Dipole-relaxation dynamics in a modified polythiourea with high dielectric constant for energy storage applications
Dipole-relaxation dynamics in a modified polythiourea with high dielectric constant for energy storage applications
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DOI：
10.1063/1.5123484
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发表时间：
2019-10
影响因子：
4
通讯作者：
Chao Wu;Zongze Li;Gregory M. Treich;M. Tefferi;R. Casalini;R. Ramprasad;G. Sotzing;Yang Cao
中科院分区：
文献类型：
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作者：
Chao Wu;Zongze Li;Gregory M. Treich;M. Tefferi;R. Casalini;R. Ramprasad;G. Sotzing;Yang Cao
增强偶极极化已被证明是提高聚合物介质的介电常数，从而提高其放电能量密度用于电力和电子系统储能的一种有效方法。然而，进一步优化以获得更高的介电常数和更低的极化损耗取决于对偶极子弛豫动力学的更深入的理解。在这里，我们展示了一种基于Dissado-Hill介电响应模型的方法，来研究由对苯二异硫氰酸酯(PDTC)作为刚性链段和Jeffamine®HK511作为柔性链段组成的全有机多硫脲(PDTC-HK511)的偶极极化动力学。我们的结果表明，在较高的温度和较低的频率范围内，PDTC-HK511具有较强的亚玻璃化转变β和γ驰豫过程以及准直流扩散过程。γ弛豫使介电常数提高20%-25%，但在工作温度和频率条件下，由于偶极子取向的高度柔韧性和较短的驰豫时间，没有明显的损耗。与β弛豫相比，γ弛豫中偶极子的弱相互作用和较短的驰豫时间证明了偶极子运动的较大灵活性。这项工作有助于更深入地了解偶极子的运动，并有助于未来聚合物介质储能的合理设计。增强偶极子极化被证明是提高聚合物介质的介电常数，从而提高其放电能量密度的有效方法，用于电力和电子系统的储能应用。然而，进一步优化以获得更高的介电常数和更低的极化损耗取决于对偶极子弛豫动力学的更深入的理解。在这里，我们展示了一种基于Dissado-Hill介电响应模型的方法，来研究由对苯二异硫氰酸酯(PDTC)作为刚性链段和Jeffamine®HK511作为柔性链段组成的全有机多硫脲(PDTC-HK511)的偶极极化动力学。我们的结果表明，在较高的温度和较低的频率范围内，PDTC-HK511具有较强的亚玻璃化转变β和γ驰豫过程以及准直流扩散过程。γ弛豫使介电常数提高了20%-25%，但没有引起明显的L效应。
Enhancing dipole polarization has been demonstrated as an effective approach to increase the dielectric constant of polymer dielectrics and thus to improve their discharged energy density for energy storage applications in electrical power and electronic systems. However, further optimization to get a higher dielectric constant and lower polarization loss hinges upon a more insightful understanding of the dynamics of dipole relaxation. Here, we demonstrate an approach, based on the Dissado-Hill dielectric response model, to probe the dynamics of dipole polarization in an all organic polythiourea (PDTC-HK511) composed of p-phenylene diisothiocyanate (PDTC) as rigid segments and Jeffamine® HK511 as flexible segments. Our results reveal that PDTC-HK511 possesses strong subglass transition β and γ relaxation processes in conjunction with the quasi-DC diffusion process at relatively high temperature and a low frequency range. The γ relaxation enhances the dielectric constant by 20%–25% but causes no apparent loss at the operating temperature and frequency conditions due to the high flexibility and short relaxation time of the dipole orientation. In comparison to β relaxation, the weak interactions and much shorter relaxation time of dipoles in γ relaxation evidenced the large flexibility of dipole movement. This work provides deeper insight into the dipole movement and aids future rational designs of polymers for dielectric energy storage.Enhancing dipole polarization has been demonstrated as an effective approach to increase the dielectric constant of polymer dielectrics and thus to improve their discharged energy density for energy storage applications in electrical power and electronic systems. However, further optimization to get a higher dielectric constant and lower polarization loss hinges upon a more insightful understanding of the dynamics of dipole relaxation. Here, we demonstrate an approach, based on the Dissado-Hill dielectric response model, to probe the dynamics of dipole polarization in an all organic polythiourea (PDTC-HK511) composed of p-phenylene diisothiocyanate (PDTC) as rigid segments and Jeffamine® HK511 as flexible segments. Our results reveal that PDTC-HK511 possesses strong subglass transition β and γ relaxation processes in conjunction with the quasi-DC diffusion process at relatively high temperature and a low frequency range. The γ relaxation enhances the dielectric constant by 20%–25% but causes no apparent l...