Supercapacitors Based on Mixture of Room Temperature Ionic Liquids Containing Specifically Adsorbed Iodide Anions. (10th February 2015)

• Record Type: Journal Article
• Authors: Thomberg, Thomas; Tooming, Tauno; Liivand, K; Siinor, Liis; Jänes, Alar; Lust, Enn
• Is Part Of: ECS transactions. Volume 64:Number 20(2014)
• Page Start: 1
• Page End: 11
• Publication Date: 2015-02-10
• Subjects: Electrochemistry -- Periodicals; Electrochemistry; Periodicals; Electronic journals; Electronic journal; 541.37
• DOI: 10.1149/06420.0001ecst
• Languages: English
• ISSNs: 1938-5862

Abstract

Abstract : The influence of 5 wt% addition of 1-ethyl-3-methylimidazolium iodide (EMImI) in 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4 ) on the melting point, bulk conductivity and electrochemical properties of the ionic liquid mixture as an electrolyte in electrical double layer capacitor (EDLC) has been studied using cyclic voltammetry, electrochemical impedance spectroscopy, constant current charge-discharge and constant power discharge methods. The specific conductivity decreased from 13.6 mS cm -1 to 12.8 mS cm -1 and the melting point increased from 17°C to 19.5°C by adding 5 wt% of EMImI into EMImBF4 . Noticeable increase in specific capacitance up to 245 F g -1 at 1.0 V, specific energy (36.7 Wh kg -1 ) and specific power values has been established. Thus, EDLC based on EMImBF4 + EMImI mixture demonstrated nearly 50% higher stored charge value than EDLC without EMImI addition. However, only minor increase in characteristic relaxation time constant from 1.45 s to 1.48 s for EDLC based on I - adsorption effect has been established.