面向超构电容器的负介电材料设计及正-负介电协同增强机理

With the policy of intelligent manufacturing technology, miniaturization, capacitors of high frequency and high capacity are in the urgent need in microelectronics industry. However, it has been a bottleneck that the dielectric constant of the capacitor material drops significantly at high frequencies. In view of this problem, the meta-stacked structure is constructed by combining the negative permittivity material with the positive permittivity material, and it is by the positive and negative synergistic effect that the permittivity is enhanced at high frequency. The relationship between the composition, morphology, distribution of the metal functional component and the negative permittivity is studied in order to elucidate the mechanism of the negative permittivity; The influence of the dielectric value, dispersion and thickness ratio of positive and negative permittivity material on the properties of the meta-stacked structure is systematically studied; Combined with the simulation results, the mechanism of microscopic transport behavior is explored in the interface of meta-stacked structure, and the microscopic mechanism of positive and negative synergistic effects is also studied. The project will promote the practical application of negative permittivity materials, and also provide a solid theoretical basis and technical support for the development of novel capacitors.

“中国制造2025” 对电子工业中新型电容器的研发提出了小型化、高频化和高容量的迫切需求，传统电容器材料在高频下介电常数大幅下降，已成为制约该领域发展的瓶颈。针对该问题本项目提出，将负介电材料与正介电材料以叠层形式构建超构电容，利用正-负介电协同效应实现高频下的介电增强。研究金属功能体组分、形貌、分布状态与负介电频散特性之间的关联，探明负介电常数的调控机制；探索正、负介电材料的厚度比、频散特性等因素对超构叠层材料性能的影响规律，结合电磁仿真，阐明超构叠层材料中等效电子的界面输运特性及正-负介电协同增强效应的机理。通过本项目的实施，推进负介电材料实用化进程，为新型电容器的研发提供理论基础与技术支持。

“中国制造2025” 对电子工业中新型电容器的研发提出了小型化、高频化和高容量的迫切需求，传统电容器材料在高频下介电常数大幅下降，已成为制约该领域发展的瓶颈。针对该问题本项目提出，将负介电材料与正介电材料以叠层形式构建超构电容，利用电阻抗分析仪、X射线衍射仪和扫描电子显微镜等试验及测试手段，研究了不同功能体组分、形貌、分布状态与负介电频散特性之间的关联，探索了负介电常数的调控机制以及超构叠层材料中界面输运特性和正-负介电协同增强效应，分析了超构叠层材料的低损机理和耐击穿性能。通过对负介电层中MWCNTs、石墨等功能填料进行研究，发现含量超过逾渗阈值时，材料的介电常数由正值转为负值，且功能填料含量越高，负介电常数绝对值越大，复合材料的负介电常数行为是自由电子低频等离体振荡所致。即改变功能填料的含量和结构可实现对该类复合材料正、负介电性能的精准调控。在此基础上，利用流延成型、旋涂以及连续热压等工艺，构建超构叠层电容。发现功能填料与基体之间存在大量微观界面，正、负介电材料之间存在大量的宏观界面，强烈的界面极化效应以及正-负介电协同效应促使叠层材料介电常数强烈增加。15wt%BN/PVDF-40wt%MWCNTs/PVDF正-负介电层厚度比为1:20时，介电常数高达292，与PVDF基体相比提高了1600%(∼18@10 kHz）。通过探索不同频段内介电损耗变化和机理，发现叠层复合材料中功能填料可以抑制漏导电流传输，保持较低损耗和适当击穿场强。利用串联电容模型对超构电容器介电常数进行模拟，发现介电常数随厚度比的降低逐渐增加，且损耗保持在较低水平，叠层材料的介电行为逐渐由完全正介电行为转变为介电谐振再转变为完全负介电行为。通过本项目的实施，推进负介电材料实用化进程，为新型电容器的研发提供理论基础与技术支持。