5LiFe_(0.9)Mn_(0.1)PO_4·4Li_3V_2(PO_4)_3/C composites as high capacity cathode materials for lithium-ion batteries

摘要

The construction of high capacity cathode materials consisting of two active components, LiFexMn1-xPO4 and Li3V2(PO4)(3), is rarely reported. Herein, 5LiFe(0.9)Mn(0.1)PO(4)center dot 4Li(3)V(2)(PO4)(3)/C (LFMVP/C) composites are synthesized by a simple two-step process, including ball milling and heat-treatment. The electrochemical reactivity of the composites with lithium is evaluated. The cathode assembled with LFMVP/C shows better electrochemical performance than that of the single active component (LiFePO4, LiMnPO4, or Li3V2(PO4)(3)) during charging and discharging in the potential range of 2.4 and 4.8 V. It delivers the specific capacities of 195, 173, and 158 mAh.g(-1) at 0.1C, 0.5C, and 2C, and retains 88% of the initial discharge capacity after 100 cycles at 0.1 C. Compared with the single active component (LiFePO4, LiMnPO4, or Li3V2(PO4)(3)), the lithium-ion diffusion coefficient of the composite composed of two active components (LFMVP/C) is higher.