Electrochemical behavior of Li3-xM′xV2-yMy(PO4)3 (M′ = K, M = Sc, Mg plus Ti)/C composite cathode material for lithium-ion batteries

Composites of monoclinic Li(3-x)M'(x)V(2-y)M ''(2y)(PO(4))(3) (M' = K, M '' = Sc, Mg + Ti) with carbon were synthesized by solid-state reaction using oxalic acid or 6% H(2)/Ar gas mixture as reducing agents at sintering temperature of 850 degrees C. The samples were characterized by X-ray diffraction (XRD), voltammetry and electrochemical galvanostatic cycling. The capacity of Li(3)V(2)(PO(4))(3) synthesized using hydrogen as the reducing agent was 127 mAh g(-1) and decreased to 120 mAh g(-1) after 20 charge-discharge cycles. The substitution of lithium and vanadium for other ions did not result in the improvement of the electrochemical characteristics of the samples. (C) 2010 Elsevier B.V. All rights reserved.