Abstract Electrochemical exfoliation of graphite has emerged as a potentially scalable approach to prepare graphene. However, most of exfoliated graphite particles are inhomogeneous and multilayer stacked structures including tens of layers thick graphite exist inevitably, thus the yield of few-layer graphene remains limited. In this study, we here propose a high-yield, scalable electrochemical exfoliation method in a ternary deep eutectic melts containing acetamide, urea and ammonium nitrate, where high viscosity, higher anionic intercalation potential and low migration speed can bring anions with solvents could co-intercalated into graphite uniformly, expand the interlayer of graphite gallery and then form steady graphite intercalation compounds, affording to complete sufficient intercalation. Finally decomposition of the intercalant facilitates expanded graphite to be exfoliated into graphene. Consequently, the yield is improved to 76% and the product primarily consists of 1–5 layer graphene, which exhibits a specific surface area (878 m2 g−1) close to the theoretical value of three-layer graphene. Furthermore, all-solid-state flexible supercapacitors based on the graphene deliver a high area capacitance of 120 mF cm−2, excellent mechanical flexibility and cycling stability (97.2% retention after 10000 cycles). This approach offers the potential for cost-effective, environmentally friendly and large-scale production of graphene and numerous advanced applications.

中文翻译：

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常温熔盐中电化学剥离的高产石墨烯及其在柔性固态超级电容器中的应用

摘要石墨的电化学剥离已成为制备石墨烯的潜在可扩展方法。然而，大多数剥离石墨颗粒是不均匀的，并且不可避免地存在包括几十层厚石墨的多层堆叠结构，因此少层石墨烯的产率仍然有限。在这项研究中，我们在含有乙酰胺、尿素和硝酸铵的三元深共熔熔体中提出了一种高产率、可扩展的电化学剥离方法，其中高粘度、更高的阴离子嵌入电位和低迁移速度可以使阴离子与溶剂共同作用。均匀地嵌入石墨中，扩大石墨廊道的夹层，形成稳定的石墨插层化合物，实现充分的插层。最后，嵌入剂的分解促进膨胀石墨剥离成石墨烯。因此，产率提高到 76%，产品主要由 1-5 层石墨烯组成，其比表面积 (878 m2 g-1) 接近三层石墨烯的理论值。此外，基于石墨烯的全固态柔性超级电容器具有 120 mF cm-2 的高面积电容、出色的机械柔韧性和循环稳定性（10000 次循环后保持率达 97.2%）。这种方法为石墨烯的低成本、环保和大规模生产以及众多先进应用提供了潜力。其比表面积 (878 m2 g-1) 接近于三层石墨烯的理论值。此外，基于石墨烯的全固态柔性超级电容器具有 120 mF cm-2 的高面积电容、出色的机械柔韧性和循环稳定性（10000 次循环后保持率达 97.2%）。这种方法为石墨烯的低成本、环保和大规模生产以及众多先进应用提供了潜力。其比表面积 (878 m2 g-1) 接近于三层石墨烯的理论值。此外，基于石墨烯的全固态柔性超级电容器具有 120 mF cm-2 的高面积电容、出色的机械柔韧性和循环稳定性（10000 次循环后保持率达 97.2%）。这种方法为石墨烯的低成本、环保和大规模生产以及众多先进应用提供了潜力。