A rechargeable nickel-cadmium cell in a jelly roll arrangement and separated by a layer soaked in moist sodium or potassium hydroxide. Another important secondary cell is the nickel-cadmium cell which has longer life than the lead storage cell but more expensive to manufacture. We shall not go into details of working of the cell and the electrode reactions during charging and discharging. The overall reaction during discharge is.
Cd(s)+2Ni(OH)3→CdO(s)+2Ni(OH)2(s)+H2O(l)
The primary cell Leclanché cell cell is represented as
Zn∣Zn2+∥MnO2∣Mn2O3∣C
Mn, Ni and Cd metals used in battery industries.