Direct printing techniques have generated significant research interest in fabricating flexible and scalable micro-supercapacitors (MSCs). In this study, we report a facile and cost-effective way to synthesize water soluble reduced graphene oxide (WSG) with a high concentration by decoration with aminobenzenesulfonic acid (ABS) and reduction with ascorbic acid. The WSG possesses excellent electrical conductivity (360 S m⁻¹), good water dispersion stability as well as a high zeta potential value (−62 mV at pH 11), and the concentration of the as-prepared WSG could reach 5 mg mL⁻¹, nearly as great as the highest value from previous reports. Then, using this high-concentration WSG dispersion directly as an electrochemically active ink material, micro-supercapacitor electrodes could be facilely fabricated via a direct printing technique on common printing paper, and the all-solid-state flexible MSCs could be further assembled. The results show that these flexible MSCs exhibit high area and volume specific capacitances of 2.67 mF cm⁻² and 6.75 F cm⁻³, maintaining 94.8% of their initial specific capacitance after 5000 cycles at a scan rate of 50 mV s⁻¹. More importantly, the capacitance and potential can be expanded by connecting a WSG-MSC device in parallel and in series, and the assembled devices are further demonstrated to be capable of lighting a liquid crystal display with three WSG-MSCs in series. These findings not only provide a simple way to synthesize WSG with a high concentration, but also facilitate its applications in printable and flexible MSCs with high performance.

中文翻译：

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高浓度水溶性还原氧化石墨烯的简便合成及其在可印刷微型超级电容器中的应用

直接印刷技术在制造柔性和可扩展的微型超级电容器（MSC）方面引起了巨大的研究兴趣。在这项研究中，我们报告了一种简便且经济高效的方法，通过用氨基苯磺酸（ABS）修饰并用抗坏血酸还原来合成高浓度的水溶性还原氧化石墨烯（WSG）。该WSG具有优良的导电性（360 S米^-1），良好的水分散稳定性以及（在pH 11 -62毫伏）的高ζ电位值，以及所制备的WSG的浓度可达到5毫克毫升^{- 1个}，几乎与以前的报告中的最高值相同。然后，直接使用这种高浓度WSG分散液作为电化学活性墨水材料，可以通过直接印刷技术在普通印刷纸上轻松制造微超级电容器电极，并可以进一步组装全固态柔性MSC。结果表明，这些柔性MSC表现出2.67 mF cm ^-2和6.75 F cm ^-3的高面积和体积比电容，在以50 mV s ^-1的扫描速率进行5000次循环后，保持其初始比电容的94.8％。。更重要地，可以通过并联和串联连接WSG-MSC设备来扩展电容和电势，并且进一步证明组装的设备能够利用三个串联的WSG-MSC来点亮液晶显示器。这些发现不仅提供了一种高浓度合成WSG的简单方法，而且还促进了其在高性能的可打印和柔性MSC中的应用。