Bioinspired Dielectric Nanocomposites with High Charge–Discharge Efficiency Enabled by Superspreading-Induced Alignment of Nanosheets

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 E b (687 kV/mm), η (71%), and U e (16.74 J/cm 3 ). 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.