Abstract A facile simple hydrothermal synthetic route has been developed for the synthesis of perovskite lanthanum aluminate (LaAlO3) and reduced graphene oxide composite (RGO). Green tea extract here is used as reducing agent for conversion of graphene oxide to reduced graphene oxide. The synthesized materials have been characterized for its morphology using, XRD, SEM, EDAX, FTIR and BET techniques. The materials are used as electrode materials for supercapacitor applications. Electron microscopic images indicate RGO sheets are densely attached to surface of LaAlO3 with perforated cage like morphology. A high specific capacitance of 721 F g−1 at a scan rate of 2 mV s−1 was exhibited by RGO/LaAlO3 hybrid structure electrode when compared to pure RGO (531 F g−1) and pure LaAlO3 (105 F g−1) electrodes at the same scan rate using cyclic voltammetry (CV). By using chronopotentiometry (CP), the RGO/LaAlO3 hybrid structure electrode out stretched specific capacitance of 283 F g−1 at a current density of 0.5 A g−1 and able to retain specific capacitance (Csp) of about 157 F g−1 even at very high current density of 20 A g−1. RGO/LaAlO3 composite also possesses an energy density of 57 Wh kg−1 with a maximum power density of 569 W kg−1. RGO/LaAlO3 nanocomposite has also been fabricated for asymmetric supercapacitor device (ASD) system. From the Electrochemical Impedance Spectroscopy (EIS), the RGO/LaAlO3 hybrid structure electrode has shown phase angle close to −90° for frequency up to 0.01 Hz, suggesting that the nanocomposite electrode material approached ideal capacitor behaviour.

中文翻译：

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用于高性能超级电容器的钙钛矿铝酸镧及其绿色还原氧化石墨烯复合材料的简便合成

摘要 开发了一种简便的水热合成路线，用于合成钙钛矿铝酸镧 (LaAlO3) 和还原氧化石墨烯复合材料 (RGO)。这里的绿茶提取物用作还原剂，将氧化石墨烯转化为还原氧化石墨烯。已使用 XRD、SEM、EDAX、FTIR 和 BET 技术表征合成材料的形态。该材料用作超级电容器应用的电极材料。电子显微图像表明 RGO 薄片紧密附着在 LaAlO3 表面，具有穿孔笼状形态。与纯 RGO (531 F g-1) 和纯 LaAlO3 (105 F g-1) 相比，RGO/LaAlO3 混合结构电极在 2 mV s-1 的扫描速率下表现出 721 F g-1 的高比电容) 电极以相同的扫描速率使用循环伏安法 (CV)。通过使用计时电位法 (CP)，RGO/LaAlO3 混合结构电极在 0.5 A g-1 的电流密度下拉伸了 283 F g-1 的比电容，并能够保持约 157 F g-1 的比电容 (Csp)即使在 20 A g-1 的非常高的电流密度下。RGO/LaAlO3 复合材料还具有 57 Wh kg-1 的能量密度和 569 W kg-1 的最大功率密度。RGO/LaAlO3 纳米复合材料也可用于非对称超级电容器装置 (ASD) 系统。从电化学阻抗谱（EIS），