithium iron manganese vanadium phosphate. This preparation method basically directly reacts to generate iron manganese vanadium phosphate Lithium, because the raw material cannot exist stably, so there are many side reactions in the preparation process, and the purity of the obtained lithium iron manganese vanadium phosphate is low, so that the performance of the obtained positive electrode material cannot fully meet certain needs.