Effect of Hydrogen Bonding on a Value of an Open Circuit Potential of Poly-(3,4-ethylenedioxythiophene) as a Beneficial Mode for Energy Storage Devices

Poly(3,4-ethylenedioxythiophene) is one of the semiconducting polymers that has attracted attention as electroactive materials for many different applications such as electrochromic devices, light-emitting diodes, biosensors, and supercapacitors. The fundamental understanding of the origin of its energy storage ability will lead to the proper design of such devices. Generally, the charge storage in supercapacitors is due to the formation of an electrical double layer and/or redox reactions. Recently, it is shown that the formation of cation radicals in PEDOT is induced by the hydrogen-bond formation between formic acid and polymer during electrochemical polymerization. The induced cation radicals play a major role in the charge storage ability of PEDOT, as studied in the current work. Furthermore, the presence of hydrogen bonds in PEDOT leads to the stable in time open circuit potential of 900 mV. This new knowledge leads to the designing of a symmetrical supercapacitor based on PEDOT as active material where hydrogen-bonds play a crucial role in the improved performance of the device.