High energy storage performance in tungsten bronze-based relaxor ceramic via doping with CuO

Developing high-performance lead-free ceramics for capacitive applications has become more and more critical owing to the increasing concern about environmental protection and electronics industry. Here, a dual defect manipulation strategy was proposed to boost energy storage performance in CuO-modifided Sr2NaNb5O15-based lead-free tungsten bronze relaxor ceramic. Induced defect dipoles and reduced oxygen vacancy concentration generate a pinched polarization hysteresis loop and high breakdown strength, thus giving rise to a high recoverable energy density of 4.17 J/cm3 and efficiency of 89.5% at 350 kV/cm, together with an ultrafast discharge speed of 55 ns and a high power density of 118.4 MW/cm3. This proposed strategy is generalizable for realizing high capacitive performance in tungsten bronze-based dielectrics and other lead-free ceramics that benefit from dual defect manipulation.