Physical and eiectrochemical properties of a mixed lithium phosphate as cathode material for lithium ion battery

摘要

A mixed lithium phosphate LiMn_(0.6)Fe_(0.4)PO_4 as cathode material for lithium ion battery was synthesized by solid-state reaction. The crystalline structure, morphology of particles and electrochemical performances of the sample were investigated by X-ray diffraction, scanning electron microscopy, charge-discharge test and cyclic voltammetry. The results show that the small LiMn_(0.6)Fe_(0.4)PO_4 particles are simple pure olive-type phase structure with uniformly distribution of gain size. The LiMn_(0.6)Fe_(0.4)PO_4 obtained has a high electrochemical capacity, good cycle ability and excellent stability under high temperature. However, the capacity loss corresponding to 4.0V plateau at high rate, which had been proved by various electrochemical tests, is the main obstacle to its practical application.