2015-Sustainable Industrial Processing Summit
SIPS 2015 Volume 7: Ionic Liquids & Energy Production
| Editors: | Kongoli F, Gaune-Escard M, Mauntz M, Rubinstein J, Dodds H.L. |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2015 |
| Pages: | 310 pages |
| ISBN: | 978-1-987820-30-0 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
< CD shopping page
Physicochemical, Thermal and Electrochemical Properties of Dicyanamide Anion Based Ionic Liquids Mixtures with I³-Butyrolactone as Electrolyte System for Lithium-Ion Batteries
Nebojsa Zec1; Marija Bester Rogac2; Slobodan Gadzuric3; Milan Vranes3;1FACULTY OF SCIENCES, Novi Sad, Serbia and Montenegro (formerly Yugoslavia); 2FACULTY OF CHEMISTRY AND CHEMICAL TECHNOLOGY, Ljubljana, Slovenia; 3FACULTY OF SCIENCES, UNIVERSITY OF NOVI SAD, Novi Sad, Serbia and Montenegro (formerly Yugoslavia);
Type of Paper: Regular
Id Paper: 164
Topic: 13
Abstract:
Ionic liquids (ILs) have been described as molten salts with a melting point below 100 °C, consisting of large asymmetric organic cations and organic or inorganic anions. In addition to the favorable physical and chemical properties of ionic liquids, their negligible vapor pressure, non-flammability, biodegradability and recyclability, make them 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 the 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 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 higher electrical conductivity. Because of the coordinating ability of the DCA anion, metal salts are often better soluble in dicyanamide based ionic liquids. Also, they are less moisture sensitive and have wide electrochemical window which makes them the good candidates for electrochemical devices.
Molecular liquids such as I³-butyrolactone (GBL) have 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. Thus, GBL can be used as a solvent at improving volumetric and transport properties of ILs and has been already usually applied in the new generation of lithium-ion batteries and electrochemical devices. In addition, since its polarity GBL possesses excellent salvation properties of lithium ions and the increasing conductivity.
In this work, density, viscosity and electrical conductivity of 1-Butyl-1-methylpyrrolidiunium dicyanamide [BMPYR][DCA] and 1-Butyl-3-methylimidazolium dicyanamide [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 high electrochemical and thermal stability and higher values of electrical conductivity and lower viscosities compared with NTf2 based ionic liquids.