LiMPO4(M=Fe,Mn,Co,etc),the olivine structure compounds,have been widely researched for their excellent thermal stability.LiFePO4 is well known and developed owing to its low cost,stable performance and no contamination.Among the olivine family,the high-voltage cathode material LiCoPO4,which operates at 4.8 V and shows a theoretical capacity of 167 mAh g-1[1],is one of the most promising candidate cathodes for the high specific energy of lithium-ion devices.However,the interface between the LiCoPO4 cathode and the electrolyte is a great concern because of the decomposition of the electrolyte on the cathode surface at high operational potentials.