TY - JOUR
T1 - Bulk-scale synthesis of randomly stacked graphene with high crystallinity
AU - Xu, Zizhao
AU - Nakamura, Shingo
AU - Inoue, Taiki
AU - Nishina, Yuta
AU - Kobayashi, Yoshihiro
N1 - Funding Information:
The authors thank Dr. R. Negishi for the fruitful discussion and technical assistance. We also appreciate Mr. T. Mikazuki and DKS Co. for providing the cellulose nanofiber samples. Part of this work was supported by JSPS KAKENHI (Grant Numbers JP15H05867 , JP17H02745 , JP19H04545 , and JP21H01763 ), Tanikawa Fund Promotion of Thermal Technology , and JST CREST ( JPMJCR18R3 ). SEM observation was performed at the Photonics Center, Osaka University.
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/11/15
Y1 - 2021/11/15
N2 - 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.
AB - 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.
KW - Bulk-scale graphene
KW - Interlayer interaction
KW - Reduced graphene oxide
KW - Stacking order
KW - Thermal reduction
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U2 - 10.1016/j.carbon.2021.09.034
DO - 10.1016/j.carbon.2021.09.034
M3 - Article
AN - SCOPUS:85115654028
VL - 185
SP - 368
EP - 375
JO - Carbon
JF - Carbon
SN - 0008-6223
ER -