Lithium iron phosphate prepared with chemical precipitation method

Abstract

The invention provides lithium iron phosphate prepared with a chemical precipitation method. Lithium iron phosphate is prepared through steps as follows: steps 1, solutions with certain concentrationsare prepared from LiOH.H2O and NH4H2PO4 in a stoichiometric ratio respectively, and a suspension with certain content is prepared from FeC2O4.2H2O; step 2, a LiOH solution is slowly dropwise added toa mixed solution of FeC2O4.2H2O and NH4H2PO4 at normal temperature and normal pressure for a reaction; step 3, a reaction liquid is filtered, and dark green precipitate is obtained; step 4, the precipitate is put in a tube furnace, dried for 5 h at 150 DEG C in N2 atmosphere, pre-decomposed for 5 h at 350 DEG C, calcined for 10 h at 700 DEG C and cooled with the furnace, and a lithium-ion batterycathode material LiFePO4 is obtained. Lithium iron phosphate prepared with the chemical precipitation method is of a single olivine crystal structure, has stable discharge plateau and good cycle performance and has a discharge voltage plateau of about 3.4 V.

Description

technical field [0001] The invention relates to battery material technology, in particular to lithium iron phosphate prepared by a chemical precipitation method. Background technique [0002] L FePO 4 etc. are considered to be used as positive electrode materials for large-scale power lithium-ion batteries. Among them, lithium iron phosphate is considered to be the most promising cathode material due to its abundant raw material sources, low cost, safety, and excellent cycle performance. However, its low electronic conductivity and lithium ion diffusion rate at room temperature limit its wide application. At present, the methods for preparing lithium iron phosphate mainly include high-temperature solid-phase reaction method, liquid-phase reaction method, hydrothermal method, microwave method, chemical lithium insertion method and mechanical ball milling method TAKAHASH IM, etc. [0003] Lithium iron phosphate was synthesized by high-temperature solid-state reaction method...

AI Technical Summary

Problems solved by technology

Although carbon coating can improve the conductivity and inhibit the growth of active particles, too much carbon will greatly reduce the LiFePO 4 / C composite cathode material specific energy

Doping metal ions can effectively improve the conductivity, and for LiFePO 4 The crystal structure does not affect, but will reduce the theoretical capacity of the material