Simultaneously achieving high energy density (U_e) and charge-discharge efficiency (η) of dielectric materials at the relatively low operating electric field remains a persistent challenge to their practical applications. Herein, a P(VDF-HFP)-based triple-layer film by introducing the core-shell Al₂O₃@CNT in the middle layer and 0.05 wt.% boron nitride nanosheets (BNNSs) in the outer layers is designed. The experimental and simulated results confirm that the strategy of in-plane aligned Al₂O₃@CNTs can rapidly improve the dielectric constant of nanocomposites and reduce the probability of forming conductive pathways between neighboring layers. Meanwhile, the outer layers with BNNSs inclusions block the propagation of electric branches and suppress the leakage current, addressing the critical problem of the sacrificed breakdown strength and efficiency in the nanocomposites. Consequently, the as-prepared nanocomposite simultaneously exhibits great U_e and η under various ranges of electric fields. For instance, our results reported its U_e of 20.4 J cm⁻³ with η of 77 % at 520 V μm⁻¹ and U_e of 27.0 J cm⁻³ with η of 76 % at 619 V μm⁻¹. Importantly, the operating electric field for these high U_e and η is significantly reduced 20–50 % than the reported ferroelectric nanocomposites. Moreover, benefitting from the ultra-low fraction (<1.0 wt.%) of nanofillers, the nanocomposites demonstrate excellent stability in energy storage performance after 10,000 bending fatigue cycles. This work offers an effective approach to explore scalable and high-performance nanocomposites used as viable electrostatic capacitors.

在相对较低的工作电场下同时实现介电材料的高能量密度（U _e）和充放电效率（η ）仍然是其实际应用的持续挑战。本文设计了一种基于P(VDF-HFP)的三层薄膜，其中间层引入了核壳Al ₂ O ₃ @CNT，外层引入了0.05 wt.%氮化硼纳米片(BNNSs)。实验和模拟结果证实，面内排列Al ₂ O ₃ @CNTs的策略可以快速提高纳米复合材料的介电常数，并降低相邻层之间形成导电通路的可能性。同时，具有BNNSs夹杂物的外层阻止了电分支的传播并抑制了漏电流，解决了纳米复合材料牺牲击穿强度和效率的关键问题。因此，所制备的纳米复合材料在不同的电场范围下同时表现出较大的U _e和η 。例如，我们的结果报告其在 520 V μm ^-1下的U _e为 20.4 J cm ^{-3 ，}η为77% ；在 619 V μm ^-1下， U _e为 27.0 J cm ^{-3 ，} η为76% 。重要的是，这些高U _e和η 的工作电场比报道的铁电纳米复合材料显着降低了 20-50%。此外，得益于纳米填料的超低含量（<1.0 wt.%），纳米复合材料在 10,000 次弯曲疲劳循环后表现出优异的储能性能稳定性。这项工作提供了一种有效的方法来探索用作可行静电电容器的可扩展和高性能纳米复合材料。