Abstract:The derivative of charge and discharge curves (dt/dE vs E plot) can be used to describe the charge and discharge process more exactly. The dt/dE—E plots of nickel hydroxide electrode at different charge/discharge rates and intermittent discharge experiment are discussed. Though the dt/dE—E plot is affected by many factors, it clearly has intrinsic relation with the nature of active material such as conductivity and thermodynamic potential of active material, which changes with the state of charge. The dt/dE—E plot can also be applied to other electrochemical active materials, especially to those having several phases during charge or discharge.

Key words:   nickel hydroxide electrode; constant-current charge/discharge curve; derivative