RE-Mg-Ni系储氢合金高倍率放电性能研究现状

RE-Mg-Ni系储氢合金具有超晶格结构,其主相晶格单元是由一定比率的AB5单元和AB2单元沿c轴交替层叠排列而成。该类型合金自问世以来便以其高容量、易活化的优势受到人们的广泛关注,然而其循环稳定性及高倍率放电性能不尽人意。人们通过大量研究有效提高了其循环稳定性,使其基本满足了商业化要求。但是要将基于该负极材料的镍氢电池应用在混合动力汽车上,仍需改进其高倍率放电性能。系统分析了元素替代、多元合金化、制备工艺、化合物复合、表面处理等手段对RE-Mg-Ni系储氢合金晶体结构及高倍率放电性能的影响。其中元素替代是一种重要且有效的手段,文中分析了不同稀土元素及B侧元素的作用机制,结果表明,B侧组分采用Ni,Co,Mn,Al的储氢合金具有较好的性能。多元合金化是一种复杂的过程,不同元素间可能存在一定的协同作用,研究其作用机制也是下一步的工作重点。通过优化实验方案,综合使用多种改性手段,可以得到高倍率放电性能良好的RE-Mg-Ni系储氢合金,使其基本满足电动工具用镍氢电池的要求,并可望在以后的研究中进一步提高其高倍率放电性能,使其满足混合动力汽车用镍氢电池的要求,实现良好的经济和社会效益。

Research Status in High Rate Dischargeability of Rare Earth-Mg-Ni-Based Hydrogen Storage Alloys

Rare earth-Mg-Ni-based hydrogen storage alloys were a new group of negative electrode materials with superlattice structures in which the AB5 units and the AB2 units were stacked with certain ratio along the c-axis direction.Because of high capacity and good activation ability,the alloys were widely concerned.But this kind of alloy exhibited poor cycling stability and high rate dischargeability.For commercial applications,numerous efforts to improve cycling stability were undertaken and studied.However,high rate dischargeability of the alloys was not able to meet the demand of hybrid electronic vehicles,and further efforts were in need.The influences of modification techniques such as element substitution,multi-component alloying,preparation technology,composite technology and surface treatment to the high rate dischargeability of rare earth-Mg-Ni-based hydrogen storage alloys were studied.Element substitution was found to be a significant means.The specific function of the constituent elements including rare earth elements and B-side elements was discussed.It was found that optimum composition of B-side contained mainly Ni,Co,Mn,and Al.As a complex process,how to find the synergy and mechanism of multi-component alloying became the key work.Taking optimized experimental scheme,and such modification techniques,rare earth-Mg-Ni-based hydrogen storage alloys with improved high rate dischargeability at industrial scale of electric tools application would be obtained.Hopefully,high rate dischargeablity of the alloys could be further improved in next work,which could meet the demand of hybrid electronic vehicles.So the study had significant economic and social benefits.