High Temperature Proton Conductors - Fundamentals and Functionalities

Oxides dissolve protons that become mobile at high temperatures resulting in proton conduction. Materials possessing this functional property find applications in environmentally friendly energy technologies and will as such become essential components in future sustainable energy production. This contribution presents the fundamentals and functionalities of oxides showing high temperature proton conduction. The working principles are addressed with basis in the thermodynamics of proton dissolution and the mechanisms for proton mobility. Effects of grain boundaries and trapping on proton transport are outlined. Several oxide families possessing proton conduction at high temperatures are reviewed. Finally some of the potential applications for these materials and the status of the technologies are briefly discussed with bases in the benchmark oxides and assemblies.