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通过化学还原共沉积法引入元素Ni制备了三元非晶态Co-Ni-B合金,并研究了元素Ni对非晶Co-B合金电化学储氢性能的影响.结果表明,含镍23.8 at%非晶态Ni-Co-B合金的可逆放电容量约为250 mAh/g,较非晶Co-B合金下降约20 mAh/g,但循环稳定性二者相同,即在650mA/g的高电流密度下循环60次容量几乎保持不变.但进一步增加Ni含量,含镍35.8 at%的非晶态Ni-Co-B合金的放电容量和循环稳定性都较不掺杂时发生大幅下降.但是,元素Ni的引入能有效抑制高电流密度充电过程中Co-B合金表面大量氢气的析出,减小电极放电电压平台和容量在循环过程中的波动.这可能得益于以下2个原因:(1) 非晶Ni-Co-B合金对水分解的电催化活性降低;(2) 吸附态氢原子在非晶Ni-Co-B合金基体中的扩散速度高于在Co-B合金中的扩散速度.

A series of ternary amorphous Ni-Co-B alloys were prepared by a chemical reduction codeposition method with Ni introduction and influence of Ni on electrochemical hydrogen storage property of the amorphous Co-B alloys was investigated. Results show that at a charge/discharge rate of 650 mA/g, the amorphous Ni-Co-B alloy with Ni content of 23.8 at% has a reversible discharge capacity of about 250 mAh/g, 20 mAh/g lower than amorphous Co-B alloy does. Discharge capacity of the two samples keeps almost unchanged after 60 cycles. Nevertheless, the amorphous Ni-Co-B alloy with Ni content of 35.8 at% shows much lower discharge capacity and capacity retention during cycling than amorphous Co-B alloy does under the same condition. However, a positive effect of Ni on electrochemical hydrogen storage of Co-B alloy is also found, i.e. element Ni could suppress H2 evolution on the surface of the amorphous Co-B alloy at a high charge rate and reduce the fluctuation of discharge potential plateau and discharge capacity during cycling. It could be attributed to that Ni decreases electrocatalytic activity for H_2O dissociation on the surface and improves hydrogen diffusion rate for amorphous Co-B alloy bulk.