| 摘要 |
PROBLEM TO BE SOLVED: To increase charging/discharging cycle characteristics and suppress increase of internal pressure at charging by improving anticorrosion characteristics of the hydrogen storage alloy electrode. SOLUTION: This hydrogen storage alloy electrode has a CaCu5 crystal structure, and includes hydrogen storage alloy powder represented by the composition formula of MmNixCoyMnzMw (M is at least one element selected from aluminum(Al) and copper(Cu); x, y, z, and w respectively satisfy 3.0<=x<=5.2, 0<=y<=1.2, 0.1<=z<=0.9, and 0.1<=w<=0.9, and the sum of x, y, z, and w satisfies 4.4<=x+y+z+w<=5.4) as the main active material. The hydrogen storage alloy powder comprises a surface area of the alloy powder, and a bulk area covered with the surface area. The existence rate of the nickel atom on the surface area is larger than that on the bulk area. The electrode includes oxide and/or hydroxide of at least one type of rare-earth element selected from ytterbium(Yb), samarium(Sm), erbium(Er), and gadolinium(Gd). |
