There is currently a strong push for high energy/high power energy storage systems for small and large scale applications, such as portable electronics, transportation, and energy generation by intermittent sources. The requirements of these technologies are not fully met by current devices (batteries and supercapacitors). Pseudocapacitors, a type of supercapacitors, have the ability to store higher amounts of charge compared to electrical double layer capacitors (EDLC) due to their faradaic storage mechanism, while still achieving high charge discharge rates. Additionally, low cost, environmentally friendly and highly abundant materials are necessary for low-cost stationary energy storage. Electroactive conductive polymers have the potential to address these major issues, along with possessing good ionic and electronic conductivity and rapid charge transfer processes. However, conducting polymer electrodes are limited by low theoretical charge capacity and stability. We report an increase in capacitance and charge capacity of polymer electrodes by incorporating 1,4-benzoquinone (QN), an abundant organic redox molecule. QN possesses a high theoretical charge capacity of 496 mA h g-1, whereas polypyrrole (PPy) is only 135 mA h g-1. The combined redox processes of the pyrrole and the quinone resulted in films with increased charge storage capacity. The effects of deposition conditions on film growth, QN confinement, and the electrochemical properties of the resulting polymer films were studied. In PPy/QN electrode materials, the highest average specific capacitance of 550 F g-1 was achieved, which represents a significant improvement over reference PPy with a highest average specific capacitance of 249.0 F g-1. This work will enable the development of supercapacitor materials that combine the high storage capacity properties of redox molecules with the high conductivity and capacitance of intrinsically conducting polymers such as PPy.

Redox solute doped polypyrrole for high-charge capacity polymer electrodes

248th National Meeting (2014)

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