High rates of oxygen reduction over a vapor phase-polymerized PEDOT electrode

The air electrode, which reduces oxygen (O-2), is a critical component in energy generation and storage applications such as fuel cells and metal/ air batteries. The highest current densities are achieved with platinum ( Pt), but in addition to its cost and scarcity, Pt particles in composite electrodes tend to be inactivated by contact with carbon monoxide ( CO) or by agglomeration. We describe an air electrode based on a porous material coated with poly( 3,4- ethylenedioxythiophene) ( PEDOT), which acts as an O-2 reduction catalyst. Continuous operation for 1500 hours was demonstrated without material degradation or deterioration in performance. O-2 conversion rates were comparable with those of Pt- catalyzed electrodes of the same geometry, and the electrode was not sensitive to CO. Operation was demonstrated as an air electrode and as a dissolved O-2 electrode in aqueous solution.