BaTiO3纳米线的制备及其复合物介电和储能性能研究

采用两步水热法合成钛酸钡(BaTiO₃)纳米线, 并以此为填充物, 聚偏氟乙烯六氟丙烯(P(VDF-HFP))为聚合物基体制备介电复合物, 研究不同含量BaTiO₃纳米线对复合物的介电及储能性能的影响。采用X射线衍射仪、扫描电镜、透射电镜、阻抗分析仪和铁电工作站等表征BaTiO₃纳米线及其复合物的物相、微观结构、介电和储能性能。结果表明: BaTiO₃纳米线具有典型的四方相, 且在聚合物基体中具有良好的分散性与相容性。相同频率下, 复合物的介电常数随着BaTiO₃纳米线含量的增加而增加。含量为20vol%的复合物, 在1 kHz频率下其介电常数取得最 大值30.69。含量为5vol%的复合物, 在场强为240 kV/mm时, 获得了最大的储能密度与放电能量密度, 分别为4.89和2.58 J/cm³。

Dielectric and Energy Storage Property of Dielectric Nanocomposites with BaTiO3 Nanofibers

In this study, BaTiO₃ nanofibers were synthesized by a two-step hydrothermal method and subsequently incorporated into poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) matrix to prepare nanocomposites for energy storage application. The crystalline phase, morphology and microstructure of BaTiO₃ nanofibers were observed by X-ray diffraction, scanning electron microscopy and transmission electron microscopy, respectively. The dielectric properties and energy storage performance of the nanocomposites were characterized by dielectric and ferroelectric analyzer. The BaTiO₃ nanofibers with tetragonal phase structure exhibited high aspect ratios, good dispersibility and compatibility in polymer matrix. The effects of volume fraction of BaTiO₃ nanofibers on the dielectric constant, breakdown strength and discharged energy density of the nanocomposites were investigated systematically. The dielectric constant of the BaTiO₃-P(VDF-HFP) nanocomposites remarkably improved with the increase of BaTiO₃ nanofiber contents at the same frequency. At 1 kHz, the maximum dielectric constant of the composite with 20vol% BaTiO₃ nanofibers is up to 30.69. The composite with 5vol% BaTiO₃ nanofibers achieves the maximum energy storage density (4.89 J/cm³) and discharged energy density (2.58 J/cm³) at 240 kV/mm.