ポリタイプ積層型希土類-Mg-Ni系合金の開発とニッケル水素電池への応用

摘要

Rare earth-Mg-Ni-based hydrogen storage alloy showed high discharge capacity of about 360 mAh/g. In this work, relation among composition, crystal structure, and electrochemical properties for the alloy was elucidated by synchrotron X-ray analysis, and its application to negative electrode of Ni-MH battery was investigated. Partial substitution of La with Pr and controlling the amount of Mg in the alloy increased the abundance of 5-19 type phase and greatly improved its durability. The finally developed (Co,Mn)-free rare earth-Mg-Ni-based alloy showed excellent high- temperature storage characteristic, and their suitability to Ni-MH battery was proven.%放電容量が360m Ah/g と高い希土類-Mg-Ni系水素吸蔵合金について放射光X線解析により組成，結晶構造，電気化学特性の関係を解明してニッケル水素電池負極へ応用した結果を報告する．Laの一部をPrで置換して，Mg量を制御することで5-19積層構造相の割合が増加して耐久性が人幅に改善された．溶出しやすいCo，Mnをなくすことで高温保存特性も向上してニッケル水素電池に適していることが実証された．