Emmanuel Pameté Yambou presented a talk entitled "Low temperature (-50 °C) extended operation of ionic liquid-based EDLCs by implementing binary mixtures and carbons with optimised porous texture" during the 10th edition of the Journées de Chimie Analytique, September 04th to 06th, Yaoundé, Cameroon 2019.
Abstract:
Low temperature (-50 °C) extended operation of ionic liquid-based EDLCs by implementing binary mixtures and carbons with optimised porous texture
Emmanuel Pameté Yambou*, Barbara Górska, Vladimir Pavlenko and François Béguin
Poznan University of Technology, ul. Berdychowo 4, 60-965, Poznan, Poland
*emmanuel.yambou@doctorate.put.poznan.pl
The present study is focused on the use of imidazolium-based ionic liquids (ILs), due to their relatively low viscosity and relatively high conductivity in contrast to their pyrrolidinium [1] or piperidinium [2] counterparts. Binary mixtures with various molar ratios were formulated using two ILs with 1-ethyl-3-methylimidazolium cation, [EMIm]+, coupled with bis(trifluosulfonyl)imide [FSI]- or tetrafluoroborate [BF4]- anions. Taking into account our differential scanning calorimetry (DSC) investigations as well as viscosity and conductivity measurements on various binary mixtures of imidazolium based ILs,we selected the EMImFSI/EMImBF4 (1:1 molar ratio) mixture, as it exhibited only a glass transition at -97 °C, relatively low viscosity of 33.0 mP s and relatively good conductivity of 12.1 mS cm-1 (at 20 °C). To uphold the low-temperature performance of carbon-based electrical double-layer capacitors (EDLCs) in 1:1 EMImFSI/EMIMBF4 electrolyte, we applied electrodes made of mesoporous materials: SC2A carbon black (by Cabot, SDFT = 1502 m2 g-1; Vmeso = 1.05 cm3 g-1) and a home-made carbon [3] MP98B (SDFT = 1556 m2 g-1;Vmeso = 1.30 cm3 g-1) having well-defined mesoporous with average size of 3.5 nm. The capacitor based on MP98B demonstrated higher capacitance (140 F g-1** at 20 °C) compared to the one with electrodes made from SC2A (115 F g-1** at 20 °C). Both EDLCs operated down to -50 ºC, while at this temperature, the cell based on MP98B exhibited lower resistance (40 Ω vs. 151 Ω) and higher gravimetric capacitance (106 F g-1** vs. 73 F g-1**).
**capacitance values are expressed per average active mass in one electrode.
Keywords: Ionic liquids, binary mixtures, low-temperature, home-made carbon, carbon-based EDLCs,
References
[1] M. Kunze, S. Jeong, E. Paillard, M. Winter, S. Passerini, J. Phys. Chem. C, 269 (2018) 12364-12369.
[2] W.-Y. Tsai, R. Lin, S. Murali, L.L. Zhang, J.K. McDonough, R.S. Ruoff, P.-L. Taberna, Y. Gogotsi, P. Simon, Nano Energy, 2 (2013) 989-997.
[3] T. Morishita, T. Tsumura, M. Toyoda, J. Przepiórski, A.W. Morawski, H. Konno, M. Inagaki, Carbon, 48 (2010) 2690-2707.
Acknowledgements: The Polish National Science Center (NCN) is acknowledged for supporting the MAESTRO project UMO-2016/22/A/ST4/00092.
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