(569g) A Novel Form of Silica-Based Ionogel Electrolyte Offering Versatility, Stability, and High Performance

Electrical double layer capacitors, known as supercapacitors, have the potential to greatly expand our ability to store electrical energy due to their unprecedented combination of high energy density and high power density. The performance of current devices is limited by their reliance on unsafe organic solvent-based electrolytes. This work describes the development of an ionic liquid-rich (~94% by mass), mechanically compliant silica-supported ionogel (ionic liquid-based gel electrolyte). This new form of ionogel was created using a straightforward sol-gel process applied to a novel formulation of reactants, resulting in a versatile, stable, and high-performance solid electrolyte. The recently-developed mechanically compliant ionogels show both capacitance and ionic conductivity at room temperature nearly equivalent to those of the neat ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, EMI TFSI), whereas previously-reported silica ionogels are mechanically brittle and have lower ionic conductivity and double-layer capacitance. In addition, the silica microstructure is shown to be formulation-dependent, allowing for the possibility of tuning the electrolyte formulation for maximal compatibility with an electrode.  Compliant ionogels may be suitable for in situ fabrication of flexible, thin-film energy storage devices such as supercapacitors.