Al对V-Fe-Ti三元贮氢合金电化学性能的影响

Effect of Al on the electrochemical properties of V-Fe-Ti hydrogen storage alloy

研究了V2．46TiFe0.54Alx（x=0～0．4）贮氢合金的相结构及其电化学性能。XRD分析表明，所有合金均由单一的BCC相结构组成；随Al含量的增加，BCC相的晶格常数逐渐增大。电化学测试结果显示，所有合金电极的放电容量随循环次数的增加均显著降低。由线性极化曲线可以看出，Al基本上对交换电流密度没有影响。经恒电位放电曲线分析表明，氢在合金电极中的扩散系数随Al含量的增加而增大。Al加入后，合金的高倍率放电性能也得到了一定改善。

The phase structures and electrochemical behaviour of V2.46 TiFe0.54 Alx （x= 0-0. 4） hydrogen storage alloys have been investigated. XRD analysis shows that all of the alloys are consisted of only BCC phases. After Al added, the lattice parameter of the BCC phase expands. Electrochemical measurements show that the discharge capacities of all the alloy electrodes decrease markedly with charge-discharge cycles. And Al has little influence on the exchange current density. However,the hydrogen diffusion coefficient increases with Al content increasing. Furthermore, the Al contained alloy electrodes get a larger discharge capacity comparing with the Alfree one at any discharge current density.