Zn_(100-x)Ti_x合金电极的电化学性能

Electrochemical Property of Zn_100-x Ti_x Alloy Electrodes

用固相扩散法制备了 Zn10 0 -x Tix 合金 ,并用电化学方法研究其在碱液中的腐蚀等性能。实验结果表明 ,金属 Zn由于 Ti的加入 ,使合金电极的腐蚀电位 Ecorr正移 ,改善电极在循环过程中活性物质 Zn的沉积性能 ,合适 Ti含量的合金电极可以获得较正的致钝电位 φp和较高的维钝电流密度 ,以及较好的氧化还原反应可逆性 ,并有消除电解液中锌酸盐的过饱和现象的可能。但 Ti的添加同时也使合金电极腐蚀电流密度 icorr增大 ,析氢过电位 η降低 ,阳极极化加大。实验结果表明 ,Zn10 0 -x Tix 合金中 x=5时的电极综合性能较好 ,其第 3 0和 3 5周时放电容量分别达到 3 2 1和 2 78m A· h/ g。

Zn 100- x Ti x alloy was prepared by solid phase diffusion method, and its corrosion behavior in alkaline solution was studied by CV. The results indicate that addition of Ti to Zn shifts the corrosion potential E corr of alloy electrodes to the more positive level and improves the deposition property of Zn(the active material) during the process of charge discharge circulation. Alloy electrode with proper Ti content( x =5 et al.) gives a more positive passivating potential φ p and higher passive current density , as well as a better reversibility in oxidation and reduction reactions. Titanium eliminates the over saturation phenomenon of zincate in electrolyte. In other hand, it is found that adding Ti also increases the corrosion current density i corr of alloy electrode, decreases the overpotential of hydrogen evolution and increases anode polarization. The Zn 100- x Ti x alloy electrode with x =5 exhibits the best electrochemical property. Its discharge capacity at 30th and 35th charge discharge cycle achieves 321 and 278 mA·h/g, respectively.