Supercapacitive properties of micropore- and mesopore-rich activated carbon in ionic liquid electrolytes with various constituent ions

Journal Article · Mon Dec 10 00:00:00 EST 2018 · ChemSusChem

DOI:https://doi.org/10.1002/cssc.201802489· OSTI ID:1493121

Nguyen, Quoc Dat ^[1]; Patra, Jagabandhu ^[2]; Hsieh, Chien-Te ^[3]; Li, Jianlin ^[4]; Dong, Quan-Feng ^[5]; Chang, Jeng-Kuei ^[6]

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1. National Central Univ., Taoyuan (Taiwan). Dept. of Chemical and Materials Science and Engineering
2. National Chiao Tung Univ., Hsinchu (Taiwan). Dept. of Materials Science and Engineering; National Cheng Kung Univ., Tainan (Taiwan). Hierarchical Green-Energy Materials (Hi-GEM) Research Center
3. Yuan Ze Univ., Taoyuan (Taiwan). Dept. of Chemical Engineering and Materials Science; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Mechanical, Aerospace, and Biomedical Engineering
4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Energy and Transportation Science Division
5. Xiamen Univ., Xiamen (China). State Key Lab. for Physical Chemistry of Solid Surfaces, Dept. of Chemistry
6. National Central Univ., Taoyuan (Taiwan). Dept. of Chemical and Materials Science and Engineering; National Chiao Tung Univ., Hsinchu (Taiwan). Dept. of Materials Science and Engineering; National Cheng Kung Univ., Tainan (Taiwan). Hierarchical Green-Energy Materials (Hi-GEM) Research Center

Ionic-liquid (IL) electrolytes, characterized by large potential windows, intrinsic ionic conductivity, low environmental hazard, and high safety, are used for micropore- and mesopore-rich activated-carbon (AC_micro and AC_meso) supercapacitors. IL electrolytes consisting of various cations [1-ethyl-3-methylimidazolium (EMI⁺), N-propyl-N-methylpyrrolidinium (PMP⁺), and N-butyl-N-methylpyrrolidinium (BMP⁺)] and various anions [bis(trifluoromethylsulfonyl)imide (TFSI^-), BF₄^-, and bis(fluorosulfonyl)imide (FSI-)] are investigated. The electrolyte conductivity, viscosity, and ion transport properties at the AC_micro and _ACmeso electrodes are studied. In addition, the capacitance, rate capability, and cycling stability of the two types of AC electrodes are systematically examined and post-mortem material analyses are conducted. The effects of IL composition on the charge–discharge capacitances of the AC_micro electrodes are more pronounced than those for the AC_meso electrodes. The FSI-based IL electrolytes, for which electrochemical properties are cation dependent, are found to be promising. Incorporating EMI⁺ with FSI^- results in a low electrolyte viscosity and a fast ion transport, giving rise to optimized electrode capacitance and rate capability. Replacing EMI⁺ with PMP⁺ increases the cell voltage (to 3.5 V) and maximum energy density (to 42-Wh kg^-1) of the AC_micro cell at the cost of cycling stability.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1493121
• Journal Information: ChemSusChem, Vol. 12, Issue 2; ISSN 1864-5631
• Publisher: ChemPubSoc Europe
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE