Zhang Jisong, Hou Dajun, Wang Jian, Liu Hexing, Huang Cheng, Cheng Sha, Zhou Ling, Shen Zhonghui, Li Baowen, Zhou Jing, Zhang Pengchao, Chen Wen
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China.
Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics, Wuhan University of Technology, Wuhan 430070, China.
ACS Appl Mater Interfaces. 2024 Mar 20;16(11):14162-14170. doi: 10.1021/acsami.3c19546. Epub 2024 Mar 12.
High-performance dielectric nanocomposites are promising candidates for thin-film dielectric capacitors for high-power pulse devices. However, the existing nanocomposites suffer from low charge-discharge efficiency (η), which results in severe generation and accumulation of Joule heat and subsequently the failure of the devices. In this work, we report nacre-inspired dielectric nanocomposites with outstanding η, which are enabled by superspreading shear flow-induced highly aligned two-dimensional (2D) nanofillers. Taking boron nitride nanosheets (BNNS) as an example, the highly aligned BNNS in the poly(vinylidene fluoride) (PVDF)-based nanocomposites contributes to a highly efficient Coulomb blockade effect for the injected charge carriers. Therefore, the bioinspired nanocomposites with highly aligned BNNS show significantly reduced dielectric loss (tan δ) (63.3%) and improved η (144.8%), compared to the ones with partially aligned nanosheets fabricated by solution casting. Furthermore, the optimized loading content of BNNS is as low as 3.6 wt %. The resulting nanocomposites exhibit reduced tan δ (0.018) and enhanced (687 kV/mm), η (71%), and (16.74 J/cm). Our work demonstrates that the realization of high alignment of 2D nanofillers enabled by the superspreading shear flow is a promising way for the development of high-performance dielectric nanocomposites.
高性能介电纳米复合材料是用于高功率脉冲器件的薄膜介电电容器的有前途的候选材料。然而，现有的纳米复合材料存在充放电效率（η）低的问题，这导致焦耳热的严重产生和积累，进而导致器件失效。在这项工作中，我们报道了受珍珠母启发的具有出色η的介电纳米复合材料，这是由超扩展剪切流诱导的高度取向二维（2D）纳米填料实现的。以氮化硼纳米片（BNNS）为例，基于聚偏二氟乙烯（PVDF）的纳米复合材料中高度取向的BNNS有助于对注入的电荷载流子产生高效的库仑阻塞效应。因此，与通过溶液浇铸制备的具有部分取向纳米片的纳米复合材料相比，具有高度取向BNNS的仿生纳米复合材料的介电损耗（tan δ）显著降低（63.3%），η提高（144.8%）。此外，BNNS的优化负载量低至3.6 wt%。所得纳米复合材料的tan δ降低（0.018），介电常数（ε）提高（687 kV/mm），η提高（71%），储能密度（W）提高（16.74 J/cm）。我们的工作表明，通过超扩展剪切流实现二维纳米填料的高度取向是开发高性能介电纳米复合材料的一种有前途的方法。
