In Situ ZnO-Activated Hierarchical Porous Carbon Nanofibers as Self-Standing Electrodes for Flexible Zn-Air Batteries

With the advantages of low cost, non-pollution, and strong controllability over composition, morphology, nanostructures, as well as surface characters, carbon-based nanomaterials are regarded as ideal substitutes of traditional platinum-based catalysts for oxygen reduction reaction (ORR) electrocatalysis in ORR-involved devices. Herein, an in situ ZnO activation-coupled electrospinning strategy was employed to facilely construct nitrogen-doped porous carbon nanofibers (NPCNF) for flexible Zn-air batteries. In situ formation and thermal removal of ZnO make a critical difference in construction of micro/meso-hierarchically porous structures as well as highly active N-doped sites, therefore generating self-standing carbon nanofibers with high nitrogen doping content as well as specific Brunauer-Emmett-Teller of 501 m(2)/g and 5.6 at. %. As a result, the prepared NPCNF as a self-standing electrode delivers an excellent performance both in alkaline liquid-state and quasi-solid-state Zn-air batteries, giving the possibility of applications in flexible devices.