LAUSR

This paper provides details on the design of protic ionic liquids (PILs) containing silica-based ionogel for nonhumidified proton exchange membrane (PEM) applications. Specifically, we described herein a simple method of encapsulating individually four different PILs within the silica network via the sol-gel technique. The choice of the PIL, with primary consideration on its chemical structure and the appropriate ratio of tetraethylorthosilicate (TEOS)/PIL to bring about effective encapsulation inside the silica matrix, would be integral to the design of an ionogel PEM with good ionic conductivity and high thermal and stable mechanical properties. Conductivity data suggests that both vehicle and Grotthus mechanisms could play a role in the proton conduction in the PIL-based ionogels. Further, results showed that the ionogel prepared from triethylammonium methanesulfonate PIL (ES) yielded the highest ion conductivity of 3.85 × 10−2 S/cm measured at 120 °C under nonhumidified condition. Moreover, the same ionogel when used in real proton exchange membrane fuel cell (PEMFC) systems under nonhumidified condition possessed a maximum power density of 43.3 mW/cm2 at a current density of 92 mA/cm2 at 30 °C, thus confirming, for the first time, the potential of PIL-containing silica-based ionogels fabricated via the facile sol-gel technique for PEMFC applications. Results presented herein merit further investigation and optimization on the use of ionogels as PEM for nonhumidified and moderately high-temperature PEMFC applications.