Application of Functionalized Graphene in Li-O2 Batteries.

Li-O2 batteries (LOB) are considered as one of the most promising energy storage devices using renewable electricity to power electric vehicles because of its exceptionally high energy density. Carbon materials have been widely employed in LOB according to its light weight and facile availability. Graphene is a suitable candidate due to its unique two-dimensional structure, high conductivities, large specific surface areas, and good stability at high charge potential. However, the intrinsic catalytic activity of graphene is insufficient for the sluggish kinetics of oxygen reduction reaction and oxygen evolution reaction in LOB. Therefore, various surface functionalization schemes for graphene have been developed to tailor the surface chemistry of graphene. In this review, the properties and performances of functionalized graphene cathodes are discussed from theoretical and experimental aspects, including heteroatomic doping, functional group modifications, and catalyst decoration. The application of functionalized graphene in anode and separators are reviewed as well.