What is a fuel cell? Write a note on it.

(N/A) fuel cell is a galvanic cell that converts the chemical energy of fuels directly into electrical energy.
Construction: In fuel cells,reactants are fed continuously to the electrodes,and products are removed continuously from the electrolyte compartment. These cells are designed to convert the energy of combustion of fuels like $H_2$,$CH_4$,$CH_3OH$,etc.,directly into electrical energy.
Advantages of fuel cell:
$(i)$ There is no air or noise pollution.
(ii) Fuel cells have a high efficiency of $70 \%$ or more,whereas thermal power stations have a low efficiency of $40 \%$ or less.
(iii) Various fuels can be used in fuel cells.