Modulating the surfaces functional groups and defects in carbon via salt template method for high-performance capacitor deionization

Conventional carbon-based materials have been widely applied for capacitive deionization (CDI) because of their excellent electrical conductivity and specific surface area. The surface functional group and defect of carbon materials have a critical impact on CDI performance. Hence, a hierarchical mesoporous/macropores carbon (MPC) with abundant quinone functional groups (C = O) and defects were synthesized by a salt template method. The introduction of C = O functional groups and defects not only effectively shortens the ions transport path, but also enhances the pseudocapacitive behavior of carbon materials. As a result, the MPC represents a fantastic desalting capacity of 31.3 mg g−1 for sodium salt (500 mg L–1 NaCl) at an applied voltage of 1.2 V. Meanwhile, the MPC also shows superior salt adsorption rate and great cycling performance. In addition, the desalination mechanism was analyzed in detail by systematic ex-situ measurements. Here, this work presents a novel perspective for designing high-performance carbon-based CDI electrode materials.