High temperature performance of La0.6Ce0.4Ni3.45Co0.75Mn0.7Al0.1 hydrogen storage alloy for nickel/metal hydride batteries

• La0.6Ce0.4Ni3.45Co0.75Mn0.7Al0.1 alloy was prepared by arc-melting.
• Kinetic and high temperature properties of the alloy have been studied.
• La0.6Ce0.4Ni3.45Co0.75Mn0.7Al0.1 alloy reveals good high temperature properties.
• The exchange current density of hydrogen increases with increasing temperature.
• The diffusion coefficient also increases with increasing temperature.

La0.6Ce0.4Ni3.45Co0.75Mn0.7Al0.1 hydrogen storage alloy has been prepared and its electrochemical characteristics and gas hydrogen absorption/desorption properties have been investigated at different temperatures. X-ray diffraction results indicated that the alloy consists of a single phase with CaCu5-type structure. It is found that the investigated alloy shows good cycle performance and high-rate discharge ability, which display its promising use in the high-power type Ni-MH battery. The exchange current density and the diffusion coefficient of hydrogen in the bulky electrode increase with increasing temperature, indicating that increasing temperature is beneficial to charge-transfer reaction and hydrogen diffusion. However, the maximum discharge capacity, the charge retention and the cycling stability degrade with the increase of the temperature.