Research Progress of Graphene and Its Composites as Electrodes for Capacitive Deionization

Capacitive deionization is an energy-efficient and environment-friendly desalination method, which forces ionic species toward oppositely charged high-surface-area electrodes under an electric field to achieve the purpose of desalination.The key technology is to prepare electrode materials, which require high specific surface area, reasonable pore size distribution and excellent electrical conductivity.Graphene is a desired kind of electrode material used in capacitive deionization for its high specific surface area and wonderful conductivity.However, the actual specific surface area is far below the theoretical value due to the effect of aggregation of graphene.The three-dimensional graphene or the composite materials can overcome aggregation effect to improve the performance of electrode.The research progress of the capacitive deionization technology based on graphene and its composite electrode are reviewed in detail.The existing problems and application prospect are also objectively pointed out in this review.