Li Yushu, Zhou Yao, Cheng Sang, Hu Jun, He Jinliang, Li Qi
State Key Lab of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084, China.
Materials (Basel). 2021 Aug 24;14(17):4780. doi: 10.3390/ma14174780.
The development of high-energy-density electrostatic capacitors is critical to addressing the growing electricity need. Currently, the widely studied dielectric materials are polymer nanocomposites incorporated with high-dielectric-constant nanoparticles. However, the introduction of high-dielectric-constant nanoparticles can cause local electric field distortion and high leakage current, which limits the improvement in energy density. In this work, on the basis of conventional polymer nanocomposites containing high-dielectric-constant nanoparticles, oriented boron nitride nanosheets (BNNSs) are introduced as an extra filler phase. By changing the volume ratios of barium titanate (BT) and BNNSs, the dielectric property of polymer nanocomposites is adjusted, and thus the capacitive energy storage performance is optimized. Experimental results prove that the oriented BNNSs can suppress the propagation of charge carriers and decrease the conduction loss. Using poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) as the polymer matrix, the P(VDF-HFP)/BNNS/BT nanocomposite has a higher discharged energy density compared with the conventional nanocomposite with the freely dispersed BT nanoparticles.
高能量密度静电电容器的发展对于满足不断增长的电力需求至关重要。目前，广泛研究的介电材料是掺入高介电常数纳米颗粒的聚合物纳米复合材料。然而，高介电常数纳米颗粒的引入会导致局部电场畸变和高漏电流，这限制了能量密度的提高。在这项工作中，在含有高介电常数纳米颗粒的传统聚合物纳米复合材料的基础上，引入取向氮化硼纳米片（BNNSs）作为额外的填料相。通过改变钛酸钡（BT）和BNNSs的体积比，调节聚合物纳米复合材料的介电性能，从而优化电容储能性能。实验结果证明，取向BNNSs可以抑制电荷载流子的传播并降低传导损耗。以聚（偏二氟乙烯-共-六氟丙烯）（P（VDF-HFP））为聚合物基体，与具有自由分散的BT纳米颗粒的传统纳米复合材料相比，P（VDF-HFP）/BNNS/BT纳米复合材料具有更高的放电能量密度。
