College of Information Science and Electronic Engineering, Zhejiang University , Hangzhou 310027, China.
Department of Chemistry and Biochemistry and California Nanosystems Institute, University of California , Los Angeles, California 90095, United States.
ACS Appl Mater Interfaces. 2017 Mar 1;9(8):7591-7600. doi: 10.1021/acsami.6b14984. Epub 2017 Feb 17.
Polymer dielectrics offer key advantages over their ceramic counterparts such as flexibility, scalability, low cost, and high breakdown voltages. However, a major drawback that limits more widespread application of polymer dielectrics is their temperature-dependent dielectric properties. Achieving dielectric constants with low/zero-temperature coefficient (L/0TC) over a broad temperature range is essential for applications in diverse technologies. Here, we report a hybrid filler strategy to produce polymer composites with an ultrawide L/0TC window of dielectric constant, as well as a significantly enhanced dielectric value, maximum energy storage density, thermal conductivity, and stability. By creating a series of percolative polymer composites, we demonstrated hybrid carbon filler based composites can exhibit a zero-temperature coefficient window of 200 °C (from -50 to 150 °C), the widest 0TC window for all polymer composite dielectrics reported to date. We further show the electric and dielectric temperature coefficient of the composites is highly stable against stretching and bending, even under AC electric field with frequency up to 1 MHz. We envision that our method will push the functional limits of polymer dielectrics for flexible electronics in extreme conditions such as in hybrid vehicles, aerospace, power electronics, and oil/gas exploration.
聚合物电介质相对于陶瓷电介质具有许多优势，如柔韧性、可扩展性、低成本和高击穿电压。然而，限制聚合物电介质更广泛应用的一个主要缺点是其温度相关的介电性能。在较宽的温度范围内实现具有低/零温度系数（L/0TC）的介电常数对于在各种技术中的应用至关重要。在这里，我们报告了一种混合填充剂策略，用于生产具有超宽介电常数 L/0TC 窗口以及显著增强的介电值、最大储能密度、热导率和稳定性的聚合物复合材料。通过制备一系列渗滤型聚合物复合材料，我们证明了基于混合碳填充剂的复合材料可以表现出 200°C 的零温度系数窗口（从-50°C 到 150°C），这是迄今为止报道的所有聚合物复合电介质中最宽的 0TC 窗口。我们进一步表明，复合材料的电和介电温度系数在拉伸和弯曲下非常稳定，即使在高达 1 MHz 的交流电场下也是如此。我们设想我们的方法将推动聚合物电介质在极端条件下（如混合动力汽车、航空航天、电力电子和石油/天然气勘探）的柔性电子功能极限。
