may bypass the chemical step where electrochemical oxygen reduction to superoxide then becomes rate-limiting. Additionally, this interpretation explains the difference between the observed performance of the glassy carbon substrate and the mixed conducting polymers through the difference between their superoxide disproportionation rates, 𝑘 𝑓,3 . As seen on p(NDI-T2 P75), the catalytic disproportionation of superoxide leads to the same observed E1/2 for oxygen reduction but results in almost twice the limiting current density.