491675 Solubilities and Diffusivities of Oxygen in Ionic Liquids for Electrochemical Applications

Tangqiumei Maggie Song1, Oscar Morales1, Kan Huang2, Hongfei Jia2 and Joan F. Brennecke1, (1)Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN, (2)Toyota Research Institute of North America, Ann Arbor, MI

Ionic liquids (ILs) have been recognized as potential electrolytes for various electrochemical applications due to their favorable properties, such as good ionic conductivity, tunable hydrophobicity, and controllable gas solubility.  In particular, protic ionic liquids (PILs) have received considerable interest as proton transfer media in proton exchange membrane fuel cells (PEMFC).

Previous researchers have shown that PILs with high O2 solubility enhance the oxygen reduction reaction (ORR) activity1-2; therefore, the goal of this research is to design PILs with even higher O2 uptake in order to achieve better PEMFC performance. A series of PILs with different fluoroalkyl chain lengths (shown below), all paired with the [MTBD]+ cation, were investigated. Here we present the O2 solubility and diffusivity in these ILs, measured using a gravimetric microbalance. Other physical properties, such as thermal stability, density, and viscosity, are also reported.

Further, we compare the O2 solubility in the PILs to ILs we have designed for other applications3. These ILs include [PP13][Tf2N], [PP12O1][Tf2N], [Pyrro12O1][Tf2N], [DEME][Tf2N], [P2228][Tf2N], whose structures are shown below. Additionally, the temperature dependence of O2 dissolution in the ILs is examined, to provide information on both the interaction energy between the IL and O2, and the underlying driving force for O2 dissolution.

Figure 1. Structures of Investigated Ionic Liquids

References:

1.         Snyder, J.; Livi, K.; Erlebacher, J., Oxygen Reduction Reaction Performance of [MTBD][beti]_Encapsulated Nanoporous NiPt Alloy Nanoparticles. Advanced Functional Materials 2013, 23 (44), 5494-5501.

2.         Snyder, J.; Fujita, T.; Chen, M.; Erlebacher, J., Oxygen reduction in nanoporous metalÐionic liquid composite electrocatalysts. Nature materials 2010, 9 (11), 904-907.

3.         Seo, S.; Song, T. M.; Mizuno, F.; Takechi, K.; Brennecke, J. F., Influence of Ion Diffusivity and Gas Solubility in Ionic Liquids on Li-Air Battery Performance. ECS Transactions 2016, 75 (15), 147-160.

 


Extended Abstract: File Not Uploaded
See more of this Session: Ionic Liquids: Thermodynamics and Properties
See more of this Group/Topical: Topical Conference: Innovations of Green Process Engineering for Sustainable Energy and Environment