A Review of Modification of Carbon-Based Materials Based on Defect Engineering in Capacitive Deionization

Capacitive deionization (CDI) is a novel water treatment technology based on the principle of double-electric-layer adsorption, which stores ions in the solution on the surface of electrodes by applying a low potential difference to achieve desalination. CDI has the advantages of low operating voltage (<1.2 V), small equipment footprint, low energy consumption, low cost and environmental friendliness. The performance of CDI is heavily dependent on the electrode materials. Carbon-based materials are widely used in CDI systems because of the large specific surface areas, lower price, and remarkable stability. To improve the CDI performance, extensive research efforts have been made for the modification of carbon-based materials. Defects in carbon-based materials play an important role in electrochemical processes and the introduction of defects is an important method to modify carbon-based materials. However, there is a lack of systematic summary of modification of carbon-based materials through introducing defects in CDI system. Therefore, this study makes the first attempt to review the modification of carbon-based materials of CDI based on defect engineering. The mechanism of enhancing CDI performance of carbon-based materials with the induction of different defects is analyzed and the future research prospects are proposed.