A flexible cotton-derived carbon sponge for high-performance capacitive deionization

Capacitive deionization (CDI) with a high energy efficiency and low cost is considered a promising desalination technique to obtain clean water. To achieve excellent CDI performance, a rational design of the structure of the electrode material is essential. In this study, a flexible cotton-derived carbon sponge (CCS) with a high specific surface area (up to 2680 m2/g) and suitable pore size distribution (0.8–4 nm) was fabricated by the pyrolysis of raw-cotton followed by NH3 treatment and annealing at high temperature. The obtained CCS was directly used as a CDI electrode material without any binders or conductive additives, and exhibited an excellent desalination performance with an electrosorption capacity of 16.1 mg/g in 500 mg/L NaCl solution. This result is due to the high specific surface area, abundant pores, low resistance and superior hydrophilicity of CCS.