Litchi-like porous Fe/N/C spheres with atomically dispersed FeNx promoted by sulfur as highly efficient oxygen electrocatalysts for Zn-air batteries

The fabrication of carbon-based electrocatalysts that are highly active and stable as well as with plenty of pores for mass transport is essential for high-performance metal-air batteries. Herein, a new simple route involving sulfur (S) as a promoter was developed to achieve a litchi-like porous Fe/N/C catalyst with abundant FeNx species. The obtained electrocatalyst exhibits a large surface area with a high pore volume and shows high activity for oxygen reduction. Moreover, a Zn-air battery device adopting this S-promoted litchi-like Fe/N/C catalyst shows superior power density (double that of the untreated counterpart).