Achieving Remarkable Energy Storage Performances under Low Electric Field in Bi<sub>0.5</sub>N<sub>0.5</sub>TiO<sub>3</sub>-SrTiO<sub>3</sub>-Based Relaxor Ferroelectric Ceramics via a Heterostructure Doping Strategy
Yuzhe Lin, Ruifeng Wan, Peng Zheng, Zhihao Li, Yikai Wang, Qiaolan Fan, Liang Zheng, Yang Zhang, Wangfeng Bai
Abstract
The rapid growth of the electronics industry and increasing concern about environmental issues present great demands for lead-free dielectric ceramic capacitors with remarkable energy storage performances (ESPs). Lead-free perovskite ferroelectric and antiferroelectric systems are deemed as the most promising candidates, and homostructure linear dielectric doping is a widely used strategy to boost ESPs. However, the heavy doping of a linear dielectric usually leads to a great reduction of the polarization, for which an extremely high electric field is needed to achieve a large energy storage density ( W rec ). In this study, a Bi 0.5 N 0.5 TiO 3 -SrTiO 3 (BNT-ST)-based relaxor ferroelectric system was designed via a heterostructure doping strategy in which a tetragonal tungsten bronze ferroelectric phase Sr 2 NaNb 5 O 15 (SNN) was introduced into the perovskite matrix. It was found that a small SNN heterostructure doping amount could effectively enhance the relaxor behavior of the BNT-ST ceramic and depress the remnant polarization, while keeping a large maximum polarization. Moreover, the introduction of the tungsten bronze ferroelectric phase obviously decreased the grain size ( G ) of the BNT-ST ceramic, giving rise to an improved electric breakdown strength ( E b ). Finally, a remarkable W rec of 5.22 J/cm 3 and excellent efficiency (η) of 93.87% were attained under a low electric field of 340 kV/cm, which make the Bi 0.5 N 0.5 TiO 3 -SrTiO 3 - x Sr 2 NaNb 5 O 15 (BNT-ST- x SNN) ceramic system a promising choice for the dielectric energy storage field. These results demonstrate that the heterostructure doping strategy might be a feasible method to develop lead-free perovskite dielectric ceramics with remarkable ESPs under low electric fields.