“…They have attracted significant attention mainly due to their interesting physical and chemical properties, such as high melting point, high thermal stability, high resistance to radiation damage and low thermal conductivity. These properties enable them for extensive applications such as catalysts [3], nuclear waste disposal [4,5] and thermal barrier coatings [6]. Especially, their high ionic conductivity depending on structural flexibility and high compositional diversity makes them promising hosts for solid electrolytes in high-temperature fuel cells [7].…”