Encapsulating NH4Br in metal organic framework: achieving remarkable proton conduction in wide relative humidity range

Proton conducting materials are key components for constructing high-energy-density electronic devices. In this work, by accumulation of NH4Br into the nanospace of classical metal organic framework MIL-101-Cr, the highest proton conductivity of 1.53×10-1 S cm-1 was achieved at 363 K under 100% RH. The proton conduction of NH4Br@MIL-101-Cr is also prominent even at lower relative humidity, for instance, it is ~10-2 S cm-1 at 75% RH. The calculated active energy is 0.11 eV for NH4Br@MIL-101-Cr, representing tight H-bond networks and low proton transfer barrier and confirming pure proton conduction as well.