A1 Journal article – refereed
Electropolymerized polyazulene as active material in flexible supercapacitors




List of Authors: Suominen Milla, Lehtimäki Suvi, Yewale Rahul, Damlin Pia, Tuukkanen Sampo, Kvarnström Carita
Publisher: ELSEVIER SCIENCE BV
Publication year: 2017
Journal: Journal of Power Sources
Journal name in source: JOURNAL OF POWER SOURCES
Journal acronym: J POWER SOURCES
Volume number: 356
Number of pages: 10
ISSN: 0378-7753
eISSN: 1873-2755

Abstract
We report the capacitive behavior of electrochemically polymerized polyazulene films in different ionic liquids. The ionic liquids in this study represent conventional imidazolium based ionic liquids with tetrafluoroborate and bis(trifluoromethylsulfonyl)imide anions as well as an unconventional choline based ionic liquid. The effect of different ionic liquids on the polymerization and capacitive performance of polyazulene films is demonstrated by cyclic voltammetry and electrochemical impedance spectroscopy in a 3-electrode cell configuration. The films exhibit the highest capacitances in the lowest viscosity ionic liquid (92 mF cm(-2)), while synthesis in high viscosity ionic liquid shortens the conjugation length and results in lower electroactivity (25 mF cm(-2)). The obtained films also show good cycling stabilities retaining over 90% of their initial capacitance over 1200 p-doping cycles. We also demonstrate, for the first time, flexible polyazulene supercapacitors of symmetric and asymmetric configurations using the choline based ionic liquid as electrolyte. In asymmetric configuration, capacitance of 55 mF (27 mF cm(-2)) with an equivalent series resistance of 19 Omega is obtained at operating voltage of 1.5 V. Upon increasing the operating voltage up to 2.4 V, the capacitance increases to 72 mF (36 mF cm(-2)). (C) 2017 Elsevier B.V. All rights reserved.

Last updated on 2019-29-01 at 10:17