Facile Synthesis of a Highly Efficient and Durable Bifunctional Oxygen Electrocatalyst CFS@CN/F Composite for Rechargeable Zinc-Air Batteries

Synthesis of bifunctional oxygen electrocatalysts with high ORR and OER catalytic activity is important for the development of next-generation rechargeable zinc-air batteries. CoFeSNC with high ORR catalytic activity and CoNiLDH/FeOOH with high OER catalytic activity are prepared using wet chemistry and ion exchange strategies, respectively. CFS@CN/F composite electrocatalysts are prepared by grinding and mixing CoFeSNC and CoNiLDH/FeOOH together. The introduction of bimetallic sites and weakly electronegative S atoms into M–N–C catalytic materials synergistically improves the adsorption and activation of oxygenated intermediates, effectively overcoming the limitations of single-heteroatom catalytic materials. Space charge effects and built-in electric fields in CoNiLDH/FeOOH heterojunctions improve electron transfer and reduce the OER reaction energy barriers. The CFS@CN/F catalyst exhibits excellent bifunctional electrocatalytic activity (ΔE = 0.689 V vs RHE); the zinc-air battery based on CFS@CN/F shows a high peak power density (183.8 mW cm^–2) and specific capacity (792 mAh g^–1). This work provides a valuable reference for the design and development of efficient ORR/OER bifunctional electrocatalysts with practical applicability.