Using neutron spin-echo to investigate proton dynamics in proton-conducting perovskites

TL;DR

This paper demonstrates the use of neutron spin-echo spectroscopy to study proton dynamics in proton-conducting perovskites, revealing long-range proton diffusion over nanometer scales and the effects of dopant atoms.

Contribution

It introduces neutron spin-echo as a novel method for investigating proton dynamics in ceramic proton conductors, combining experimental and theoretical approaches.

Findings

Long-range proton self-diffusion observed over 2 nm scale

Dopant atoms' trapping effects are averaged out at this scale

Neutron spin-echo is effective for studying proton conduction mechanisms

Abstract

We demonstrate the applicability of studying the proton dynamics in proton-conducting perovskites using neutron spin-echo spectroscopy, a powerful method hitherto neglected for studies of the proton dynamics in ceramic proton conductors. By combining our neutron spin-echo results of hydrated BaZr0.90Y0.10O2.95 with results obtained from kinetic modeling based on first-principles calculations we show that already over a length-scale as short as 2 nm the long-range proton self-diffusion is observed, and the likely effect of dopant atoms acting as trapping centers has averaged out.