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[Display omitted] • NiCo 2 O 4 @CoS core/shell nanowire arrays on Ni foam were prepared. • The electrode exhibits a higher specific capacitance of 1902.5F g−1 at 1 A g−1. • A hybrid capacitor has an energy density of 39.7 Wh kg−1. • DFT provides assistance for the enhanced electrochemical performance. It is a preferred method by constructing core − shell structured composites with heterojunctions to enhance the charge transfer and improve electrochemical performances for supercapacitors. In this work, we prepare NiCo 2 O 4 @CoS electrode materials on nickel foam via coating n − type CoS on p − type NiCo 2 O 4 to form heterojunctions. The composite shows a synergistic effect from each component and has abundant active sites, as well as outstanding reaction kinetics. Density functional theory (DFT) analysis reveals that the NiCo 2 O 4 @CoS composite exhibits higher electronic conductivity than any single component. The NiCo 2 O 4 @CoS electrode presents an outstanding capacitance of 1902.5F g−1 at the current density of 1 A g−1. A hybrid capacitor with NiCo 2 O 4 @CoS as the positive electrode and activated carbon as the negative electrode shows a high energy density of 32.91 Wh kg−1 at the power density of 425 W kg−1 and an excellent stability of 81.5% initial capacitance after 5000 cycles at 1 A g−1. The conclusions indicate that the heterojunction of NiCo 2 O 4 @CoS can be a potential electrode for supercapacitors. [ABSTRACT FROM AUTHOR]

Antiferroelectric (AFE) materials attract widespread attention due to their unique behavior under electric field. In this work, the Pb 0.82 La 0.12 (Zr x Ti 1-x)O 3 (PLZT) films with Zr/Ti ratios close to the AFE region are deposited on the LaNiO 3 /SiO 2 /Si substrate through chemical deposition method. The dielectric, leakage, and ferroelectric performance of PLZT films are thoroughly examined. It can be concluded that the Zr content in PLZT films can effectively regulate their dielectric properties. At the same time, the increase of Zr/Ti ratio makes the double hysteresis loop of PLZT more obvious, leading to greater stability of the AFE phase, providing a significant advantage in energy storage. Notably, the PLZT film with a Zr/Ti ratio of 95/5 exhibits the highest recoverable energy storage density (W rec) of 30.8 J/cm3 and energy storage efficiency (η) of 71.5 %. These results reveal that the Zr/Ti ratio in PLZT antiferroelectric films plays a critical role in enhancing their energy storage performance. • PLZT films with different Zr/Ti ratios are investigated. • The best energy storage performance achieving W rec of 30.8 J/cm3 and η of 71.5 %. • The stability of antiferroelectric can be improved by increasing the Zr/Ti ratio. • The high switching field benefits energy storage performance in antiferroelectric. [ABSTRACT FROM AUTHOR]

PbZrO 3 (PZ) antiferroelectric films and PbZr 0·52 Ti 0·48 O 3 (PZT) ferroelectric films are widely researched due to their significance as representative film materials. The article investigates the structure-performance relationship of PZT/PZ composite films with different PZ and PZT phase structures. PZT/PZ films with different PZ and PZT phase structures were fabricated on SiO 2 /Si substrates using the sol-gel method. The electrical properties of prepared films annealed at different temperatures were characterized and were compared at different annealing temperatures (550 °C, 600 °C, 620 °C, 650 °C). At the annealing temperature of 600 °C, it was observed that the presence of pyrochlore and perovskite phases in PZ makes the composite films high breakdown field strength (BDS) and moderate polarization (P m), enhancing the energy storage properties. However, when the annealing temperature exceeds 600 °C, it would have the opposite effect on the BDS and P m due to the increased pyrochlore and perovskite phase. The above analysis indicates that regulating the phase structure of PZ and PZT films is the effective approach to obtain high energy storage density capacitors. [ABSTRACT FROM AUTHOR]

A method for significantly enhancing the breakdown field strength and energy storage density of Pb 0.88 La 0.12 ZrO 3 (PLZ) films by inserting ZrO 2 (ZO) layer is provided. PLZ films with the inserting layer of ZrO 2 were deposited on SiO 2 /Si substrates buffered with LaNiO 3 films by the sol-gel method. The effect of ZrO 2 precursor solution concentration on structure and electrical properties was investigated. The results show that for the composite films with the sandwich structure, much improved electrical breakdown strength values of 1543 kV/cm and maximum polarization values of 83.5 μC/cm2 were obtained, which are 141% and 40% higher than pure PLZ films, respectively. With the combination of a high breakdown field strength and a large maximum polarization value, the film has an energy storage density of up to 32.6 J/cm3 when ZrO 2 precursor solution concentration is 0.1 mol/L. Our results show that the design of PLZ/ZO/PLZ composite films is an effective way to obtain high energy storage density capacitors. • The composite films exhibited high electrical breakdown strength value. • The energy storage density of PLZ/ZO/PLZ composite film is raise to 32.6 J/cm3. • Inserting ZrO2 layer is a good way to improve the energy storage of PLZ films. [ABSTRACT FROM AUTHOR]

The structure and electrical properties of Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 -xBiFeO 3 ceramics (x = 0 %, 3 %, 8 % and 15 %) were investigated. The prepared samples show perovskite structure, and there is no detected second phase. The grain size of all ceramic samples doped with BiFeO 3 is significantly reduced. The doped samples have obvious relaxation characteristics, showing obvious dispersion phase transition and frequency dispersion. The P-E curve becomes thin with the increase of doping amount, but it changes reversely under higher doping content. For sample with the doping amount of 8 %, a thin and long hysteresis loop is observed, and the sample has the best energy storage characteristics with the energy storage density of 0.57 J/cm3 and the energy storage efficiency of 91.3 %. This study provides a method to improve the energy storage density and efficiency of BCZT ceramics. • The prepared samples show perovskite structure, and there is no detected second phase. • Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 -8 %BiFeO 3 has the energy storage density of 0.57 J/cm3. • Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 -8 %BiFeO 3 has the energy storage efficiency of 91.3 %. • This study provides a method to improve the energy storage performance of BCZT ceramics. [ABSTRACT FROM AUTHOR]