High Performance Polyacene-coated LiMnPO4 Cathode Material for Lithium-ion Batteries

Olivine structured lithium transition-metal phosphates LiMPO4 (M = Fe, Mn, Co, Ni) have been attracted much attention as promising cathode materials for next generation lithium ion batteries. Among these phosphates, LiCoPO4 and LiNiPO4 with very high voltage plateaus close to 4.8 V and 5.2 V are still incompatible with conventional electrolytes. LiMnPO4, possessing a moderate working voltage compatible to the present electrolyte systems, can provide a higher energy density than LiFePO4 on account of its higher redox potential of Mn3+/Mn2+(4.1 V) than Fe3+/Fe2+(3.5 V). However, the electrochemical performance of LiMnPO4 is poor due to the slow lithium diffusion kinetics within the grains and the low intrinsic electronic conductivity, even much worse than those of LiFePO4. Additionally, LiMnPO4 als