P(VDF–HFP)/BST纳米复合薄膜的制备及介电、储能性能

采用溶液铸造法,以聚(偏氟乙烯–六氟丙烯)P(VDF–HFP)]为基体、钛酸钡锶(BST)为填料制备了纳米薄膜材料。对薄膜的物相组成和微观形貌进行了表征,研究了BST含量对薄膜介电性能和储能性能的影响。结果表明,随着BST含量的增大,薄膜的介电常数显著上升,介电损耗在中、高频区域有所下降,击穿强度逐渐减小,薄膜的充电能量密度显著增大;介电常数的实测值与Maxwell-Wagner理论模型计算值基本吻合,表明填料和基体结合良好,薄膜材料内部组织均匀,无明显缺陷。此外,从实际应用的角度讲,外加电场强度低于800 kV/cm或介于800~2100 kV/cm时,为了获得最大的放电能量密度,应分别选用BST体积分数为30%或20%的P(VDF–HFP)/BST复合薄膜材料。

Preparation,Dielectric Properties and Energy-storage Properties of P(VDF–HFP)/BST Nanocomposite Films

Nanocomposite films were prepared by solution casting method with poly(vinylidene fluoride-hexafluoropropylene)P(VDF–HFP)]as matrix and barium strontium titanate(BST)as filler.The phase composition and micro-structure of the films were characterized,and the effects of BST content on the dielectric properties and energy-storage properties of the films were investigated.The results show that with the increase of BST content,the dielectric constant(εr)of the film increases significantly,the dielectric loss(tanδ)decreases in the middle and high frequency region,the breakdown strength(Eb)decreases gradually and the charge energy density(Ucharge)increases greatly.The measured values ofεr are in good agreement with calculated value of Maxwell-Wagner theoretical model,which indicates that the combination of the filler and matrix is good,the microstructure of films is uniform,and there is no obvious defect.In addition,from the perspective of practical application,when the applied electric field intensity(E)is lower than 800 kV/cm or between 800 kV/cm and 2100 kV/cm,in order to obtain the maximal discharge energy density(Udischarge),the P(VDF–HFP)/BST composite with BST content of 30 vol%or 20 vol%should be selected respectively.