Dual-Function Air Cathode for Metal-Air Batteries with Pulse-Power Capability

摘要

We demonstrate that air-breathing electrodes comprising carbon nanofoam papers painted with conformal nanoscale coatings of manganese oxide (MnOx) exhibit both energy storage and conversion function by providing electrocatalytic activity for oxygen reduction plus faradaic pseudocapacitance associated with Mn(Ⅲ/Ⅳ) redox in the oxide. This property combination, difficult to achieve in a single electrode material, allows the oxide-derived pseudocapacitance to sustain seconds-long discharge pulses at rates that cannot be met by oxygen reduction alone. Manganese (Ⅲ) sites in the post-pulsed oxide spontaneously recharge to Mn(Ⅳ) in the presence of oxygen-making the oxide ready and available for subsequent pulse-power discharge.