ABSTRACT
The need for increased energy supply and continuous and rapid depletion of fossil fuels with alarming increase in the concentration of greenhouse gases have stimulated intense research on the development of alternative sustainable energy technologies. In this way, electrochemical energy storage and conversion technologies such as fuel cells, batteries, supercapacitors, and water electrolysis have been recognized as the most feasible and efficient technologies for portable, stationary, and transportation applications. Among these technologies, fuel cells converted the energy of a fuel into electricity through a direct electrochemical reaction without any harmful emissions with efficiencies in excess of 80%, in contrast to the limiting efficiency of the Carnot cycle in principle. Thus, fuel cell technologies have received a great deal of interest among the scientific and engineering communities because they are extremely environmentally friendly and have a high energy power density.
