Electrochemical performance studies on cobalt and nickel electroplated La–Mg–Ni-based hydrogen storage alloys
Electrochemical performance studies on cobalt and nickel electroplated La–Mg–Ni-based hydrogen storage alloys
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DOI：
10.1016/j.ijhydene.2009.09.082
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发表时间：
2009-12
影响因子：
7.2
通讯作者：
Huiling Ding;Shumin Han;Yi Liu;Jiansheng Hao;Yuan Li;Jingwu Zhang
中科院分区：
文献类型：
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作者：
Huiling Ding;Shumin Han;Yi Liu;Jiansheng Hao;Yuan Li;Jingwu Zhang
对La-Mg-Ni基La0.88Mg0.12Ni2.95Mn0.10Co0.55Al0.10合金粉末进行了一种新的电镀处理。研究了镀覆钴、镍金属对镀层形貌和电化学性能的影响。场发射扫描电镜（FESEM）结果表明，镀Co和镀Ni合金表面分别形成了一层致密的球形钴颗粒层和一层起伏的片状镍层。这些涂层除了作为保护层外，还增强了导电性和催化活性，从而改善了电化学性能。最大放电容量由原来的316 mAh/g提高到335 mAh/g和336 mAh/g，循环稳定性提高，自放电得到抑制。结果表明，镀钴合金和镀镍合金电极的高倍率放电性能（HRD）明显改善，在1500 mA/g电流密度下的HRD值分别提高了10%和17%，这是由于表面金属镀层改善了电极的动力学性能。
A novel electroplating treatment was applied onto La–Mg–Ni-based La0.88Mg0.12Ni2.95Mn0.10Co0.55Al0.10alloy powders. The effect of cobalt or nickel metallic coating on morphological and electrochemical properties was studied. FESEM results showed that a dense layer of spherical cobalt particles with uniform radius and an undulate layer of lamellar nickel formed on the surface of the Co- and Ni-coated alloys, respectively. These coatings enhanced the conductivity and the catalytic activity, besides acting as a protective layer, thereby improving the electrochemical properties. The maximum discharge capacity increased from original 316mAh/g to 335mAh/g on Co-coated alloys and 336mAh/g on Ni-coated ones, the cycling stability was enhanced and the self-discharge was suppressed. The high rate dischargeability (HRD) was ameliorated remarkably, and the HRD value at 1500mA/g rose by 10% and 17%, for cobalt- and nickel-coated alloy electrodes respectively, which is believed to be ascribed to the improved kinetics from the metallic coatings on the surface.