La_(1-x)Ce_xNi_(3.54)Co_(0.78)Mn_(0.35)Al_(0.32)贮氢合金相结构和电化学性能的研究

The microstructures and electrochemical properties of La_(1-x)Ce_xNi_(3.54)Co_(0.78)Mn_(0.35)Al_(0.32) hydrogen storage electrode alloys

采用真空电弧熔炼和热处理方法制备了La1-xCexNi3.54Co0.78Mn0.35Al0.32(x=0.1,0.2,0.3,0.4,0.5,0.6)贮氢合金.X射线衍射(XRD)分析表明,合金含有单一CaCu5型六方结构相.电化学性能测试表明,随着x的增加,合金的最大放电容量从348.1mAh/g(x=0.1)单调地减小到310.1 mAh/g(x=0.6);HRD1200先从28.6%(x=0.1)增加到65.4%(x=0.5)然后降低到60.1%(x=0.6),归因于合金表面的电催化活性和合金体内氢原子扩散速率均随x的增大先增大后减小.

The hydrogen storage alloys La1- x Ce Ni3.54 Coo. 78 Mn0 35 A10.32 （ x = 0. 1,0.2,0. 3,0.4,0.5,0.6 ） were synthesized by induction melting and heat treatment. XRD analysis indicated that the alloys consisted of a single CaCu5 -type phase. The electrochemical performance test showed that with increasing x value, the maximum discharge capacity decreased monotonically from 348.1 to 310. 1 mAh/g. For the discharge current density of 1200 mA/g, the HRD of the alloy electrode first increased from 28.6% （x = O. 1 ） to 65.4% （x = 0.5） , and then decreased to 60. 1% （x = O. 6）. This was mainly attributed to the electrocatalytic activity for charge - transfer reaction at the electrode/electrolyte interface and the hydrogen diffusion in the bulk of alloys, which increased first and then decreased.