Introduction and Overview: Protons, the Nonconformist Ions

Spatial-Temporal Characteristics of Confined Polymer Motion Determine Proton Conduction of Polyoxometalate–Poly(ethylene glycol) Hybrid Nanocomposites

“…As the key elements in fuel-cell devices, proton-conductive materials are under intense research to meet urgent need for improving their conductivity and stability performances. − The target proton conductors will be superionic materials with appropriate mechanical properties that can be operated at medium-high temperature and low environment humidity. − As a group of highly charged metal oxide clusters on the nanoscale, polyoxometalates (POMs) possess appreciable stability against high temperature and promising proton conductivity at ambient environment. − Thanks to the recent development in POM chemistry, these POMs can hybridize with polymers to form nanocomposites, which could significantly enhance POMs’ proton conductivity as well as mechanical properties. − Specifically, we have previously prepared the POM–poly­(ethylene glycol) (PEG) hybrid nanocomposites with PEG molecules encapsulated inside the nanochannels defined by POMs. , The obtained anhydrous hybrid materials showed comparatively high proton conductivity at high temperature (up to 443 K) in a low humidity environment (<1% RH) . However, the proton conductivity and mechanical properties of these materials are still far from being suitable for commercial applications .…”