Zhu Yingke, Shen Zhonghui, Li Yong, Chai Bin, Chen Jie, Jiang Pingkai, Huang Xingyi
Shanghai Key Laboratory of Electrical Insulation and Thermal Ageing, State Key Laboratory of Metal Matrix Composites, Department of Polymer Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China.
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Center of Smart Materials and Devices, Wuhan University of Technology, Wuhan, 430070, People's Republic of China.
Nanomicro Lett. 2022 Jul 25;14(1):151. doi: 10.1007/s40820-022-00902-9.
Dielectric polymer nanocomposites are considered as one of the most promising candidates for high-power-density electrical energy storage applications. Inorganic nanofillers with high insulation property are frequently introduced into fluoropolymer to improve its breakdown strength and energy storage capability. Normally, inorganic nanofillers are thought to introducing traps into polymer matrix to suppress leakage current. However, how these nanofillers effect the leakage current is still unclear. Meanwhile, high dopant (> 5 vol%) is prerequisite for distinctly improved energy storage performance, which severely deteriorates the processing and mechanical property of polymer nanocomposites, hence brings high technical complication and cost. Herein, boron nitride nanosheet (BNNS) layers are utilized for substantially improving the electrical energy storage capability of polyvinylidene fluoride (PVDF) nanocomposite. Results reveal that the high conduction band minimum of BNNS produces energy barrier at the interface of adjacent layers, preventing the electron in PVDF from passing through inorganic layers, leading to suppressed leakage current and superior breakdown strength. Accompanied by improved Young's modulus (from 1.2 GPa of PVDF to 1.6 GPa of nanocomposite), significantly boosted discharged energy density (14.3 J cm) and charge-discharge efficiency (75%) are realized in multilayered nanocomposites, which are 340 and 300% of PVDF (4.2 J cm, 25%). More importantly, thus remarkably boosted energy storage performance is accomplished by marginal BNNS. This work offers a new paradigm for developing dielectric nanocomposites with advanced energy storage performance.
介电聚合物纳米复合材料被认为是高功率密度电能存储应用中最有前景的候选材料之一。具有高绝缘性能的无机纳米填料经常被引入到含氟聚合物中，以提高其击穿强度和储能能力。通常，无机纳米填料被认为会在聚合物基体中引入陷阱以抑制漏电流。然而，这些纳米填料如何影响漏电流仍不清楚。同时，高掺杂量（>5体积%）是显著提高储能性能的先决条件，这会严重恶化聚合物纳米复合材料的加工性能和机械性能，从而带来高的技术复杂性和成本。在此，利用氮化硼纳米片（BNNS）层大幅提高聚偏氟乙烯（PVDF）纳米复合材料的电能存储能力。结果表明，BNNS的高导带最小值在相邻层的界面处产生能垒，阻止PVDF中的电子穿过无机层，导致漏电流受到抑制且击穿强度优异。伴随着杨氏模量的提高（从PVDF的1.2 GPa提高到纳米复合材料的1.6 GPa），多层纳米复合材料实现了显著提高的放电能量密度（14.3 J/cm）和充放电效率（75%），分别是PVDF（4.2 J/cm，25%）的340%和300%。更重要的是，如此显著提高的储能性能是通过少量的BNNS实现的。这项工作为开发具有先进储能性能的介电纳米复合材料提供了一种新的范例。
