Improving the Performance of Dielectric Nanocomposites by Utilizing Highly Conductive Rigid Core and Extremely Low Loss Shell

Abstract

Polymer nanocomposites filled with one-dimensional "reelable" carbon-based nanoparticles can exhibit a high dielectric constant (ε′) with a small quantity of nanoparticles. However, this kind of nanoparticle easily forms a conductive network near the percolation threshold, resulting in a sharp increase in the dielectric loss (tan δ) and dramatic deterioration of the breakdown strength (E b ). In this work, the insulated silica (SiO 2 ) nanoparticles were decorated on the surface of "rigid" carbon nanofibers (CNFs) that exhibit a similar geometric feature to that of the one-dimensional ceramic fiber by a sol−gel reaction, and then the SiO 2 @CNF hybrids were subsequently incorporated into poly(vinylidene fluoride) (PVDF) matrix to fabricate SiO 2 @CNF/PVDF dielectric nanocomposites. Compared with the CNF/PVDF nanocomposites, the presence of a SiO 2 insulating barrier layer tremendously reduced the tan δ of the nanocomposites, and meanwhile, E b of the nanocomposites was greatly enhanced. For example, the nanocomposite containing 3 wt % CNFs exhibited a tan δ of 62 at 10 3 Hz and E b of 118.4 kV/mm; however, for the nanocomposite containing 3 wt % b-S@C, tan δ was reduced to 0.057 at 10 3 Hz while E b was enhanced up to 290.9 kV/mm. This work confirms that coating the insulated SiO 2 nanoparticles with extremely low tan δ onto the surface of the one-dimensional conductive nanoparticles is a promising way to prepare the excellent comprehensive performing dielectric nanocomposites, and such composites may have a bright future in the fields of energy storage, conversion, and release.

High energy efficiency nanodielectrics with relaxor ferroelectric polymer and antiferroelectric (Pb 0.97 La 0.02 ) (Zr 0.63 Sn 0.3 Ti 0.07 )O 3 ceramics

“…Antiferroelectric PLZST ceramics synthesised by the solid‐state method have a typical perovskite structure as shown in Figure 2(a). The dielectric measurement of the PLZST indicates that it has a high dielectric constant (523 at 100 Hz) yet a low dielectric loss (0.012 at 100 Hz) as shown in Figure 2(b), which is lower than the common high‐ ε r ceramics, such as BaTiO 3 (∼0.05 at 100 Hz), BaSrTiO 3 (∼0.03 at 100 Hz) and CaCu 3 Ti 4 O 12 (∼0.1 at 100 Hz) [11–14, 33]. The most striking thing is that PLZST is an antiferroelectric ceramic with extremely small P r unlike conventional ferroelectric ceramics such as BaTiO 3 as shown in Figure 2(c)–(d), which means utilising antiferroelectric materials as fillers of nanocomposites may simultaneously allow a high energy efficiency.…”

“…However, high-ε r ceramics such as BaTiO 3 and PVDF-based polymer matrix are both ferroelectrics. Ferroelectrics could form polarised ferroelectric domains spontaneously, which lag behind the instantaneous reverse electric field after being polarised by an external electric field and have a large P r value [10][11][12][13][14][15]. Therefore, PVDF-based polymer/ceramics ferroelectric composites usually have a large P r and will produce a large energy loss during charge-discharge cycles.…”

Current and future applications of PVDF-carbon nanomaterials in energy and sensing

“…At the same time, among the chemical methods one can mention CNM surface modifications: grafting, coating, and polymerization. As an example, one can consider an interesting procedure proposed by Yang et al [18] who by decorating of CNFs with SiO2, introducing this material into PVDF matrix, highly improved CNFs dispersibility (an increase in dielectric constant was simultaneously observed). In this case SiO2@CNFs prevented agglomeration.…”

Probing the Interface Activation in Designing Defect-Free Multilayered Polymer Nanocomposites for Dielectric Capacitor Applications

“…In a single-layered polymer nanocomposite, dielectric properties of core@shell nanofillers of different aspect ratios like 0-D [e.g., nanoparticles (NPs) − ], 1-D [e.g., nanowires (NWs), , and nanofibers (NFs) ,, ], and 2-D (e.g., graphene oxides, reduced graphene oxides, and TiO 2 ) have been studied. The researchers have used different linkers such as polydopamine, , silicon dioxide (SiO 2 ), − polyvinylpyrrolidone (PVP), , and so forth.…”

“…In a single-layered polymer nanocomposite, dielectric properties of core@shell nanofillers of different aspect ratios like 0-D [e.g., nanoparticles (NPs) 7−9 ], 1-D [e.g., nanowires (NWs), 10,11 and nanofibers (NFs) 8,12,13 ], and 2-D (e.g., graphene oxides, 14 reduced graphene oxides, 15 and TiO 2 16 )…”