Single-compartment hydrogen peroxide fuel cells with poly(3,4-ethylenedioxythiophene) cathodes

Abstract

Single-compartment hydrogen peroxide fuel cells have recently emerged as a promising energy conversion platform since H₂O₂ is a high energy-density liquid that functions as both fuel and oxidizer. Finding suitable electrocatalysts is challenging since most metallic electrodes also catalyze the disproportionation reaction of H₂O₂ into H₂O and O₂, representing a significant loss mechanism in peroxide fuel cells. Herein we demonstrate that the conducting polymer poly(3,4-ethylenedioxythiophene), PEDOT, is a versatile electrocatalyst for peroxide fuel cells without generating losses due to disproportionation. We find that PEDOT is a cathodic catalyst for reduction of peroxide to water, performing at a level on par with the best reported inorganic catalysts. Using PEDOT as the cathode and nickel as the anode material, open circuit potentials in the range of 0.5–0.6 V are possible, with power densities of 0.20–0.30 mW cm⁻². We provide evidence to understand mechanistically how PEDOT functions as a catalyst for hydrogen peroxide reduction to water. The result of our efforts is a scalable hydrogen peroxide fuel cell cathode, which serves to demonstrate also the capabilities of organic semiconducting materials as electrocatalysts.