Why does a fuel cell not require recharging?

A fuel cell operates by converting chemical energy directly into electrical energy through an electrochemical reaction, typically involving hydrogen and oxygen. The correct choice highlights that a fuel cell does not require recharging because the reactants—hydrogen and oxygen—are supplied continuously during operation.

In a fuel cell, as long as there is a flow of the necessary reactants, electricity can be generated without interruption. For instance, hydrogen can be stored in tanks, and as it is used up in the fuel cell reaction, fresh hydrogen can be replenished, enabling continuous operation. Similarly, oxygen, usually sourced from the air, can also be supplied continuously.

This continuous supply of reactants is what differentiates fuel cells from rechargeable batteries, which store energy and require recharging when their energy is depleted. In a battery, once the stored chemical reacts, the energy must be replenished by connecting to an external electrical source, hence the need for recharging. In contrast, since fuel cells rely on an external supply of reactants, they can operate for extended periods without stopping for a recharge as long as there is a supply.

The other choices do not accurately describe why a fuel cell does not require recharging. For example, saying that hydrogen is consumed completely