Xiaohui Tang,Hongjun Zhang,Fangzhe Li,Dongliang Wang,Yong Huang,Hua Ke
Dielectric capacitors play an increasingly important role in power systems because of their fast charging and discharging speed. Applications are usually limited due to the low W rec . We design materials with high values of Δ P ( P max - P r ) and recoverable energy storage density( W rec ) from the high entropy perspective. Two single phases with a large Curie temperature T c difference have been selected, which leads to the enlarged entropy. The ceramics (Bi 0.85 Nd 0.1 Sm 0.05 ) 1- x Ba x )(Fe 1- x Ti x )O 3 (BNSBFT x ) are prepared by the solid-state reaction. As x increases, the corresponding configuration entropy( S config ) goes from 1.4 R to 1.52 R. The increased entropy destroys the long-range order, accompanied by the reduced remanent polarization( P r ) and the improved W rec . The W rec of BNSBFT 0.5 ceramics reaches 4.9 J/cm 3 at a low field of 250 kV/cm. Both temperature change(∼ 0.5% from 30 °C to 140 °C) and frequency variation(∼ 4.8% from 1 Hz∼50 Hz) in W rec show excellent stability.
Lead-free ceramics have received considerable research interest because of their environmentally friendly characteristics and superb performance in energy storage applications, which are critical for pulsed power electronic systems. In this work, we sintered a series of (0.90 − x)BiFeO3–xBaTiO3–0.10CaHfO3 lead-free ceramics and comprehensively probed the crystallographic structure, grain morphology, electrical properties, etc., to assess their capability for use in energy storage applications. The 0.50BiFeO3–0.40BaTiO3–0.10CaHfO3 ceramic achieved an ultrahigh recoverable energy storage density of 4.70 J cm−3 and an outstanding energy conversion efficiency of 79% and can be considered an excellent material candidate for use in high-power energy storage devices.
Tiandong Zhang,Shimin Sun,Chao Yin,Xinle Zhang,Changhai Zhang,Yue Zhang,Yongquan Zhang,Qingguo Chi
SrTiO 3 paraelectric materials exhibit significant potential to be used as lead-free energy storage dielectrics due to their distinctive linear-like polarization behavior. Nonetheless, the application in advanced thin-film capacitors is challenging due to their low polarization strength and structural anomalies, which reduce the breakdown field strength and diminish the energy storage density. This study proposes a synergistic approach that integrates ion doping with the optimization of thermal treatment to enhance the energy storage capabilities of SrTiO 3 thin films. Initially, Mn 2+ doping in SrTiO 3 films mitigates oxygen vacancies and forms Mn 2+ -V O •• defect dipoles, thereby refining the polarization behavior and reducing the leakage current density. Subsequently, the crystalline degree of SrTi 0.99 Mn 0.01 O 3 thin films can be regulated by adjusting the annealing temperature. The optimal breakdown field strength of the resultant SrTi 0.99 Mn 0.01 O 3 films reaches 4681 kV/cm with a 1 mol% Mn 2+ doping level, enhancing the recoverable energy storage density ( W rec ) to 32.17 J/cm 3 . Furthermore, the recoverable energy storage density of SrTi 0.99 Mn 0.01 O 3 films escalates to 36.62 J/cm 3 with an efficiency of 80.28 %, upon reducing the annealing temperature to 625 °C. Moreover, SrTi 0.99 Mn 0.01 O 3 films demonstrate superior thermal stability, frequency stability, and electrical fatigue resistance, underscoring their potential as efficacious materials for film capacitor applications.
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