Polypyrrole/polyaniline composites with enhanced performance for capacitive deionization

Polypyrrole/polyaniline (PPy/PANI) composites used for capacitive deionization were synthesized by in situ chemical oxidation polymerization method. The preparation parameters including the acid type, the acid concentration and the oxidant concentration were investigated and optimized in terms of the textual properties, the cyclic voltammetry tests, and the electrochemical impedance spectroscopy measurements. The obtained PPy/PANI composites present relatively uniform nanorod morphology with an average pore diameter of 13.1 nm. The specific capacitance of the composites under the optimal conditions is up to 341.4 F/g, which is approximately thrice that of pure PPy and twice that of pure PANI. The saturated adsorption capacity of the PPy/PANI-carbon nanotube (CNTs) cell was obtained as high as 197.8 mg NaCl/g, which is approximately 1.7 times of the PPy-CNT cell and 2.1 times of the PANI-CNT cell, respectively.