LiFe 1/3 Mn 1/3 Co 1/3 PO 4 /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 LiFe 1/3 Mn 1/3 Co 1/3 PO 4 /C is crystallized in an orthorhombic structure. The scanning electron microscopy and transmission electron microscopy show that the particles are about 200nm with a uniform carbon coating of about 8nm in thickness to form a core–shell nanostructure. During charge–discharge cycles, LiFe 1/3 Mn 1/3 Co 1/3 PO 4 /C presented three plateaus corresponding to Fe 3+ /Fe 2+ , Mn 3+ /Mn 2+ and Co 3+ /Co 2+ redox couples, and a discharge capacity of 150.8mAhg −1 in the first cycle, remaining 121.2mAhg −1 after 30 cycles. Core–shell structure can optimize the performances of polyoxoanionic materials for lithium ion batteries.