Nitrogen-Doped Hollow Mesoporous Carbon Spheres for Efficient Water Desalination by Capacitive Deionization

Water desalination performance of capacitive deionization (CDI) largely depends on electrode materials properties. Rational design and regulation of the structure and composition of electrode materials to acquire high CDI performance is of great significance. Herein, nitrogen-doped hollow mesoporous carbon spheres (N-HMCSs) were investigated as electrode material for CDI application. To understand the effect of structure and composition on CDI performance, another two CDI electrode materials, i.e., hollow mesoporous carbon spheres (HMCSs) and solid mesoporous carbon spheres (SMCSs) were prepared for comparison. The obtained N-HMCSs possessed unique hollow cavity and excellent nitrogen doping property, resulting in fast ion diffusion, good charge transfers ability and fine wettability. Compared with HMCSs and SMCSs electrodes, N-HMCSs electrode exhibited an improved electrosorption capacity and rate, demonstrating the dependence of CDI performance on the synergistic effect of hollow structure and nitrogen doping property. N-HMCSs electrode also present excellent cycle stability over 20 adsorption–desorption cycles. These results indicate the promising prospect of N-HMCSs for CDI application.