Flexible Lead-Free Film Capacitor Based on Bimg0.5ti0.5o3-Srtio3 for High-Performance Energy Storage

Abstract

Flexible dielectric film capacitors with high performance of energy storage has shown great promise as a solution to the flexibility and stability of modern electronics and electric power systems. Herein, a novel relaxor-ferroelectric BiMg 0.5 Ti 0.5 O 3 - x SrTiO 3 (BMT- x STO, x= 0.1, 0.2, 0.3 and 0.4) thin film capacitors are obtained via one-step fabrication on flexible mica substrates. A superior energy storage density of 109.7 J cm -3 and a pretty high efficiency of 80.6% are simultaneously achieved in the BMT-0.3STO film capacitor. At the same time, the energy storage performance can be stable in the temperature range of 25 to 200 ° C, the wide frequency range of 500Hz to 10kHz, and even after 10 8 electrical cycles. In addition, under the bending radii from 16mm to 4mm, there is no obvious variation in performance even after 10 4 mechanical fatigue cycles, indicating the super flexibility and stability of the film capacitors. The prominent properties of the BMT-based film capacitor are mainly attributed to the improvement of relaxation behavior by introducing appropriate STO, which are explained by the domain evolution via piezo-response force microscopy and phase field simulation. The present work suggests a new way to obtain lead-free and flexible dielectric film capacitors for flexible energy storage technology.

Keywords: energy storage performance, flexible BMT-based film, relaxor-ferroelectric, lead-free