Describe `Ni-Cd` storage cell.

Explanation

It is a secondary cell with life more than lead storage cell. However, it is more expensive than lead storage cells its nominal cell voltage is 1.2 V. it was nickel oxide, hydroxide (cathode) and metallic cadmium (anode) as electrodes. The electrolytic used in sodium or potassium hydroxide. its construction involves jelly soil arrangement in which the electrodes are separated by a layer soaked in moist sodium or potassium hydroxide which acts as electrolyte. the overall reaction during discharge is,
`Cd(d)+2N(OH)_(3)(s) to CaO(s)+2Ni(OH)(s)+H_(2)O(l)`