Double gradient composite dielectric with high energy density and efficiency

Abstract

Composites that possess ultra-high breakdown strength together with high dielectric constant have always been the pursuit of energy storage polymer-based dielectric. However, the constrained relationship between them makes uniform filled...

Ultrahigh energy storage performance of all-organic dielectrics at high-temperature by tuning the density and location of traps

“…U and Z of the dielectric are calculated according to the equation U ¼ Ð DdE and Z = U discharge /U charge , where E is the polarized electric field, D is the electric displacement, U discharge is the energy storage density during discharge, and U charge is the energy storage density during charge. [43][44][45] The variation of high-temperature U and Z with electric field for pristine PEI and ITIC/PEI at different temperatures is displayed in Fig. 4.…”

The simple synthesis of all‐organic polymer bilayer films: Achieving simultaneous enhancements in energy storage density and efficiency

“…where U d represents the energy storage capacity of the dielectric, E b represents the breakdown strength, ε 0 and ε r represent the dielectric constant of vacuum and relative dielectric constant. [13][14][15] Obviously, breakdown strength and dielectric constant are two important variables for energy storage density. 16 Although the ultra-low remanent polarization of the linear dielectric itself close to zero makes it have high energy storage efficiency, the low dielectric constant leads to its limited energy storage density, which limits its application.…”

“…Formula () is used to represent the energy storage density of the linear dielectrics. where U d represents the energy storage capacity of the dielectric, E b represents the breakdown strength, ε 0 and ε r represent the dielectric constant of vacuum and relative dielectric constant 13–15 …”

Polyimide-Based Composite Films with Largely Enhanced Energy Storage Performances toward High-Temperature Electrostatic Capacitor Applications

“…Polymer-based dielectrics, characterized by their outstanding electrical dielectric strength, relatively low dielectric loss, fast charge–discharge capability, and mechanical flexibility, have become a research hotspot in current work and are widely applied in energy storage devices. − Typically, discharge energy density ( U d ) and charge/discharge efficiency (η) are the basic performance parameters for evaluating capacitors, and researchers have made substantial efforts to improve the U d and η values of capacitors at room temperature (RT) in the past decades. − Nowadays, owing to electric power system installation close to the motor and the ever-increasing requirement of high-power applications (which are always exposed to elevated temperatures), capacitors, the fundamental component of power inverters, are required to function efficiently at temperatures above 140 °C. , Nevertheless, the poor thermal stability of polymers and the inevitable conduction loss caused by the fundamental issue of thermally and electrically assisted charge injection, excitation, and transport will lead to the drastically deteriorated capacitive properties of polymer-based dielectrics at high temperature, which severely hampers their usage in extreme environments. − …”