GO/ZIF-67模板制备rGO/NiCo2S4及高性能不对称超级电容器

以氧化石墨烯(GO)为基底,在GO表面原位生长ZIF-67并作为模板,经硝酸镍刻蚀、碳化、水热硫化制得rGO/NiCo_2S_4复合材料。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)表征复合材料的结构与形貌。随后将rGO/NiCo_2S_4复合材料制成正极材料,测试其电化学性能,测试结果显示:rGO/NiCo_2S_4-1.5 h电极材料在1 A·g~(-1)的电流密度下,其比电容值高达1 577 F·g~(-1),当电流密度达到10 A·g~(-1)时,倍率性能为86.4%,在10 A·g~(-1)的电流密度下循环2 000次后,电容保持率为76.9%。另外,在6 mol·L-1KOH电解液中,由AC//rGO/NiCo_2S_4-1.5 h组成的不对称电容器在功率密度为723 W·kg~(-1)时,能量密度为33 Wh·kg~(-1);在高功率密度为7 277 W·kg~(-1)时,能量密度仍保持为23 Wh·kg~(-1)。

Preparation of rGO/NiCo2S4 and High-Performance Asymmetric Supercapacitors Using GO/ZIF-67 Template

This study based on ZIF-67, which was grown on the surface of GO to make GO/ZIF-67 as a template. After etching by nickel nitrate, carbonizing and treating by hydrothermal with sodium sulfide, the final product of rGO/NiCo₂S₄ composite was obtained. X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure and morphology of the composite which confirmed the expected product was obtained. Subsequently, the rGO/NiCo₂S₄ composite material was made into a positive electrode material and tested the electrochemical performance. The test results show that the rGO/NiCo₂S₄-1.5 h electrode material has a specific capacitance of 1 577 F·g^-1 at current density of 1 A·g^-1. When the current density reached 10 A·g^-1, the rate performance was 86.4%. After 2 000 cycles at a current density of 10 A·g^-1, the capacitance retention rate of rGO/NiCo₂S₄-1.5 h was 76.9%. In addition, an asymmetric capacitor of AC//rGO/NiCo₂S₄-1.5 h was assembled in a 6 mol·L^-1 KOH electrolyte. It delivered an energy density of 33 Wh·kg^-1 at a power density of 723 W·kg^-1, and it remained as high as 23 Wh·kg^-1 even at 7 277 W·kg^-1.