Novel BaTiO3-based lead-free ceramic capacitors featuring high energy storage density, high power density, and excellent stability

The development of energy storage devices with a high energy storage density, high power density, and excellent stability has always been a long-cherished goal for many researchers as they tackle issues concerning energy conservation and environmental protection. In this work, we report a novel BaTiO3-based lead-free composition (0.85BaTiO(3)-0.15Bi(Zn1/2Sn1/2)O-3) with an ultrahigh energy storage density (2.41 J cm(-3)) and a high energy storage efficiency of 91.6%, which is superior to other lead-free systems reported recently. The energy storage properties of 0.85BT-0.15BZS ceramic manifest excellent frequency stability (5-1000 Hz) and fatigue endurance (cycle number: 10(5)). The pulsed charging-discharging process is measured to elucidate the actual operation performance in the 0.85BT-0.15BZS ceramic. Delightfully, the 0.85BT-0.15BZS ceramic also possesses an ultrahigh current density of 551 A cm(-2) and a giant power density of 30.3 MW cm(-3), and the stored energy is released in sub-microseconds. Moreover, the 0.85BT-0.15BZS ceramic exhibits outstanding temperature stability of its dielectric properties, energy storage properties, and charging-discharging performance over a broad temperature range (20-160 degrees C) due to the weakly-coupled relaxor behavior. These results not only indicate the superior potential of environment-friendly BaTiO3-based relaxor ferroelectric ceramics for the design of ceramic capacitors of both high energy storage and power applications, but they also show the merit of the weakly-coupled relaxor behavior to improve the thermal stability of energy storage properties.