基于多层结构设计的高储能密度氧化石墨烯/聚酰亚胺复合材料

采用逐层涂布、 分层控制固化程度的方法, 利用聚酰胺酸(PAA, 聚酰亚胺前体)溶液和含有氧化石墨烯（GO）的PAA溶液制备了一系列由高绝缘性PI层与GO@PI介电层交替组合而成的界面清晰且紧密衔接的多层复合薄膜. 通过调控介电层中GO含量及分层结构, 使多层复合薄膜兼具高介电常数和高击穿强度特征. 结果表明, 三层复合薄膜PI/1.0GO@PI/PI的击穿强度为261.5 kV/mm, 储能密度达到1.27 J/cm³, 与相同介电层厚度的单层薄膜相比, 击穿强度和储能密度分别提高了97%和144%, 同时, 其介电损耗也保持在较低水平(tanδ=0.0079). 绝缘层和高介电常数层的协同作用提升了氧化石墨烯/聚酰亚胺复合薄膜的储能密度. 这种简单的多层结构设计有利于氧化石墨烯/聚合物复合材料在介质储能领域的应用.

Graphene Oxide/Polyimide Composites with High Energy Storage Density Based on Multilayer Structure

A variety of multi-layer nanocomposite films composed of both high insulation polyimide（PI） layer and high dielectric constant graphene oxide/polyimide（GO@PI） composite layer were fabricated through layer by layer coating. The GO content and layered structure of the dielectric layer were adjusted to make the multilayer composite films with high dielectric constant and high breakdown strength. The results showed that the energy storage density of tri-layer PI/1.0 GO@PI/PI composite film was 1.27 J/cm³ at 261.5 kV/mm. Compared with the mono-layer 1.0 GO@PI film， the breakdown strength and energy storage density of the tri-layer PI/1.0 GO@PI/PI composite film were increased by 97% and 144%， respectively. Meanwhile， the dielectric loss of the composite film remained at a relatively low level（tanδ=0.0079）. The composition of insulating layer and high dielectric layer afforded the synergistic effect to remedy the energy density of the multilayer composite film. The multi-layer structure strategy is benefical to the application of graphene oxide/polyimide composites in dielectric energy storage filed.