Abstract
A highly performing proton conducting composite was prepared through the impregnation of EMIMCl ionic liquid in the mesoporous MIL-101(Cr)–SO3H MOF. The resulting EMIMCl@MIL-101(Cr)–SO3H composite displays high thermal and chemical stability, alongside retention of a high amount of EMIMCl even at temperatures as high as 500 K, as well as under moisture conditions. Remarkably, this composite exhibits outstanding proton conductivity not only at the anhydrous state (σ473 K = 1.5 × 10−3 S cm−S) but also under humidity (σ(343 K/60%–80%RH) ≥ 0.10 S cm−1) conditions. This makes EMIMCl@MIL-101(Cr)–SO3H a unique candidate to act as a solid state proton conductor for PEMFC applications under versatile conditions.