Role of different nanoparticulate cores on the thermal, mechanical and electrochemical cycling behaviour of nanoscale hybrid ionic fluids

Abstract

Herein, two different nanoscale hybrid ionic fluids (NHIFs) have been demonstrated as potential electrolytes for electrochemical cyclic applications. These NHIFs are prepared by tethering 1-ethyl-3-(3-trimethoxysilylpropyl)-imidazolium bis(trifluoromethanesulfonyl)imide ionic liquids to the surfaces of SiO2 and Al2O3 nanoparticulate cores by simple sol–gel process, resulting in a class of versatile, stable and high-performance gel like materials. Both the NHIFs are mechanically compliant and thermally stable. The NHIFs show wide electrochemical stability window of 8volt that does not shrink with the increase of temperature. Furthermore, the NHIF electrolytic cells containing planar steel electrodes show very good capacitance retentivity (>90%) and long term cyclic stability above room temperature. Relatively higher grafting density of the ionic liquid chains to SiO2 nanoparticles as compared to Al2O3 nanoparticles enables the respective NHIF to show better morphology with superior thermal, mechanical, electrical and electrochemical properties than its Al2O3 tethered analogue. Results obtained from the study highlight the applicability of these hybrid ionic fluids as promising electrolytes in secondary charge storage devices, even at higher temperature.