Enhanced rate capability and cycling life of nickel modified Li3V2(PO4)3 cathode material

Abstract

Monoclinic Li3V2(PO4)3 (LVP) is an appealing cathode material of Li-ion batteries for its high operation voltage, high capacity and great thermal stability. However, the low electronic conductivity plagues its practical application. Here, LVP/C has been modified by introducing nickel as a coating element via ultrasonic dispersion assisted solid-state reaction. The LVP particles are closely covered with amorphous carbon and mixed with NiO nanoparticles, besides some Ni element enters into the LVP lattice due to the Ni atom thermal diffusion. Compared with carbon coated LVP electrode, due to the increased electronic conductivity, decreased charge-transfer resistance and enhanced lithium ion diffusion coefficient, all the three Ni-modified LVP/C electrodes exhibit enhanced electrochemical performance. Especially when the amount of nickel acetate is 0.06 g (corresponding to 1.0 g LVP/C), the resulting product (LVP/C-6Ni) owns the highest initial capacity of 122 mA h g−1 with a very low capacity fading of ~0.003% per cycle even after 1000 cycles at 1 C. Furthermore, LVP/C-6Ni also displays an outstanding average capacity of 120.6 mA h g−1 at 20 C.