Study on Energy Storage Characteristics of Layered Composite Dielectric with Alternating Stacking of Insulation Layer and Polarization Layer

Abstract

With superhigh power density and environmentally friendly electrostatic energy storage function, dielectric capacitors have broad application prospects in pulsed power systems and new energy fields. Increasing capacitor energy storage density can markedly cut down the size of the device and save physical space. In this work, the insulation, polarization and energy storage properties of 3-, 5- and 7-layer composite dielectrics were investigated, with layer structures consisting of alternating stacks of insulation and polarization layers. Specifically, a mixture of PMMA and P(VDF-TrFE-CFE) was designated as the substrate, a composite dielectric with 1 vol% BNNS introduced was used as the insulating layer, and a composite dielectric doped with 3 wt% TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> was used as the polarization layer. An energy density of 18.26 J/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> was obtained with an efficiency of up to 80% in a 3-layer structure where the insulation layer is located on the outside. Furthermore, the effects of the positions of the polarization and insulation layers on the energy storage performance of the composites were discussed by constructing 3-, 5-, and 7-layer structures with the polarization layer located on the outer side. In addition, the distribution of B, N and Ti elements in the crosssection of the composites was characterized by EDS mapping, which confirmed the presence of functional layers. This work provides guidance for the reasonable format of energy storage composites with excellent general properties.