An air-stable electrochromic conjugated microporous polymer as an emerging electrode material for hybrid energy storage systems
An air-stable electrochromic conjugated microporous polymer as an emerging electrode material for hybrid energy storage systems
复制标题
空气稳定的电致变色共轭微孔聚合物作为混合储能系统的新兴电极材料
DOI：
10.1039/c9ta03001h
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发表时间：
2019-07-21
影响因子：
11.9
通讯作者：
Zhang, Cheng
中科院分区：
文献类型：
--
作者：
Dai, Yuyu;Li, Weijun;Zhang, Cheng
聚合物的氧化态及其稳定性对于其在储能系统中的应用非常重要。在本文中，我们报道了一种空气稳定的三苯胺-三嗪基共轭微孔聚合物（pTTPATA），其具有通过简单地改变施加的电压来改变颜色的智能功能。独特的是，黄色中性聚合物在氧化（p 掺杂）时转变为红色，并且即使在去除施加的电位后十小时，红色仍保持稳定，这使得可以对氧化状态的 pTTPATA 进行深入分析。 X 射线光电子能谱 (XPS) 证实，大量来自三嗪基团的自由基阳离子以及一小部分来自氧化三苯胺的自由基阳离子以稳定的红色氧化态存在于 pTTPATA 薄膜中。电化学和密度泛函理论（DFT）计算表明，在施加电压下，pTTPATA 聚合物中只有三苯胺基团被氧化。因此，我们得出结论，pTTPATA聚合物的大部分氧化是由于三苯胺基团氧化为相对更稳定的三嗪基团自由基阳离子的结构共振而发生的，从而导致稳定的红色氧化态。更重要的是，特殊氧化态下的结构共振诱导了除三苯胺之外的三嗪的电荷存储，从而导致了类似于81 mA h g(-1)的高比容量，是基于聚合物的储能系统的最佳报道值之一。这些令人着迷的特性相结合，形成了一种智能储能设备，该设备可以根据其充电状态改变其颜色，从而可以通过简单的目视检查来监控充电状态。
The oxidation states of polymers and their stabilities are of great importance for their application in energy storage systems. In this paper, we report an air-stable triphenylamine-triazine-based conjugated microporous polymer (pTTPATA) with the smart function of changing color by simply changing the applied voltage. Uniquely, the yellow colored neutral polymer switches to a red color upon oxidation (p-doping) and the red color remains stable even for ten hours after removal of the applied potential, which allows an in-depth analysis of the pTTPATA in the oxidized state. X-ray photoelectron spectroscopy (XPS) confirms that large amounts of radical cations from the triazine groups as well as a small proportion of those from oxidized triphenylamine are present in the stable red-colored oxidized state of the pTTPATA film. Electrochemistry and density functional theory (DFT) calculations demonstrate that only the triphenylamine group is oxidized in the pTTPATA polymer under the applied voltages. Thus, we conclude that most of the oxidation of the pTTPATA polymer occurs from the structural resonance from the oxidation of the triphenylamine group to the relatively more stable radical cation of the triazine group, which results in a stable red colored oxidation state. More importantly, the structural resonance in the special oxidation state induces the charge storage of triazine except the charge storage of triphenylamine, which results in a high specific capacity of similar to 81 mA h g(-1), among the best reported values for conducting polymers-based energy storage systems. The combination of these fascinating properties results in an intelligent energy storage device that changes its color based on its charged state so that the state of charge can be monitored by simple visual inspection.