Dielectric capacitors are widely used in electronic devices due to their ultra-fast charge/discharge rate and ultra-high power density, but their lower energy density and poor thermal stability limit their further application. In contrast to the traditional strategy of suppressing defects, this work combines oxygen vacancies with defect dipoles to improve the breakdown strength and polarization behavior of ferroelectric films. Low concentration of oxygen vacancies and defect dipoles can trap charge carriers and increase breakdown strength, but if the concentration is too high, it can easily make films prone to breakdown. Moreover, the defect dipoles can reduce Pr by providing intrinsic restoring force for polarization switching, while excessive defect dipoles and oxygen vacancies can pin domain walls and increase Pr. By delicately controlling the concentration of oxygen vacancies and defect dipoles in the film, the BT-BMH film deposited at 0.135 mbar achieved the maximum breakdown strength and slim P-E loops, inducing the energy density to reach 108.9 J·cm-3 with an efficiency of 79.6 % at room temperature and excellent thermal stability in the wide temperature range of -100∼350 °C with the energy density of 69.1 J·cm-3. This work reveals the important significance of reasonable defect control for improving energy storage performance and provides an effective method for developing high-performance dielectric capacitors.

中文翻译：

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通过缺陷偶极子和氧空位工程的协同作用增强 0.85BaTiO3–0.15Bi（Mg0.5Hf0.5）O3 薄膜的储能性能


介电电容器因其超快的充放电速率和超高功率密度而广泛用于电子设备，但其较低的能量密度和较差的热稳定性限制了其进一步应用。与传统的抑制缺陷策略相反，这项工作将氧空位与缺陷偶极子相结合，以提高铁电薄膜的击穿强度和极化行为。低浓度的氧空位和缺陷偶极子可以捕获电荷载流子并增加击穿强度，但如果浓度过高，很容易使薄膜容易击穿。此外，缺陷偶极子可以通过为极化开关提供内禀恢复力来降低 Pr，而过多的缺陷偶极子和氧空位可以固定畴壁并增加 Pr。通过巧妙控制薄膜中氧空位和缺陷偶极子的浓度，沉积在 0.135 mbar 的 BT-BMH 薄膜实现了最大的击穿强度和细长的 P-E 回路， 诱导能量密度达到 108.9 J·cm-3，室温下效率为 79.6 %，在 -100∼350 °C 的宽温度范围内具有优异的热稳定性，能量密度为 69.1 J·cm-3。这项工作揭示了合理缺陷控制对提高储能性能的重要意义，为开发高性能介电电容器提供了一种有效的方法。