Enhancement of breakdown electric field in (Ca, Sr)Cu3Ti4O12 ceramics prepared via polymer pyrolysis

CaCu 3 Ti 4 O 12 (CCTO) has been widely studied for capacitor applications due to its excellent giant dielectric constant and frequency stability, but its development is limited by its low breakdown field strength ( E b ). To promote E b and primarily clarify the intrinsic mechanism, a synergistic strategy combining Sr substitution for Ca in CCTO ceramics with the polymer pyrolysis method was adopted. With the increase of Sr substitution, the average grain size of the ceramics gradually decreased and E b was remarkably enhanced. In particular, an E b of 106.0 kV/cm at a current density of 0.05 mA/cm 2 was achieved for Ca 0.4 Sr 0.6 Cu 3 Ti 4 O 12 ceramics, which is mainly attributed to the tremendous increase in grain boundary resistance induced by the increase of grain boundary density and formation of the insulating secondary phase SrO resulting from Sr substitution. We hope this study will provide a potential solution for the fabrication of CCTO-based dielectric ceramics with excellent E b .