Abstract

The emergence of global warming driven by greenhouse gases has put tremendousemphasis on the need to develop improved large scale energy storage systems includinglow-cost, and high energy density batteries such as rechargeable metalbatteries. Batteries in which metals such as lithium, magnesium, sodium and zinc act as the electroactive speciesoffer great potential in these applications. Room temperature ionic liquids (RTILs) that are, generally, non-volatile, non-flammable and thermally stable have recently been shown to enhance the electrochemical characteristicsand long-term cycling of some of these metals.

Recent work has demonstrated the importance of functional groups in the RTIL cations and anions[1] and the role of additives[2] in influencing speciation and electrochemical behaviour of metal ions in lithium[3] and sodium[4] batteries.These functionalised ILs are further providing a pathway towards cheaper, rechargeable metal batteries such as those based on zinc[5-6] and magnesium[7].

This talk will discuss recent work from our group, and others, in these areas.

1. Kar, M.; Winther-Jensen, B.; Forsyth, M.; MacFarlane, D. R., Chelating Ionic Liquids for Reversible Zinc Electrochemistry. Phys. Chem. Chem. Phys. 2013, 15, 7191-7197.
2. Simons, T. J.; Torriero, A. A. J.; Howlett, P. C.; MacFarlane, D. R.; Forsyth, M., High Current Density, Efficient Cycling of Zn 2+ in 1-Ethyl-3-Methylimidazolium Dicyanamide Ionic Liquid: The Effect of Zn 2+ Salt and Water Concentration. Electrochem. Commun. 2012, 18, 119-122.

3. Yoon, H.; Howlett, P. C.; Best, A. S.; Forsyth, M.; MacFarlane, D. R., Fast Charge/Discharge of Li Metal Batteries Using an Ionic Liquid Electrolyte. J Electrochem Soc 2013, 160, A1629-A1637.

4. Pope, C. R.; Macfarlane, D. R.; Armand, M.; Forsyth, M.; O'Dell, L. A., Ion Dynamics in a Mixed-Cation Alkoxy-Ammonium Ionic Liquid Electrolyte for Sodium Device Applications. ChemPhysChem 2016.

5. Kar, M.; Winther-Jensen, B.; Armand, M.; Simons, T. J.; Winther-Jensen, O.; Forsyth, M.; MacFarlane, D. R., Stable Zinc Cycling in Novel Alkoxy-Ammonium Based Ionic Liquid Electrolytes. Electrochim Acta 2016, 188, 461-471.

6. Simons, T. J.; Salsamendi, M.; Howlett, P. C.; Forsyth, M.; Macfarlane, D. R.; Pozo-Gonzalo, C., Rechargeable Zn/Pedot Battery with an Imidazolium-Based Ionic Liquid as the Electrolyte. ChemElectroChem 2015.

7. Kar, M.; Ma, Z.; Azofra, L. M.; Chen, K.; Forsyth, M.; MacFarlane, D. R., Ionic Liquid Electrolytes for Reversible Magnesium Electrochemistry. Chem. Commun. 2016, 52, 4033-4036.