The local structure of titania–ceria composites in a Gd-doped ceria solid electrolyte material is obtained by a combination of X-ray absorption fine structure and X-ray diffraction over the entire range of Ti composition. A compositional region (between 19 and 57%) with strongly distorted TiO6units and coexistence of Ce(III) and Ce(IV) was discovered,i.e.optimized for oxygen transport conduction and in agreement with the enhanced electro-chemo-mechanical effect previously observed in this composition range.