Ultrahigh Energy Storage Density in Poly(vinylidene fluoride)‐Based Composite Dielectrics via Constructing the Electric Potential Well

Abstract

Dielectric capacitors are fundamental energy storage components in electronics and electric power systems due to their unique ultrahigh power density. However, their relatively low energy storage density is a long‐standing challenge which greatly limits their practical application range. Chitosan (CS) and montmorillonite (MMT) are two kinds of materials that exist abundantly on the earth with natural surface charges. The positively charged CS and negatively charged MMT can be self‐assembled into the typical sandwich‐structured CS/MMT/CS 2D structure through an electrostatic attraction. Loading these surface‐charged sandwich‐structured nanosheets into poly(vinylidene fluoride)‐based composite with a weight fraction as tiny as 0.3 wt.%, an ultrahigh energy storage density of 32.5 J cm−3 accompanied with a high efficiency of 64% are concurrently achieved with a very low cost and scalable process. Guided by finite element simulation, it is revealed that a number of electric potential wells that exist in the charged sandwich nanosheets impede the acceleration of internal charges and hinder the growth of electrical trees. The results offer a novel paradigm for exploring ultrahigh energy storage density capacitors in an economical way.

Enhanced Energy Storage Density of Ferroelectric Polymer-Based Composite Dielectrics via Introducing Surface-Charged Kaolin Nanosheets

“…These sandwiched fillers can establish a significant reversed electric field to suppress the generation of secondary collision electrons and the formation of breakdown paths, thereby effectively improving the energy storage properties of the composite. In addition, our previous study also further confirmed that the charged nanofiller could effectively enhance the E b and energy density of polymer-based composite dielectrics …”

“…In spite of the slight enhancement in D r , the η of composites exhibits a significant increase, which is consistent with the trend of D max – D r . It is attributed to the fact that the negatively charged KLNS could decelerate and rebound the free charges in composites rather than capture the free charges in deep traps like positively charged nanofillers do. , Thus, a majority of injected and collision-ionized free charges can be relatively easily discharged from the KLNS/PVDF composite dielectrics. Moreover, it is observed that the composite incorporated with 0.2 wt % KLNS possesses the highest charge–discharge efficiency (η = 62.9%) at 530.9 MV/m, which is much greater than that of PVDF (η = 42.5% at 243.3 MV/m).…”

“…In addition, our previous study also further confirmed that the charged nanofiller could effectively enhance the E b and energy density of polymer-based composite dielectrics. 39 Consequently, in this study, we selected an extremely low cost and inherently charged kaolin nanosheet (KLNS) as the 2D nanofillers in order to effectively regulate the electrical insulating property of composite dielectrics. The bulk kaolin is a natural 2D multilayer structured mineral with a typical crystalline structure mainly consisting of SiO 2 , Al 2 O 3 , and small fractions of other oxides of Ca, Mg, K, Na, etc.…”

Superior capacitive performance achieved in wide HOMO–LUMO gap cyanoethyl cellulose nanocomposites via forming a built-in electric field

“…3b). 9,[26][27][28][29][30] The dielectric breakdown of the CRC films and the nanocomposite films is commonly illustrated by the Weibull distribution (Fig. 3c).…”

Achieving Higher Dielectric and Energy Storage Performances of Methyl Methacrylate-co-glycidyl Methacrylate Films through the Nanocomposite Strategy

“…In recent years, dielectric materials with ultrafast charge–discharge time, high power density, and outstanding cycling stability have been widely applied in various electrical power systems. − To meet the demands of lightweight and miniaturization of modern electronic devices, how to achieve the higher energy density and efficiency of the dielectric materials remains crucial . In general, the energy density ( U e ) of dielectric materials between the two electrodes can be calculated using the following equation U e = ∫ E normald D where E and D represent the applied electric field and electric displacement, respectively .…”