Observing reduced field fluctuation in interfacial engineered organic–inorganic dielectric nanocomposite for enhanced breakdown strength

Abstract

Organic–inorganic nanocomposites with superior dielectric energy density are highly sought after for high-power electronics and pulsed power systems, and interfacial engineering turns out to be one of the most successful strategies to improve their breakdown strength. However, a microscopic mechanism responsible for such improvement, thought to be closely related to local field fluctuation in the nanocomposites, has never been directly demonstrated experimentally. Here, we develop a powerful yet readily applicable in situ technique to evaluate the fluctuation of electric field in dielectrics, revealing reduced field fluctuation in interfacial engineered nanocomposites that clearly correlates with its enhanced breakdown strength. This work, thus, validates field fluctuation-based breakdown criterion of nanocomposite proposed more than one decade ago and provides further support to improve organic–inorganic nanocomposites for high density dielectric energy storage.

Electric Field Assist on Enhancing the Electrical Breakdown Strength of Cross-Linked Polyethylene for Power Cable Insulation

“…Cross-linked polyethylene (XLPE) is the common insulating material for the commercially extruded HVDC cables . Reducing the imperfections in XLPE is the most traditional strategy for enhancing the electrical breakdown strength. , However, it is not always feasible to improve purity in an economical or practical way today, as the cleanliness of XLPE has been developed to an extremely advanced level. , In recent years, extensive work has been carried out to improve electrical breakdown strength via nanotechnology. − For example, the doping of inorganic nanoparticles (MgO, Al 2 O 3 , SiO 2 , etc.) in XLPE is able to effectively enhance the electrical breakdown strength of XLPE nanocomposite. , Nevertheless, the uniform dispersion of nanoparticles in the XLPE is still unsolved, and the nanoparticles tend to block the metal mesh in extruder, so the nanotechnology has not been widely applied in power cables. − …”

Composition-Driven Polarization Distribution in Poly(vinylidene fluoride)-Based Copolymer Blends for High Power Density Capacitors

“…Compared to dielectric ceramics, polymers generally possess mechanical flexibility, light weight, high E b , low loss, easy processability, and low cost, and the most successful commercial productbiaxially oriented polypropylene (BOPP) filmhas been widely used in advanced electronics, electricity grids, and electrified transportation. Nevertheless, the low permittivity (∼2.2) of BOPP severely limits its energy storage performance; i.e., U dis is lower than 5 J/cm 3 at an electric field of 700 MV/m, which could not meet the ever-increasing need for high power supply. − Several strategies have been developed to boost the energy storage performances of polymer-based dielectrics, such as constructing nanocomposites with various nanostructured inorganic fillers based on the idea to increase permittivity without deteriorating the E b of the polymer or even to further enhance E b − or building multilayers to make use of the mesoscopic interfaces forming between adjacent layers to block the charge migration, so as to reduce the dielectric loss. , …”