Dual ZIFs-derived Support Enabling Uniformly Dispersed Co Nanoparticles for Robust Zinc-Air Batteries

Dual-ZIF-derived strategy enables uniform dispersion of Co nanoparticles. • XAFS confirms coexistence of Co nanoparticles with Co–N 2 and Zn–N 4 single atoms. • Co NPs/Co, Zn-CNFs catalyst achieves Δ E of 0.726 V for ORR/OER. • Zinc-air battery with Co NPs/Co, Zn-CNFs delivers 980 h stable cycling at 10 mA·cm –2 . Cobalt nanoparticles (Co NPs) represent a class of efficient bifunctional electrocatalysts considered ideal for zinc-air battery (ZAB) cathodes. However, their high surface energy leads to severe agglomeration and operational instability, significantly limiting their practical utility. To overcome these limitations, rational support design is essential. This work presents a carbon nanofiber support modified with Co–N 2 and Zn–N 4 sites, enabling the in situ formation of uniformly dispersed and stable Co NPs. The material was synthesized by carbonizing electrospun ZIF-67-containing fibers coated with ZIF-8, which served as a self-sacrificing template. This process yielded highly dispersed Co NPs anchored on the dual-metal modified carbon matrix, effectively preventing NP coalescence. The optimized catalyst demonstrates exceptional bifunctional oxygen electrocatalytic performance, achieving a half-wave potential ( E 1/2 ) of 0.86 V for oxygen reduction reaction (ORR) and an overpotential of 356 mV at 10 mA·cm –2 for oxygen evolution reaction (OER). In practical applications, rechargeable ZABs incorporating this catalyst attained a peak power density of 191.6 mW·cm –2 , a specific capacity of 815.0 mAh·g –1 , and remarkable cycling stability exceeding 980 hours at 10 mA·cm –2 , substantially outperforming conventional Pt/C+RuO 2 catalysts. This work provides an effective and feasible strategy for developing high-performance, durable electrocatalysts for advanced energy conversion systems. Download: Download high-res image (247KB) Download: Download full-size image