Benign Solvation Effect on Electrochemical Intercalation of Triethylmethyl Ammonium into Graphite from Propylene Carbonate. Issue 16 (1st January 2018)

• Record Type: Journal Article
• Authors: Li, Jiayu; Huang, Yuhao; Wang, Hongyu
• Is Part Of: Journal of the Electrochemical Society. Volume 165:Issue 16(2018)
• Page Start: A4012
• Page End: A4017
• Publication Date: 2018-01-01
• Subjects: Batteries -- Electroanalytical Electrochemistry -- Supercapacitors -- graphite intercalation compounds -- quaternary alkyl ammonium -- solvation effect; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.1161816jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : Tetraethyl ammonium/triethylmethyl ammonium tetrafluoroborates dissolved in propylene carbonate (PC) are the most common non-aqueous electrolyte solutions for supercapacitors using both carbonaceous electrodes. In this work, they are applied in the graphite/activated carbon asymmetric capacitors, in which the charge storage at graphite negative electrode is based on the intercalation of quaternary alkyl ammonium cations. The capacitor containing triethylmethyl ammonium (TEMA + ) shows a much higher capacity and superior cycle-ability than that containing tetraethyl ammonium (TEA + ). In situ X-ray diffraction and in situ dilatometry are combined to determine the larger recoverable expansion in graphite negative electrodes due to a reversible intercalation of TEMA + . Electrochemical quartz crystal microbalance verifies the dramatic structural changes stem from the considerable co-intercalation PC molecules together with TEMA + . A benign solvation effect is proposed for facilitating the transportation and storage of TEMA + inside graphite.