BaTiO_3纳米线的制备及其复合物介电和储能性能研究

Dielectric and Energy Storage Property of Dielectric Nanocomposites with BaTiO_3 Nanofibers

采用两步水热法合成钛酸钡(BaTiO_3)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BaTiO_3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BaTiO_3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:BaTiO_3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BaTiO_3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240kV/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/cm^3。

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 nanocom- posites 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 20vo1% BaTiO3 nanofibers is up to 30.69. The composite with 5vol% BaTiO3 nanofibers achieves the maximum energy storage density （4.89 J/cm^3） and discharged energy density （2.58 J/cm^3） at 240 kV/mm.