Yang Mingcong, Wang Shaojie, Fu Jing, Zhu Yujie, Liang Jiajie, Cheng Sang, Hu Shixun, Hu Jun, He Jinliang, Li Qi
State Key Laboratory of Power System, Department of Electrical Engineering, Tsinghua University, Beijing, 100084, China.
Adv Mater. 2023 Jul;35(30):e2301936. doi: 10.1002/adma.202301936. Epub 2023 Jun 11.
Polymer dielectrics need to operate at high temperatures to meet the demand of electrostatic energy storage in modern electronic and electrical systems. The polymer nanocomposite approach, an extensively proved strategy for performance improvement, encounters a bottleneck of reduced energy density and poor discharge efficiency beyond 150 °C. In this work, a polymer/metal oxide cluster composite prepared based on the "site isolation" strategy is reported. Capitalizing on the quantum size effect, the bandgap and surface defect states of the ultrasmall inorganic clusters (2.2 nm diameter) are modulated to markedly differ from regular-sized nanoparticles. Experimental results in conjunction with computational simulation demonstrate that the presence of ultrasmall inorganic clusters can introduce more abundant, deeper traps in the composite dielectric with respect to conventional polymer/nanoparticle blends. Unprecedented high-temperature capacitive performance, including colossal energy density (6.8 J cm ), ultrahigh discharge efficiency (95%) and superior stability at different electric field frequencies, are achieved in these polymer/cluster composites up to 200 °C. Along with the advantages in material preparation (inexpensive precursors and one-pot synthesis), such polymer/inorganic cluster composite approach is promising for high-temperature dielectric energy storage in practical power apparatus and electronic devices.
聚合物电介质需要在高温下运行，以满足现代电子和电气系统中静电能量存储的需求。聚合物纳米复合材料方法是一种经过广泛验证的性能改进策略，但在超过150°C时会遇到能量密度降低和放电效率差的瓶颈。在这项工作中，报道了一种基于“位点隔离”策略制备的聚合物/金属氧化物簇复合材料。利用量子尺寸效应，将超小无机簇（直径2.2nm）的带隙和表面缺陷态调制为与常规尺寸的纳米颗粒明显不同。结合计算模拟的实验结果表明，相对于传统的聚合物/纳米颗粒共混物，超小无机簇的存在可以在复合电介质中引入更丰富、更深的陷阱。在这些聚合物/簇复合材料中，高达200°C时实现了前所未有的高温电容性能，包括巨大的能量密度（6.8J/cm）、超高的放电效率（95%）以及在不同电场频率下的优异稳定性。连同材料制备方面的优势（廉价的前驱体和一锅法合成），这种聚合物/无机簇复合材料方法在实际电力设备和电子器件的高温介电能量存储方面具有广阔前景。
