Nitrogen-Doped Cobalt Pyrite Yolk-Shell Hollow Spheres for Long-Life Rechargeable Zn-Air Batteries

Limited by the sluggish four-electron transfer process, designing high-performance nonprecious electrocatalysts for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is urgently desired for efficient rechargeable Zn-air batteries (ZABs). Herein, the successful synthesis of porous nitrogen-doped cobalt pyrite yolk-shell nanospheres (N-CoS₂ YSSs) is reported. Benefiting from the abundant porosity of the porous yolk-shell structure and unique electronic properties by nitrogen doping, the as-prepared N-CoS₂ YSSs possess more exposed active surface, thus giving rise to superior activity for reversible oxygen electrocatalysis and outstanding cycling stability (more than 165 h at 10 mA cm^-2) in ZABs, exceeding the commercial Pt/C and RuO₂ hybrid catalysts. Moreover, the assembled ZABs, delivering a specific capacity of 640 mAh g_Zn ^-1, can be used for practical devices. This work provides a novel tactic to engineer sulfides as high efficiency and promising bifunctional oxygen electrocatalysts for advanced metal-air batteries.