Co nanoparticles combined with nitrogen-doped graphitic carbon anchored on carbon fibers as a self-standing air electrode for flexible zinc-air batteries

Although zinc-air batteries (ZABs) have been extensively studied due to their advantages, there is still room for improving flexible ZABs especially by identifying suitable self-standing flexible electrode materials. Here, flexible porous nanofibers embedded with Co nanoparticles and nitrogen-doped graphitic carbon (Co@NPCFs) have been synthesized to work as self-standing and binder-free electrodes in flexible ZABs. These unique nanofibers with nitrogen-doped graphitic carbon are beneficial for electron transport, oxygen capture and desorption of the OH^- ions. The Co@NPCFs could provide rich active sites and exhibit good catalytic activity for both the oxygen evolution reaction and the oxygen reduction reaction. The fabricated composites with a flexible self-standing network structure can be applied directly to flexible ZABs and contact well with gel electrolyte when bending the batteries. As a result, this strategy provides a good example of flexible self-standing electrodes for ZABs and can also be extended to other flexible electric energy storage devices.