(武漢大學 化學與分子科學學院, 武漢 430072)
摘 要: 研究稀土元素La和Ce以不同比例混合對貯氫合金La1-xCexNi5(x=0~1)的結(jié)構和活化特性的影響。 采用X射線衍射儀分析不同Ce含量樣品的結(jié)構， 并用不添加任何粘結(jié)劑的粉末微電極技術及循環(huán)伏安方法考察貯氫合金的活化特性。 結(jié)果表明： 所制備的貯氫合金都是CaCu5單相結(jié)構； 隨著Ce含量的增加， 晶胞參數(shù)a和晶胞體積明顯減小， 而晶胞參數(shù)c隨Ce含量的變化略有增加。 Ce的取代會降低合金在活化過程中的容量活化速度， 但可以提高放電反應能力活化速度以及活化參數(shù)降低速度。 同時還發(fā)現(xiàn)電勢掃描速度對貯氫合金活化過程有顯著影響。 合金的容量活化速度和放電反應能力活化速度都隨電勢掃描速度降低而提高。
關鍵字: 鎳氫電池； 貯氫合金； AB5合金； 活化特性； 粉末微電極
La1-xCexNi5 hydrogen storage alloy
（College of Chemistry and Molecular Science, Wuhan University,
Wuhan 430072, China）
Abstract: The effects of the ratio of rare earth metals Ce and La on the structure and the activation performance of La1-xCexNi5 (x=0-1) hydrogen storage alloys were investigated. The structure of the alloys was analyzed by X-ray diffractrometry and the activation performance of the alloys was evaluated by CV with a cavity microelectrode which was featured without using any binding additives. The results show that all the hydrogen storage alloys have CaCu5 phase; both the cell parameter a and cell volume of the alloys decrease whereas the parameter c increases very slowly with the increase of Ce content. The substitution of Ce for La in the alloys results in the reduction of the capacity increase rate, the increase of the reaction capability increase rate, and the increase of the activation energy reduction rate during the activation process of the alloys. The effect of the potential scan rate on the activation performance was also studied. It is found that the capacity and the reaction capability increase when the scan rate decreases.
Key words: Ni-MH battery; hydrogen storage alloy; AB5 alloy; activation performance; cavity microelectrode
