Wu Jie, Tan Hua, Qi He, Yu Huifen, Chen Liang, Li Wenchao, Chen Jun
Hainan University, Haikou, Hainan, 570228, China.
School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 100083, China.
Small. 2024 Sep;20(36):e2400997. doi: 10.1002/smll.202400997. Epub 2024 May 7.
Dielectric capacitors are widely used in advanced electrical and electronic systems due to the rapid charge/discharge rates and high power density. High comprehensive energy storage properties are the ultimate ambition in the field of application achievements. Here, the high-entropy strategy is proposed to design and fabricate single-phase homogeneous (BiBaSrCaNa)(FeTiZrNb)O ceramic, the hierarchical heterostructure including rhombohedral-tetragonal multiphase nanoclusters and locally disordered oxygen octahedral tilt can lead to the increased dielectric relaxation, diffused phase transition, diverse local polarization configurations, grain refinement, ultrasmall polar nanoregions, large random field, delayed polarization saturation and improved breakdown field. Accordingly, a giant W ≈13.3 J cm and a high η ≈78% at 66.4 kV mm can be simultaneously achieved in the lead-free high-entropy BiFeO-based ceramic, showing an obvious advantage in overall energy-storage properties over BiFeO-based lead-free ceramics. Moreover, an ultrafast discharge rate (t = 18 ns) can be achieved at room temperature, concomitant with favorable temperature stability in the range of 20-160 °C, due to the enhanced diffuse phase transition and fast polarization response. This work provides a feasible pathway to design and generate dielectric materials exhibiting high comprehensive energy-storage performance.
介电电容器因其快速的充/放电速率和高功率密度而广泛应用于先进的电气和电子系统中。高综合储能性能是应用成果领域的最终目标。在此，提出了高熵策略来设计和制备单相均匀的(BiBaSrCaNa)(FeTiZrNb)O陶瓷，包括菱方-四方多相纳米团簇和局部无序氧八面体倾斜的分级异质结构可导致介电弛豫增加、扩散相变、多样的局部极化构型、晶粒细化、超小极性纳米区域、大的随机场、延迟的极化饱和以及改善的击穿场强。因此，在无铅高熵BiFeO基陶瓷中，在66.4 kV/mm下可同时实现巨大的W≈13.3 J/cm³和高的η≈78%，在整体储能性能方面相对于BiFeO基无铅陶瓷具有明显优势。此外，由于增强的扩散相变和快速的极化响应，在室温下可实现超快的放电速率(t = 18 ns)，并在20 - 160°C范围内具有良好的温度稳定性。这项工作为设计和制备具有高综合储能性能的介电材料提供了一条可行的途径。
