Electrochemical performance of the lithium insertion in Mn0.5−xCoxTi2(PO4)3/C composites (x = 0, 0.25, and 0.5) as electrode material for lithium batteries

A number of Mn0.5−xCoxTi2(PO4)3/C composites with x = 0, 0.25, and 0.5 have been examined as electrode materials for lithium batteries. A solid solution was observed in the whole range of substitution of manganese by cobalt. Co0.50Ti2(PO4)3 is characterized by a high capacity value of 183.85 mAh/g after the first discharge at 1.6 V which is above the theoretical capacity for Ti4+/Ti3+ reduction. Partially reversible cobalt reduction may justify the progressive capacity fading. In turn, the substitution by manganese enhances the cycling stability by avoiding the manganese reduction at the lower cut off voltage. Capacities of 110 mAh/g were kept after 40 cycles for the cobalt compound.