2017-Sustainable Industrial Processing Summit
SIPS 2017 Volume 3. Gaune-Escard Intl. Symp. / Molten Salt and Ionic Liquid
| Editors: | Kongoli F, Fehrmann R, Gadzuric S, Gong W, Seddon KR, Malyshev V, Iwata S |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2017 |
| Pages: | 151 pages |
| ISBN: | 978-1-987820-65-2 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Physicochemical and Electrochemical Properties of Dicyanamide Based Ionic Liquids with γ Butyrolactone as Electrolyte for Lithium Ion Batteries
Slobodan Gadzuric1; Nebojsa Zec1; Milan Vranes1; Marija Bester Rogac2; Nikola Cvjeticanin3;1FACULTY OF SCIENCES, UNIVERSITY OF NOVI SAD, Novi Sad, Serbia and Montenegro (formerly Yugoslavia); 2FACULTY OF CHEMISTRY AND CHEMICAL TECHNOLOGY, UNIVERSITY OF LJUBLJANA, Ljubljana, Slovenia; 3FACULTY OF PHYSICAL CHEMISTRY, UNIVERSITY OF BELGRADE, Belgrade, Serbia and Montenegro (formerly Yugoslavia);
Type of Paper: Regular
Id Paper: 118
Topic: 13
Abstract:
Due to the favorable physical and chemical properties of ionic liquids (ILs), such as negligible vapor pressure, non-flammability, biodegradability and recyclability, they became interesting for a wide range of applications as potentially green solvents associated with little waste, risk and hazard problems. Since the ionic liquids are essentially ionic conductors, their utilization as novel electrolytes for electrochemical devices, such as lithium-ion batteries has also been subject of intense studies. Exchange of common organic solvents by ILs can enhance the safety of lithium-ion batteries. The high viscosity of ILs, which is a limiting factor for their practical application can be overcome by mixing ILs with appropriate molecular solvents.
Ionic liquids with dicyanamide anion (DCA) were investigated due to their properties such as low melting point and low viscosity, efficient mass transport and a high electrical conductivity. Due to the coordinating ability of the DCA anion, metal salts are often better soluble in dicyanamide based ionic liquids. Also, they are not moisture sensitive and have wide electrochemical window which makes them good candidates for electrochemical devices.
Molecular liquid y-butyrolactone (GBL) has a high boiling point, low melting point and low vapor pressure. The GBL is also a non-corrosive liquid suitable for electrochemical cells operating over a wide temperature range for a long time. These properties make GBL a good solvent candidate to be used to improve volumetric and transport properties of ILs. Thus, GBL is usually applied as a solvent in the new generation of lithium-ion batteries and electrochemical devices since the polarity of GBL provides excellent solvation of lithium ions and the increasing conductivity.
Density, viscosity and electrical conductivity of [BMPYR][DCA] and [BMIM][DCA] binary mixtures with GBL were examined in the temperature range from (273.15 to 323.15) K and at atmospheric pressure. The results are compared with those obtained in our previous studies of the systems with bis(trifluoromethylsulfonylimide) (NTf2) based ionic liquids containing the same cations. After that, lithium salt was added at the appropriate IL-GBL mixtures and physicochemical properties, electrochemical and thermal properties were investigated. The systems with DCA show higher values of electrical conductivity, lower viscosities and better electrochemical and thermal stability compared with NTf2 based ionic liquids. The most suitable ternary mixtures for the application as the electrolyte in lithioum ion batteries were tested together with anatase TiO2 nanotube arrays (NTAs) electrode. Also, cyclic voltammetry experiments are performed at different temperatures and scan rates.