Synthesis and evaluation of Co9S8/CoS/NSC bifunctional electrocatalyst for Zinc-air battery

초록

The development of clean and efficient energy storage and conversion systems is essential to address the ongoing challenges of fossil fuel depletion, increasing global energy demands, and environmental pollution. Among these technologies, zinc-air batteries (ZABs) have attracted significant attention as a promising candidate for sustainable energy storage due to their numerous advantages. ZABs offer high theoretical specific energy density, inherent safety, low production costs, and environmentally friendly zero-carbon emissions. These attributes make them an excellent alternative to traditional energy storage devices. However, their performance is limited by the slow kinetics of the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) at the air cathode during charging and discharging. While noble metal-based catalysts like Pt/C and RuO₂ have been used for these reactions, their high cost, scarcity, and poor durability hinder commercialization. To overcome these challenges, non-noble metal-based electrocatalysts are being explored. Transition metal sulfides (TMSs) show great promise due to their high conductivity, tunable redox properties, and faster reaction kinetics compared to other materials like oxides or nitrides. Additionally, strategies such as heteroatom doping (e.g., N, S, or P in carbon materials) and heterojunctions (e.g., creating Mott-Schottky) further enhance catalytic activity by optimizing the adsorption/desorption energies of reaction intermediates (*O, *OH, *OOH). These advancements are essential for improving ZAB performance and enabling their use as a sustainable energy solution. Inspired by the above features, we synthesized Co9S8/CoS supported on N, S doped carbon (Co9S8/CoS/NSC) though simple impregnation and annealing process. First, MF sphere was prepared by thermal polymerization and used as sacrifice template that decomposed at high temperatures. Second, polypyrrole was evenly coated on the mf sphere through the