Enhanced capacitive deionization boosted by Co and N co-doping in carbon materials

In this study, cobalt, nitrogen co-doped porous carbon materials (Co-N/CN) as effective electrode materials were synthesized via salt melt synthesis method for capacitive desalination (CDI). The as-synthetized materials possess suitable micro/mesoporous cross-linking structure, more structure defect and multi-function groups. The systematic investigations demonstrated that Co, N codoping can promote the electrochemical performance and CDI performance. By comparison with the single N doped sample, the Co-N/CN samples achieve higher specific capacitance, lower ion/electron transport resistance and larger deionization capacity. Such superior capacitive desalination performance can be contributed to the synergistic effect of doped Co and N, such as the generation of Co-N sites. Additionally, the optimum Co-N/CN electrode displays an outstanding desalination capacity of 58.82 mg NaCl g−1 (71.4 mg Cl g−1 of anode) at 1.4 V in a NaCl concentration of 824 mg L−1 and great cycling stability with no obvious degradation in charge storage during 100 charge/discharge cycles. Therefore, we believe that Co-N/CN electrode has great potential for CDI practical applications.