不同形貌BiFeO_(3)微量填充PVDF复合膜的储能性能研究

Study on energy storage performance of PVDF composite films filled with BiFeO_(3) with different morphologies

采用固相法、水热法和静电纺丝法分别制备了块状、花状和纤维状的BiFeO_(3)粉体.采用流延法制备了三种填料的BiFeO_(3)/PVDF复合材料.通过红外光谱(FT-IR)观察到PVDF的三种晶相(α、β、γ).由氮气吸附/脱附实验证明,不同形貌BiFeO_(3)粉体的比表面积存在较大差异.其中,纤维状BiFeO_(3)粉体的比表面积最大.BiFeO_(3)粉体形貌也影响了复合材料的磁介电性能,通过磁介电测试进行研究.对于三种0.5 vol%BiFeO_(3)/PVDF复合材料,纤维状BiFeO_(3)/PVDF复合材料在10^(4)Hz时具有较高的介电常数(~21)和较低的介电损耗(~0.12).在相同电场下,纤维状BiFeO_(3)/PVDF复合材料中纤维的偶极距较大,使其具有较高的极化率和储能密度.

Massive,flowerlike,and fibrous BiFeO_(3) powders are prepared by solid phase method,hydrothermal method,and electrospinning method,respectively.And BiFeO_(3)/PVDF composites are fabricated by tape casting.Three crystalline phases(α-,β-,γ-)of PVDF are observed by Fourier Transform Infrared(FT-IR)spectra.The specific surface area of BiFeO_(3) powders with different morphologies is quite different,which has been proved by the N_(2) adsorption/desorption test.Among them,fiber BiFeO_(3)among them has the largest specific surface area.The magnetodielectric properties of composites are affected by the different morphology of BiFeO_(3),which is characterized by the magnetodielectric measurement.Compared with massive BiFeO_(3)/PVDF composites and flowerlike BiFeO_(3)/PVDF composites,in 0.5 vol%BiFeO_(3)/PVDF composites,the fibrous BiFeO_(3)/PVDF composites have a higher dielectric constant(~21)and lower dielectric loss(~0.12)at 10^(4) Hz.In the same electric field,the fibrous BiFeO_(3)/PVDF composites have higher polarization and energy storage density due to the large dipole distance of the fibers.