Li Qizheng, Tan Shaobo, Gong Honghong, Lu Junyong, Zhang Wenjing, Zhang Xiao, Zhang Zhicheng
Department of Applied Chemistry, School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Materials Chemistry, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University, Xi'an, 710049, P. R. China.
National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan, 430034, P. R. China.
Phys Chem Chem Phys. 2021 Feb 19;23(6):3856-3865. doi: 10.1039/d0cp05233g.
A dielectric polymer with high energy density is in high demand in modern electric and electronic systems. The current polymer dielectrics are facing the tradeoff between high energy density and low energy loss. Although many efforts have been devoted to solving the problem by modifying biaxially oriented polypropylene (BOPP), poly(vinylidene fluoride) (PVDF) and glassy polymers, limited success has been achieved. In the present work, we disperse the high polar nitrile units in a low polar polystyrene (PSt) matrix to avoid the strong coupling force among the adjacent polar groups and reduce the relaxation-induced high dielectric loss. In addition, the possible charge transportation offered by phenyl groups could be blocked by the enlarged bandgap. Notably, the induced polarization is established between the nitrile and phenyl groups, which may lead to the copolymer chain being more densely packed. As a result, excellent energy storage performances, including the high energy density and low loss, are achieved in the resultant poly(styrene-co-acrylonitrile) (AS). For instance, AS-4 exhibits a Ue of 11.4 J cm-3 and η of 91% at ambient temperature and 550 MV m-1. Manipulating the dipole polarization in the low polar glassy polymer matrix is verified to be a facile strategy for the design of a high-energy storage dielectric polymer.
现代电气和电子系统对具有高能量密度的介电聚合物有很高的需求。目前的聚合物电介质面临着高能量密度和低能量损耗之间的权衡。尽管人们已经做出了许多努力，通过对双轴取向聚丙烯（BOPP）、聚偏二氟乙烯（PVDF）和玻璃态聚合物进行改性来解决这个问题，但取得的成功有限。在本工作中，我们将高极性腈基单元分散在低极性聚苯乙烯（PSt）基体中，以避免相邻极性基团之间的强耦合力，并降低弛豫引起的高介电损耗。此外，苯基提供的可能的电荷传输可以被扩大的带隙所阻挡。值得注意的是，在腈基和苯基之间建立了诱导极化，这可能导致共聚物链排列得更加紧密。结果，在所得的聚（苯乙烯 - 丙烯腈）（AS）中实现了优异的储能性能，包括高能量密度和低损耗。例如，AS - 4在环境温度和550 MV m-1下表现出11.4 J cm-3的Ue和91%的η。在低极性玻璃态聚合物基体中操纵偶极极化被证实是设计高储能介电聚合物的一种简便策略。
