The development of efficient and cheap bifunctional catalysts for oxygen reduction and oxygen evolution reactions, is vital for the design of rechargeable Zn-air batteries. Herein, a facile strategy to fabricate Co/Co₉S₈ nanoparticles-encapsulated in carbon nanotubes, on an N-doped porous graphene sheet (Co/Co₉S₈@CNTs) via pyrolysis of a mixture of Co(NO₃)₂, melamine and L-cysteine is reported, the composition can be facile controlled using the molar ratio of melamine and L-cysteine. By controlling the molar ratio of melamine and L-cysteine and the pyrolysis temperature, Co/Co₉S₈@CNTs obtained at 900 °C (Co/Co₉S₈@CNTs-900) perform with high activities in oxygen reduction and oxygen evolution reactions, which promotes their application for rechargeable Zn-air batteries. Furthermore, the rechargeable Zn-air battery assembled with Co/Co₉S₈@CNTs-900 shows a high peak power density of 184.7 mW cm⁻² and good long-term durability, holding great potential in practical applications.

中文翻译：

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碳片上的Co / Co9S8 @碳纳米管：容易控制的合成，及其在氧还原/放氧反应中的电催化中的应用，以及在可充电锌空气电池中的应用

开发用于氧气还原和氧气释放反应的高效，廉价的双功能催化剂，对于可充电锌空气电池的设计至关重要。本文中，一种通过将Co（NO ₃）₂混合物热解在N掺杂的多孔石墨烯片（Co / Co ₉ S ₈ @CNTs）上制备封装在碳纳米管中的Co / Co ₉ S ₈纳米粒子的简便策略。据报道，三聚氰胺和L-半胱氨酸可以使用三聚氰胺和L-半胱氨酸的摩尔比容易地控制组成。通过控制三聚氰胺与L-半胱氨酸的摩尔比和热解温度Co / Co在900°C下获得的₉ S ₈ @CNT（Co / Co ₉ S ₈ @ CNTs-900）在氧还原和氧释放反应中表现出很高的活性，这促进了它们在可再充电锌空气电池中的应用。此外，组装有Co / Co ₉ S ₈ @ CNTs-900的可再充电锌空气电池显示出184.7 mW cm ^-2的高峰值功率密度和良好的长期耐久性，在实际应用中具有巨大潜力。