PEDOT: PSS hydrogel film for supercapacitors via AlCl3-induced cross-linking and subsequent organic solvent treatments

An ionically crosslinked conducting polymer poly (3, 4-ethylenedioxythiophene): poly (4-styrenesulfonate) (PEDOT: PSS) hydrogel was synthesized by fast gelation of PEDOT: PSS dispersion (PH1000) using a high concentration of Al3+ (2 M) with a high water content of 94.4 wt% and three-dimensional interconnected networks. The highly conductive PEDOT: PSS hydrogel film was achieved by soaking it in ethylene glycol (EG) for a certain time. It was found for the first time that the conductivity of the PEDOT: PSS hydrogel film can be further improved with the vapors of m-cresol. It delivers 158 F g(-1) at a scan rate of 50 mV s(-1) with an outstanding rate capability and good cycling stability with 84.9% capacitance retention after 2000 cycles.