Balancing Polarization and Breakdown for High Capacitive Energy Storage by Microstructure Design

• Published in: Advanced materials (Weinheim) Vol. 36; no. 32; pp. e2403400 - n/a
• Main Authors: Yang, Bingbing, Liu, Yiqian, Li, Wei, Lan, Shun, Dou, Lvye, Zhu, Xuebin, Li, Qian, Nan, Ce‐Wen, Lin, Yuan‐Hua
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.08.2024
• Subjects: Amorphous materials; Breakdown; Crystallinity; Design parameters; Energy storage; Grain size; Microcrystals; Microstructure; phase‐field simulation; Polarization; polarization; microstructure; phase‐field simulation; energy storage; breakdown
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202403400

The compromise of contradictive parameters, polarization, and breakdown strength, is necessary to achieve a high energy storage performance. The two can be tuned, regardless of material types, by controlling microstructures: amorphous states possess higher breakdown strength, while crystalline states have larger polarization. However, how to achieve a balance of amorphous and crystalline phases requires systematic and quantitative investigations. Herein, the trade‐off between polarization and breakdown field is comprehensively evaluated with the evolution of microstructure, i.e., grain size and crystallinity, by phase‐field simulations. The results indicate small grain size (≈10–35 nm) with moderate crystallinity (≈60–80%) is more beneficial to maintain relatively high polarization and breakdown field simultaneously, consequently contributing to a high overall energy storage performance. Experimentally, therefore an ultrahigh energy density of 131 J cm−3 is achieved with a high efficiency of 81.6% in the microcrystal‐amorphous dual‐phase Bi3NdTi4O12 films. This work provides a guidance to substantially enhance dielectric energy storage by a simple and effective microstructure design. Balancing polarization and breakdown by microstructure control—amorphous for breakdown, crystalline for polarization—is key to energy storage. Phase‐field simulations reveal that small grains with moderate crystallinity optimize both, leading to high energy density. This approach yielded a 131 J cm−3 energy density with 81.6% efficiency in Bi3NdTi4O12 films, offering a strategy for advanced dielectric energy storage through microstructure design.