两段热处理对贮氢合金电极性能的影响
来源期刊：中南大学学报(自然科学版)2003年第1期
论文作者：刘开宇 张平民 唐有根 桑商斌 杨幼平
文章页码：44 - 48
关键词：两段热处理； 贮氢合金； 热力学； 活化
Key words：two-step heat treatment； hydrogen storage alloys； thermodynamic； activition
摘 要：采用电化学方法测定了铸态合金和850～1000℃时二步法热处理合金(即热处理合金)的P-C-T曲线,研究了二步法热处理对Ml(NiCoMnAl)5贮氢合金热力学性能的影响;应用三电极体系测定了贮氢合金电极的活化性能及温度特性.研究结果表明;合金经热处理后,平台压力下降,贮氢合金放氢平台的倾斜度减小;同时.X衍射的特征衍射峰明显加高,主峰半高宽由0.36下降到0.20;在常温(25℃)和0.0C(其中C为放电容量)充放电的条件下,合金电极达到最大电化学容量的循环次数由铸态舍金电极的8次提高到热处理合金电极的3次;在不同的充电率下,合金电极在-20℃(1C)时放电效率由铸态合金电极的73.5%提高到热处理合金电极的94.8%.但热处理合金电极在45℃(1C)时放电效率则比铸态合金电极下降近3%,表明两段热处理能明显提高合金的活化速度,但合金电极的高温充放电容量下降.
Abstract: The effects of two-step method heat treatment on the thermodynamic properties of Ml（NiCoM-nAl）5 hydrogen storage alloys are studied. The P-C-T curves of casting alloy and 8501 000 ℃ two step heat treatment alloys are measured by electrochemistry method, and the activation performance and the temperature characteristics of hydrogen storage alloy electrode are measured with a three-electrode system. The results show that the hydrogen flat pressure decreased and the gradient of discharging hydrogen flat of the hydrogen storage alloys diminishes after heat treatment. The results of X-ray diffraction shows that the diffraction peak becomes higher and steeper, the FWHM declines from 0. 36 to 0. 20 after heat treatment. The activation times decreases from 8 times to 3 times, the discharge efficiency with lC at -20℃ increases from 73. 5 % to 94. 8%, the discharge efficiency with 1C at 45 ℃ declines nearly 3% of hydrogen storage alloy electrode after heat treatment.
