In Situ Aniline-Polymerized Interfaces on GO–PVA Nanoplatforms as Bifunctional Supercapacitors and pH-Universal ORR Electrodes

We report unique additive-free bifunctional electrodes, composed of graphene oxide (GO), reduced GO (rGO), polyaniline (PANI), and poly(vinyl alcohol) (PVA) on carbon cloths, which were fabricated using an easy and innovative in situ aniline polymerization strategy under mild conditions. The resulting electrodes were tested for energy storage and energy conversion reactions, and they exhibited competitive bifunctional supercapacitor and pH-universal oxygen reduction reaction (ORR) properties. Surprisingly, GO/PANI/PVA electrodes delivered a significant specific capacitance of 450 F·g–1 at a current density of 25 A·g–1, an ultrahigh cycling stability of 93% after 10 000 cycles of charge–discharge at 10 A·g–1, and an outstanding ORR onset potential value of 0.93 V vs reversible hydrogen electrode (RHE) in basic media. Additionally, the nanocomposite showed remarkable stability in acid media for the electroreduction of oxygen, maintaining 98% of the initial current applied after 25 000 s. The impressive performance of GO/PANI/PVA electrodes was attributed to their excellent electron-transfer (ET) properties, improved conductivity, and the highly stable behavior of PANI-functionalized GO layers.