Preparation and electrochemical performances of hexacyanoferrate-doped poly(3,4-ethylenedioxythiophene) hydrogel

In this article, potassium hexacyanoferrate (K 3 Fe(CN) 6 ) was introduced into poly(3,4-ethylenedioxythiophene) (PEDOT) hydrogel by in situ polymerization to prepare K 3 Fe(CN) 6 -doped PEDOT hydrogel. The specific capacitance of PEDOT hydrogel was efficiently increased by the doping effect of K 3 Fe(CN) 6 . The increase in capacitance achieved by introducing K 3 Fe(CN) 6 into PEDOT hydrogel was attributed to the doping effect of anionic ferricyanide/ferrocyanide couple. The specific capacitance of PEDOT hydrogel increased from 38 F g −1 to the maximum value of 98 F g −1 (current density = 500 mA g −1 ) when the concentration of K 3 Fe(CN) 6 reached 5 mM. On the basis of cycle life tests, the capacitance retention of about 75% for the doped PEDOT hydrogel after 5000 cycles suggested a high cycle stability of redox-active PEDOT hydrogel and its potential as an electrode material for supercapacitor applications.