BaTiO3-based lead-free relaxor ferroelectric ceramics for high energy storage

Barium titanate (BaTiO 3 , BT) is widely used in capacitors because of its excellent dielectric properties . However, owing to its high remanent polarisation ( P r ) and low dielectric breakdown field strength ( E b ), achievement of high energy storage performance is challenging. Herein, a systematic strategy was proposed to reduce P r and elevate E b of BT via: (i) modification of the relaxor behavior by alloying it with Bi(Mg 2/3 Ta 1/3 )O 3 (BMT) and (ii) heightening E b by introducing NaTaO 3 (NT) with high band gap. Consequently, the energy storage efficiency ( η ) of 90 % and high E b of 780 kV cm −1 were achieved simultaneously for the BT-BMT- x NT system, which facilitated the recoverable energy density ( W rec ) of 6.02 J cm −3 . At 300 kV cm −1 , its temperature (20–120 °C) and frequency (1–500 Hz) stabilities were found to be good. Moreover, the BT-BMT-0.15NT possessed ultrafast discharge rate ( t 0.9 < 51 ns) and ultrahigh power density ( P D > 94 MW cm −3 ). This study offers an effective strategy for the design of novel high-performance dielectric energy storage materials .