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通过控制水热反应温度以及氧化石墨烯(GO)与高锰酸钾的填料比,合成了两组部分还原的GO-K2Mn4O8纳米复合材料.X射线衍射(XRD)分析说明水热过程中合成了α-MnO2和一种新的晶相K2Mn4O8.通过X射线光电子能谱(XPS)分析了水热反应前后氧化石墨的含氧官能团的变化.扫描电子显微镜(SEM)显示样品由片状还原的氧化石墨烯构成,其表面附有许多小的纳米颗粒,这种结构有利于储能时电子的传递.通过这两组复合材料的结构分析,更好地理解了材料的电化学性能的变化.利用循环伏安法和恒流充放电测试比较了材料的电容性能.用1mol·L-1的硫酸钠做电解液,电位范围是0-1V,在1A·g-1的电流密度下,测得的样品最佳比电容达到251F·g-1,能量密度为32Wh·kg-1,功率密度为18.2kW·kg-1.并且在5A·g-1的电流密度下循环1000次后样品的比电容仍维持在初始比电容的88%.
Two partially-reduced GO-K2Mn4O8 nanocomposites were synthesized by controlling the hydrothermal reaction temperature and the filler ratio of graphene oxide (GO) to potassium permanganate. X-ray diffraction (XRD) analysis showed that α-MnO2 and a new K2Mn4O8 crystal phase were prepared.The change of oxygen-containing functional groups of graphite oxide before and after hydrothermal reaction was analyzed by X-ray photoelectron spectroscopy (XPS) Scanning electron microscopy (SEM) showed that the sample was oxidized by flake reduction Graphene, with many small nanoparticles attached to its surface, which is conducive to the transfer of electrons during energy storage.According to the structural analysis of the two composites, the change of the electrochemical performance of the material is better understood. Cyclic voltammetry and constant current charge and discharge tests comparing the capacitive properties of the material.Using 1mol·L-1 sodium sulfate as electrolyte, the potential range is 0-1V, measured at a current density of 1A · g-1 Of the sample had a specific capacitance of 251F · g-1, an energy density of 32Wh · kg-1 and a power density of 18.2kW · kg-1, and the ratio of samples after 1000 cycles at a current density of 5A · g-1 The capacitance remains at 88% of the initial specific capacitance.