Xi Jiachen, Liu Jikang, Bai Wangfeng, Wu Shiting, Zheng Peng, Li Peng, Zhai Jiwei
College of Materials and Environmental Engineering, Hangzhou Dianzi University, No. 2 Street, Hangzhou, 310018, P. R. China.
College of Materials Science and Engineering, Liaocheng University, Liaocheng, 252059, P. R. China.
Small. 2024 Oct;20(42):e2400686. doi: 10.1002/smll.202400686. Epub 2024 Jun 12.
High-performance energy storage dielectrics capable of low/moderate field operation are vital in advanced electrical and electronic systems. However, in contrast to achievements in enhancing recoverable energy density (W), the active realization of superior W and energy efficiency (η) with giant energy-storage coefficient (W/E) in low/moderate electric field (E) regions is much more challenging for dielectric materials. Herein, lead-free relaxor ferroelectrics are reported with giant W/E designed with polymorphic heterogeneous polar structure. Following the guidance of Landau phenomenological theory and rational composition construction, the conceived (BiNa)TiO-based ternary solid solution that delivers giant W/E of ≈0.0168 µC cm, high W of ≈4.71 J cm and high η of ≈93% under low E of 280 kV cm, accompanied by great stabilities against temperature/frequency/cycling number and excellent charging-discharging properties, which is ahead of most currently reported lead-free energy storage bulk ceramics measured at same E range. Atomistic observations reveal that the correlated coexisting local rhombohedral-tetragonal polar nanoregions embedded in the cubic matrix are constructed, which enables high polarization, minimized hysteresis, and significantly delayed polarization saturation concurrently, endowing giant W/E along with high W and η. These findings advance the superiority and feasibility of polymorphic nanodomains in designing highly efficient capacitors for low/moderate field-region practical applications.
能够在低/中场运行的高性能储能电介质在先进的电气和电子系统中至关重要。然而，与提高可恢复能量密度（W）方面的成就相比，在低/中场（E）区域中实现具有巨大储能系数（W/E）的优异W和能量效率（η）对介电材料来说更具挑战性。在此，报道了具有多晶型异质极性结构设计的巨大W/E的无铅弛豫铁电体。遵循朗道唯象理论和合理的成分构建指导，所设想的基于（BiNa）TiO的三元固溶体在280 kV/cm的低E下具有≈0.0168 μC/cm的巨大W/E、≈4.71 J/cm的高W和≈93%的高η，同时具有对温度/频率/循环次数的高稳定性以及优异的充放电性能，这在相同E范围内测量的大多数目前报道的无铅储能块状陶瓷中处于领先地位。原子观察表明，构建了嵌入立方基体中的相关共存局部菱面体-四方极性纳米区域，这使得能够同时实现高极化、最小化滞后和显著延迟的极化饱和，赋予了巨大的W/E以及高W和η。这些发现推进了多晶型纳米域在设计用于低/中场区域实际应用的高效电容器方面的优越性和可行性。
