A new composite from graphene quantum dots (GQDs) and NiFe layered double hydroxide was successfully prepared by the coprecipitation method under optimal conditions. The nanoparticles of the composite were analyzed by X‐ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT‐IR), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA) to obtain the structure, composition and morphology information. Also, the electrochemical properties were investigated by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. The nanocomposite displays a specific capacitance of 712.7 F g⁻¹ and excellent cycle life after 2500 cycles by applying 10 A g⁻¹ of the current density in 1 M KOH electrolyte, which confirms that the nanocomposite has superb capacitance retention (∼94.8 %) and can be used as a capable supercapacitor. Furthermore, this study provides a desirable procedure for the preparation of novel nanocomposites based on graphene quantum dots, which can be used in energy storage/conversion devices.

中文翻译：

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石墨烯量子点/ NiFe层状双氢氧化物纳米复合材料的制备及电容性能

在最佳条件下，采用共沉淀法成功制备了石墨烯量子点（GQDs）和NiFe层状双氢氧化物复合材料。通过X射线衍射（PXRD），傅里叶变换红外光谱（FT-IR），扫描电子显微镜（SEM）和热重分析（TGA）分析复合材料的纳米颗粒，以获得结构，组成和形态信息。而且，通过循环伏安法，恒电流充电/放电测量和电化学阻抗谱研究了电化学性质。通过施加10 A g ^-1的纳米复合材料，其比电容为712.7 F g ^-1，并且在2500次循环后具有出色的循环寿命。1 M KOH电解质中的电流密度的一半，这证实了纳米复合材料具有极好的电容保持率（〜94.8％），可以用作功能强大的超级电容器。此外，这项研究为基于石墨烯量子点的新型纳米复合材料的制备提供了理想的方法，该复合材料可用于储能/转换装置。