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为了提高V基固溶体贮氢合金的充放电循环稳定性能,研究了O含量对V2-xTi0.5Cr0.5NiO x(x=0~0.35)合金的组织结构和电化学性能的影响。组织结构分析表明,当没有添加O时,合金主要由bcc结构的V基固溶体相和TiNi相组成,随着O含量的增加,合金中出现了Ti4Ni2O新相。电化学测试表明,随着O含量的增加合金电极的最大放电容量有所降低,从x=0时的366.8 mAh/g降低到x=0.35时的225.3 mAh/g,而较少氧含量时,合金电极的循环稳定性能明显得到了改善,从x=0时的69.9%增大到x=0.2时的83.7%,而后又降低到76.9%(x=0.35)。电化学动力学分析结果表明,合金的高倍率放电性能,交换电流密度和氢的扩散系数均随着O含量的增加先增加而后减小。
In order to improve the charge-discharge cycle stability of V-based solid solution hydrogen storage alloys, the effect of O content on the microstructures and electrochemical properties of V2-xTi0.5Cr0.5NiO x (x = 0 ~ 0.35) alloys was investigated. Tissue structure analysis shows that when O is not added, the alloy mainly consists of Vcc solid solution phase and TiNi phase with bcc structure. With the increase of O content, a new phase of Ti4Ni2O appears in the alloy. Electrochemical tests show that the maximum discharge capacity of the alloy electrode decreases with the increase of O content, from 366.8 mAh / g at x = 0 to 225.3 mAh / g at x = 0.35, whereas at lower oxygen content, The cycling stability of the alloy electrode obviously improved from 69.9% at x = 0 to 83.7% at x = 0.2 and then to 76.9% (x = 0.35). Electrochemical kinetic analysis showed that the high-rate discharge performance, exchange current density and hydrogen diffusion coefficient of the alloy first increased and then decreased with the increase of O content.