Polymer nanocomposite dielectrics for electrical energy storage

• 来源期刊: 国家科学评论（英文版）
• 关键词: dielectric materials electric field electrical displacement critical parameter electrical energy power generation energy density power density
• 年，卷（期）: 2017,（1）
• 页码范围: 23-25
• 页数: 3页
• 语种: 英文
• DOI: 10.1093/nsr/nww066

摘要

Dielectric materials store and release electrical energy electrostatically through dielectric polarization and depolarization by the application and removal of an electric field (as shown in Fig.1).As the only energy-storage device that is capable of delivering power density on the order of mega or even giga watts,electrostatic capacitors based on dielectric materials are recently considered as the major enabler for a number of modem electrical applications,such as high-frequency inverters,IGBT snubbers,power factor correction and pulsed power generation [1].The application of electrostatic capacitors as viable energy-storage devices has currently been limited by their low energy-storage density.The energy-storage density (Ue) of dielectric materials is determined by electrical displacement (D) and electric field (E) as Ue =fEdD and is usually obtained from the D-E loop (as shown by the area shaded in green).For linear dielectrics,Ue scales linearly with dielectric permittivity (εr) and quadrically with E as Ue =1/2εoεrE2,where εo is the vacuum dielectric permittivity.The breakdown strength (Eb) that signifies the highest electric field applicable to the dielectrics is thus the most critical parameter that defines the maximal energy density achievable.