MOF-derived CoCu-N-doped porous carbon frame electrocatalyst for high performance zinc-air battery

Abstract

Zinc-air batteries (ZABs) have received considerable interest because of the growing demand for high-energy–density and safe energy storage systems. Efficient and economical catalysts for the cathodic oxygen reduction reaction (ORR) in ZABs play a crucial role in reducing expenses and facilitating industrialization. In this study, an efficient alkaline ORR electrocatalyst derived from ZIF-67 is synthesized by a simple one-pot method followed by high-temperature calcination. The optimized catalyst, CoCu-NPC-1000, demonstrates outstanding electrocatalytic performance in ORR, with a half-wave potential (E_1/2) of 0.849 V and an onset potential (E_onset) of 0.988 V. Notably, CoCu-NPC-1000 also shows excellent methanol tolerance, stability, and durability under alkaline conditions. These superior catalytic properties are attributed to the synergistic effect of Co-N_x and Cu-N_x dual active sites, along with the increased average pore diameter facilitated by the pore-forming agent Zn(NO₃)₂·6H₂O. The CoCu-NPC-1000-based zinc-air battery outperforms the power density of Pt/C, achieving 107.1 mW cm^⁻2 at a current density of 124.3 mA cm^⁻2, compared to 84.79 mW cm^⁻2 at 143 mA cm^⁻2 for Pt/C. Additionally, its specific capacity reaches 851 mAh \({g}_{Zn}^{-1}\), exceeding that of Pt/C (688 mAh \({g}_{Zn}^{-1}\)). This study not only confirms the effectiveness of Zn(NO₃)₂·6H₂O as a pore-forming agent but also offers valuable insights into synthesizing bimetallic organic framework-derived electrocatalysts for ZABs.