Improving the electrochemical performance of LiMn0.85Fe0.15PO4-LiFePO4 core-shell materials based on an investigation of carbon source effect

Abstract

Core-shell type C-LiMn0.85Fe0.15PO4-LiFePO4 olivine materials are synthesized by a co-precipitation method followed by double carbon coating with different kinds of carbon sources. Through EDX analysis, the distribution of the carbon layer is confirmed within the pores and the surface of the particles varied with different types of carbon sources. Among them, the ascorbic acid-pitch mix coated core-shell electrode show the best discharge capacity of 154 mAh g(-1) at 1/20 C-rate and 100 mAh g(-1) at 5 C-rate. This improved electrochemical property is ascribed to the uniform carbon coating layer both inside the pores and on the outside surface using different molecular weight carbon sources.