Graphene oxide: A promising membrane material for fuel cells

Graphene has captured the attention of many researchers due to its wide potential in energy-related applications; it possess high thermal and electrical conductivity, great mechanical strength, optical transparency, inherent flexibility, huge surface area, and unique two-dimensional structure. Graphene oxide and polymer composites are commonly blended for various purposes, especially in energy devices. The fuel cell technology has discovered as one of the best alternative for future energy source; however, an extensive research is still required for the further improvement of key components such as proton exchange membranes, anode and cathode. This review has highlighted the influence of graphene in membrane modification for various fuel cells. There are many reviews on polymer exchange membranes but this is the only review that specifically deals with the graphene based membranes for fuel cells. Also, the review has covered the substantial types of fuel cells; however, focus is given to the polymer electrolyte fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs). The discussion will provide a better understanding of graphene features, its compatibility with different polymers and solvents, its working principle in polymer matrices, and future prospects of graphene-based membranes in fuel cells.