Fan Zhenhao, Dai Jian, Huang Yuyan, Xie Hang, Jiao Yitao, Yue Wenfeng, Huang Fu, Deng Yuqun, Wang Dawei, Zhang Qingfeng, Chang Yunfei
School of Instrumentation Science and Engineering, Harbin Institute of Technology, Harbin, China.
School of Materials Science and Engineering, Hubei University, Wuhan, China.
Nat Commun. 2025 Jan 30;16(1):1180. doi: 10.1038/s41467-024-55112-1.
Dielectric polymer capacitors suffer from low discharged energy density and efficiency due to their low breakdown strength, small dielectric constant and large electric hysteresis. Herein, a synergistic enhancement strategy is proposed to significantly increase both breakdown strength and dielectric constant while suppressing hysteresis, through introducing 2-dimensional bismuth layer-structured NaBiTiO micro-sheets and designing a unique bilayer structure. Excitingly, an ultra-high discharged energy density of 25.0 J cm and a large efficiency of 81.2% are achieved in NaBiTiO-poly(vinylidene fluoride-co-hexafluoropropylene)/NaBiTiO-polyetherimide bilayer composites under a dramatically enhanced breakdown strength of 8283 kV cm. Finite element simulations along with experimental test results demonstrate that greatly improved breakdown strength is ascribed to uniform and horizontal alignments of NaBiTiO sheets (~1-2 μm) in the matrix and interface effect of adjacent layers with large dielectric differences, which effectively inhibit electrical tree evolution and conduction loss. This work provides a strong foundation for developing high-performance polymer-based energy storage devices.
介电聚合物电容器由于其击穿强度低、介电常数小和电滞大，导致放电能量密度和效率较低。在此，通过引入二维铋层状结构的NaBiTiO微片并设计独特的双层结构，提出了一种协同增强策略，以在抑制滞后的同时显著提高击穿强度和介电常数。令人兴奋的是，在8283 kV/cm的显著增强的击穿强度下，NaBiTiO-聚偏二氟乙烯-共-六氟丙烯/NaBiTiO-聚醚酰亚胺双层复合材料实现了25.0 J/cm的超高放电能量密度和81.2%的高储能效率。有限元模拟和实验测试结果表明，击穿强度的大幅提高归因于基质中NaBiTiO片（~1-2μm）的均匀水平排列以及具有大介电差异的相邻层的界面效应，这有效地抑制了电树的发展和传导损耗。这项工作为开发高性能聚合物基储能器件奠定了坚实基础。
