Fuel cell

A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, whereas in a battery the chemical energy usually comes from chemicals already present in the battery. Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied.

Types of Fuel Cells

There are several types of fuel cells, each using a different combination of fuel and oxidant and having different applications and advantages:

• Proton-exchange membrane fuel cells (PEMFC): These use a solid polymer as an electrolyte and porous carbon electrodes containing a platinum catalyst. They operate at relatively low temperatures and are used in applications such as automobiles and portable power systems.

• Solid oxide fuel cells (SOFC): These use a solid ceramic electrolyte and operate at high temperatures. They are typically used for stationary power generation and can run on a variety of fuels, including natural gas.

• Molten carbonate fuel cells (MCFC): These use a molten carbonate salt mixture as an electrolyte and operate at high temperatures. They are used for large-scale power generation.

• Alkaline fuel cells (AFC): These use an alkaline electrolyte such as potassium hydroxide and are used in applications such as spacecraft.

• Phosphoric acid fuel cells (PAFC): These use liquid phosphoric acid as an electrolyte and are used for stationary power generation and cogeneration.

Applications

Fuel cells have a wide range of applications, including:

• Transportation: Fuel cells are used in fuel cell vehicles (FCVs) such as cars, buses, and trucks. They offer the advantage of quick refueling and longer range compared to battery electric vehicles.

• Stationary power generation: Fuel cells are used for primary power and backup power in buildings, data centers, and other facilities. They can also be used in combined heat and power (CHP) systems to increase overall efficiency.

• Portable power: Fuel cells are used in portable electronic devices, military applications, and remote power systems where traditional power sources are impractical.

Advantages and Disadvantages

Advantages

• High efficiency: Fuel cells can achieve higher efficiencies than combustion engines.
• Low emissions: When using hydrogen as a fuel, the only byproduct is water.
• Quiet operation: Fuel cells operate quietly compared to internal combustion engines.
• Scalability: Fuel cells can be scaled for different applications, from small portable devices to large power plants.

Disadvantages

• Cost: Fuel cells and the infrastructure for hydrogen production and distribution are currently expensive.
• Durability: Some types of fuel cells have limited lifespans and require frequent maintenance.
• Fuel storage: Storing and transporting hydrogen can be challenging due to its low energy density by volume.

See Also

• Electrolyzer
• Hydrogen economy
• Renewable energy
• Battery (electricity)
• Energy storage