ABSTRACT

Graphene, the two-dimensional sp2-hybridized carbon, has emerged as a versatile material. Characterized by a long-range π-conjugation and a comb-like network, graphene possesses extraordinary mechanical and electronic properties, which makes it a very promising candidate for critical materials in fuel cell systems. Graphene has already been intensively studied as an ideal support for catalysts used in fuel cells. Owing to its large surface area, fast electronic transfer process, superior mechanical, and chemical stability, graphene-based support can signicantly prompt oxygen reduction kinetics and enhance the durability of a well-dispersed catalyst layer under fuel cell operation conditions. The benets offered by graphene and its derivatives also make them important components for the nonprecious metal catalyst, Me─N─C (Me ═ Fe, Ni, Co, etc.), and the metal-free oxygen reduction reaction catalyst, which have been currently considered as the potential material to solve the efciency and cost problems in fuel cell commercialization. The utilization of graphene-based material in fuel cells is not only limited as the catalyst support or as a metal-free catalyst, but it has also been developed as (i) an additive in the polymer/graphene oxide composite proton exchange membrane, (ii) bipolar plate materials, and (iii) as

hydrogen storage systems, etc. By means of the nanoscaled manipulation of physical geometry and chemical functionality, a selectively facilitated transport behavior of graphene/ polymer composite can be achieved. Hence, graphene has been recognized as a cost-effective and performance-superior alternative with the potentially large-scaled production for the traditional key components in fuel cells.