Good temperature stability and colossal permittivity in TiO2 ceramics doped with Cu2+ and W6+ ions.

The rutile TiO 2 ceramics substituted with acceptor and donor ions are regarded to be promising candidate materials for energy storage because of their colossal permittivity (CP). In this work, a good CP performance (ϵ r >104) was achieved in all of (Cu 0.5 W 0.5) x Ti 1- x O 2 (CWTO x) ceramics fabricated by a traditional solid reaction method. Remarkably, CWTO 0.015 ceramic obtained an acceptable temperature stability accompanied a low dielectric loss (tan δ < 0.1) within a broad frequency/temperature range, which satisfies the application requirement of X8R. Two kinds of abnormal dielectric relaxation at low and high temperature region were interpreted by interface polarization and ionization of oxygen vacancies, respectively. Data of complex impedance combined XPS and EPR results proved that the IBLC effect is dominant to the CP performance of CWTO x ceramics. The finding in this work is expected to promote the further development and application of CP materials. [ABSTRACT FROM AUTHOR]