聚醚酰亚胺/改性钛酸钡复合材料制备及介电储能性能

Preparation of Polyetherimide/Modified Barium Titanate Composites and Their Dielectric and Energy Storage Properties

采用Stober法对高介电常数陶瓷填料钛酸钡(BT)进行改性,得到二氧化硅(SiO_(2))包覆BT(BT@SiO_(2))填料,并采用溶液浇铸法制备具有高介电储能性能的聚醚酰亚胺(PEI)/BT@SiO_(2)复合材料薄膜,研究了复合材料薄膜的表面结构、结晶行为、介电性能、储能性能等。X射线衍射(XRD)及透射电子显微镜结果表明,SiO_(2)成功包覆在BT粒子的表面,制备了具有“核-壳”结构的BT@SiO_(2)填料;扫描电子显微镜、XRD结果表明,BT@SiO_(2)填料在PEI基体中分散均匀,SiO_(2)层增强了填料的分散性;介电性能、储能性能测试结果表明,高介电常数BT@SiO_(2)填料的引入有效增强了PEI复合材料的介电常数,降低介电损耗。当BT@SiO_(2)填料的体积分数为0.2%时,PEI复合材料的特征击穿强度达到最大值468 MV/m,相对纯PEI提高了16%,在电场强度为400 MV/m的条件下,其放电能量密度为4.1 J/cm^(3),相对纯PEI提高了192%,充放电效率为72%。

A ceramic filler with high dielectric constant—barium titanate(BT)was firstly coated with silicon dioxide(SiO_(2))via Stober method for preparing BT@SiO_(2),and then polyetherimide(PEI)/BT@SiO_(2)composite film with high dielectric and energy storage properties was prepared by solution casting method.The surface structure,crystallization behavior,dielectric properties and energy storage properties of the composite film were investigated.The X-ray diffraction(XRD)and transmission electron microscope results show that SiO_(2)is successfully coated on the surface of BT particles,and BT@SiO_(2)filler with a"core-shell"structure is prepared.Scanning electron microscope(SEM)and XRD results show that BT@SiO_(2)filler is uniformly dispersed in the PEI matrix,and SiO_(2)layer enhances the dispersion of the filler.The test results of dielectric properties and energy storage performance show that the introduction of high dielectric constant BT@SiO_(2)fillers effectively enhances the dielectric constant of PEI composites and reduces dielectric loss.When the volume fraction of BT@SiO_(2)filler is 0.2%,the characteristic breakdown strength of PEI composite reaches the maximum of 468 MV/m,which is 16%higher than that of pure PEI,under the condition of 400 MV/m,the discharge energy density is 4.1 J/cm^(3),which is 192%higher than that of pure PEI,and the charge-discharge efficiency is 72%.