基于陶瓷颗粒结构-功能设计的聚合物基复合材料储能机理研究

In this project in order to obtain high energy storage nanocomposites and study the mechanism of enhanced energy storage, structural-functional nonpenetrating porous ceramic particles with conductor embedded in the porous are designed and prepared on the basis of the theory of interfacial polarization and the mechanism of trapped carrier in the surface of inorganic crystal. The nonpenetrating porous ceramic particles are prepared and the conductor is embedded in the porous to form structural-functional particles. Composites containing the particles as fillers and polymer are prepared. The high conductivity of conductor and high dielectric constant of ceramics can provide strong interfacial polarization, which can improve the dielectric constant of the composite. And the ceramics serves as a barrier which makes the conductor is insulated, which may avoid the effect of through and dendronized breakdown caused by isolated conductor. In addition, the surface of ceramics particles can trap the carriers because of the conductor on the particles, which can also improve the dielectric breakdown strength of the composites. Consequently, dielectric constant and breakdown strength of composites can be improved synchronously. The effect of depth and volume of the porous, type and quantity of the conductor on the dielectric constant, breakdown strength and energy density of the composites will be studied. The internal relation between the parameters, such as particle structure, conductor characteristic and interfacial polarization, and energy density of composites will be revealed.

本本申请以界面极化和导体诱发无机晶体表面捕获电子机制为出发点，设计并制备负载非贯通导体的结构-功能纳米陶瓷颗粒，旨在将其与聚合物复合制备高储能密度复合材料，探索陶瓷颗粒的结构与功能设计及提高材料储能密度的机制。 制备非贯通孔道的多孔陶瓷颗粒并将导体负载到孔道中形成结构功能性颗粒，使其与聚合物基体复合，颗粒的介电性和导体的导电性与聚合物形成强的界面极化以提高材料整体的介电常数，非贯通导体有助于陶瓷颗粒表面捕获更多的电子并消除相连导电区引起的贯通性及树枝化击穿以提高击穿场强，协同作用的结果是材料的介电常数和击穿场强同时提高，材料储能密度提高。 利用多种先进测试手段研究结构-功能性陶瓷颗粒的结构包括"芯"尺寸、孔道形貌、导体种类及特性等对复合材料介电及击穿性能的影响规律，取得优化的功能性颗粒结构参数，获得高储能密度复合材料，弄清颗粒结构和相态及界面特性与材料储能密度的内在联系。

设计并制备了4种负载非贯通导体的结构-功能纳米陶瓷颗粒，经表面改性后颗粒与有机相PVDF复合制备的新型复合材料在介电常数、击穿场强和储能密度均得到提高，对材料性能提高的机制进行了解释。.(1)采用化学法制备了Ag@p-BaTiO3、Ni@p-BaTiO3、C@p-BaTiO3和GQDs@p-BST四种非贯通导体的结构-功能纳米陶瓷颗粒，颗粒尺寸约为120nm，负载导体颗粒尺寸5~15nm；对颗粒表面改性以增加与有机相相容性。.(2)分别制备了Ag@p-BaTiO3/PVDF、Ni@p-BaTiO3/PVDF、C@p-BaTiO3/PVDF和GQDs@p-BST/PVDF复合材料并研究了结构-功能纳米BaTiO3或BST陶瓷颗粒含量对复合材料介电性能和储能密度影响，所有复合材料介电常数均随颗粒含量增加而增加且介损较小，击穿场强具有相似变化规律，随陶瓷颗粒含量增加出现先增后降趋势，每种材料的储能密度最大值对应较优陶瓷颗粒含量。材料介电常数(10vol%)、击穿场强和储能密度最高分别可达24.2、20.2、19.2和26，263kV/mm(3vol% BaTiO3)、305kV/mm(3vol% BaTiO3)、272kV/mm(3vol% BaTiO3)和330kV/mm(5vol% BST)，4.3J/cm3(7vol% BaTiO3)、4.9J/cm3(5vol% BaTiO3)、4.3J/cm3(7vol% BaTiO3)和7.9J/cm3(7vol% BST)。.(3)研究了引入第三相Ni颗粒对复合材料介电性能的影响，制备的Ni/Ni@p-BaTiO3/PVDF三相复合材料的材料介电常数、击穿场强和储能密度最大分别为15(0.2vol%Ni)、426kV/mm(0.1vol%Ni)和11.4J/cm3(0.1vol%Ni)，结果可解释为Ni的引入增强属于库伦阻塞效应和导体诱导无机颗粒表面捕获电子机制。.(4)解释了材料性能提高的机理，界面极化效应是提高材料介电常数的主要机制，库伦阻塞效应和导体诱导无机颗粒表面捕获电子机制可以解释材料击穿场强的提高的原因。.(5)探索了异形陶瓷颗粒合成及其对材料性能的影响，介电常数、击穿场强和储能密度最大为16(10vol% BaTiO3)、393kV/m393kV/mm(1vol% BaTiO3)、9.7J/cm3(5vol）。