Preface
Dielectrics, which are materials responding to an external electric field with a polarization, have been widely used in industries.Dielectrics with high permittivity and high breakdown strength are
required for the applications including high charge capacitors and energy storage devices, where the dielectric composites could found their position as the potential candidates. As the commonly used matrix for dielectric composite, glasses and polymers exhibit high breakdown strength, but small permittivity. To increase the permittivity and energy storage density, a great deal of effort has gone into developing the high breakdown strength matrix filled with high permittivity ceramics or conductive materials to create new types of dielectrics that is easier to
process while maintaining useful dielectric properties.
For the purpose of getting the optimized composites for dielectric and energy storage applications, both polymer based and glass based composites were fabricated and studied in the research. By the using of different matrix and fillers and optimization of fabrication process, the
dielectric composites with excellent performances were obtained.
According to the analysis of the data from testing, these composites were proved to be the potential candidates for the applications including high charge capacitors, energy storage device and even wearable electronics.
For the purpose of effectively increase dielectric constant, conductorpolymer was firstly introduced as potential dielectric composites. In this part of research, the 2-D conductors was used as the filler due to its high conductivity and polar polymers was used as the matrix because of the relatively good permittivity and high breakdown strength. It was found that although the increase of dielectric constant by combining 2-D conductive fillers and polymer matrix was proved by previous studies, the application of the composites is still limited by the high loss and low breakdown strength. Therefore, ceramic-polymer dielectric composites were studied as the secondary part of the research to create a composite with high energy and low loss. In both conductor- polymer and ceramic-polymer composites, methods including solution casting, hot
pressing and silicon coupling agent was used in the preparation of polymer-based composites. In the tertiary part of research, the focus points was turned to the detailed studies glass based dielectric composites due to the fact that the type of materials have the ability to keep the balance between high permittivity and energy storage density.
The varieties of nanopowders were studied in making composite pellets by conventional sintering under different conditions, such as molding pressure, sintering temperature, and ceramic powder size. By summarize the results, several conclusions about processing effects were obtained.
The Chapter 1, 2, 3 and 5 of this book was edited by Dr. Yang Tong from Taiyuan University of Science and Technology; the Chapter 4 of this book was cooperatively edited by Mr. Dong Zhang, Mr. Dengyu Zhang, Mr. Zechen Li, Mr. Jun cai Yu from Beijing Institute of Aerospace System Engineering, and Mr. Lei Han, Mr. Yu Cao from Tianjin Long March Launch Vehicle Manufacturing Co. Ltd.
This book was sponsored by the Fund of Shanxi Key Subjects Construction, the Key Laboratory of Magnetic and Electric Functional Materials and Applications in Shanxi Province, Institute of Magnetic Material Engineering and Adcanced Materials, Key Innovation Centre of \"1331\" Project in Shanxi Province for Magnetoelectronic Materials and Devices, Heavy Machinery Engineering Research Center of the Ministry of Education, Collaborative Innovation Centre of Taiyuan Heavy Machinery Equipment, Shanxi Provincial Key Laboratory of Metallurgical Device Design Theory and Technology, and the works relevant to this book were supported by the Taiyuan University of Science and Technology Scientific Research Initial Funding (20182028), Doctoral Starting Foundation of Shanxi Province (20192006), Science and Technology Major Project of Shanxi Province (MC2016-01), National Natural Science Foundation of China (Grant No. 51731003), and Project U610256 supported by National Natural Science Foundation of China.

Yang Tong
September 10th, 2019
Development of Dielectric Composites for Dielectric and Energy Storage Applications