TY - JOUR
T1 - Capacitance of edge-free three-dimensional graphene
T2 - New perspectives on the design of carbon structures for supercapacitor applications
AU - Tang, Rui
AU - Nomura, Keita
AU - Inoue, Kazutoshi
AU - Kotani, Motoko
AU - Kyotani, Takashi
AU - Nishihara, Hirotomo
N1 - Funding Information:
Funding: This work was supported by JSPS KAKENHI [Grant Nos. 20K22458, 19H00913, and 21K18862], JST SICORP Grant No. JPMJSC2112, Japan Association for Chemical Innovation, and Cooperative Research Program “Five-star Alliance” in “NJRC Mater. & Dev.” The authors acknowledge the kind support of Prof. H. Kato during the Raman spectroscopy. The authors thank Nippon Kodoshi Co. and Kuraray Chemical Co. Ltd. for kindly supplying the cellulose separators and the activated carbon fiber, respectively. Theoretical calculations were partially conducted using the facilities of the Supercomputer Center at the Institute for Solid State Physics at the University of Tokyo.
Funding Information:
Funding: This work was supported by JSPS KAKENHI [Grant Nos. 20K22458 , 19H00913 , and 21K18862 ], JST SICORP Grant No. JPMJSC2112 , Japan Association for Chemical Innovation, and Cooperative Research Program “Five-star Alliance” in “NJRC Mater. & Dev.” The authors acknowledge the kind support of Prof. H. Kato during the Raman spectroscopy. The authors thank Nippon Kodoshi Co. and Kuraray Chemical Co., Ltd., for kindly supplying the cellulose separators and the activated carbon fiber, respectively. Theoretical calculations were partially conducted using the facilities of the Supercomputer Center at the Institute for Solid State Physics at the University of Tokyo.
Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2022/10/10
Y1 - 2022/10/10
N2 - The current target for expanding the application scope of supercapacitors is to increase their energy density (E) beyond 20 Wh kg−1. In this regard, edge-free carbon materials show considerable potential because of their high working voltage (U) in organic electrolytes; however, their capacitance (C) remains limited. In this study, we synthesized edge-free three-dimensional (3D) graphene materials with different numbers of graphene stacking layers (nstack). These carbon materials have similar pore morphologies and an edge-free structure because a template method and annealing at 1800 °C were applied, respectively. These features allowed C to remain unaffected by the pore size effect, wettability, parasitic side reactions, and pseudocapacitance. Our results suggested that increasing nstack slightly enhances the areal C; however, such an increase cannot compensate for the decrease in C attributed to the decrease in the specific surface area. We also confirmed that the C of 3D graphene materials has a quantum origin, which results in a “butterfly shaped” cyclic voltammetry curve; we also successfully quantified the quantum capacitance (CQ) for the complete understanding of the origin of C. Based on this knowledge, we estimated that this 3D graphene material can yield a high E of 43 Wh kg−1 once CQ is optimized.
AB - The current target for expanding the application scope of supercapacitors is to increase their energy density (E) beyond 20 Wh kg−1. In this regard, edge-free carbon materials show considerable potential because of their high working voltage (U) in organic electrolytes; however, their capacitance (C) remains limited. In this study, we synthesized edge-free three-dimensional (3D) graphene materials with different numbers of graphene stacking layers (nstack). These carbon materials have similar pore morphologies and an edge-free structure because a template method and annealing at 1800 °C were applied, respectively. These features allowed C to remain unaffected by the pore size effect, wettability, parasitic side reactions, and pseudocapacitance. Our results suggested that increasing nstack slightly enhances the areal C; however, such an increase cannot compensate for the decrease in C attributed to the decrease in the specific surface area. We also confirmed that the C of 3D graphene materials has a quantum origin, which results in a “butterfly shaped” cyclic voltammetry curve; we also successfully quantified the quantum capacitance (CQ) for the complete understanding of the origin of C. Based on this knowledge, we estimated that this 3D graphene material can yield a high E of 43 Wh kg−1 once CQ is optimized.
KW - Chemical vapor deposition
KW - Quantum capacitance
KW - Supercapacitor
KW - Templated carbon
KW - Three-dimensional graphene
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U2 - 10.1016/j.electacta.2022.141009
DO - 10.1016/j.electacta.2022.141009
M3 - Article
AN - SCOPUS:85135934893
SN - 0013-4686
VL - 429
JO - Electrochimica Acta
JF - Electrochimica Acta
M1 - 141009
ER -