Abstract In this work, mixed nickel-cobalt sulfides (NCSs) were prepared by a facile solvothermal method. Structural and morphological characterization of synthesized materials were confirmed by X-ray diffractometry, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy. Electrochemical measurements revealed that mixed NCSs exhibit pseudocapacitor behaviour and their capacitance was strongly dependent on the composition. Interestingly, the electrochemical performance of the mixed NCSs has been significantly improved in comparison to the pristine nickel sulfide or cobalt sulfide. Particularly, the mixed NCS prepared at a nickel:cobalt molar ratio of 3:1 exhibited a specific capacitance of 2599.6 F g−1 at a scan rate of 10 mV s−1 (or 1345 F g−1 at a current density of 2 A g−1) and retained 95% of its initial capacitance after 3000 charge-discharge cycles. The excellent electrochemical performances of NCSs indicate they are promising candidate for supercapacitor electrode.

中文翻译：

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混合镍钴硫化物的一步溶剂热合成作为高性能超级电容器电极材料

摘要 在这项工作中，通过简便的溶剂热法制备了混合镍钴硫化物 (NCSs)。通过 X 射线衍射、X 射线光电子能谱、扫描和透射电子显微镜证实了合成材料的结构和形态表征。电化学测量表明，混合 NCS 表现出赝电容器行为，并且它们的电容强烈依赖于成分。有趣的是，与原始硫化镍或硫化钴相比，混合 NCS 的电化学性能得到了显着改善。特别是，以 3:1 的镍:钴摩尔比制备的混合 NCS 表现出 2599 的比电容。6 F g-1 在 10 mV s-1 的扫描速率下（或 1345 F g-1 在 2 A g-1 的电流密度下）并在 3000 次充放电循环后保持其初始电容的 95%。NCS 优异的电化学性能表明它们是超级电容器电极的有希望的候选者。