Title: Microscopic vertical orientation of nano-interspaced graphene architectures in deposit films as electrodes for enhanced supercapacitor performance

Abstract

This paper reported a novel two-step process to fabricate high-performance supercapacitor films that contain microscale domains of nano-interspaced, re-stacked graphene sheets oriented perpendicular to the surface of current collector substrate, i.e., carbon fiber paper. In the two-step process, we first used ligand molecules to modify the surface of graphene oxide (GO) sheets and manipulate the interspacing between the re-stacked GO sheets. The ligand-modified GOs, i.e., m-GOs, were then reduced to obtain more conductive graphene (m-rGO), where X-ray diffraction measurement results indicated well-controlled interlayer spacing between the restacked m-rGO sheets up to 1 nm. The typical lateral dimension of the restacked m-rGO sheets were ~40 µm. Then, electrical field was introduced during m-rGO slurry deposition process to induce the vertical orientation of the m-rGO sheets/stacks in the film deposit. The direct current electrical field induced the orientation of the domains of m-rGO stacks along the direction perpendicular to the surface of deposit film, i.e., direction of electric field. Also, the applied electric field increased the interlayer spacing further, which should enhance the diffusion and accessibility of electrolyte ions. As compared with the traditionally deposited “control” films, the field-processed film deposits that contain oriented structure of graphene sheets/stacks have shown up tomore » ~1.6 times higher values in capacitance (430 F/g at 0.5 A/g) and ~67% reduction in equivalent series resistance. Finally, the approach of using electric field to tailor the microscopic architecture of graphene-based deposit films is effective to fabricate film electrodes for high performance supercapacitors.« less

Authors:

Jang, Gyoung Gug ^[1]; Song, Bo ^[2]; Li, Liyi ^[2]; Keum, Jong Kahk ^[3]; Jiang, Yongdong ^[4]; Hunt, Andrew ^[4]; Moon, Kyoung-sik ^[2]; Wong, Ching-Ping ^[2]; Hu, Michael Z. ^[1]

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+ Show Author Affiliations

1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Energy and Transportation Science Division
2. Georgia Inst. of Technology, Atlanta, GA (United States). School of Material Science and Engineering
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences. Chemical and Engineering Materials Division
4. nGimat Co., Norcross, GA (United States)

Publication Date:

Wed Dec 14 00:00:00 EST 2016

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Georgia Institute of Technology, Atlanta, GA (United States)

Sponsoring Org.:

USDOE Advanced Research Projects Agency - Energy (ARPA-E); USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Sustainable Transportation Office. Bioenergy Technologies Office

Contributing Org.:

nGimat Co., Norcross, GA (United States)

OSTI Identifier:

1337819

Alternate Identifier(s):

OSTI ID: 1413051

Grant/Contract Number:  

AC05-00OR22725; AR0000303

Resource Type:

Accepted Manuscript

Journal Name:

Nano Energy

Additional Journal Information:

Journal Volume: 32; Journal ID: ISSN 2211-2855

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; Graphene film deposits; Supercapacitor; Vertically oriented graphene; Functionalized graphene; Graphene interspacing