Enhanced capacitive deionization performance by an rGO–SnO2 nanocomposite modified carbon felt electrode

Abstract

The capacitive deionization (CDI) is a potential desalination technology in which brackish water flows between electrodes; by this process, ions are generated and stored in an electrical double layer formed at the electrode surface. In this work, we report efficient electrode materials which enable the capacitive deionization system to overcome the several issues of desalination. The rGO–SnO₂ nano-composite has been fabricated by an eco-friendly and facile hydrothermal process. The synthesized composite presents an improvement in electrochemical performance and an excellent capacitance retention of 60% even at relatively high scan-rates. In a specially designed CDI cell, the synthesized nanocomposite has shown excellent cyclic performance, high reversibility, and a remarkable electrosorption capacity of 17.62 mg g⁻¹ at an applied potential of 1.2 V with an initial salt concentration of 400 mg L⁻¹. The enhancement in electrosorption capacity of the electrode emerges due to its high specific capacitance in NaCl aqueous solution. Moreover, the system has shown a fast ion-removal rate with excellent stability and reversibility in an aqueous sodium-chloride (NaCl) solution. These results suggest that the rGO–SnO₂ composite prepared in this work is a feasible electrode material for desalination in the capacitive deionization process.