▎ 摘　　要

In this study, nickel hexacyanoferrate (NiHCF) was incorporated with reduced graphene oxide (rGO) as a pseudocapacitive intercalation cathode in asymmetric capacitive deionization (ACDI) for desalination. The electrochemical characterization results demonstrated that the NiHCF@rGO nanocomposite exhibited an excellent specific capacitance of 158.2 F g-1 at a scan rate of 5 mV s-1 and high electrical conductivity. The desalination experiments were carried out in single-pass mode for the performance analysis under different operational parameters. For desalting 4 g L-1 NaCl solution at 1.2 V, NiHCF@rGO-assembled ACDI exhibited a large salt adsorption capacity of 80.2 mg g-1 and a high charge efficiency of 86.6%, associated with an energy consumption of 0.053 kWh m- 3. It is noted that the NiHCF@rGO-assembled ACDI significantly outperformed the activated carbon-based membrane capacitive deionization for desalination. More importantly, the incorporation of rGO can improve the 27.7% salt adsorption capacity of NiHCF. The significant improvement can be ascribed to rGO uniformly distributing NiHCF particles on its surface via conductive bridges, which enable a low charge transfer resistance and facilitate the transport of ions. The X-ray photoelectron spectroscopy analysis further verified the Na+ intercalation/deintercalation of the NiHCF@rGO electrode, accompanied by the Fe3+ to Fe2+ redox reaction in a cyclic charging-discharging process. Overall, this work demonstrates the great potential of NiHCF@rGO as a cathode for efficiently improving desalination performance.