Final answer:
Fuel cells and galvanic cells both generate electricity from chemical reactions; batteries are self-contained galvanic cells while fuel cells require external reactants. Batteries use solids or pastes to maximize electrical output, whereas fuel cells can operate continuously given a steady fuel supply. Fuel cells are more efficient but cost and reliability issues limit their widespread adoption.
Step-by-step explanation:
In comparing fuel cells and galvanic cells, it's essential to understand both serve as sources for electrical energy derived from chemical reactions. However, the key difference lies in their operation and use. A battery, which is a type of galvanic cell, contains all necessary reactants internally and releases electrical energy until the reactants are depleted. In contrast, a fuel cell operates somewhat like a traditional galvanic cell but with a continuous supply of external reactants; thus, it can generate electricity as long as fuel and oxidant are provided.
Commercial batteries, used in various electronics, typically utilize solids or pastes to maximize electrical output per unit mass versus solution-phase chemistry that is common in traditional galvanic cells. An example is the Leclanché dry cell, which operates under alkaline conditions to produce power. Conversely, a hydrogen fuel cell employs a catalyzed electrochemical pathway with fuels like hydrogen, using electrodes embedded with catalysts such as platinum to improve efficiency and create electricity from fuel and an oxidant.
Despite their potential for higher efficiency (40%-60%), fuel cells face significant cost and reliability challenges, limiting their widespread use. Applications where they are favored often involve scenarios where weight and space are at a premium, such as in space exploration vehicles.