Shengtao Li

Bio: Shengtao Li is an academic researcher from Xi'an Jiaotong University. The author has contributed to research in topics: Dielectric & Space charge. The author has an hindex of 41, co-authored 489 publications receiving 8436 citations. Previous affiliations of Shengtao Li include South China Normal University & Shandong Normal University.

Large dielectric constant and high thermal conductivity in poly(vinylidene fluoride)/barium titanate/silicon carbide three-phase nanocomposites.

Abstract: Dielectric polymer composites with high dielectric constants and high thermal conductivity have many potential applications in modern electronic and electrical industry. In this study, three-phase composites comprising poly(vinylidene fluoride) (PVDF), barium titanate (BT) nanoparticles, and β-silicon carbide (β-SiC) whiskers were prepared. The superiority of this method is that, when compared with the two-phase PVDF/BT composites, three-phase composites not only show significantly increased dielectric constants but also have higher thermal conductivity. Our results show that the addition of 17.5 vol % β-SiC whiskers increases the dielectric constants of PVDF/BT nanocomposites from 39 to 325 at 1000 Hz, while the addition of 20.0 vol % β-SiC whiskers increases the thermal conductivity of PVDF/BT nanocomposites from 1.05 to 1.68 W m–1 K–1 at 25 °C. PVDF/β-SiC composites were also prepared for comparative research. It was found that PVDF/BT/β-SiC composites show much higher dielectric constants in compariso...

Fabrication and Dielectric Characterization of Advanced BaTiO3/Polyimide Nanocomposite Films with High Thermal Stability

Abstract: Barium titanate/polyimide (BaTiO3/PI) nanocomposite films with high dielectric permittivity (20), high breakdown strength (67 MV m−1), and high thermal stability are prepared by an in-situ polymerization process. A very thin polymer layer (about 5 nm) is coated on the surface of nanosized BaTiO3 particles to form a core–shell-like structure, which can guarantee homogeneous dispersion of the BaTiO3 particles in the PI matrix. It is confirmed that the core–shell-like structure originates from both the electrostatic attraction between the precursor poly(amic acid) (PAA) and the BaTiO3 particles and the hydrogen bond interaction between PI and the BaTiO3 particles. Such a structure also has some influence on the dielectric properties and breakdown strength of films. After casting and degassing of the sticky film, the dielectric permittivity of the nanocomposite film is close to or even higher than that of submicrocomposite films, which is attributed to the advanced interfacial structure between the BaTiO3 and PI phases.

Short-term breakdown and long-term failure in nanodielectrics: a review

Abstract: Nanodielectrics, which are concentrated in polymer matrix incorporating nanofillers, have received considerable attention due to their potential benefits as dielectrics. In this paper, short-term breakdown and long-term failure properties of nanodielectrics have been reviewed. The characteristics of polymer matrix, types of nanoparticle and its content, and waveforms of the applied voltage are fully evaluated. In order to effectively comment on the published experimental data, a ratio k has been proposed to compare the electric properties of the nanodielectrics with the matrix and assess the effect for nanoparticles doping. There is evidence that the short-term breakdown properties of nanodielectrics show a strong dependence on the applied voltage waveforms. The polarity and the cohesive energy density (CED) of polymer matrix have a dramatic influence on the properties of nanodielectrics. Nanoparticle doped composites show a positive effect on the long-term failure properties, such as ageing resistance and partial discharge (PD) properties of nanocomposites are superior than microcomposites and the matrix. The larger the dielectric constant and CED of the matrix become, the more significant improvements in long-term performance appear. Based on the reported experimental results, we also present our understandings and propose some suggestions for further work.

Nanoalloys: From Theory to Applications of Alloy Clusters and Nanoparticles

Abstract: 5.1. Nanoalloys of Group 11 (Cu, Ag, Au) 865 5.1.1. Cu−Ag 866 5.1.2. Cu−Au 867 5.1.3. Ag−Au 870 5.1.4. Cu−Ag−Au 872 5.2. Nanoalloys of Group 10 (Ni, Pd, Pt) 872 5.2.1. Ni−Pd 872 * To whom correspondence should be addressed. Phone: +39010 3536214. Fax:+39010 311066. E-mail: ferrando@fisica.unige.it. † Universita di Genova. ‡ Argonne National Laboratory. § University of Birmingham. | As of October 1, 2007, Chemical Sciences and Engineering Division. Volume 108, Number 3

Recent Progress on Ferroelectric Polymer-Based Nanocomposites for High Energy Density Capacitors: Synthesis, Dielectric Properties, and Future Aspects.

Abstract: Dielectric polymer nanocomposites are rapidly emerging as novel materials for a number of advanced engineering applications. In this Review, we present a comprehensive review of the use of ferroelectric polymers, especially PVDF and PVDF-based copolymers/blends as potential components in dielectric nanocomposite materials for high energy density capacitor applications. Various parameters like dielectric constant, dielectric loss, breakdown strength, energy density, and flexibility of the polymer nanocomposites have been thoroughly investigated. Fillers with different shapes have been found to cause significant variation in the physical and electrical properties. Generally, one-dimensional and two-dimensional nanofillers with large aspect ratios provide enhanced flexibility versus zero-dimensional fillers. Surface modification of nanomaterials as well as polymers adds flavor to the dielectric properties of the resulting nanocomposites. Nowadays, three-phase nanocomposites with either combination of fillers...