Enhanced Electric Breakdown Strength and Excellent Recoverable Storing Density in Batio3-Based Ceramic Via Regulating Polyvinyl Alcohol Contents in Viscous Polymer Processing

Despite as the key component in modern electronic devices or power systems, ceramic dielectric capacitors have drawbacks like low energy storage density and efficiency that limits their extensively wide application. Compared to the frequently utilized composition modification, this work adopted a different route to improve energy storage performance. 0.98Ba0.65Sr0.245Bi0.07TiO3-0.02Ce (BSBT-Ce) Pb-free ceramics with different PVA contents were prepared through viscous polymer processing. The rheological and energy storing performance were systematically studied. It can be seen that high PVA content results in more pores and larger grain sizes that will deteriorate the breakdown strength of ceramics. The highest breakdown strength is reaching 420 kV/cm while the concentration of PVA was 5 wt%. The mechanism of grain sizes on breakdown strength (BDS) is studied by electrical tree simulation based on COMSOL. Obviously, viscous polymer processing with proper PVA content is very effective to generate dense and homogenous structures. Finally, the ceramic with 5 wt% PVA possesses a high density up to 4.41 J/cm3 and an efficiency of about 84.21 % at 420 kV/cm. Simultaneously, this ceramic owns improved stability of both temperature (30 ~ 150 °C) and frequency (1 ~ 300 Hz) at 350 kV/cm, while the η keeping above 90 % and Wrec exceeding 3.6 J/cm3. The pulse performance with a power density about 245.74 MW/cm3 and discharge time around 0.075 μs suggests the developed composition owns very good potential for actual application.