立方体状SrTiO_(3)粉体/聚偏氟乙烯电介质复合薄膜的储能性能

Energy storage performance of cubic SrTiO_(3)powder/polyvinylidene fluoride dielectric composite films

高工作场强、高储能效率的电介质储能材料对提高电力设备的性能、减小电力设备体积具有重要影响。采用混合碱法制备出立方体状SrTiO_(3)粉体作为陶瓷填料,采用聚乙烯吡咯烷酮(PVP)表面包覆改性对立方体状SrTiO_(3)粉体进行表面处理,利用流延法制备出了均匀的聚偏氟乙烯(PVDF)电介质复合薄膜。系统研究了表面PVP包覆改性立方体状SrTiO_(3)粉体对PVDF电介质复合薄膜介电性能和储能密度的影响。结果表明:混合碱法制备出的SrTiO_(3)粉体的形貌为立方体状,尺寸为200~400 nm,粒径分布比较均匀,PVP的官能团和立方体状SrTiO_(3)粉体的表面建立起共价的相互作用,在立方体状SrTiO_(3)粉体表面形成PVP包覆层,可以有效防止立方体状SrTiO_(3)粉体在PVDF电介质复合薄膜中的团聚,同时PVP包覆层可以改善立方体状SrTiO_(3)粉体在PVDF聚合物中分散和结合情况。PVDF电介质复合薄膜具有良好的介电性能和耐击穿性能,PVDF电介质复合薄膜的介电常数随着填充量的增加而增加,当立方体状SrTiO_(3)粉体填充量为40vol%时,电介质复合薄膜的介电常数为34.9。PVDF电介质复合薄膜的储能密度随着填充量的增加而先增加后降低,当表面PVP包覆改性处理立方体状SrTiO_(3)粉体的填充量为5vol%时,电介质复合薄膜的储能密度达5.3 J/cm^(3)。

Dielectric energy storage materials with high working field strength and high energy storage efficiency have an important impact on improving the performance of power equipment and reducing the volume of power equipment.The cubic SrTiO_(3)powder was prepared as ceramic filler by the mixed alkali method,and the surface of the cubic SrTiO_(3)particles was treated by polyvinylpyrrolidone(PVP)surface modification.The uniform polyvinylidene fluoride(PVDF)flexibility composite was prepared by the casting method.The effect of surface PVP modified cubic SrTiO_(3)filler on the dielectric properties and energy storage density of PVDF dielectric composites was systematically studied.The results show that the morphology of the SrTiO_(3)powder is cubic and the size is 200-400 nm.The particle size distribution is relatively uniform.The PVP coating layer formed on the surface of the cubic SrTiO_(3)filler can effectively prevent the agglomeration of the cubic SrTiO_(3)filler in the PVDF composites.At the same time,the PVP coating layer can improve the dispersion and bonding of the cubic SrTiO_(3)filler in the PVDF polymer.PVDF dielectric composite has excellent dielectric properties and breakdown strength.The dielectric constant of PVDF composites increases with the increase of the filling amount.When the filling amount of cubic SrTiO_(3)filler is40vol%,the dielectric constant of the composite is 34.9.The energy storage density of PVDF dielectric composite increases first and then decreases with the increase of the filling volume.When the filling volume of the cubic SrTiO_(3)filler modified by the surface PVP is 5vol%,the energy storage density of the composite reaches 5.3 J/cm^(3).