Ultra-high energy storage density and ultra-wide operating temperature range in Bi2Zn2/3Nb4/3O7 thin film as a novel lead-free capacitor

Abstract Capacitor with high energy density, wide operating temperature range, large power density and environmental friendliness is strongly demanded in modern electrical and electronic devices. In this work, Bi2Zn2/3Nb4/3O7 (BZN) thin film as a novel lead-free material with ultra-high energy storage density and ultra-wide operating temperature range, is prepared by magnetron sputtering. Dielectric properties and electric breakdown strength depend on the substrate temperature, resulting in the change of energy storage performance. The dielectric constant and breakdown strength reach respectively 182 and 3.81 MV/cm for the BZN thin film prepared at 700 °C, while the maximum recoverable energy storage density (63.5 J/cm3) at 100 Hz is achieved. Moreover, the BZN thin films possess excellent thermal stability of energy storage properties in an ultra-wide temperature range (-150- 250 °C) and strong fatigue endurance after 1 × 106 charge–discharge cycles. These results reveal that the BZN thin film can be a promising candidate for lead-free energy storage application in equipment working in harsh environment.