Open AccessAn Artificial Interface for High Cell Voltage Aqueous-Based Electrochemical Capacitors
Author(s) -
Marco Olarte,
Marie-Joëlle Menu,
Patrice Simon,
Marie Gressier,
PierreLouis Taberna
Publication year - 2021
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ac10f5
Subject(s) - supercapacitor , electrochemical window , ionic liquid , electrolyte , electrochemistry , aqueous solution , materials science , electrode , capacitor , chemical engineering , ionic bonding , ionic conductivity , chemistry , voltage , ion , organic chemistry , electrical engineering , engineering , catalysis
Aqueous electrolytes are very effective for supercapacitor applications but their narrow electrochemical potential window (∼1 V) and associated limited energy currently limits their use. Here, we demonstrate a new strategy to enlarge the potential window by designing an artificial interface ( ai ). An effective ai was achieved via a mixture of siloxanes doped with an ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI TFSI). Indeed, the as-deposited ai on the carbon-based electrode hinders the electron charge transfer but not the ionic charge transfer, making the ai ionic conductive. As a result, a cell voltage of about 1.8 V was obtained in aqueous electrolyte-EMI HSO 4 1 mol l −1 in water. Used as a membrane, the ai was found to be ionically specific to EMI + ; the proton transference number being close to zero. These results show the strategy of developing an ai at the electrode/electrolyte interface could represent a new path for aqueous-based carbon-carbon supercapacitors to reach higher cell voltages, providing both higher specific energy and power.