Tailoring the dipole properties in dielectric polymers to realize high energy density with high breakdown strength and low dielectric loss

• Published in: Journal of applied physics 2015-03, Vol.117 (11)
• Main Authors: Thakur, Yash, Lin, Minren, Wu, Shan, Cheng, Zhaoxi, Jeong, D.-Y., Zhang, Q. M.
• Format: Article
• Language: English
• Subjects: Applied physics; CHARGE CARRIERS; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPARATIVE EVALUATIONS; Current carriers; Dielectric breakdown; Dielectric loss; DIELECTRIC MATERIALS; Dielectric properties; Dielectric strength; DIPOLE MOMENTS; DIPOLES; ELECTRIC FIELDS; Electronic systems; ENERGY DENSITY; Flux density; MATERIALS SCIENCE; ORGANIC POLYMERS; PERMITTIVITY; PHASE STABILITY; Polymers; RELAXATION LOSSES; Thermal stability
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4915942

High energy density polymer materials are desirable for a broad range of modern power electronic systems. Here, we report the development of a new class of polymer dielectrics based on polyurea and polythiourea, which possess high thermal stability. By increasing the dipole density, the dielectric constant of meta-phenylene polyurea and methylene polythiourea can be increased to 5.7, compared with aromatic polyurea and aromatic polythiourea, which have a dielectric constant in the range of 4.1–4.3. The random dipoles with high dipolar moment and amorphous structure of these polyurea and polythiourea based polymers provide strong scattering to the charge carriers, resulting in low losses even at high electric fields. Consequently, this new class of polymers exhibit a linear dielectric response to the highest field measured (>700 MV/m) with a high breakdown strength, achieving high energy density (>13 J/cm3) with high efficiency (>90%).