Optimized hydrothermal synthesis and electrochemical performance of LiMnPO4/C cathode materials using high specific area spherical structure Li3PO4

Abstract

Olivine structure LiMnPO4/C cathode is synthesized by a hydrothermal method with high specific surface area Li3PO4 precursor in PEG400-H2O mixed solution system. The synthetic conditions are systematically optimized and statistical analysis using orthogonal experiments. The physical and electrochemical properties of Li3PO4 and LiMnPO4/C samples prepared under the optimized conditions are investigated in detail. The XRD and SEM results show that Li3PO4 powders are pure phase with uniformly hollow spherical morphology. The Nitrogen adsorption-desorption isotherm exhibits the specific surface area of Li3PO4 powders are 79.19 m2/g. LiMnPO4 reveals a well ordered olivine structure and possess small and unagglomerated particles, which generates from the Li3PO4 precursor structure. The electrochemical measurements show that pure LiMnPO4/C sample prepared under the optimal conditions delivers a maximum discharge capacity of 121.3 mAh/g at a 0.1 C rate. After 100 cycles, the discharge capacity decreases to 115.1 mAh/g with the capacity retention of 94.89%.