钛酸锶纳米纤维表面氟化处理对PVDF电介质复合薄膜介电储能性能的影响

Effect of surface fluorination treatment of strontium titanate nanofibers on the dielectric energy storage performance of PVDF dielectric composite films

  • 摘要: 界面是影响电介质复合材料储能性能的关键因素,为了制备高性能电介质复合薄膜,本文通过静电纺丝技术成功制备了一维结构纳米钛酸锶(SrTiO3)纤维,随后对纳米纤维实施表面氟化改性处理。采用流延成型工艺制备了一维纳米SrTiO3纤维/聚偏氟乙烯(PVDF)复合薄膜。通过实验研究与理论建模相结合的方法,系统探讨了表面氟化改性的一维纳米SrTiO3纤维对PVDF复合体系微观结构特性、介电性能及储能特性的调控机制。测试结果表明:静电纺丝法制备的纳米SrTiO3材料呈现出典型的一维纤维形貌特征,纤维直径分布在50-110 nm区间,长度范围为4-10 μm,且具有优良的分散特性。表面氟化处理有效增强了纳米纤维在聚合物基体中的分散均匀性及界面结合强度。介电性能测试结果表明,随着功能化纳米纤维含量的增加,SrTiO3纤维/PVDF复合薄膜的介电常数呈现显著上升趋势。当氟化改性纳米SrTiO3纤维的体积分数为7.5vol%时,纳米SrTiO3纤维/PVDF复合体系在常温下的介电常数达到18.7,同时复合薄膜具有较高的耐击穿场强。储能性能分析显示:当表面氟化处理的纳米SrTiO3纤维填充量达到2.5vol%时,SrTiO3纤维/PVDF复合薄膜的储能密度提升至7.92 J/cm3,较纯PVDF薄膜提高了172%。性能提升机制主要源于氟化处理带来的两重效应:一是纳米填料在基体中的均匀分散,二是优化的界面结合状态。通过有限元模拟进一步验证了表面氟化处理可有效调控电场分布,显著提升了纳米SrTiO3纤维/PVDF复合薄膜的耐击穿场强。

     

    Abstract: The interface is a key factor affecting the energy storage performance of dielectric composite materials. In order to prepare high-performance dielectric composite films, one-dimensional strontium titanate (SrTiO3) nanofibers were synthesized via electrospinning in this study and subsequently subjected to surface fluorination treatment. A one-dimensional SrTiO3 nanofiber/polyvinylidene fluoride (PVDF) composite film system was prepared using the casting process. By combining experimental research with theoretical modeling, the influence of surface-fluorinated SrTiO3 one-dimensional nanofibers on the microstructure, dielectric behavior, and energy storage performance of the PVDF-based composite system was thoroughly examined. Experimental characterization shows that SrTiO3 nanomaterials prepared by electrospinning exhibit typical one-dimensional fiber morphology characteristics, with fiber diameters ranging from 50-110 nm and lengths ranging from 4-10 μm, and excellent dispersion properties. Surface fluorination treatment effectively enhances the dispersion uniformity and interfacial bonding strength of nanofibers in the polymer matrix. The dielectric performance test results show that with the increase of functionalized nanofiber content, the dielectric constant of the SrTiO3 nanofiber/ PVDF composite film shows a significant upward trend. When the volume fraction of fluorinated modified SrTiO3 nanofibers is 7.5vol%, the dielectric constant of the SrTiO3 nanofiber/ PVDF composite system at room temperature reaches 18.7, while exhibiting better dielectric loss control characteristics and breakdown field strength performance. Energy storage performance analysis shows that when the filling amount of SrTiO3 nanofibers treated with surface fluorination reaches 2.5vol%, the energy storage density of the SrTiO3 nanofiber/ PVDF composite film increases to 7.92 J/cm3, which is 172% higher than that of pure PVDF. The performance improvement mechanism mainly stems from the dual effects brought by fluorination treatment. The finite element simulation further verified that surface fluorination treatment can effectively regulate the electric field distribution and significantly improved the breakdown field strength of SrTiO3 nanofiber/ PVDF composite films.

     

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