Polyaniline/activated carbon composite based flowing electrodes for highly efficient water desalination with single-cycle operational mode

[Display omitted] •Polyaniline/activated carbon (PAC) composite served as the flowing electrodes of FCDI.•The desalination performance of PAC composite for FCDI single-cycle mode is excellent.•The mechanism was due to the synergy between electric-double-layer capacitance of AC and pseudocapacitance of PANI. Flow-electrode capacitive deionization (FCDI) is a promising technique for water desalination and has received considerable attention. The desalination efficiency of FCDI is significantly influenced by the flowing electrode material. Therefore, it is necessary to develop highly efficient flowing electrode materials to obtain excellent desalination capability. Polyaniline (PANI) is regarded as a promising pseudocapacitive material with high conductivity and desirable hydrophilicity. Herein, in order to improve the stability of PANI, a rod-like polyaniline loaded on activated carbon (AC) was prepared by a simple in-situ polymerization to obtain the PAC composite for FCDI electrode. The composite successfully combined the characteristics of AC and polyaniline. The desalination performance of PAC composite for FCDI single-cycle mode was explored, and the mechanism was ascribed to the synergy between electric-double layer capacitance of AC and pseudocapacitance of PANI. The PAC-9 composite with the best electrochemical performance achieved a salt removal efficiency of 94.3 % and an average salt removal rate of 0.963 μmol cm−2 min−1 at 1.2 V. In addition, the PAC-9 composite did not decay after 12 h of long-term operation, showing that the composite is a promising active material for water desalination.