Development of an ionogel membrane PVA/[EMIM] [SCN] with enhanced thermal stability and ionic conductivity for electrochemical application

• Published in: Journal of molecular liquids 2019-01, Vol.274, p.402-413
• Main Authors: Safna Hussan, K.P., Thayyil, M. Shahin, Jinitha, T.V., Kolte, Jayant
• Format: Article
• Language: English
• Subjects: [EMIM] [SCN]; Application; Electrical properties; Ionic liquid-based polymer composite membrane; PVA; Thermal properties
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2018.10.128

In recent years, enormous research effort has been devoted to immobilize ionic liquid for electrochemical applications. Recent studies have described that the ionogel electrolytes would be an excellent substitute for liquid electrolytes since it overcomes all the limitations of liquid electrolytes. Among all the well-known strategies, entrapping IL in the polymer matrix can be considered as a feasible, low-cost method for large-scale production of ionogel. This work is intended to report a novel approach to tune the properties of polyvinyl alcohol (PVA) by immobilizing 1-Ethyl, 3-methylimidazolium thiocyanate [EMIM] [SCN] in its matrix. With the help of computer simulations and Fourier Transform Infrared Spectrometry, the possible interactions between [EMIM] [SCN] and PVA matrix were studied. Further, the impact of varying concentration of [EMIM] [SCN] was investigated by means of X-ray Diffractometer, Differential Scanning Calorimetry, and Thermal Gravitometry Analysis. In order to have a better understanding of the membranes detailed electrochemical characterization were done with the help of broadband dielectric spectroscopy and cyclic voltammetry. Among these, PVA with 20% IL (in terms of mass concentration) having a glass transition temperature of 339 K exhibits superior performance with the fairly smooth surface, increased flexibility, enhanced thermal stability, highest ionic conductivity with low activation energy and maximum capacitance of 0.26C/g with nonohmic behaviour. [Display omitted] •Freestanding flexible ionogel membranes were prepared.•Incorporation of [EMIM] [SCN] in PVA enhanced its fragility, thermal stability, and conductivity.•A membrane with 20% IL exhibits superior performance with ionic conductivity and capacitance.