New solid-state electrolytes based on organic ionic plastic crystals

The development of new solid-state electrolytes for energy storage devices is important for increasing their stability, reliability and safety. Organic ionic plastic crystals (OIPCs) are a relatively new class of material that show increasing promise as solid state electrolytes for devices such as lithium or sodium batteries.[1] OIPCs are crystalline phases found in many of the same organic salt families as ionic liquids but these materials have elevated melting points and exhibit various forms of disorder, which is the origin of their plastic mechanical properties. One of the keys to the development of OIPCs as solid state electrolytes is expanding the range of cations and anions available, and understanding the structure and dynamics of the resultant material. For application in a device, OIPCs are combined with salts of the target ion (e.g. Li+ or Na+), after which detailed analysis of the electrochemical and device parameters is performed. OIPC-based electrolytes can also be combined with polymer nanofibers to further improve their mechanical and transport properties. This presentation will provide an overview of the new OIPC families that we have recently designed and synthesized, and progress of these materials towards their use in practical solid-state lithium and sodium based batteries. We have also investigated the use of nanoscale polymer composites and the combination of OIPCs with very high concentrations of lithium or sodium salts,2 and the recent work on developing these composite materials will be discussed. References: [1] H. Zhu, D. R. MacFarlane, J. M. Pringle, M. Forsyth Trends in Chemistry, 2019, 1 (1), 126 [2] D. Al-Masri, R. Yunis, H. Zhu, L. Jin, P. Bruce, A. F. Hollenkamp, J. M. Pringle Journal of Materials Chemistry A, 2019, 7, 25389-25398