Abstract Nanoflakes MnO2/reduced graphene oxide (NMG) composite and MnO2 nanoflakes (MN) were successfully synthesized through a modified method in which periodic repetition of stirring and microwave irradiation simultaneously were done for 21 cycles. The as-synthesized samples were characterized using X-ray diffraction, Fourier transformed infrared spectroscopy, Scanning electron microscopy, Energy-dispersive X-ray spectroscopy and Brunauer-Emmett-Teller analysis. Symmetric supercapacitors were fabricated using prepared MN and NMG composite as electrode materials. The NMG symmetric supercapacitor exhibited higher specific capacitance (140.3 Fg−1at 1 mA) and specific capacitance retention (91%) than MN symmetric supercapacitor. At the same time, the NMG symmetric supercapacitor also delivered a maximum energy density of 19.5 Wh kg−1at a power density of 633.7 W kg−1and remained 17 Wh kg−1 at 1864.3 W kg−1. Moreover, the efficiency of this composite symmetric supercapacitor is 99.4% retained even after 5000 charge/discharge cycles at 2 mA current.

中文翻译：

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同时搅拌和微波辅助合成纳米薄片 MnO2/rGO 复合电极材料，用于具有增强的电化学性能的对称超级电容器

摘要 纳米薄片 MnO2/还原氧化石墨烯 (NMG) 复合材料和 MnO2 纳米薄片 (MN) 通过改进的方法成功合成，其中周期性重复搅拌和微波辐射同时进行 21 个循环。使用 X 射线衍射、傅里叶变换红外光谱、扫描电子显微镜、能量色散 X 射线光谱和布鲁诺-埃米特-泰勒分析对合成的样品进行表征。使用制备的 MN 和 NMG 复合材料作为电极材料制造对称超级电容器。NMG 对称超级电容器比 MN 对称超级电容器表现出更高的比电容（140.3 Fg-1at 1 mA）和比电容保持率（91%）。同时，NMG 对称超级电容器还提供了 19 的最大能量密度。在 633.7 W kg-1 的功率密度下为 5 Wh kg-1，在 1864.3 W kg-1 时保持为 17 Wh kg-1。此外，即使在 2 mA 电流下进行 5000 次充电/放电循环后，这种复合对称超级电容器的效率仍能保持 99.4%。