Structural modifications induced by free protons in proton conducting perovskite zirconate membrane

Recently hydrogen appears as an alternative energy vector for a sustainable modern world. Proton conducting perovskite ceramics showing significant proton conduction (~10−2S/cm at 600°C) at medium temperature exhibit high potential as electrolytic membranes of water steam electrolysers. Prior to industrial requirements (mechanical and chemical stability, long working life) the structural behaviour of the host perovskite structure disturbed by the Ln/RE substitution and the presence of protonic species have to be well determined as a function of severe operating conditions. Ex situ neutron diffraction and thermal expansion as well as in situ high water pressure Raman studies were performed on non-protonated, protonated and deprotonated high dense SrZr0.9Yb0.1O2.95 ceramics. The results show that the proton doping (SrZr0.9Yb0.1O2.95H0.003) induces long range order structural modifications, weak enough to guaranty the stability during the high water pressure–high temperature cycling.