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

Barium titanate (BaTiO3, BT) is widely used in capacitors because of its excellent dielectric properties. However, owing to its high remanent Barium titanate (BaTiO3, 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(Mg2/3Ta1/3)O-3 (BMT) and (ii) heightening E-b by introducing NaTaO3 (NT) with high band gap. Consequently, the energy storage efficiency (eta) of 90 % and high E-b of 780 kV cm(-1) were achieved simultaneously for the BT-BMT-xNT system, which facilitated the recoverable energy density (W-rec) of 6.02 J cm(-3). At 300 kV cm(-1), its temperature (20-120 degrees 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.