Zeolitic Imidazolate Frameworks Derived Co₉S₈/Nitrogen‐Doped Hollow Porous Carbon Spheres as Efficient Bifunctional Electrocatalysts for Rechargeable Zinc–Air Batteries

Abstract

Abstract The development of nonprecious metal‐based electrocatalysts with remarkable catalytic activity and long‐cycling lifespan toward oxygen reduction reaction (ORR) and evolution reaction (OER) is especially important for rechargeable zinc–air batteries (ZABs). Herein, monodispersed Co 9 S 8 nanoparticles embedded in nitrogen‐doped hierarchically porous hollow carbon spheres (Co 9 S 8 NPs/NHCS) are synthesized through a template‐assisted strategy followed by a co‐assembly, thermal annealing, and sulfurization process. Benefiting from larger specific surface area, hierarchically porous hollow structure, and carbon nanotubes self‐growth, the obtained Co 9 S 8 NPs/NHCS‐0.5 electrocatalyst exhibits decent performance for ORR ( E 1/2 =0.85 V) and OER ( E 10 =1.55 V). A rechargeable ZAB assembled using the Co 9 S 8 NPs/NHCS‐0.5 as air cathode delivers a maximum power density of 116 mW cm −2 , high open circuit voltage of 1.47 V, and good durability (no obvious voltage decay after 1200 cycles (200 hours)). Such a hierarchically porous hollow structure of Co 9 S 8 NPs/NHCS‐0.5 provides a confined space shell and an interconnected hollow core to achieve outstanding bifunctional catalytic activity and cycling stability, which surpass the benchmark Pt/C‐RuO 2 .