pEDOT: Vitamin K1 Composites: An Electrochemical Study on Stable, Water-Permeable, Proton-Bonding Thin-Film Electrodes

Herein we report detailed electrochemical studies of a conducting polymer composite that is engineered to selectively react with protons and that has reactive sites across the entirety of the volume due to the excellent water permeability throughout the film. This chemically modified electrode (CME) utilises a conducting polymer as the source of charge carrier and Vitamin-K as the water-insoluble redox species that bonds protons in reduction and releases protons in oxidation. The overall number of active proton bonding sites was found to be 1.36 × 10¹⁶ sites/cm², with a redox capacity of ∼64 mAh/g, which makes this CME comparable to modern inorganic cathodes. The electrode exhibited insignificant degradation after 500 cycles. The composite is relatively simple to manufacture as it requires no purification steps as part of the processing.