Both electrical conductivity and surface wettability
are required
for the selection of active carbon materials in flow-electrode capacitive
deionization, while a trade-off exists between these two properties.
In this work, a hybrid material with a thin layer of polyaniline (PANI)
coating on activated carbon (AC/PANI) was successfully developed to
retain excellent electrical conductivity and acquire good surface
wettability. By adjusting the dosage of initiator, AC/PANI composites
with different loading fractions of PANI were obtained. The electrochemical
testing demonstrated that the AC/PANI composites have higher specific
capacitance and lower ion diffusion resistance compared to pure AC,
resulting in better desalinization performance. Specifically, with
a feed concentration of 1600 mg/L, excellent adsorption capacity and
high charge efficiency can be simultaneously achieved at 13.51 mg/g
and 92.21%, respectively. Benefiting from the formation of a continuous
electrical percolation network and reduced solid/liquid interfacial
transport resistance, a 39% enhancement of average salt adsorption
rate (from 0.54 to 0.75 μmol/min/cm2) was obtained.