Sol-gel preparation and electrochemical performances of LiFe1/3Mn1/3Co1/3PO4/C composites with core-shell nanostructure

LiFe1/3Mn1/3Co1/3PO4/C solid solution was prepared via a poly(ethylene glycol) assisted sol-gel method and exploited as cathode materials for lithium ion batteries. X-ray diffraction patterns indicate that LiFe1/3Mn1/3Co1/3PO4/C is crystallized in an orthorhombic structure. The scanning electron microscopy and transmission electron microscopy show that the particles are about 200 nm with a uniform carbon coating of about 8 nm in thickness to form a core-shell nanostructure. During charge-discharge cycles, LiFe1/3Mn1/3Co1/3PO4/C presented three plateaus corresponding to Fe3+/Fe2+, Mn3+/Mn2+ and Co3+/Co2+ redox couples, and a discharge capacity of 150.8 mAh g(-1) in the first cycle, remaining 121.2 mAh g(-1) after 30 cycles. Core-shell structure can optimize the performances of polyoxoanionic materials for lithium ion batteries. (C) 2009 Elsevier B.V. All rights reserved.