Since the strong interlayer interaction of AB-stacked graphene in bulk form degrades the superior property of single-layer graphene, formation of randomly stacked graphene is required to apply the high performances of graphene to macroscopic devices. However, conventional methods to obtain bulk-scale graphene suffer from a low crystallinity and/or the formation of a thermodynamically stable AB-stacked structure. This study develops a novel approach to produce bulk-scale graphene with a high crystallinity and high fractions of random stacking by utilizing the porous morphology of a graphene oxide sponge and an ultrahigh temperature treatment of 1500–1800 °C with ethanol vapor. Raman spectroscopy indicates that the obtained bulk-scale graphene sponge possesses a high crystallinity and a high fraction of random stacking of 80%. The large difference in the random-stacking ratio between the sponge and the aggregate samples confirms the importance of accessibility of ethanol-derived species into the internal area. By investigating the effect of treatment temperature, a higher random-stacking ratio is obtained at 1500 °C. Moreover, the AB-stacking fraction was reduced to less than 10% by introducing cellulose nanofiber as a spacer to prevent direct stacking of graphene. The proposed method is effective for large-scale production of high-performance bulk-scale graphene.

由于块状 AB 堆叠石墨烯的强层间相互作用降低了单层石墨烯的优越性能，因此需要形成随机堆叠的石墨烯，以将石墨烯的高性能应用于宏观器件。然而，获得块状石墨烯的常规方法具有低结晶度和/或形成热力学稳定的 AB 堆叠结构的问题。本研究开发了一种新方法，通过利用氧化石墨烯海绵的多孔形态和用乙醇蒸汽在 1500-1800°C 的超高温处理，生产具有高结晶度和高比例随机堆积的大块石墨烯。拉曼光谱表明，所获得的块状石墨烯海绵具有高结晶度和 80% 的高随机堆积分数。海绵和聚集体样品之间随机堆积比的巨大差异证实了乙醇衍生物种进入内部区域的重要性。通过研究处理温度的影响，在 1500 °C 时获得了更高的随机堆叠率。此外，通过引入纤维素纳米纤维作为间隔物来防止石墨烯的直接堆积，AB堆积率降低到10%以下。所提出的方法对于大规模生产高性能块状石墨烯是有效的。通过引入纤维素纳米纤维作为间隔物来防止石墨烯的直接堆积，AB堆积率降低到10%以下。所提出的方法对于大规模生产高性能块状石墨烯是有效的。通过引入纤维素纳米纤维作为间隔物来防止石墨烯的直接堆积，AB堆积率降低到10%以下。所提出的方法对于大规模生产高性能块状石墨烯是有效的。