Realizing high comprehensive energy storage performance in lead-free bulk ceramics via designing an unmatched temperature range. Issue 48 (15th November 2019) - Yang, Zetian
Abstract : Simultaneous achievement of a large W rec of 3.51 J cm −3 and a high η of 80.1% in 0.86NN–0.14BNH ceramics under 350 kV cm −1, leading to an excellent comprehensive energy storage performance in lead-free bulk ceramics. Abstract : The study of lead-free dielectric ceramics for capacitors has become one of the most active academic research areas in advanced functional materials owing to the environmental regulations. A large recoverable energy storage density ( W rec ), a high energy storage efficiency ( η ) and good temperature stability in lead-free dielectric ceramics are highly desired simultaneously to meet the requirements of light weight and integration of dielectric capacitors in pulsed power devices. Unfortunately, a large W rec of lead-free dielectric ceramics is usually achieved at the cost of η, and vice versa, hindering their practical applications. More importantly, despite the considerable efforts made so far to develop a large amount of lead-free bulk ceramics for dielectric capacitor applications, there is still a lack of scientific and feasible guidelines on how to design new material systems with a large W rec, a high η and excellent thermal stability. Herein, we propose a new strategy to tailor the temperature region between the temperature corresponding to the maximum dielectric permittivity ( T m ) and the Burns temperature ( T B ) of relaxor ferroelectrics to room temperature via composition optimization, to explore lead-free bulk ceramics with high comprehensive energy storage properties. A large W rec of 3.51 J cm −3 and a high η of 80.1% are simultaneously obtained in 0.86NaNbO3 –0.14(Bi0.5 Na0.5 )HfO3 (0.86NN–0.14BNH) ceramics under an electric field of 350 kV cm −1, leading to an excellent comprehensive energy storage performance in lead-free bulk ceramics. Furthermore, both the W rec and η of 0.86NN–0.14BNH ceramics show good temperature stability over 20 °C to 200 °C at 280 kV cm −1, which is superior to that of other lead-free bulk ceramics. Most importantly, this work provides significant guidelines for designing new high-performance bulk ceramics for electrical energy storage applications.