High energy density of polyimide films employing an imidization reaction kinetics strategy at elevated temperature

Abstract

Polymer dielectrics have been widely used in electrical energy storage devices. However, the relatively low operating temperature hinders their applications in harsh environments. Herein, the polyimide (PI) energy storage performance...

Enhanced High-Temperature Capacitive Performance of a Bilayer-Structured Composite Film Employing a Charge Blocking Layer

“…Figure a illustrates the comparison of U e and η of PI/BNNS film with reported PI dielectric materials, including intrinsic PI, , PI nanocomposites, − all-organic PI composites, ,, multilayer-structured PI composites, , and PI composites containing inorganic layer. ,,− The blue, gray, yellow, purple, and green boxes are used to classify the above materials on the right of Figure a. It is found that the PI/BNNS film achieves the maximum U e when η is greater than 90%, which is far superior to the reported PI-based dielectric materials at different temperatures.…”

“…11−13 With further increase in temperature, the exponential increase in conductivity loss leads to a significant drop in energy density (U e ) and efficiency (η), limiting the application of the BOPP film in harsh environments. 14 Low energy storage performance and operating temperature become bottlenecks in the development of polymer film capacitors. 15 The maximum operating temperature of polymer capacitor films is significantly limited by their low glass transition temperature (T g ).…”

“…Polymer film capacitors are widely used in electronic and electrical systems due to their high power density, graceful failure, and ease of large-scale fabrication. − The most commonly used capacitor film is biaxially oriented polypropylene (BOPP), which has the advantages of high breakdown strength ( E b ), excellent safety, and long life cycle. However, the low inherent thermal stability of the BOPP film makes its maximum working temperature is only 105 °C after adding the secondary cooling system. − With further increase in temperature, the exponential increase in conductivity loss leads to a significant drop in energy density ( U e ) and efficiency (η), limiting the application of the BOPP film in harsh environments . Low energy storage performance and operating temperature become bottlenecks in the development of polymer film capacitors …”

High-temperature energy storage performances of “isomer-like” polyimide and its thermoplastic polyurethane blending system

“…For example, film capacitors usually operate above 125 1C in aviation power systems, oil/gas exploration and hybrid vehicles, and require high temperature resistance capacitor materials with a high energy density (U e ). [1][2][3][4] A high glass transition temperature (T g ) is one of the key conditions for high temperature resistant polymers. The relaxation of polymer chains leads to a decrease in dielectric properties when the temperature is around T g .…”

“…For example, film capacitors usually operate above 125 °C in aviation power systems, oil/gas exploration and hybrid vehicles, and require high temperature resistance capacitor materials with a high energy density ( U e ). 1–4…”