关键词: 锂离子电池, 正极材料, VO₂(B), 铬掺杂, 水热, 化学反应, 电化学

Abstract:

Cr-doped VO₂(B) has been successfully prepared via the hydrothermal method by adding appropriate amount of Cr(NO₃)₃·9H₂O in the process of synthesis. Combined with some characterization methods such as XRD, XPS, FESEM, EDS, FTIR and so on, the influence of different doping amounts on the phase, morphology, and the electrochemical performance of the Cr-doped VO₂(B) sample were investigated. The constant current charge-discharge test result shows that doping appropriate amount of Cr³⁺ can improve the cycling stability and charge-discharge capacity. When the doping amount was 0.49% and the current density was 0.1C, the initial discharge capacity of the sample was up to 282 mA·h·g^-1, about 36 mA·h·g^-1 more than that of the sample with no doping, and still more than 189 mA·h·g^-1 after 50 cycles, the capacity retention was 67%, better than that of the undoped sample (60.6%) significantly. The results of electrochemical impedance spectra (EIS) and cyclic voltammetry (CV) tests showed that the charge transfer impedance resistance and electrochemical polarization of the sample which doping amount was 0.49% decreased greatly, which further demonstrated its excellent electrochemical properties.

Key words: lithium ion battery, cathode material, VO₂(B), chromium doping, hydrothermal, chemical reaction, electrochemistry