Metal‐containing Ionic Liquid/Polyacrylonitrile‐derived Carbon Nanofibers for Oxygen Reduction Reaction and Flexible Zn–Air Battery

: Practical applications of Zn-air batteries are usually limited by sluggish kinetics of oxygen reduction reaction. Replacing Pt-based catalysts with convenient, efficient and low-cost materials to boost oxygen reduction reaction is highly desirable. Herein, a class of Fe-N co-doped carbon nanofibers is successfully synthesized by pyrolysis of polyacrylonitrile/metal-containing ionic liquid-based electrospun films. The ionic liquids act as porogen to provide multiscale pores as well as activator to bring carbon nanofibers active sites. The catalyst possessing appropriate active sites and unique 3D porous architecture exhibits remarkable long-term stability and electrocatalytic activity. Particularly, the catalyst maintains a shape of membrane after carbonization, manifesting its direct use as air electrode without binders. It is notable that an all solid-state Zn-air battery based on the carbon nanofibers exhibits good flexibility, indicating its promising application as wearable devices.