Abstract

Here reports a hollow cube NiCo₂S₄ nanomaterial, which was prepared via facile hydroxylation and sulfuration steps using the self-prepared ZIF-67 as a precursor. This kind of NiCo₂S₄ as an electrode material for supercapacitor presents a specific capacitance high up to 1350 F g^-1 at 1 A g^-1 due to the contribution of pseudocapacitance. Particularly, the hybrid supercapacitor PC//NiCo₂S₄, assembled using the NiCo₂S₄ as the positive electrode material and the PC as the negative electrode material, delivers a high energy density of 33 Wh kg^-1 at the power density of 800 W kg^-1. Meanwhile, it presents a good cyclic stability with 67% capacitance retention after 10,000 cycles of charge–discharge at the current density of 5 A g^-1. However, the rate capability is not good enough because of the polarization effect of NiCo₂S₄ as a battery-type electrode material. Therefore, this research provides a reference for enhancing capacitance performance of an electrode material. For instance, reversibility in redox reaction and stability in structure are more important than the capacity in many cases.

Graphic abstract

Preparation of a hollow cube NiCo₂S₄ and its application in supercapacitor.

中文翻译：

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空心NiCo 2 S 4的制备及其在超级电容器中的应用

摘要

此处报道了一种空心立方体NiCo ₂ S ₄纳米材料，该材料是使用自行制备的ZIF-67作为前体，通过容易的羟基化和硫化步骤制备的。这类NiCo ₂ S ₄作为超级电容器的电极材料，由于拟电容的作用，在1 A g ^-1时具有高达1350 F g ^-1的比电容。特别地，使用NiCo ₂ S ₄作为正极材料而PC作为负极材料组装而成的混合超级电容器PC // NiCo ₂ S ₄具有33 Wh kg ^-1的高能量密度。在800 W kg ^-1的功率密度下。同时，在电流密度5 A g ^-1进行10,000次充放电后，它具有良好的循环稳定性和67％的电容保持率。但是，由于作为电池型电极材料的NiCo ₂ S ₄的极化作用，因此倍率能力不够好。因此，本研究为增强电极材料的电容性能提供了参考。例如，在许多情况下，氧化还原反应的可逆性和结构的稳定性比容量更重要。

图形摘要

中空立方体NiCo ₂ S _4的制备及其在超级电容器中的应用。