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Dielectric capacitors prepared by antiferroelectric (AFE) materials have the advantages of large power density and fast discharge ability. It has been a focus on the improvement of the recoverable energy density (Wrec) and discharge energy–density (Wdis) in the AFE ceramics. To address the above issue, optimizing the proportion of components is proposed for enhancing ceramic antiferroelectricity, ultimately improving the breakdown strength (Eb) and Wrec. In this work, an ultrahigh Wrec (14.3 J/cm3) with an excellent energy efficiency (η) of 81.1% is obtained in (Pb0.96Sr0.02La0.02)(Hf0.9Sn0.1)O3 AFE ceramic at electric field of 490 kV/cm, which is the maximum value reported in lead-based AFE ceramics fabricated by the conventional solid-state reaction method so far. The multistage phase transition induced by the electric field is observed in the polarization–electric field (P–E) hysteresis loops. Furthermore, an outstanding power density (PD) of 335 MW/cm3 and an excellent Wdis of 8.97 J/cm3 with a rapid discharge speed (102 ns) are obtained at electric field of 390 kV/cm. In addition, (Pb0.96Sr0.02La0.02)(Hf0.9Sn0.1)O3 ceramics also possess an excellent thermal and frequency stability. These exceptional properties indicate that (Pb0.98−xSrxLa0.02)(Hf0.9Sn0.1)O3 ceramics are a potential candidate for pulsed power devices and power electronic devices. [ABSTRACT FROM AUTHOR]

A strategy is developed to enhance the energy storage properties of lead-free Bi 0.5 Na 0.5 TiO 3 -based solid solutions, which is implemented through coupling the lattice instability in 0.94(Bi 0.5 Na 0.5)TiO 3 -0.06BaTiO 3 (0.94BNT-0.06BT) ferroelectric with a composition at its morphotropic phase boundary with the chemical disorder in (Bi 0.2 Na 0.2 K 0.2 La 0.2 Sr 0.2)TiO 3 (BNKLST) high-entropy ceramic (HEC). The addition of BNKLST in 0.94BNT-0.06BT could suppress the relaxor behaviors in the resulting solid solutions (1-x)(0.94BNT-0.06BT)-xBNKLST. With increasing content x, BNKLST may triggers more polar nano-regions which are in ergodic states at elevated temperatures. As a result, the thermal stability for energy storage properties is increased. In particular, the solid solution with x = 0.3 not only possesses large dielectric constants but also has a low content of oxygen vacancies, beneficial to its dielectric properties; It exhibits an excellent recoverable energy storage density of 2.24 J/cm3 under an electric field of 140 kV/cm, and a good thermal stability at 50 kV/cm with energy storage efficiency η >80 % up to 200 °C. The results demonstrate that the synergy effect of lattice instability and chemical disorder in the solid solutions is effective in enhancing energy storage properties of HECs, facilitating the design and optimization of dielectric energy storage devices. [ABSTRACT FROM AUTHOR]

High‐entropy ceramics (HECs) (Bi0.2Na0.2K0.2La0.2Sr0.2)TiO3 (BNKLST) with single‐phase perovskite structure have been successfully prepared by a modified citrate acid method. In comparison to (Bi0.5Na0.5)TiO3 (BNT) ceramics prepared by the same synthesis route, the BNKLST HECs exhibit dense nanostructures with grain sizes as small as 45 nm, which are suggested to be responsible for the significantly improved electric breakdown fields and reduced leakage currents in the ceramics, and they have much enhanced elastic modulus owing to the entropy‐stabilized perovskite structure. The electrical and dielectric characterizations reveal that BNKLST has high electrical resistances and dielectric constants at elevated temperatures, and, in particular, a recoverable energy storage density of 0.959 J/cm3 can be achieved under an applied electric field of 180 kV/cm. Moreover, the energy storage efficiency in BNKLST can be maintained to be larger than 90% at 40–200°C. These excellent properties suggest that entropy‐stabilized BNT‐based ceramics are promising dielectrics for electrical energy storage applications. [ABSTRACT FROM AUTHOR]

The nanocomposites consisting of graphene oxide (GO) and ferroelectric copolymer poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] have been successfully synthesized by a co-evaporation method. The structural, dielectric and ferroelectric properties of the composite papers are investigated. The Raman spectroscopy analyses on the nanocomposites GO/P(VDF-TrFE) reveal that the defects in GOs are reduced significantly by the loading of ferroelectric P(VDF-TrFE). The IG/ID ratio increases from 1.02 (for pure GO) to 1.17 [for GO/P(VDF-TrFE)-10%], revealing that the defects are reduced by the introduction of the nano-fillers due to a strong interaction between GO and P(VDF-TrFE) in the nanocomposites. The permittivity of the nanocomposites is enhanced by almost 3-times as compared to that of the pristine GOs. The nanocomposites show a notably raised polarization with high applied electric field. Furthermore, due to the high dielectric constants, the electrical energy storage density of the nanocomposites is as high as ~ 39.89 J cm−3 at 2.8 MV cm−1. The large energy density and high dielectric break down strength suggest that GO/P(VDF-TrFE) could be the promising novel materials for electrical energy storage. [ABSTRACT FROM AUTHOR]

Highlights: Two-dimensional black phosphorus (2D BP) possesses huge potential in electrochemical energy storage field owing to its unique electronic structure, high charge carrier mobility, and large interlayer spacing. Comparison on the different preparation methods and processes, characteristics, and applications of few-layer BP is presented. The applications of 2D BP in electrochemical energy storage devices in these years are well reviewed. Two-dimensional black phosphorus (2D BP), well known as phosphorene, has triggered tremendous attention since the first discovery in 2014. The unique puckered monolayer structure endows 2D BP intriguing properties, which facilitate its potential applications in various fields, such as catalyst, energy storage, sensor, etc. Owing to the large surface area, good electric conductivity, and high theoretical specific capacity, 2D BP has been widely studied as electrode materials and significantly enhanced the performance of energy storage devices. With the rapid development of energy storage devices based on 2D BP, a timely review on this topic is in demand to further extend the application of 2D BP in energy storage. In this review, recent advances in experimental and theoretical development of 2D BP are presented along with its structures, properties, and synthetic methods. Particularly, their emerging applications in electrochemical energy storage, including Li−/K−/Mg−/Na-ion, Li–S batteries, and supercapacitors, are systematically summarized with milestones as well as the challenges. Benefited from the fast-growing dynamic investigation of 2D BP, some possible improvements and constructive perspectives are provided to guide the design of 2D BP-based energy storage devices with high performance. [ABSTRACT FROM AUTHOR]