高倍率放电型贮氢合金的研制

Study on hydrogen storage alloy with high-rate dischargeability

研制了 5个LaNi5型贮氢合金样品 ,分别对 5种合金样品电极的电化学容量、高倍率充放电和宽温度范围内充放电性能、循环稳定性及其相结构进行了测试和分析。结果表明 :Sn及Si的搀杂增加了合金的非化学计量比 ,增强了合金的循环稳定性并改善了合金的高倍率充放电性能 ;合金样 (Ml0 .90 Nd0 .10 )Ni3 .60 Co0 .50 Mn0 .40 Al0 .18Si0 .42 的容量较高。 5C充电效率大于 95 % ,5C放电效率大于 90 % ,40 0次充放循环后容量保持率大于 70 % ;所设计合金晶型均为CaCu5相 ,充放电循环后合金主相仍是CaCu5相 ,同时发生氧化和粉化现象。

Five LaNi 5 type hydrogen storage alloys were prepared and their electrochemical discharge capacity, charge/discharge performance at high rate and wide temperature range, cyclic stability and crystal structures were tested and analyzed. The XRD results show that by the doping of Sn and Si, the non stoichiometric proportion of alloys is increased and their cyclic stability is improved while their charge/discharge performance at high rate are modified. The electrochemical capacity of alloy sample (Ml 0.90 Nd 0.10 )Ni 3.60 Co 0.50 Mn 0.40 Al 0.18 Si 0.42 is 290.72 mAh/g and its capacity retention is more than 70% after 400 cycles while its charge and discharge efficiency at 5 C is more than 95% and 90% respectively. The crystal structures of all the designed alloys are CaCu 5, and their main crystal structure after charge/discharge cycles are still maintained as CaCu 5 while oxidation and pulverizaton occurs.