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用真空熔炼法制备了多种贮氢合金原样,分别经不同温度、时间热处理和保护气氛下球磨处理。改性前后样品晶体结构用SEM和XRD测试进行结构表征,结果表明合金为LaNi5和LaMg2Ni9晶相的复合相,经过热处理的合金颗粒粒径变小针刺变少、分布也相对更均匀。采用LANDAN进行电化学相关测试(电流密度为150mA/g),表明经过热处理使得晶体结构优化,放电容量有显著增加,且经由Al替代Ni的合金容量达到353.7mAh/g,循环50周容量保持率为76.7%,循环100周容量保持率为62.7%,表现出更好的循环稳定性。实验结果表明,无Co替代贮氢合金经热处理后电化学性能有显著提高,有望降低合金材料成本的同时提高材料的环境友好性。
A variety of hydrogen storage alloys were prepared by vacuum melting method, and were respectively ball-milled under different temperature, time and protective atmosphere. The crystal structure of samples before and after modification was characterized by SEM and XRD. The results showed that the alloy was a composite phase of LaNi5 and LaMg2Ni9 crystal phases. The diameter of the alloy after heat treatment became smaller and the distribution was relatively uniform. The electrochemical correlation test with LANDAN (current density of 150 mA / g) showed that after heat treatment the crystal structure was optimized and the discharge capacity increased significantly, and the capacity of the alloy via Al instead of Ni reached 353.7mAh / g. The capacity retention after 50 cycles Was 76.7%, and the capacity retention rate after 100 cycles was 62.7%, showing better cycling stability. The experimental results show that the electrochemical performance of the Co-free hydrogen storage alloy after heat treatment has been significantly improved, which is expected to reduce the cost of the alloy material and improve the environmental friendliness of the material.