Dual-active-sites design of CoNx anchored on zinc-coordinated nitrogen-codoped porous carbon with efficient oxygen catalysis for high-stable rechargeable zinc-air batteries

The sluggish kinetics of oxygen reduction reaction (ORR) is the bottleneck for practical applications of zinc-air batteries (ZABs). Developing highly efficient ORR electrocatalysts is of the essence for large-scale applications of ZABs. Herein, we design and synthesize the CoNx/Zn, N co-doped porous carbon structure (CoNx/Zn-NC) by self-polymerization of biomass materials and coupling of nitrogen-rich species with metallic ions. The introduced zinc element can regulate electronic structures of electrocatalysts and construct bimetallic active sites (N-Co/N-Zn species), facilitating the adsorption of reaction intermediates and further enhancing electrocatalytic performance. The porous carbon structure obtained by the self-polymerization of locust bean gum not only disperses active sites but also improves the O2 and electron transfer efficiency of electrocatalysts. The CoNx/Zn-NC exhibited excellent ORR electrocatalytic performance (E1/2 = 0.85 V) as well as outstanding stability. Impressively, the ZABs assembled with CoNx/Zn-NC demonstrated a high maximum power density, specific capacitance, and excellent charge/discharge cycling stability for 115 h, surpassing Pt/C catalyst.