核壳结构SiC-W@SiO_2/PVDF复合材料的制备与储能特性

Preparation and energy storage performance of core@shell SiC-W@SiO_2/PVDF composite

以碳化硅晶须(SiC-W)为原料,采用一步法热氧化工艺制备核壳结构SiC-W@SiO_2功能体。利用红外光谱仪、X线衍射仪、动态接触角测试仪、透射电镜、扫描电镜,以及力学试验机、精密阻抗分析仪、耐压击穿测试仪及铁电测试综合系统,表征核壳结构功能体及其PVDF基复合材料的结构、界面、组成、拉伸、介电、击穿与储能等特性。确定热氧化处理条件与SiO_2壳层厚度的对应关系,考察SiO_2壳层对复合材料的性能影响。结果表明:随SiO_2壳层的引入和厚度的增加,复合材料的介电损耗和电导率逐渐降低,介电常数先增加后减小,特征击穿场强大幅度提高,能量释放效率逐渐增加。当SiO_2壳层厚度为13~14nm时,复合材料的能量储存密度和能量释放密度取得最优值,分别为4.03J/cm^3和1.78J/cm^3;当SiO_2壳层厚度为20~21nm时,能量释放效率达到55.1%。

SiC-W@SiO_2 core@shell filler was successfully fabricated through a facile calcination process of raw SiC-W under air.Infrared spectrometer,X ray diffractometer,dynamic contact angle tester,transmission electron microscope,scanning electron microscope,mechanical testing machine,precision impedance analyzer,high voltage resistance tester and ferroelectric test comprehensive system were adopted characterizing the structure of SiC-W@SiO_2 and SiC-W@SiO_2/PVDF composite.The results were listed as follows:As SiO_2 shell thickness increased,dielectric loss and AC conductivity gradually decreased,dielectric permittivity firstly increased and then decreased,both characteristic breakdown strength and energy discharge efficiency were improved.Specially,at the SiO_2 shell thickness of 13～14 nm,both energy storage and discharge density reached highest value of 4.03 J/cm^3 and 1.78 J/cm^3,while the energy discharge efficiency reached 55.1%,at SiO_2 shell thickness of 20～21 nm.