posted on 2021-06-03, 19:05authored bySung-Yub Ji, Han-Bo Jung, Min-Kyu Kim, Ji-Ho Lim, Jin-Young Kim, Jungho Ryu, Dae-Yong Jeong
Polymer-based
dielectrics have attracted considerable attention
for a wide range of applications as energy storage devices with high
power. However, high loss from low thermal conductivity (K) and leaky current may limit their practical utilization greatly.
To overcome these issues, two-dimensional hexagonal boron nitride
(h-BN) modified with polydopamine (PDA) and metal palladium nanoparticles
(h-BN@PDA@Pd NPs) are introduced into a poly(vinylidene fluoride-hexafluoropropylene)
P(VDF-HFP) copolymer matrix. The PDA coating improves the compatibility
between the ceramic h-BN filler and the polymer matrix. Contrary to
the general idea, the metallic Pd NPs enhance the breakdown strength
of the polymer nanocomposites through the Coulomb-blockade effect.
The nanocomposite film filled with 6 vol % h-BN@PDA@Pd NPs exhibits
significantly improved recoverable energy density (Urec) of 58.6 J cm–3, which is increasedby
496% compared to pure P(VDF-HFP) film, maintaining an efficiency of
65%, even under a high voltage of 500 MV m–1. The
in-plane thermal conductivity of the nanocomposites was improved from
0.21 to 1.02 W m–1 K–1 with increasing
ceramic h-BN content. This study suggests that a dielectric polymer
with surface-engineered ceramic h-BN fillers through a Coulomb-blockade
effect of metal Pd NPs might be a promising strategy for high energy
storage devices.