Hydroxy functionalized ionic liquids as promising electrolytes for supercapacitor study of alpha-Fe2O3 thin films

作者：Patil Sandip K; Vadiyar Madagonda M; Bhise Sagar C; Patil Suryakant A; Awale Deepak V; Ghorpade Uma V; Kim Jin H^*; Ghule Anil V; Kolekar Sanjay S^*

来源：Journal of Materials Science: Materials in Electronics , 2017, 28(16): 11738-11748.

DOI：10.1007/s10854-017-6978-3

Herein, we are exploring hydroxy functionalized ionic liquids (HFILs) as electrolytes in electrochemical studies of Fe2O3 thin films in aqueous medium. The thin films are deposited by simple and cost effective successive ionic layer adsorption and reaction (SILAR) method at room temperature. Four HFILs, [HEMIM][Cl], [TEHEA][Cl], [(EtOH)NH3][Ac] and [(EtOH)(3)NH][Ac] are synthesized and their aqueous solutions have been studied as electrolytes. Syntheses of ILs are confirmed by NMR spectra whereas the structural and surface properties of Fe2O3 thin film is determined by X-ray diffraction pattern (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDAX) and Brunauer-Emmett-Teller (BET) analysis. XRD pattern confirms the rhombohedral phase of alpha-Fe2O3 (hematite). Electrochemical performance of Fe2O3 electrode in 0.1 M HFILs is investigated with cyclic voltammetry (CV), galavanostatic charge/discharge (GCD) analysis and electrochemical impedance spectroscopy (EIS). Fe2O3 electrode exhibited good capacitive nature in all HFILs, however, [HEMIM][Cl] conferred highest specific capacitance of 124 Fg(-1) at 4.0 mA cm(-2) current density amongst the studied HFILs. Good cycle stability and up to 91% retention of capacitance over 1000 cycles is availed with [HEMIM][Cl]. Such promising results are strongly emphasizing the possible utilization of HFILs as environmental benign media in supercapacitor application.

• 出版日期2017-8