Excellent energy storage capability in Sr0.6Ba0.4Nb2O6-based ceramics via incommensurate modulation and grain boundary reinforcement

• Published in: Applied materials today 2024-08, Vol.39, p.102326, Article 102326
• Main Authors: Zheng, Peng, Zheng, Xiangting, Wang, Jiaqi, Sheng, Linsheng, Zheng, Liang, Fan, Qiaolan, Bai, Wangfeng, Zhang, Yang
• Format: Article
• Language: English
• Subjects: Energy storage; Incommensurate modulation; Reinforced grain boundary; Tungsten bronze; Two-step optimization strategy
• ISSN: 2352-9407; 2352-9415
• DOI: 10.1016/j.apmt.2024.102326

•A novel tetragonal tungsten bronze-based lead-free dielectric energy storage ceramic system was designed by a mutually synergistic two-step strategy.•Incorporating the BKT into the TB-structured SBN induces a transition from commensurate to incommensurate modulation, leading to an enhancement in relaxor behavior.•CuO was introduced as a sintering aid and accumulated at the grain boundaries of the SBN-based ceramics, resulting in reinforced grain boundaries and significantly enhancing the breakdown strength.•A high wrec of 6.31 J/cm3 with an excellent η of 91.8 % was achieved under an electric field of 600 kV/cm. The energy storage performances for tungsten bronze ferroelectric ceramics have always been constrained by the weak relaxor behavior and low breakdown strength. To enhance the energy storage capacity of the tungsten bronze ferroelectric ceramics, a synergistic two-step optimization strategy is proposed based on the Sr0.6Ba0.4Nb2O6 ceramic in this work, that is, enhance the relaxor behavior to generate slim hysteresis loops through the introduction of Bi0.5K0.5TiO3, and then optimize the microstructure to improve the breakdown strength by adding the sintering aid CuO. Ultimately, a remarkable comprehensive performance is achieved, characterized by a recoverable energy storage density of approximately 6.31 J/cm³ and an efficiency of about 91.8 % under 600 kV/cm. Notably, a high power density (∼178 MW/cm³) and an ultrafast discharge speed (