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研究了Cr添加量对V_(2.1)Ti Ni_(0.3)Crx(x=0,0.2,0.4,0.6)贮氢合金的结构和电化学性能的影响。结果表明,所有合金均由V基固溶体主相和Ti Ni基第二相组成,且第二相呈网状分布在晶界上,部分呈颗粒状分布于合金主相之中。随着Cr含量增大,合金主相的晶胞体积与合金电极的最大放电容量逐渐减小,而循环稳定性逐渐增加,同时合金电极的动力学性能得到改善。在合金中添加Cr使合金电极的活化性能变差,但添加量的进一步增多对其活化性能影响不大。综合考虑,V_(2.1)Ti Ni_(0.3)Cr_(0.4)合金的电化学性能最好,最大放电容量可达442.20 m Ah·g~(-1),20次充放电循环后容量保持率达81.91%。
The effect of Cr content on the structure and electrochemical performance of V_ (2.1) Ti Ni_ (0.3) Crx (x = 0,0.2,0.4,0.6) hydrogen storage alloys was investigated. The results show that all the alloys consist of the main phase of V-based solid solution and the second phase of Ti-Ni-based phase. The second phase is distributed on the grain boundary in the shape of a network and partly distributed in the main phase of the alloy. With the increase of Cr content, the unit cell volume of the alloy and the maximum discharge capacity of the alloy electrode gradually decrease, while the cyclic stability increases gradually, meanwhile, the kinetic performance of the alloy electrode is improved. The addition of Cr to the alloy deteriorates the activation performance of the alloy electrode, but the further increase of the addition amount has little effect on the activation performance of the alloy electrode. The results show that the electrochemical properties of V 2.1 Ni 0.3 Cr 0.4 alloy are the best, the maximum discharge capacity is up to 442.20 mA · g -1, and the capacity retention rate is up to 20 81.91%.