Relaxor-ferroelectric thin film heterostructure with large imprint for high energy-storage performance at low operating voltage

Excellent energy storage performance in combination with a low operating voltage is a very important factor for pulse-power dielectric capacitor devices to achieve miniaturization and integration. Here the heterostructure of the relaxor ferroelectric Pb_0.9La_0.1(Zr_0.52Ti_0.48)O₃ (PL), with a slim hysteresis loop, on the normal ferroelectric Pb(Zr_0.52Ti_0.48)_0.99Nb_0.01O₃ (PN), causing a large voltage imprint, is shown to improve the energy-storage performance. A large recoverable energy-storage density of 43.5 J/cm³ and a high energy-storage efficiency of 84.1%, under an electric field of 2450 kV/cm (i.e. a 49 V voltage bias), are obtained in the 180 nm PL/20 nm PN thin film heterostructure. Due to the small total film thickness the excellent energy-storage properties are obtained at a low operating voltage of 49 V. Moreover, the PL/PN heterostructure also exhibits an excellent charge-discharge endurance up to 10¹⁰ cycles and good thermal stability in a wide temperature range from room temperature to 200 °C. These performances show that these heterostructures form a promising design for high-temperature pulse-power capacitors, with superior energy-storage performance at low operating voltages.