Wang Wen, Dai Shuyang, Li Xide, Yang Jiarui, Srolovitz David J, Zheng Quanshui
Department of Engineering Mechanics, Center for Nano and Micro Mechanics, Applied Mechanics Lab, Tsinghua University, Beijing 100084, China.
Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Nat Commun. 2015 Aug 28;6:7853. doi: 10.1038/ncomms8853.
The basal plane cleavage energy (CE) of graphite is a key material parameter for understanding many of the unusual properties of graphite, graphene and carbon nanotubes. Nonetheless, a wide range of values for the CE has been reported and no consensus has yet emerged. Here we report the first direct, accurate experimental measurement of the CE of graphite using a novel method based on the self-retraction phenomenon in graphite. The measured value, 0.37±0.01 J m(-2) for the incommensurate state of bicrystal graphite, is nearly invariant with respect to temperature (22 °C≤T≤198 °C) and bicrystal twist angle, and insensitive to impurities from the atmosphere. The CE for the ideal ABAB graphite stacking, 0.39±0.02 J m(-2), is calculated based on a combination of the measured CE and a theoretical calculation. These experimental measurements are also ideal for use in evaluating the efficacy of competing theoretical approaches.
石墨的基面解理能（CE）是理解石墨、石墨烯和碳纳米管许多独特性质的关键材料参数。尽管如此，文献中报道的CE值范围很广，尚未达成共识。在此，我们报告了首次使用基于石墨自收缩现象的新方法对石墨的CE进行直接、精确的实验测量。对于双晶石墨的非公度状态，测量值为0.37±0.01 J m⁻²，该值几乎不随温度（22°C≤T≤198°C）和双晶扭转角变化，且对大气中的杂质不敏感。基于测量的CE与理论计算相结合，得出理想ABAB石墨堆积的CE为0.39±0.02 J m⁻²。这些实验测量结果也非常适合用于评估相互竞争的理论方法的有效性。
