Highly efficient bifunctional electrocatalyst for rechargeable zinc-air batteries: N, S dual-doped carbon encapsulating sulfur vacancy-rich FeCo/Fe-CoS nanoparticles

초록

In this research, we present a highly efficient bifunctional electrocatalyst, N, S dual-doped carbon framework encapsulating sulfur vacancy-rich FeCo/Fe-CoS nanoparticles (VS-FeCo/Fe-CoS/NSC), synthesized via co- precipitation, sequential pyrolysis and sulfidation process. The prepared electrocatalyst exhibits exceptional performance in oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and rechargeable Zn-air batteries (ZABs). The VS-FeCo/Fe-CoS/NSC-based ZAB demonstrates outstanding bifunctionality, exhibiting high specific capacity of 793 mAh g(Zn)(-1) and peak power density of 164.68 mW cm(-2). These values surpass those of noble metal-based ZAB, highlighting the superior electrochemical performance of the VS-FeCo/Fe-CoS/NSC catalyst. Such superior activity stems from synergistic effect of abundant heterointerfaces and sulfur vacancies in FeCo/Fe-CoS structure, resulting in enhanced charge transfer efficiency and reaction kinetic performance. Furthermore, the encapsulation of nanoparticles within the heteroatom-doped carbon matrix prevents aggregation and dissolution of active species, ensuring long-term stability during the battery operation. The electrochemical reversibility and stability of VS-FeCo/Fe-CoS/NSC are confirmed through extensive cycling tests, highlighting its potential for practical applications in energy conversion and storage systems.

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