Reduced graphene oxide (RGO) with a porous nanostructure and large surface area suffers from poor volumetric capacitance when it is employed in supercapacitors. This paper reports a facile, scalable and efficient method to produce self-assembled reduced graphene oxide with high packing density (1.55 g cm⁻³) via phosphoric acid treatment (PAT) at moderate temperatures (200–400 °C). The PAT process could not only controllably preserve redox-active C–OH and CO groups which can provide large and stable pseudocapacitance, but also contribute to the formation of a well self-assembled compact structure. Due to the pseudocapacitive behavior of the electrochemically active oxygen functional groups as well as the compact layered structure, the reduced graphene oxide (RGO-MP40) exhibits an ultrahigh volumetric capacitance (482 F cm⁻³ and 384 F cm⁻³ at a mass loading of 2.5 mg cm⁻² and 19.7 mg cm⁻², respectively). This novel strategy holds great promise for designing graphene-based materials for compact energy-storage devices.

中文翻译：

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通过磷酸处理氧化石墨烯的自组装生产的具有超高体积电容的超级电容器

当将其用于超级电容器时，具有多孔纳米结构和大表面积的还原氧化石墨烯（RGO）的体积电容较差。本文报道了一种简便，可扩展且有效的方法，该方法可在中等温度（200–400°C）下通过磷酸处理（PAT）来生产具有高堆积密度（1.55 g cm ^-3）的自组装还原氧化石墨烯。PAT过程不仅可以可控地保留氧化还原活性的C-OH和CO基团可以提供大而稳定的伪电容，但也有助于形成良好的自组装致密结构。由于电化学活性氧官能团的拟电容行为以及紧密的层状结构，还原的氧化石墨烯（RGO-MP40）在质量负载下表现出超高的体积电容（482 F cm ^-3和384 F cm ^-3）分别为2.5 mg cm ^-2和19.7 mg cm ^-2）。这种新颖的策略为设计用于紧凑型储能装置的石墨烯基材料具有广阔的前景。