关键词: 贮氢合金, 镍合金, 钴合金, 锰合金, 铝合金, 电极反应, 扩散系数, 电化学反应, 活化能

Effects of temperature on the kinetic performance of hydrogen storage alloy MINi~3~.~7~5Co~0~.~6~5Mn~0~.~4Al~0~.~2 have been systematically investigated in the temperature range from -20℃ to 85℃. The results show that temperature has pronounced effects on the characteristics of the electrode. With the increase of temperature, the polarization resistance R~t, the ohmic resistance R~0, the cathodic polarization overpotential, the anodic polarization overpotential, and the activation overpotential η~a and the concentration overpotential η~c under anodic polarization decrease, while the exchange current density i~0, the symmetry factor β, and the hydrogen diffusion coefficient D increase. At lower discharge current densities, charge-transfer is the rate-determining step of the electrode reaction, at higher discharge current densities, the diffusion of hydrogen in the bulk of the alloy is the rate-controlling step, whereas at medium discharge current densities, the electrode reaction is under mixed control of charge-transfer and hydrogen-diffusion. The activation energy for charge-transfer and for hydrogen-diffusion in the electrode are calculated to be 28.1 kJ.mol^-^1 and 19.9 kJ.mol^-^1 respectively.

Key words: HYDROGEN STORAGE ALLOY, NICKEL ALLOYS, COBALT ALLOYS, MANGANESE ALLOYS, ALUMINIUM ALLOYS, ELECTRODE REACTION, DIFFUSION COEFFICIENTS, ELECTROCHEMICAL REACTION, ACTIVATION ENERGY