Energy Storage Performance Of Composites Research Articles

Antiferroelectric AgNbO3 @KH550 Doped PVDF/PMMA Composites with High Energy Storage Performance.

The residual polarization of antiferroelectric ceramics is very small, yet they possess high energy storage density and efficiency. Incorporating antiferroelectric ceramic particles into a polymer matrix is beneficial for improving the energy storage performance of composites. However, excessive amounts of ceramic particles can lead to aggregation within the polymer, resulting in defects and a significant reduction in composite film performance. In this study, the antiferroelectric AgNbO3 is selected as the filler and modified with silane coupling agent KH550. poly(vinylidene fluoride) (PVDF) and polymethyl methacrylate (PMMA) are blended as the matrix, and the energy storage performance of the composite is improved by adjusting the additional amount of PVDF. The structure, dielectric properties, and energy storage properties of the composites are systematically studied. The results show that hydrogen bonds are formed between PVDF and PMMA, and PVDF and PMMA are tightly bonded under the action of hydrogen bonds. The compatibility of PVDF with PMMA is optimal when the mass fraction of PVDF is 30 wt%. Moreover, with the synergistic effect of the antiferroelectric filler AgNbO3 , the breakdown strength of AgNbO3 /PVDF/PMMA composites reaches 430kV mm-1 , and the energy storage density reaches 14.35 J cm-3 .

Effects of suface hydroxylated strontium titanate nanofibers on dielectric and energy storage properties of polyvinylidene fluoride composites

With the rapid development of the electronics industry, the dielectric materials with high energy storage density, fast charge and discharge speed, easy-to-process and easy-to-mold, and stable performance are urgently needed to meet the requirements for lightweight and miniaturization of electronic component equipment. Dielectric ceramics has a high dielectric constant, but low breakdown field strength. Polyvinylidene fluoride (PVDF) has the advantages of good flexibility, high breakdown field strength, and light weight, but its dielectric constant is low. Achieving the ability to tailor the interface between dielectric ceramics filler and PVDF polymer matrix is a key issue for realizing the desirable dielectric properties and high energy density in the nanocomposites. As a result, much effort has been made to prepare the polymer composites through the surface modification of the nanoparticles with high dielectric constant fillers dispersed in a matrix, with the hope of preparing composites containing the high dielectric constant of the ceramic fillers and the high breakdown strength of polymers. In this work, in order to obtain the high dielectric-constant and high-energy-storage-density dielectric ceramics, the electrospinning method is used to prepare the SrTiO<sub>3</sub> one-dimensional nanofibers as the inorganic fillers and the casting method is adopted to prepare PVDF as the polymer matrix. To improve the interface between inorganic nanofiber fillers and PVDF matrix, the SrTiO<sub>3</sub> nanofibers are modified by surface hydroxylation. The effects of suface hydroxylated SrTiO<sub>3</sub> nanofibers on the dielectric properties and energy storage properties of PVDF composites are studied. The correlation between interface modification and energy storage performance of composites is investigated to reveal the mechanism of enhanced energy storage performance of SrTiO<sub>3</sub> nanofibers/PVDF composites. The results show that the dispersion of surface-hydroxylating SrTiO<sub>3</sub> nanofibers in PVDF polymer can be improved. The composites exhibit improved dielectric properties and enhanced breakdown strength. When the filling quantity of the surface-hydroxylating SrTiO<sub>3</sub> nanofiber fillers is 2.5 vol%, the energy storage density of the composite reaches 7.96 J/cm<sup>3</sup>. Suface-hydroxylating SrTiO<sub>3</sub> nanofibers exhibit excellent dispersion in the PVDF polymer matrix and strong interfacial adhesion with the matrix, leading the composites to possess excellent dielectric constant and energy storage performance. The surface hydroxylation of ceramic fillers can improve the energy storage performance of the composites.

Ultrahigh discharge efficiency and excellent energy density in oriented core-shell nanofiber-polyetherimide composites

A new energy storage dielectric system-polyetherimide (PEI) based composite was developed and investigated intensively. The system possesses the advantages of excellent energy storage efficiency along with energy storage density. A comprehensive energy storage performance with ultrahigh efficiency of 90% and outstanding density of 11.3 J/cm3 is simultaneously achieved in PEI/BaTiO3 nanofiber coated by thick SiO2 layer (PEI/BT@T-SiO2) composites. The optimized energy storage efficiency is ascribed to the lower intrinsic dielectric loss of PEI matrix, insulted SiO2 shell outside the BaTiO3 nanofibers, and the oriented arrangement (parallel to the composite surface) of above “core-shell” structured fillers. In addition, three types of “core-shell” structured fillers ((BaSr)TiO3@SiO2, BT@SiO2 and BT@T-SiO2) were fabricated. The effects of dielectric constant for “core” and thickness for “shell” in the “core-shell” structured fillers on the dielectric and energy storage performance of composites were also investigated. The combination of experimental and simulated results indicates that larger dielectric constant of “core” doesn’t mean the high polarization it can provide, and thickness of “shell” can influence the electric field distribution on “core”. This work not only provides a new choice for matrix selection, but also points out a design route for the “core-shell” structured fillers used in the polymer based dielectric composites.

Effect of BaTiO3 nanowire distribution on the dielectric and energy storage performance of double-layer PVDF-based composites

A series of novel double-layer PVDF-based composites filled with different concentration of BaTiO3 nanowire were fabricated employing hot-pressing process. The effects of various BT-NWs concentrations in isolated layers on the dielectric properties, energy storage density of the composites were investigated. The experimental dielectric constants of double-layer composites are lower than expected. The breakdown strength (Eb) of double-layer composites was obtained in the experiment, and predicted via capacitance series formula (CSF) and finite element analysis (FEA). Results show that the data predicted by FEA are closer to the experimental values. Compared with dielectric constant, the enhancement of Eb induced by double-layer structure is more significant for the energy storage performance of composites. A design route including Eb measurement of single-layer composites, Eb prediction of double-layer composites via FEA, selection of single-layer material and composites fabrication is proposed to prepare the multi-layer composites with excellent dielectric properties and energy storage.

High Energy Storage Density for Poly(vinylidene fluoride) Composites by Introduced Core–Shell CaCu3Ti4O12@Al2O3 Nanofibers

In this paper, the one-dimensional (1D) Al2O3 nanofibers (Al2O3 NFs), CaCu3Ti4O12 nanofibers (CCTO NFs), and core–shell CaCu3Ti4O12@Al2O3 nanofibers (CCTO@Al2O3 NFs) were prepared via electrospinning technique. The surface modification with dopamine (PDA) was employed for the above three kinds of nanofibers before being filled the PVDF matrix, which can improve their dispersion and compatibility with the matrix. The microstructure, dielectric properties, leakage current density, breakdown strength, and energy storage performance of composites with three kinds of filler, CCTO NFs/PVDF, Al2O3 NFs/PVDF, and CCTO@Al2O3 NFs/PVDF, were systematically investigated. By comparing the three composites, it can be found that energy storage density of CCTO@Al2O3 NFs/PVDF were enhanced compared to that of pure PVDF, which can be attributed to improvement of polarization and electric breakdown strength. The energy density of 8.46 J/cm3 at 340 kV/mm was obtained for 4 vol % CCTO@Al2O3 NFs/PVDF nanocomposites, which is 23...