Relationship between BaTiO₃ Nanowire Aspect Ratio and the Dielectric Permittivity of Nanocomposites

Abstract

The aspect ratio of barium titanate (BaTiO3) nanowires is demonstrated to be successfully controlled by adjusting the temperature of the hydrothermal growth from 150 to 240 °C, corresponding to aspect ratios from 9.3 to 45.8, respectively. Polyvinylidene fluoride (PVDF) nanocomposites are formed from the various aspect ratio nanowires and the relationship between the dielectric constant of the nanocomposite and the aspect ratio of the fillers is quantified. It was found that the dielectric constant of the nanocomposite increases with the aspect ratio of the nanowires. Nanocomposites with 30 vol % BaTiO3 nanowires and an aspect ratio of 45.8 can reach a dielectric constant of 44.3, which is 30.7% higher than samples with an aspect ratio of 9.3 and 352% larger than the polymer matrix. These results demonstrate that using high-aspect-ratio nanowires is an effective way to control and improve the dielectric performance of nanocomposites for future capacitor applications.

High-k Polymer Nanocomposites for Energy Storage Applications

“…A direct relationship was observed with the aspect ratio of nanocomposites and dielectric constant. A high dielectric constant of 44.3 was reported for the BT-30 vol% nanocomposites with an aspect ratio of 45.8, which was 30.7% higher than BT samples with an aspect ratio of 9.3 while 352% higher than polymer matrix samples [48]. Despite the high dielectric constant fillers for high dielectric nanocomposite applications, such as BT and PbZrTiO 3 -based derivatives, these filler materials still suffer from some disadvantages, which include low dielectric response even with high loading concentration, low breakdown strength, and deteriorated flexibility.…”

“…Tang et al [48] studied the effect of different aspect ratios of the BT nanowires on the dielectric properties of the BT/PVDF nanocomposites. The aspect ratios of the nanowires were tuned by controlling the temperature during hydrothermal synthesis, where they were varied from 9.3 to 45.8 corresponding to the temperature ranges from 150 to 240°C, respectively.…”

Synthesis of calcium copper titanate (CaCu3Ti4O12) nanowires with insulating SiO2 barrier for low loss high dielectric constant nanocomposites

“…The dielectric constant of the nanocomposite with 40 vol% CCTO NWs reached 68, which was 6.9 times higher than the PVDF matrix (9.8) and 70% larger than a similar nanocomposite with PZT NWs at the same volume fraction (40) [7]. This improvement in dielectric constant can be further enhanced using NWs of various morphologies and orientations which provides a route to tailor the nanocomposite properties and enhance dielectric constant further [21,28,29,33]. The high dielectric permittivity and low loss tangent created by the hierarchical SiO 2 /CCTO NWs have the capability to produce higher energy density nanocomposites with higher energy storage efficiency, which has the potential to replace existing materials in the energy storage field.…”

“…The first hydrothermal reaction synthesized HTO NWs, which have been widely investigated and offers an easily controllable morphology [17,[30][31][32][33]. More importantly, HTO is a layered titanate, which is an ideal precursor for soft chemical synthesis because its open structure is compatible with ion exchange reactions [30,34].…”

Ni-coated CaCu3Ti4O12/low density polyethylene composite material with ultra-high dielectric permittivity

“…[1][2][3][4] Recently, polymer composites with ceramic fillers have been shown to be a promising materials for energy storage devices, because they can combine the high dielectric permittivity of ceramics with the good mechanical strength, flexibility, and the ease of processing of polymers. [5][6][7] To produce high dielectric permittivity ceramic-polymer composites, many studies have focused on the addition of ceramic particles with high dielectric permittivity, such as Pb(Zr, Ti)O 3 , 8 BaTiO 3 (BT), 6,9 and CaCu 3 Ti 4 O 12 (CCTO) 10,11 to polymers such as polyimide (PI), polyvinylidene fluoride (PVDF), or their copolymer matrix. For example, Dang et al 12 synthesized PVDF/BT composites containing 50 vol.% of nanoparticles and obtained a dielectric permittivity of 40.74 at 1 kHz.…”