Polyoxometalate-Poly(Ethylene Oxide) Nanocomposites for Flexible Anhydrous Solid-State Proton Conductors

Films that can maintain their flexibilities and conductivities under low humidity and broad temperature range represent the next generation of solid-state proton conductors, which would extend the applications of energy storage and conversion devices in extreme environments. Owing to their strong interactions with poly(ethylene oxide) (PEO), polyoxometalates (POMs), a group of nanoscale metal oxide clusters, can form stable nanocomposites with PEO and fully inhibit its crystallization, facilitating the fast dynamics of PEO chains/segments, as evidenced from dielectric spectroscopy studies. It thus enables the fast proton transportation in the PEO matrix and the improvement of the composites' proton conductivities. With POMs' loading ratio approaching to 70% wt, the nanocomposite's proton conductivity reaches as high as 6.86 x 10(-3) S cm(-1) at 100 degrees C in anhydrous environment. The composites' mechanical properties can be further optimized upon the tuning of PEOs' molecular weight and finally, a flexible, self-supported anhydrous proton conductor can be obtained, which also demonstrates high compatibility to electrodes. The nanocomposite can maintain promising proton conductivities ranging from -20 to 100 degrees C in an anhydrous environment, enabling the fabrication of long-term robust performance of supercapacitor devices under extreme conditions, which has never been achieved before.

Automated summary

The study shows that stable nanocomposites can be formed by strong interactions between poly(ethylene oxide) (PEO) and polyoxometalates (POMs), facilitating fast proton transportation and enhancing proton conductivity in an anhydrous environment up to 6.86 x 10(-3) S cm(-1). Additionally, by adjusting the molecular weight of PEO, mechanical properties of the composites can be further optimized to achieve a self-supported anhydrous proton conductor with high compatibility to electrodes, enabling long-term robust performance of supercapacitor devices under extreme conditions.