Research progress on the application of carbon-based composites in capacitive deionization technology

Capacitive deionization (CDI) technology is favored by researchers for its environmental friendliness and higher selectivity. Among a number of electrode materials, carbon-based nanomaterials are considered suitable materials for CDI electrodes due to their excellent chemical stability, better economic benefits, etc. However, the conductivity and hydrophilicity of pure carbon electrode materials are generally poor. Therefore, researchers have focused on carbon-based composites. This paper provides a comprehensive review of carbon‑carbon composite materials and various carbon-based materials composited with metal oxides, metal-organic frameworks (MOFs), and polymers. In addition, the article summarizes the ion storage mechanism of CDI. Finally, the article provides an outlook on the future applications of CDI. It could provide good guidance for designing carbon-based materials for capacitive deionization.