Electrochemical characteristics of lithium vanadate, Li_3VO_4 as a new sort of anode material for Li-ion batteries

摘要

Li_3VO_4 is fabricated by a facile hydrothermal method and subsequent annealing treatment. The electrochemical performance and the possible charge/discharge mechanism of the as-prepared Li_3VO_4 as anode for Li-ion battery are firstly studied. Galvanostatic battery testing shows that the Li_3VO_4 electrode exhibits excellent cycle stability and rate capability. At a current density of 0.25 C, it delivers initial discharge and charge capacity about 624 and 481 mAh g~(-1) respectively, which maintains of 398 and 396 mAh g~(-1) after 100 cycles. After 60 cycles at various rates from 0.2 to 4.0 C, the discharge capacity can restore 98% when lowering the charge/discharge rate to 0.2 C. A possible redox reaction mechanism is proposed to interpret the lithiation/delithiation process of Li_3VO_4 according to experimental observations. The electrochemical reaction kinetic of the Li_3VO_4 electrode is studied by cyclic voltammetry measurement at various scan rate, which indicates the anodic and cathodic peak currents show linear dependence on the square root of scan rate from 0.3 to 1.0 mV s~(-1), suggesting a lithium ion diffusion controlled mechanism in the charge/discharge process.