Phosphonium-based protic ionic liquid as electrolyte for carbon-based supercapacitors

• Published in: Electrochemistry communications Vol. 13; no. 10; pp. 1112 - 1115
• Main Authors: Timperman, Laure, Galiano, Hervé, Lemordant, Daniel, Anouti, Mériem
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.10.2011; Amsterdam Elsevier; New York, NY
• Subjects: Applied sciences; Capacitors. Resistors. Filters; Electrical engineering. Electrical power engineering; Exact sciences and technology; Phosphonium; Protic ionic liquids; Supercapacitors; Tetrafluoroborate; Various equipment and components; Tetrafluoroborate; Supercapacitors; Phosphonium; Protic ionic liquids; Temperature effect; Secondary cell; Protic solution; Electrolytic capacitor; Carbon; Discharge charge cycle; Operating conditions; Ionic liquid; Electrodes; Electrolyte; Acetonitrile; Supercapacitor; Boron Compounds; Electrical characteristic; Glassy state
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2011.07.010

This study describes the use of a solution of a phosphonium protic ionic liquid [Bu 3HP][BF 4] (3.4 mol L −1) in acetonitrile as an electrolyte for carbon-based supercapacitors, with an operating voltage of 1.5 V and capacities comparable to conventional aqueous electrolytes. The combination of good cycling abilities and an operating temperature ranging from − 40 °C to 80 °C rendered possible the realization of supercapacitors having an extended specific energy in a large temperature range. [Display omitted] ► The conductivity of mixture PIL + acetonitrile increased when increasing the temperature (from σ = 29 mS cm −1 at 25 °C to σ = 46.8 mS cm −1 80 °C). ► The PIL exhibited in a mixture with acetonitrile on glassy carbon working electrode a large electrochemical window at around 6 V. ► At 20 °C, the PIL electrolyte for carbon-based supercapacitors could operate up to 1.5 V. ► Stability tests performed at 3.5 A.g −1 shows that the capacitance evolved from 130 F.g −1 to 120 F.g −1 after 1000 cycles. ► The combination of remarkable cycling stability and large temperature operating (from 80 °C to −40 °C).