Defects within crystalline solids can exhibit a strong impact on the ionic conductivity of the material. In 1926, the pioneering work of the Russian scientist Frenkel 10 marked the introduction of the point defects concept. Frenkel proposed that the movement caused by thermal agitation leads to atom transitions from their regular lattice positions to interstitial sites, resulting in the creation of lattice vacancies. This phenomenon is now known as Frenkel defect, which already encompassed the notions of vacancies and self-interstitials. In the early 1930s, Wagner and Schottky 11 expanded on this idea by investigating the general occurrence of disorder in binary AB compounds, considering the presence of vacancies, self-interstitials, and defects where atoms occupy the wrong sublattices.