Hydrostatic pressure decreases the proton mobility in the hydrated BaZr0.9Y0.1O3 proton conductor

Impedance spectroscopy on the hydrated proton conductor BaZr0.9Y0.1O3 at high temperatures shows that the bulk proton conductivity activation energy Eb scales with the strain parameter ε, as achieved by hydrostatic pressures up to 2 GPa, suggesting that large lattices favor proton diffusivity. At high temperature, Eb increases upon pressure by 40%. The grain boundary activation energy Eg is around twice as Eb, indicating higher proton mobility in grain boundaries as a result of pressure induced sintering. An expanded lattice with strain parameter ε>1 should have lower Eb, suggesting that thin films expansive tensile strain could have larger proton conductivity.