(西安交通大學 金屬材料強度國家重點實驗室, 西安 710049)
摘 要: 通過X射線衍射、 掃描電鏡和能譜分析了新型低鈷儲氫合金La1-xCaxNi3.2Co0.3Al0.3(0≤x≤0.4)合金的晶體結構、 組織形貌及各相化學成分， 并研究了該合金的電化學性能。結果表明： 當x≤0.1時， 合金基本保持LaNi5主相和LaNi3第二相；當0.1＜x≤0.3時，出現(xiàn)的Al(NiCo)3第二相替代了LaNi3第二相。隨著Ca含量的增加， 合金活化性能變差， 當x＝0.2時， 放電容量達到最高值（為295mA·h/g）， 合金經300次充放電后， 循環(huán)容量保持率為82.5%， 且循環(huán)壽命得以改善。
關鍵字: 儲氫合金； 放電容量； 循環(huán)穩(wěn)定性
La1-xCaxNi3.2Co0.3Al0.3(0≤x≤0.4) low-cobalt hydrogen storage alloys
（State Key Laboratory for Mechanical Behavior of Materials,
Xi'an Jiaotong University, Xi'an 710049, China）
Abstract: The crystal characteristics, microstructure and chemical composition of the new-type low-cobalt hydrogen storage alloys La1-xCaxNi3.2Co0.3Al0.3(0≤x≤0.4) were analyzed by X-ray diffractrometry, scanning electron microscopy and EDX, and the electrochemical properties of the alloys were investigated. The results show that the prepared alloys are basically composed of LaNi5 as matrix phase and LaNi3 as second phase when x≤0.1. When 0.1＜x≤0.3, the second phase LaNi3 is substituted by a new phase Al(NiCo)3. The activity of alloys become bad with the increase of Ca content. When x=0.2, the discharge capacity reaches the highest value of 295 mA·h/g, and the capacity of the alloys can hold 82.5% after 300 charge/discharge cycles.
Key words: hydrogen storage alloy; discharge capacity; cycle stability
