Application of functionalized graphene in Li–O₂ batteries

Abstract

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 for its light weight and facile availability. In particular, 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 (ORR) and oxygen evolution reaction (OER) 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, oxygen functional group modifications, and catalyst decoration. Heteroatomic doping breaks electric neutrality of sp2 carbon of graphene, which forms electron-deficient or electron-rich sites. Oxygen functional groups mainly create defective edges on graphene oxides with C−O, C=O, and −COO−. Catalyst decoration is widely attempted by various transition and precious metal and metal oxides. These induced reactive sites usually improve the ORR and/or OER in LOB by manipulating the adsorption energies of O2, LiO2, Li2O2, and promoting electron transportation of cathode. In addition, functionalized graphene is used in anode and separators to prevent shuttle effect of redox mediators and suppress growth of Li dendrite.

Phosphorus-Doped Graphene Electrocatalysts for Oxygen Reduction Reaction

“…Accordingly, great attention has been given to the study of fuel cells and metal-air batteries as the next-generation energy conversion techniques because these devices can directly convert chemical energy into electric energy with nearly zero carbon footprint [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. In fuel cells and metal-air batteries, the electrochemical reactions, in particular, the oxygen reduction reaction (ORR) in the cathode, determine the performance [ 10 , 11 ]. Hence, a suitable catalyst is highly needed to boost the kinetics and reduce the overpotential.…”

Anchoring NiO Nanosheet on the Surface of CNT to Enhance the Performance of a Li-O2 Battery

“…Carbon materials, considered as common electrode materials, possess excellent properties, including environmental friendliness, brilliant electrical conductivity and a high surface area, which have been paid a lot of attention. In Li-O 2 batteries, carbon materials exhibit prominent catalytic performance as electrocatalysts owing to the complex porous structure [26,27]. They are usually considered as important carriers in cathode catalysts [28][29][30][31][32].…”

Understanding Lithium-Mediated Oxygen Reactions at the Au|DMSO interface: Are We There?

“…This delimitation distinguishes this paper from existing review articles that are more comprehensive, and thus less focused, in the scope. For instance, the readers can refer to refs , , and − for reaction mechanisms and interface in various systems, refs − for the development of cathode materials, refs − for the development of oxygen reaction catalysts, refs and for studies using first-principles calculations, and refs , , and for related characterization methods.…”