Alkaline fuel cell

Definition

An alkaline fuel cell is a type of electrochemical cell that uses an alkaline electrolyte, typically potassium hydroxide, to facilitate the reaction between hydrogen and oxygen to produce electricity, water, and heat. This type of fuel cell operates at lower temperatures compared to others, making it suitable for various applications like stationary power generation and transportation.

5 Must Know Facts For Your Next Test

1. Alkaline fuel cells can achieve higher efficiencies compared to other types due to their favorable reaction kinetics and lower activation energy.
2. The typical operating temperature range for alkaline fuel cells is between 60°C and 80°C, which allows for quicker start-up times and easier thermal management.
3. These cells are sensitive to carbon dioxide, which can form carbonates in the electrolyte and reduce efficiency; thus, CO2 removal is crucial in practical applications.
4. Alkaline fuel cells have been used in various space missions, including those by NASA, because of their reliability and efficiency in converting hydrogen into electricity.
5. The main products of the reaction in an alkaline fuel cell are water and heat, making it an environmentally friendly option as it does not emit harmful pollutants.

Review Questions

• How does the use of an alkaline electrolyte affect the efficiency of alkaline fuel cells compared to other fuel cell types?
  • The use of an alkaline electrolyte in alkaline fuel cells leads to higher efficiencies because it promotes faster reaction kinetics and reduces the activation energy needed for the reactions. This allows for more effective utilization of the hydrogen fuel and results in improved overall performance. In contrast, other fuel cells may use different electrolytes that can have slower reaction rates, thus affecting their efficiency levels.
• Discuss the challenges faced by alkaline fuel cells regarding carbon dioxide sensitivity and how this impacts their practical applications.
  • Alkaline fuel cells are particularly sensitive to carbon dioxide because CO2 can react with potassium hydroxide in the electrolyte to form carbonates, which can impede ion conductivity and reduce the efficiency of the cell. This challenge necessitates measures to remove CO2 from the system or operate in environments with low CO2 concentrations. As a result, while they are effective in specific applications such as space missions or controlled settings, their deployment in more variable environments is limited.
• Evaluate the potential of alkaline fuel cells for future applications in sustainable energy systems and their role in reducing environmental impact.
  • Alkaline fuel cells hold significant potential for future applications within sustainable energy systems due to their high efficiency and low environmental impact. As global efforts shift towards cleaner energy solutions, these fuel cells can be integrated into renewable energy systems where hydrogen is produced from electrolysis powered by solar or wind energy. By converting hydrogen back into electricity efficiently without harmful emissions, alkaline fuel cells can play a critical role in reducing reliance on fossil fuels and contributing to a sustainable energy future.

Related terms

Electrolyte: A substance that conducts electricity when dissolved in water or melted, allowing ions to move freely, which is essential for the functioning of fuel cells.

Anode:

The electrode where oxidation occurs in a fuel cell, specifically where hydrogen molecules lose electrons during the electrochemical reaction.

Proton exchange membrane (PEM) fuel cell: A type of fuel cell that uses a solid polymer membrane as an electrolyte, allowing protons to pass through while blocking electrons, which creates electricity.