A novel sol-gel method to synthesize nanocrystalline LiVPO4F and its electrochemical Li intercalation performances

Lithium vanadium fluorophosphate, LiVPO4F, a cathode material for lithium ion batteries, was synthesized by a sol-gel method followed by low temperature calcinations. V(2)O(5)(.)nH(2)O hydro-gel, NH4H2PO4, LiF and carbon were used as starting materials to prepare a precursor, and LiVPO4F was finally obtained by sintering the precursor at 550 degrees C for 2 h. X-ray diffraction results show that the LiVPO4F sample is triclinic structure. TEM image indicates that the LiVPO4F particles are about 70 nm in diameter embedded in carbon network. The LiVPO4F system showed the discharge capacity of about 130 mAh g(-1) in the range of 3.0-.6 V at the first cycle, and the discharge capacity remained about 124 mAh g(-1) after 30 cycles. The sol-gel method is suitable for the preparation of LiVPO4F cathode materials with good electrochemical Li intercalation performances. (c) 2006 Elsevier B.V. All rights reserved.