Herein, we reasonably designed MOF-derived Co₉S₈ polyhedrons coated on NiCo₂S₄ nanowire composites for high performance hybrid supercapacitors. The NiCo₂S₄ nanowires have one-dimensional structure that can provide better electronic transmission characteristics and Co₉S₈ polyhedrons modified on nanowires can further expand the contact surface area and increase active sites of the Faraday reaction. Besides, the proportion of components can be adjusted and optimized by controlling the reaction time. The synergistic effects between the two components significantly improve their pseudocapacitance. The test results indicated that the specific capacitance of the NiCo₂S₄/Co₉S₈ electrode with an optimal ratio can reach up to 2390.2 F g⁻¹ (331.8 mA h g⁻¹) at a current density of 1 A g⁻¹. Even when the current density increased to 10 A g⁻¹, its rate performance was still maintained at 88.2%. A hybrid supercapacitor was assembled with NiCo₂S₄/Co₉S₈ and activated carbon shows a high energy density of 47.7 W h kg⁻¹ when the power density is 1275 W kg⁻¹, as well as good cycle stability (84.1% capacitance retention after 8000 charging/discharging cycles). Therefore, this device has a potential practical space in portable energy storage devices.

中文翻译：

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NiCo2S4纳米线上的MOF衍生的Co9S8多面体，用于高性能混合超级电容器

在这里，我们合理设计了MOF衍生的Co ₉ S ₈多面体，该多面体涂覆在NiCo ₂ S ₄纳米线复合材料上，用于高性能混合超级电容器。NiCo ₂ S ₄纳米线具有一维结构，可以提供更好的电子传输特性和Co ₉ S ₈在纳米线上修饰的多面体可以进一步扩大接触表面积并增加法拉第反应的活性部位。此外，可以通过控制反应时间来调节和优化组分的比例。这两个组件之间的协同效应显着提高了它们的伪电容。测试结果表明，在电流密度为1 A g ^-1时，具有最佳比率的NiCo ₂ S ₄ / Co ₉ S ₈电极的比电容可以达到2390.2 F g ^-1（331.8 mA hg ^-1）。。即使电流密度增加到10 A g ^-1，其利率表现仍保持在88.2％。将混合超级电容器与NiCo ₂ S ₄ / Co ₉ S ₈组装在一起，当功率密度为1275 W kg ^-1时，活性炭显示出47.7 W h kg ^-1的高能量密度，以及良好的循环稳定性（84.1％ 8000次充电/放电循环后的电容保持率）。因此，该设备在便携式能量存储设备中具有潜在的实用空间。