Present Status and Limitations of Fuel Cells Fuel cell technology has been ignored in the recent past due to success of I.C. engines and batteries since the fuel cells were costly and uneconomical. However, the interest in fuel cells have been revived due to their direct energy conversion, high efficiency with negligible or no environmental … Read more

Selection of Fuel Cells The selection of a fuel cell is mainly based on the following factors : Cost Size/volume of cell Availability of fuel and its heat Transportability. Hydrocarbons like methane, ethane, and propane gases are not used since they are less reactive and their oxidation in fuel cell is difficult. Therefore, these fuels … Read more

Losses in Fuel Cells The theoretical e.m.f. generated is given by the Equation as, E = △G/n.F. It is also called as open circuit voltage or no load voltage. However, as the fuel cell is subjected to load i.e. current is supplied, the voltage of the cell drops considerably with increase in load. The voltage- … Read more

Regenerative Fuel Cells (RFC) The Regenerative Fuel Cell (RFC) is a system that can operate in a closed loop and could serve as the basis of a hydrogen economy operating on renewable energy. Fuel cells generating electricity, heat, and water from hydrogen and oxygen would be used throughout the economy, powering factories, vehicles, and houses. … Read more

Solid Oxide Fuel Cells (SOFC) Certain solid ceramic oxides (e.g. zirconium dioxide) are able to conduct electricity at high temperatures, therefore such ceramic oxides can be used as electrolytes in such fuel cells. This material is able to conduct O— ions at high temperatures. Therefore these cells operate at high temperatures in the range of 650°C … Read more

Polymer Electrolyte Membrane Fuel Cell (PEMFC) or Solid Polymer Fuel Cell (SPFC)  The schematic diagram of a low temperature polymer electrolyte membrane fuel cell shown in Figure A. In this type of cell, the electrolyte is a solid polymer membrane of an organic material such as polystyrene sulfonic acid. This polymer is permeable to H+ ions … Read more

Molten Carbonate Fuel Cell (MCFC) A schematic diagram of a molten carbon fuel cell is shown in Figure. It is a high temperature fuel cell. The fuel, oxidant, electrodes and the electrolyte used are as follows : Fuel : Mixture of H2, and COOxidant : O2, or airElectrodes : Porous nickel electrodesElectrolyte : Mixture of carbonate … Read more

Phosphoric Acid Fuel Cells (PAFC) A schematic diagram of phosphoric acid fuel cell is shown in Figure. It was developed in 1980s. It uses either pure hydrogen or rich hydrogen gas as fuel and oxygen or air as oxidant. The concentrated phosphoric acid (H3PO4) is used as electrolyte. It is a medium temperature type of … Read more

Classification of Fuel Cells The fuel cells can be classified as follows : Fuel cells classified based on type of electrolyte : Alkaline fuel cell (AFC) Phosphoric acid fuel cell (PAFC) Molten carbonate fuel cells (MCFC) Solid oxide fuel cells (SOFC) Proton/polymer exchange membrane fuel cells (PEMFC) Fuel cells classified based on type of fuel and … Read more