Na0.5Bi0.5TiO3纳米线/PVDF复合材料的高储能密度

The high energy density of Na0.5Bi0.5TiO3 nanowires/PVDF composites

采用水热法制备了Na0.5Bi0.5TiO3(NBT)纳米线,并系统地研究了NBT纳米线/PVDF复合材料的介电性能、铁电特性、阻抗谱对储能密度的影响,其中介电性能和铁电特性对提高极化强度有着重大意义,阻抗图对应着击穿性能,而极化强度和击穿强度决定了储能密度的大小.NBT纳米线通过多巴胺的表面改性改善了陶瓷颗粒在聚合物基体中的分散性和两者的相容性.从不同体积分数的NBT纳米线/PVDF复合材料可以发现4.5 vol.%NBT纳米线/PVDF纳米复合材料具有更高的介电常数(100 Hz时为20).0.5vol.%NBT纳米线/PVDF纳米复合材料在300 kV/mm电场下保持较高的储能密度(9.4 J/cm^3),该电场的电位移达到了14.93μC/cm^2.与NBT立方块/PVDF纳米复合材料相比,NBT纳米线/PVDF具有高的介电常数、低的介质损耗、高的击穿强度、大的激活能,最终获得了较高的储能密度.

Na0.5Bi0.5TiO3(NBT)nanowires were prepared by hydrothermal method,and the influences of the dielectric properties,ferroelectric properties and impedance spectrum of NBT nanowires/PVDF composite on the energy storage density were systematically studied.Among them,the dielectric properties and ferroelectric properties are of great significance to improve the polarization strength.The impedance map corresponds to the breakdown performance,and the polarization strength and breakdown strength determine the energy storage density.NBT nanowires improve the dispersion and compatibility of ceramic particles in polymer matrix by dopamine surface modification.The dielectric constant of 4.5 vol.%NBT nanowires/PVDF nanocomposites is higher(20 at 100 Hz).0.5 vol.%NBT nanowires/PVDF nanocomposites maintain a high energy storage density(9.4 J/cm^3)under the electric field of 300 kV/mm,and the potential shift of the electric field reaches 14.93μC/cm^2.Compared with NBT Cube/PVDF nanocomposites,NBT nanowires/PVDF have high dielectric constant,low dielectric loss,high breakdown strength and large activation energy,and finally obtain high energy storage density.