Cao Weiwei, Li Tianyu, Li Kai, Huang Yueyun, Xie Hailong, Yao Yonghao, Sun Zheng, Lou Chenjie, Zhang Wenda, Xu Chengxin, Zhu Lifeng, Xie Bing, Zhang Ji, Tucker Matthew G, Liu Hui, Luo Huajie, Tang Mingxue, Chen Jun
School of Materials Science and Engineering & Key Laboratory of Advanced Materials and Devices for Post-Moore Chips, Ministry of Education, University of Science and Technology Beijing, Beijing, 100083, China.
Department of Physical Chemistry and Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
Angew Chem Int Ed Engl. 2025 Jan 21;64(4):e202416291. doi: 10.1002/anie.202416291. Epub 2024 Nov 7.
Dielectric capacitors harvest energy through an electrostatic storage process, which enables an ultrafast charging-discharging rate and ultrahigh power density. However, achieving high energy density (W) and efficiency (η) simultaneously, especially when preserving them across a wide frequency/temperature range or cycling numbers, remains challenging. In this work, by especially introducing NaTaO into the representative ferroelectric relaxor of BiKTiO-BiNaTiO and leveraging the mismatch between B-site atoms, we proposed a method of enhancing local structural fluctuation to refine the polar configuration and to effectively improve its overall energy-storage performances. As a consequence, the ceramic exhibits an ultrahigh W of 15.0 J/cm and high η up to 80 %, along with a very wide frequency stability of 10-200 Hz and extensive cycling number up to 10. In-depth local structure and chemical environment investigations, consisting of atom-scale electron microscopy, neutron total scattering, and solid-state nuclear magnetic resonance, reveal that the randomly distributed A/B-site atom pairs emerge in the system, leading to the evident local structural fluctuations and concomitant polymorphic polar nanodomains. These key ingredients contribute to the large polarization, minimal hysteresis, and high breakdown strength, thereby promoting energy-storage performances. This work opens a new path for designing high-performance dielectric capacitors via manipulating local structural fluctuations.
介电电容器通过静电存储过程来收集能量，这使得其具有超快的充放电速率和超高的功率密度。然而，要同时实现高能量密度（W）和效率（η），尤其是在宽频率/温度范围或循环次数内保持这些性能，仍然具有挑战性。在这项工作中，通过特别将NaTaO引入到代表性的铁电弛豫体BiKTiO-BiNaTiO中，并利用B位原子之间的不匹配，我们提出了一种增强局部结构波动的方法，以优化极性配置并有效改善其整体储能性能。结果，该陶瓷表现出15.0 J/cm的超高W和高达80%的高η，以及10 - 200 Hz的非常宽的频率稳定性和高达10次的广泛循环次数。由原子尺度电子显微镜、中子全散射和固态核磁共振组成的深入局部结构和化学环境研究表明，系统中出现了随机分布的A/B位原子对，导致明显的局部结构波动和伴随的多晶型极性纳米域。这些关键因素有助于实现大极化、最小滞后和高击穿强度，从而提升储能性能。这项工作为通过操纵局部结构波动来设计高性能介电电容器开辟了一条新途径。
