Open-Framework Chalcogenide Showing Both Intrinsic Anhydrous and Water-Assisted High Proton Conductivity

Proton-conducting materials have attracted increasing interest because of the promising technological applications as key components in various electrochemical devices. It is of great significance for technique application to seek superior proton-conducting materials, operating under both anhydrous and humidified conditions in a wide temperature range. Herein we demonstrate the proton conductance of an open-framework chalcogenide, (CH₃NH₃)₂Ag₄Sn₃S₈ (1), and the postsynthesis product 2 achieved by doping hydrochloric acid into 1. Hybrid 2 displays both intrinsic anhydrous and water-assisted high proton conductance, with σ = 1.87 × 10^-4 S·cm^-1 at 463 K under N₂ atmosphere and 1.14 × 10^-3 S·cm^-1 at 340 K and 99% relative humidity, and these conductivities are comparable to that in the efficient metal-organic frameworks-based proton-conducting materials. Moreover, hybrid 2 shows excellent thermal stability and long-term stability of proton conduction.