Hollow FeCo Alloy Nanoparticles Electrospun in Nitrogen-doped Carbon Nanofiber Enable High Performing Flexible All-Solid-State Zinc-Air Battery
Hollow-structuring of active components is among the most effective strategies for improving the kinetics of oxygen electrode catalysts, benefiting from the much-boosted active surface area, enhanced accessible active sites, and formation of the desired defects on the exposed surface. Integration of the active hollow nanostructures with functionalized carbon nanofibers synergizes the electrochemical performance and mechanical flexibility, which are particularly of interest for all-solid-state zinc-air batteries (FASS ZABs). In the present work, we demonstrate that the electrospinning of Co-containing Prussian blue analogs can give rise the hollow FeCo alloy nanoparticles assembled in the nitrogen-doped carbon nanofibers (h-FeCo alloy/N-CNFs). The h-FeCo alloy/N-CNFs as-derived exhibits superior bifunctional activities of oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), and thus impressive performance in rechargeable Zn-air batteries. When integrated into a rechargeable FASS ZAB, they enable a high open circuit voltage of 1.335 V and a stable discharge-charge plateau around 1.1 V to 2.0 V, together with a stable voltage efficiency of 63.5% under bending conditions.