Hydrogen is known to be the cleanest fuel due to its zeroemission capability. It's inherently immense energy content makes it the fuel for future but, it's economical, safe and efficient usage for power generation remains a challenge. Fuel cell is a chemical device that runs on hydrogen and oxygen gases to give out electricity and water that is capable of replacing the conventional fossil-fuels in various applications. This paper gives construction and functional details of various fuel cells

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... at are commercially available. The reported types of fuel cell are categorized based on fuel oxidizer electrolyte, state of aggregation of the reactants, and electrolyte/operating temperatures. The operational parameters of each type are disclosed. Pros and cons of specific fuel cell types are listed along with their possible applications. Further, performance of typical fuel cells is analyzed with the help of a polarization curve and their respective efficiencies. The presented work summarizes the trends in hydrogen fuel cell market and throws light on the technology that probably would contribute towards sustainable development of society. The state of the art review on this promising technology would help better understanding the future directions of a sustainable energy development and its usage thereof.