Design of an all-inorganic flexible Na0.5Bi0.5TiO3-based film capacitor with giant and stable energy storage performance

Abstract

With the significant advancement of portable/wearable electronics, the demand for flexible electronic devices has significantly increased; in the field of energy storage, the development of dielectric capacitors is still facing challenges due to the difficulty in integrating large recoverable energy storage density (W_rec), high efficiency (η), and robust bendability with fully flexible pulsed power systems operating in harsh environments. Herein, the all-inorganic flexible Mn-doped (1−x)(0.94Na_0.5Bi_0.5TiO₃-0.06BaTiO₃)-xSrTiO₃ (Mn:NBT-BT-xST, x = 0.30, 0.45, 0.60, and 0.75) film capacitors were obtained via simple one-step fabrication on a mica substrate. The Mn:NBT-BT-0.45ST film capacitor shows the desirable W_rec of 76.1 J cm⁻³ and the high η of 80.0% owing to the predominant relaxor feature and weak antiferroelectric-like behavior. Furthermore, stable properties in the frequency range from 500 Hz to 20 kHz and the ultra-wide working temperature range of −100 to 200 °C and robust fatigue and retention endurance over 10⁸ cycles and 10³ s were achieved, respectively. Moreover, mechanical bending processes at the small radius of 2 mm or even 10⁴ mechanical bending cycles had no influence on the energy storage performances. This study is expected to pave the way for the application of high-performance bendable dielectric film capacitors in energy storage and flexible electronic devices.