Write a note on the $Ni-Cd$ cell.

(N/A) The $Ni-Cd$ cell is a secondary cell,meaning it is rechargeable.
Construction:
It consists of a cadmium anode and a metal grid containing nickel$(IV)$ oxide $(NiO_2)$ as the cathode. The electrolyte is an aqueous solution of potassium hydroxide $(KOH)$.
Cell Reactions:
The overall discharging reaction is:
$Cd_{(s)} + 2NiO(OH)_{(s)} + 2H_2O_{(l)} \rightarrow Cd(OH)_{2_{(s)}} + 2Ni(OH)_{2_{(s)}}$
During discharge,cadmium is oxidized to $Cd(OH)_2$ at the anode,and nickel$(IV)$ oxide is reduced to nickel$(II)$ hydroxide at the cathode.
Characteristics:
It has a longer life than the lead storage cell but is more expensive to manufacture.