论文部分内容阅读
研究了CeMn0.25Al0.25Ni1.5+x(x=0.0,0.3,0.5,0.7,0.9,1.1)超化学计量比合金的相结构和电化学性能。XRD、SEM和电化学性能测试结果表明:CeMn0.25Al0.25Ni1.5+x(x=0.0,0.3,0.5,0.7,0.9,1.1)合金主要含有六方的CeAl相和立方的CeNi相,合金的粒径随x值的增大而变大。Ni的超化学计量比添加能够大大提高合金的电化学活性,298K时,合金的放电容量从x=0.0时的118.3mAh/g提高到x=1.1时的200.7mAh/g;338K时,其放电容量随x值增大呈先增后减的趋势,x=0.0合金的放电容量为170.4mAh.g-1,当x=0.9时,放电容量出现最大值271.4mAh/g。合金电极的P-C-T曲线表明:随Ni超化学计量的增加,合金的平衡氢压平台斜率变小,宽度增大,平衡氢压升高,这可能是使合金电极放电容量增加的主要原因。
The phase structure and electrochemical performance of CeMn0.25Al0.25Ni1.5 + x (x = 0.0,0.3,0.5,0.7,0.9,1.1) superstoichiometric alloys were studied. The results of XRD, SEM and electrochemical tests show that the CeMn0.25Al0.25Ni1.5 + x (x = 0.0,0.3,0.5,0.7,0.9,1.1) alloy mainly contains hexagonal CeAl phase and cubic CeNi phase, Particle size increases with increasing x value. The addition of Ni in the superstoichiometric ratio can greatly improve the electrochemical activity of the alloy. At 298K, the discharge capacity of the alloy increases from 118.3mAh / g at x = 0.0 to 200.7mAh / g at x = 1.1. At 338K, The capacity increases with the increase of x, then increases first and then decreases. The discharge capacity of x = 0.0 alloy is 170.4mAh.g-1. When x = 0.9, the maximum discharge capacity is 271.4mAh / g. The P-C-T curve of the alloy electrode shows that with the increase of Ni stoichiometry, the equilibrium hydrogen pressure of the alloy decreases, the width increases and the equilibrium hydrogen pressure increases, which may be the main reason for increasing the discharge capacity of the alloy electrode.