Preparation of xLiMnPO4-Li3V2(PO4)3/C composite cathode materials from the novel Mn2V2O7/MnV2O6 precursors

Abstract

The composite cathode materials xLiMnPO4-Li3V2(PO4)3/C (x = 1, 2) are prepared from Mn2V2O7 and MnV2O6 precursors with a simple solid-state method. XRD results show that the composites consist of orthorhombic LiMnPO4 and monoclinic Li3V2(PO4)3 phases, without any other impurity phases. The average particle size and agglomeration degree of the materials are reduced with Li3V2(PO4)3 compounded into LiMnPO4. Electrochemical performance tests manifest that the specific discharge capacities of xLiMnPO4-Li3V2(PO4)3/C (x = 1, 2) at various C-rates are much higher than those of LiMnPO4/C. The discharge profiles of both composites contain three voltage plateaus of 3.62, 3.68 and ∼ 4.05 V. Especially, 2LiMnPO4-Li3V2(PO4)3/C delivers the first specific capacity of 159.6, 133.5 and 112.2 mAh/g at 0.1C, 2C and 5C, respectively, and exhibits excellent cyclic stability.