College of Physics, Sichuan University, Chengdu, 610064, China.
Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, London, WC1E 7JE, UK.
Small Methods. 2023 Jun;7(6):e2201557. doi: 10.1002/smtd.202201557. Epub 2023 Mar 9.
Reduced graphene-oxide (RGO)-based electrodes in supercapacitors deliver high energy/power capacities compared to typical nanoporous carbon materials. However, extensive critical analysis of literature reveals enormous discrepancies (up to 250 F g ) in the reported capacitance (variation of 100-350 F g ) of RGO materials synthesized under seemingly similar methods, inhibiting an understanding of capacitance variation. Here, the key factors that control the capacitance performance of RGO electrodes are demonstrated by analyzing and optimizing various types of commonly applied electrode fabrication methods. Beyond usual data acquisition parameters and oxidation/reduction properties of RGO, a substantial difference of more than 100% in capacitance values (with change from 190 ± 20 to 340 ± 10 F g ) is found depending on the electrode preparation method. For this demonstration, ≈40 RGO-based electrodes are fabricated from numerous distinctly different RGO materials via typically applied methods of solution (aqueous and organic) casting and compressed powders. The influence of data acquisition conditions and capacitance estimation practices are also discussed. Furthermore, by optimizing electrode processing method, a direct surface area governed capacitance relationship for RGO structures is revealed.
与典型的纳米多孔碳材料相比，基于还原氧化石墨烯（RGO）的电极在超级电容器中具有更高的能量/功率容量。然而，对文献的广泛深入分析表明，在看似相似的方法下合成的 RGO 材料的电容（100-350 F g 的变化）报告值存在巨大差异（高达 250 F g ），这阻碍了对电容变化的理解。在这里，通过分析和优化各种常见的电极制造方法，证明了控制 RGO 电极电容性能的关键因素。除了 RGO 的通常数据采集参数和氧化/还原性质外，根据电极制备方法，电容值存在显著差异（从 190 ± 20 到 340 ± 10 F g ，变化超过 100%）。为此演示，通过通常应用的溶液（水相和有机相）浇铸和压缩粉末方法，从许多明显不同的 RGO 材料中制备了 ≈40 个基于 RGO 的电极。还讨论了数据采集条件和电容估算实践的影响。此外，通过优化电极处理方法，揭示了 RGO 结构的直接表面积控制的电容关系。
