Energy storage and loss capacity of graphene‐reinforced poly(vinylidene fluoride) nanocomposites from electrical and dielectric properties perspective: A review

Abstract

Polymer/graphene nanocomposites have shown promising potentials in energy storage applications due to their high permittivity, enhanced energy storage density, flexibility, and improved thermal and mechanical properties. The addition of graphene nanosheets to polymer matrix improves existing and incorporate new properties on such nanocomposites for various engineering applications. For instance, graphene nanosheets in polymer matrix are believed to form microcapacitors. Each microcapacitor contributes to the effective capacitance and dielectric constant of the composite. Although research has proved polymer/graphene composites as high dielectric constant materials, the major challenges facing their practical applications are high energy dissipation, high dielectric loss, and low electric field strength. In view of this, many researchers have shown efforts to minimize energy losses associated with polymer/graphene composites by insulating graphene nanosheets with different organic and inorganic substances. This is believed to prevent direct contact of graphene nanosheets and reduce the high mobility of π‐orbital or free electrons in the polymer matrix. However, maintaining high dielectric constant at low dielectric loss in polymer/graphene composites has not been achieved. If this challenge can be addressed in the future, polymer/graphene composites can yield energy storage capacity comparable with those of electrochemical capacitors. Therefore, this review considered energy storage and loss capacity of poly(vinylidene fluoride)/graphene nanocomposites from the perspective of electrical and dielectric properties. This article to the best of our ability reviewed various research results on dielectric constants/losses, breakdown strengths, energy densities, and electrical and thermal conductivities of poly(vinylidene fluoride)/graphene nanocomposites. Results extracted from the different published literature were tabulated and discussed at length to outline the reasons for the high dielectric loss in the neighborhood of percolation thresholds and the way forward.

Graphene–polyamide‐6 composite for additive manufacture of multifunctional electromagnetic interference shielding components

“…The decreasing trend of ε 00 with increasing frequency can be attributed to the dipoles being unable to remain in phase and reduction in charge accumulation due to hindered ion diffusion with the increasing rate of electrical field variation. 42,43 As frequency dependence of ε 00 is only observed when filler content is sufficiently high, 44 the reduced frequency sensitivity in ε" of GC (ME) can be attributed to reduced influence of interfacial polarization following printing due to the presence of inter-layer voids.…”

Modulation and mechanism of spatial structure for multi-layer cyanate ester resin composites to achieve remarkably increased energy storage density and decreased dielectric loss

“…However, their high dielectric constant is originated from percolation threshold effect, that is, the formation of conductive path, so it is not surprised to simultaneously find the jump of dielectric loss and sharp reduce of breakdown strength ( E b ). 9–13…”

Enhanced dielectric performance and energy storage density of polymer/graphene nanocomposites prepared by dual fabrication

“…The limited applications of PGNs as ESC are due to high energy dissipation, high dielectric loss and low voltage endurance resulting from high current leakage. 1,15,16 Poor dispersion of graphene and interfacial interaction with polymer matrix are also challenges restricting excellence fabrications and broad applications of PGNs. 17 Therefore, various fabrication techniques have been used in the preparation of PGNs.…”

“…However, solution blending has high tendency of re-clustering or settling of graphene sheets in polymer matrix during recovering of PGNs from solution, especially by evaporation technique. 16 Hence, it may result in poor and undesired properties such as low dielectric constant and high energy dissipation.…”

“…According to Uyor et al, 16 melt compounding can provide well distribution of graphene sheets in the polymer matrix by mechanical mixing at high temperature and shear forces, which enables effective entangling and intercalation of polymer molecular chains with graphene sheets. In this study, we took advantages of both solution blending and melt compounding in the fabrication of PGNs.…”