Surface Active Ionic Liquids in Ionic Liquid Solvents for Enhanced Supercapacitor Energy Storage NR

Surface active ionic liquids (SAILs) are a unique group of ionic liquids (ILs) that combine the properties of self-assembling surfactants with that of ILs. From the results of previous neutron reflectivity (NR) studies, we have found that due to their electroresponsive nature, specific phosphonium/imidazolium (Im) orthoborate SAILs (Figure 1) are able to self-assemble into multi-layered structures on a charged electrode surface. They thus display great potential as electrolytes for enhanced supercapacitor energy storage. However, this was accomplished in the organic solvent propylene carbonate (PC), limiting the applicability of such a system with its intrinsic volatility and flammability. ILs on the other hand, provide a “green” alternative with their tunable properties and proven ability to support self-assembly1. They provide a plethora of “solvents” to choose from but due to their ionic nature (Figure 1), also provide a competing molecular species for interaction with a charged electrode interface. Therefore, we propose the use of NR to study the electroresponsive SAILs interfacial assembly when combined with an IL solvent. This has significant implications for the design of future supercapacitors and will be paired with SANS experiments on SANS2D.