Le Shangwang, Wen Shengshan, Zou Zhengguang, Li Yanwei
School of Materials Science and Engineering, Key Laboratory of Nonferrous Materials and New Processing Technology of Ministry of Education, Guilin University of Technology, Guilin 541004, China.
Guangxi Key Laboratory of Electrochemical and Magneto-Chemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, China.
J Nanosci Nanotechnol. 2019 Nov 1;19(11):7421-7426. doi: 10.1166/jnn.2019.16633.
La-doped vanadium pentoxide (V₂O) was prepared by sol-gel method and subsequent heat treatment in air at 400 °C. The influence of La-doping on the crystalline structure, surface morphology, and lithium storage performance of V₂O were investigated by XRD, SEM, CV, EIS, and discharge-charge tests. The results demonstrated that La doping did not change the phase structure of orthorhombic V₂O, but significantly refined the crystal grain of V₂O; La doping obviously improved the cycling stability and rate capability of V₂O due to the decreased electrode polarization, smaller electron-transfer resistance, and enhanced lithium diffusivity. For example, the La-doped V₂O delivered a reversible capacity of 131 mAh/g after 50 cycles at a current density of 200 mA/g, while the pure V₂O showed a reversible capacity of only 63 mAh/g under the same condition. At the high rate of 500 mA/g, the La-doped V₂O still displayed a reversible capacity of 106 mAh/g, which is two times higher than that (45 mAh/g) of pure V₂O sample.
采用溶胶 - 凝胶法并随后在空气中400℃进行热处理制备了镧掺杂五氧化二钒（V₂O）。通过XRD、SEM、CV、EIS和充放电测试研究了La掺杂对V₂O的晶体结构、表面形貌和储锂性能的影响。结果表明，La掺杂并未改变正交晶系V₂O的相结构，但显著细化了V₂O的晶粒；由于电极极化降低、电子转移电阻减小以及锂扩散率提高，La掺杂明显改善了V₂O的循环稳定性和倍率性能。例如，在200 mA/g的电流密度下循环50次后，La掺杂的V₂O可逆容量为131 mAh/g，而纯V₂O在相同条件下的可逆容量仅为63 mAh/g。在500 mA/g的高倍率下，La掺杂的V₂O仍显示出106 mAh/g的可逆容量，是纯V₂O样品（45 mAh/g）的两倍。
