| abstract |
A sealed nickel-metal hydride storage battery having excellent high-rate discharge characteristics and charge / discharge cycle characteristics is provided. A nickel-rich layer having a thickness of 50 nm to 400 nm is provided on the surface of a hydrogen storage alloy powder, and a nickel-rich layer is provided on a surface of a crack communicating with the surface of the alloy powder. The alloy powder has a mass saturation magnetization of 2.5 to 9 emu / g and a magnetic nickel content of 0.5 to 1.9 mmol / g of hydrogen storage alloy powder. A battery having the above characteristics can be obtained by using an alloy powder obtained by subjecting a hydrogen storage alloy powder to a hydrogen storage step, an alkali treatment step, a product removal step, a hydrogen desorption step, and a partial oxidation step with air. It is effective when applied to a corrosion-resistant hydrogen storage alloy containing Er, Y, and Yb. |