Colossal dielectric constant in K2Ti2O5

Abstract Potassium dititanate ( K 2 Ti 2 O 5 ) ceramics are shown to exhibit solid electrolyte properties with a colossal dielectric constant (up to 10 7 ) together with a high ionic conductivity (up to 10 - 5  S  cm - 1 ) at room temperature. Compared to Rb 2 Ti 2 O 5 crystals and ceramics, this is 2 orders of magnitude below but uses more abundant and eco-friendly compounds. For both materials, the dielectric constant and the ionic conductivity as a function of temperature and frequency seem to be linked together. The 2-order-of-magnitude difference can be attributed to a c-axis variation in the structure. K 2 Ti 2 O 5 material can be interesting for electronic applications as a supercapacitor compound.