核壳结构纳米纤维掺杂PMMA/PVDF基复合介质的储能特性研究

Study on Energy Storage Properties of PMMA/PVDF Based Composites Filled With Core-shell Nanofibers

为探索核壳结构纳米纤维对聚甲基丙烯酸甲酯(polymethyl methacrylate,PMMA)/聚偏氟乙烯(polyvinyllidene fluoride,PVDF)基复合介质储能特性的影响规律。该研究采用静电纺丝技术制备了高长径比的掺锰钛酸锶纳米纤维(Mn-ST NFs),并对纤维表面进行二氧化硅(SiO_(2))包裹处理。通过溶液铸造法制备了Mn-ST-PMMA/PVDF和Mn-ST@SiO_(2)-PMMA/PVDF两种复合介质。利用X射线衍射仪和扫描电子显微镜对复合介质进行晶体结构和形貌表征,利用宽频介电谱仪和铁电测试系统获得复合介质的介电性能与储能特性,采用COMSOL Multiphysics软件对复合介质的基本电学参数进行仿真模拟分析。综合实验测试与仿真分析结果可知,Mn-ST@SiO_(2)-PMMA/PVDF复合薄膜具有更优异的介电和储能特性,其中Mn-ST@SiO_(2)-PMMA/PVDF复合薄膜在填充相体积含量为0.5%时其放电能量密度为11.29J/cm^(3),充放电效率为84.07%。优异的电学性能主要源自无机Mn-ST与聚合物之间的界面极化效应,以及非晶SiO_(2)壳层能够有效提高无机填料和聚合物基体间的界面相容性,并限制界面间空间电荷的迁移。该研究为提高聚合物纳米复合介质的储能特性开辟了一种新的途径。

To explore the effect of core-shell nanofibers on the energy storage properties of polymethyl methacrylate(PMMA)/polyvinylidene fluoride(PVDF)-based composites. In this study, the high aspect ratio Mn-doped SrTiO3 nanofibers(Mn-ST NFs) were prepared via electrospinning, the nanofibers were coated by silica(SiO_(2)). The Mn-ST-PMMA/PVDF and Mn-ST@SiO_(2)-PMMA/PVDF composites were fabricated by solution casting method. The crystal structure and morphology of the composites was analyzed by X-ray diffraction and scanning electron microscopy. The dielectric properties and energy storage characteristics of the composites were obtained by using a broadband dielectric spectrometer and ferroelectric test system. The COMSOL Multiphysics software was used to simulate and analyze the basic electrical parameters of the composites. According to the experimental test and simulation analysis results, Mn-ST@SiO_(2)-PMMA/PVDF composite film has more excellent dielectric and energy storage properties, including that the discharge energy density of Mn-ST@SiO_(2)-PMMA/PVDF composite film is 11.29 J/cm^(3) and charge and discharge efficiency is 84.07% when the filling phase content is 0.5%. The excellent electrical properties are mainly derived from the interface polarization effect between the inorganic Mn-ST and the polymer matrix, and the amorphous SiO_(2) shell enhanced the interfacial compatibility between the inorganic filler and the polymer matrix, limiting the transfer of space charge between the interfaces. This study may open up a new method to improve the energy storage of polymer nanocomposites.