Calculate the ideal efficiency of the fuel cell.

The ideal efficiency ($\eta$) of a fuel cell is given by the ratio of the Gibbs free energy change ($\Delta G$) to the enthalpy change ($\Delta H$).

Given:
$\Delta G = -237 \text{ kJ/mol}$
$\Delta H = -286 \text{ kJ/mol}$

Substitute the values:

Convert to percentage:

The ideal efficiency of the fuel cell is \boxed{\text{82.87%}}.

• Hydrogen has a very low volumetric energy density, meaning a large volume is required to store a significant amount of energy, even when compressed or liquefied. This necessitates high-pressure tanks or cryogenic temperatures, which are energy-intensive and costly.
• Hydrogen is highly flammable and explosive when mixed with air, posing significant safety challenges for storage and transportation.