Graphene-based materials for capacitive deionization

Capacitive deionization is an emerging technology for energy-efficient water desalination and has attracted more and more attention in recent years. The capacitive deionization technology is based on ion electrosorption at the surface of a pair of electrically charged electrodes, which are commonly composed of carbon materials. Among numerous electrode materials, graphene-based materials are outstanding, playing a vital role during the deionization process due to their intriguing features. After a brief introduction of the theory and instruments of capacitive deionization, we systematically summarize the current progress in graphene nanosheets, porous graphene, graphene-based composites, surface tuned graphene and its composites as electrodes for capacitive deionization. We also present our perspectives on the development of graphene-based electrodes for capacitive deionization.