CAJ | 학술논문

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.
통과화학환원공침적법인입원소Ni제비료삼원비정태Co-Ni-B합금,병연구료원소Ni대비정Co-B합금전화학저경성능적영향.결과표명,함얼23.8 at%비정태Ni-Co-B합금적가역방전용량약위250 mAh/g,교비정Co-B합금하강약20 mAh/g,단순배은정성이자상동,즉재650mA/g적고전류밀도하순배60차용량궤호보지불변.단진일보증가Ni함량,함얼35.8 at%적비정태Ni-Co-B합금적방전용량화순배은정성도교불참잡시발생대폭하강.단시,원소Ni적인입능유효억제고전류밀도충전과정중Co-B합금표면대량경기적석출,감소전겁방전전압평태화용량재순배과정중적파동.저가능득익우이하2개원인:(1) 비정Ni-Co-B합금대수분해적전최화활성강저;(2) 흡부태경원자재비정Ni-Co-B합금기체중적확산속도고우재Co-B합금중적확산속도.
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.