Polymer dielectric composites are of great interest as film capacitors that are widely used in pulsed power systems. For a long time, huge efforts have been devoted to achieving energy densities as high as possible to satisfy the miniaturization and high integration of electronic devices. However, the discharge efficiency which is particularly crucial to practical applications has gained little attention. With the target of achieving concurrently improved energy density and efficiency, a class of rationally designed bilayer composites consisting of a pure polyetherimide layer and a BaTiO3/P(VDF-HFP) composite layer were prepared. Interestingly, the bilayer composites exhibit ultrahigh discharge efficiencies η (>95%) under external electric fields up to 400 kV mm−1 which are much higher than most of the so far reported results (η < 80%). Meanwhile, a low loss (tan δ < 0.05 @ 10 kHz) comparable to that of the pure polyetherimide is obtained. In addition, the bilayer composites show impressive improvements in breakdown strengths Eb, i.e., 285%, 363%, 366% and 567% for composites with 5 vol%, 10 vol%, 20 vol% and 40 vol% BaTiO3, compared to their single layer counterparts, resulting in obviously improved energy densities Ud. In particular, the bilayer composite with 10 vol% BaTiO3 displays the most prominent comprehensive energy storage performance, i.e., η ∼ 96.8% @ 450 kV mm−1, Ud ∼ 6 J cm−3 @ 450 kV mm−1, tan δ ∼ 0.025 @ 10 kHz, and Eb ∼ 483.18 kV mm−1. The ultrahigh discharge efficiencies and high energy densities, along with low loss and breakdown strengths, make these bilayer composites ideal candidates for high-performance dielectric energy-storage capacitors.

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Ultrahigh discharge efficiency and improved energy density in rationally designed bilayer polyetherimide–BaTiO3/P(VDF-HFP) composites

High-temperature dielectric ceramics are in urgent demand due to the rapid development of numerous emerging applications. However, producing dielectric ceramics with favorable temperature, frequency and electric field stability is still a huge challenge. The construction of multi-phase coexistence material systems is an effective way to obtain stable dielectric and energy storage properties. In this work, NaNbO3 (NN) modified 0.95Bi0.5Na0.5TiO3–0.05SrZrO3 (BNTSZ) ceramics ((1 − x)BNTSZ–xNN) are designed to achieve the coexistence of rhombohedral and tetragonal phases. The variation in the dielectric permittivity of the 0.8BNTSZ–0.2NN ceramic is less than ±15% over the temperature range from −55 °C to 545 °C, which is the reported record-high upper operating temperature, with a high room-temperature dielectric permittivity of 1170. The 0.8BNTSZ–0.2NN ceramic exhibits excellent frequency and electric field stability as well. Additionally, a large discharge energy density of 3.14 J cm−3 is obtained in the 0.85BNTSZ–0.15NN ceramic with an energy efficiency of 79% at a high temperature of 120 °C under 230 kV cm−1, with the variation in the discharge energy density being less than ±4% in the temperature range from 25 °C to 180 °C under 120 kV cm−1. All these features demonstrate that the (1 − x)BNTSZ–xNN ceramics are promising candidates for use at extremely high temperature in both dielectric and energy storage capacitor applications.

High temperature lead-free BNT-based ceramics with stable energy storage and dielectric properties

Asymmetric Trilayer All-Polymer Dielectric Composites with Simultaneous High Efficiency and High Energy Density: A Novel Design Targeting Advanced Energy Storage Capacitors

Recent developments in various technologies, such as hybrid electric vehicles and pulsed power systems, have challenged researchers to discover affordable, compact, and super-functioning electric energy storage devices. Among the existing energy storage devices, polymer nanocomposite film capacitors are a preferred choice due to their high power density, fast charge and discharge speed, high operation voltage, and long service lifetime. In the past several years, they have been extensively researched worldwide, with 0D, 1D, and 2D nanofillers being incorporated into various polymer matrixes. However, 1D nanofillers appeared to be the most effective in producing large dipole moments, which leads to a considerably enhanced dielectric permittivity and energy density of the nanocomposite. As such, this Review focuses on recent advances in polymer matrix nanocomposites using various types of 1D nanofillers, i.e., linear, ferroelectric, paraelectric, and relaxor-ferroelectric for energy storage applications. Correspondingly, the latest developments in the nanocomposite dielectrics with highly oriented, surface-coated, and surface-decorated 1D nanofillers are presented. Special attention has been paid to identifying the underlying mechanisms of maximizing dielectric displacement, increasing dielectric breakdown strength, and enhancing the energy density. This Review also presents some suggestions for future research in low-loss, high energy storage devices.

Polymer Matrix Nanocomposites with 1D Ceramic Nanofillers for Energy Storage Capacitor Applications.

With the problems of resource consumption and environmental harm, increasing attention has been paid to the conversion and storage of energy. The development of flexible nanodielectric materials with high energy density is one of the most active academic research directions in the field of functional materials and has important practical significance. Barium titanate/polyvinylidene fluoride- (BT/PVDF-) based nanocomposite film possesses excellent physicochemical properties and electrical properties, is a type of composite material with excellent energy density and has great application potential. In this paper, related studies on high energy density BT/PVDF-based nanocomposite films are classified and summarized. The possible mechanisms for the enhancement in energy density of BT/PVDF-based nanocomposite films under different strategies are discussed. This expected result of this paper is explaining the mechanisms of the increase in energy density of BT/PVDF-based nanocomposites and providing a new idea for the development of BT/PVDF-based nanocomposites with higher energy density. Finally, BT/PVDF-based nanocomposite for energy storage films are summarized, providing an outlook for future development and the problems to be solved. It is believed that future research may be directed toward optimizing raw materials, multiphase doping, three dimensional modulation, and optimization of process, of which three dimensional modulation will become the focus.

Design strategy of barium titanate/polyvinylidene fluoride-based nanocomposite films for high energy storage

Synergy of micro-/mesoscopic interfaces in multilayered polymer nanocomposites induces ultrahigh energy density for capacitive energy storage

Triply periodic minimum surfaces (TPMS), which outperform other structures in terms of bulk moduli and relative density, have been widely used to dramatically improve the mechanical strength of natural echinoderm skeletons and engineered scaffolds. Herein, TPMS‐structure‐based 3D‐printed hydroxyapatite (HAp) scaffolds to highly improve their limited mechanical strength and evaluate the underlying mechanism in terms of mechanical match and biological bone repair process as a bone regeneration scaffold are constructed. The results show that TPMS‐structure‐based HAp scaffolds have a greater compressive strength range that is sufficient to meet the strength requirements for human cortical and trabecular bone, and outperform traditional HAp scaffolds with Cross‐hatch structures in terms of compressive strength, cell density, and osteogenic differentiation. The reduction of stress concentration and open‐cell permeable structure of Split‐P scaffolds can benefit the generation and ingrowth of new bone after the in vivo implantation in the rabbit femur bone. Furthermore, RNA‐seq and immunochemistry staining results of in vivo samples unravel the bone repair mechanism in a time sequence. The optimized scaffolds with TPMS macrostructures and an in‐depth understanding of repair mechanisms will contribute to the development of bone regeneration materials that perform on par with load‐bearing bone.

High‐Strength Hydroxyapatite Scaffolds with Minimal Surface Macrostructures for Load‐Bearing Bone Regeneration

https://doi.org/10.1016/j.bioactmat.2022.09.018

Yue He

Papers

Synergy of micro-/mesoscopic interfaces in multilayered polymer nanocomposites induces ultrahigh energy density for capacitive energy storage

High‐Strength Hydroxyapatite Scaffolds with Minimal Surface Macrostructures for Load‐Bearing Bone Regeneration

Design of single-phased magnesium alloys with typically high solubility rare earth elements for biomedical applications: Concept and proof

Study on the chemical corrosion dressing technology for Cu3Sn-bonded diamond grinding block

Study on the preparation of Ni Al intermetallic-bonded diamond grinding block and grinding performance for sapphire