Enhanced Energy‐Storage Properties and Good Temperature Stability in 0.92(Sr_0.7Bi_0.2)TiO₃–0.08Bi(Mg_0.5Hf_0.5)O₃ Relaxor Ferroelectric Ceramic

Abstract

Herein, the (1 − x)(Sr0.7Bi0.2)TiO3–xBi(Mg0.5Hf0.5)O3 (SBT–100xBMH, x = 0.04–0.10) relaxor ferroelectric ceramics are fabricated via the high‐temperature solid‐state reaction method. Dielectric and ferroelectric measurements reveal a typical relaxor characteristic with diffused and frequency‐dependent dielectric peaks. The characteristic Weibull breakdown strength (BDS) of 470 kV cm−1 with satisfied reliability is obtained by DC breakdown measurement. A maximum recoverable energy density of 3.5 J cm−3 with the corresponding energy efficiency of 92% is simultaneously achieved at 380 kV cm−1. The recoverable energy density exhibits minor degradations from ambient temperature to 200 °C with variation below 20%, whereas the energy efficiency is maintained above 90%. In addition, the SBT–8BMH ceramic possesses a fast charge–discharge speed with high discharge power density of 2.9 MW cm−3. All the results make this lead‐free relaxor ferroelectric ceramic a promising potential candidate for high‐temperature energy‐storage capacitor applications.

(K0.5Bi0.5)(Mg1/3Nb2/3)O3‐modified Sr0.7Bi0.2TiO3 lead‐free ceramics for energy storage applications

“…Hong et al reported that the doping of Bi(Mg 0.5 Hf 0.5 )O 3 to SBT ceramic increased the BDS to 460 kV/cm, recoverable energy density (W rec ) to 3.1 J/cm 3 , and η to 93% at 360 kV/cm. 15 The majority of dielectric capacitors used for energy storage are for lowvoltage applications. As a result, in a medium electric field, high energy storage properties are required.…”