Abstract

Carbon-coated mesoporous Co₉S₈ nanoparticles supported on reduced graphene oxide (rGO) are successfully synthesized by a simple process. This composite makes full use of the protection of the carbon layer on the surface, the good conductivity and three-dimensional (3D) structure of rGO, the mesoporous structure and nanoscale size of Co₉S₈, thereby presenting the excellent electrochemical performances in potassium-ion batteries, 407.9 mAh·g⁻¹ after 100 cycles at 0.2 A·g⁻¹ and 215.1 mAh·g⁻¹ at 5 A·g⁻¹ in rate performances. After 1,200 cycles at 1.0 A·g⁻¹, this composite still remains a capacity of 210.8 mAh·g⁻¹. The redox reactions for potassium storage are revealed by ex-situ transmission electron microscope (TEM)/high-resolution TEM (HRTEM) images, selected area electron diffraction (SAED) patterns and X-ray photoelectron spectroscopy (XPS) spectra. The application of this composite as the host of sulfur for Li-S batteries is also explored. It sustains a capacity of 431.8 mAh·g⁻¹ after 800 cycles at 3 C, leading to a degradation of 0.052% per cycle. These results confirm the wide applications of this composite for electrochemical energy storage.

中文翻译：

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氧化石墨烯上碳包覆的介孔Co 9 S 8纳米粒子，作为钾离子电池的长寿命高倍率负极材料

摘要

通过简单的方法成功合成了负载在还原氧化石墨烯（rGO）上的碳包覆的介孔Co ₉ S ₈纳米粒子。该复合材料充分利用了表面碳层的保护，rGO的良好电导率和三维（3D）结构，Co ₉ S ₈的介孔结构和纳米级尺寸，从而在钾中表现出出色的电化学性能。 -离子电池，407.9毫安·克^-1 0.2 A 100次循环后·克^-1和215.1毫安·克^-1在5 A·克^-1在速率性能。在1.0 A·g ^-1下1,200次循环后，该复合材料仍保持210.8mAh·g ^-1的容量。通过异位透射电子显微镜（TEM）/高分辨率TEM（HRTEM）图像，选定区域电子衍射（SAED）图案和X射线光电子能谱（XPS）光谱揭示了钾的氧化还原反应。还探讨了这种复合材料作为锂硫电池硫的主体的应用。在3 C下进行800次循环后，其容量维持在431.8 mAh·g ^-1，导致每循环0.052％的降解。这些结果证实了该复合材料在电化学能量存储中的广泛应用。