Bulk-scale synthesis of randomly stacked graphene with high crystallinity
Bulk-scale synthesis of randomly stacked graphene with high crystallinity
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DOI：
10.1016/j.carbon.2021.09.034
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发表时间：
2021-11
期刊：
影响因子：
10.9
通讯作者：
Zizhao Xu;Shingo Nakamura;Taiki Inoue;Y. Nishina;Yoshihiro Kobayashi
中科院分区：
文献类型：
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作者：
Zizhao Xu;Shingo Nakamura;Taiki Inoue;Y. Nishina;Yoshihiro Kobayashi
由于体相AB堆积石墨烯的强烈层间相互作用降低了单层石墨烯的优异性能，因此需要形成随机堆积的石墨烯，以将石墨烯的高性能应用于宏观器件。然而，传统的获得块状石墨烯的方法存在结晶度低和/或形成热力学稳定的AB堆积结构的问题。本研究开发了一种新的方法，利用氧化石墨烯海绵的多孔形态和1500-1800℃的超高温处理乙醇蒸汽来制备高结晶度和高无规堆积分数的块状石墨烯。拉曼光谱表明，得到的块状石墨烯海绵具有较高的结晶度和高的无规堆积分数，达到80%。海绵样品和聚集体样品之间随机堆积比率的巨大差异证实了乙醇衍生物种进入内部区域的重要性。通过考察处理温度的影响，在1500℃下获得了较高的无规堆积比，并且通过引入纤维素纳米纤维作为间隔物，将AB堆积分数降低到10%以下，以防止石墨烯的直接堆积。该方法是大规模生产高性能块状石墨烯的有效方法。
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.