The effect of the temperature on the electrochemical properties of the hydrogen storage alloy for nickel–metal hydride accumulators

• The activation of ally becomes faster with increasing temperature.
• The enthalpy change, the entropy change and the activation energy are (-29 kJmol−1), (26.5 JK−1mol−1) and (24.6 kJ mol−1), respectively.
• The corrosion current density increases with increasing the temperature.
• The corrosion potential becomes more positive and increases linearly with temperature.
• This result is confirmed by the values of Rf and the Cf determined by EIS modeling.

The electrochemical properties of The LaNi3.55Mn0.4Al0.3Co0.75 alloy as a negative electrode material of a nickel–metal hydride accumulator have been investigated at different temperatures. The Activation of the alloy becomes faster with an increasing temperature. The enthalpy, the entropy and the apparent activation energy of the LaNi3.55Mn0.4Al0.3Co0.75Hx hydride formation are evaluated. The calculated results show that the enthalpy change, the entropy change and the activation energy are (−29 kJ mol−1), (26.5 JK−1 mol−1) and (24.6 kJ mol−1), respectively. The corrosion current density increases with increasing the temperature and the corrosion potential becomes more positive and increases linearly with the temperature. This result is confirmed by the values of corrosion film resistance and the corrosion film capacitance determined through the electrochemical spectroscopy impedance modeling.