Patent ID: 6420068
Filing Date: 2002-07-16
Classification: C01B,H01M,Y02E,Y10S,Y10T

Abstract:
A hydrogen storage alloy electrode containing, as a principal active material, a powder of hydrogen storage alloy having a CaCu5 crystal structure and represented by the formula MmNixCoyMnzMw, where M is at least one element selected from aluminum (Al) and copper (Cu), x is between 3.0 and 5.2, y is between 0 and 1.2, z is between 0.1 and 0.9, w is between 0.1 and 0.9, and the sum of x, y, z and w is between 4.4 and 5.4;said hydrogen storage alloy powder comprising powder particles having a surface region and a bulk region enclosed within the surface region and having a higher nickel content in the surface region than in the bulk region; and said electrode further containing an oxide and/or hydroxide of at least one rare-earth element selected from ytterbium (Yb), samarium (Sm), erbium (Er) and gadolinium (Gd).