基于高分子水凝胶的高性能可拉伸超级电容器

Stretchable supercapacitors are promising to be used in flexible and wearable electronics. However, stretchabilities (30%-200%) and energy storage efficiency of stretchable supercapacitors reported previously were relative lower than expected. The main challenges are derived from stretchable substrates, electrolyte and electrode materials, especially, the problem of the weak interaction force between interfaces of the above functional layers greatly limits the stretchability of the obtained all-solid-state supercapacitors. On the basis of our previous researches, this project aims to develop highly flexible and stretchable all-solid-state supercapacitors with high performance by using polymer hydrogel-based stretchable substrate and electrolyte, and highly aligned carbon nanotubes electrodes. The main concepts and novelties are as following: (1) hydrogels with the same polymer used as both stretchable substrate and electrolyte in supercapacitors can efficiently prevent separating of substrate and electrolyte during stretching process. Meanwhile, the interaction forces in the interfaces of substrate/electrode/electrolyte can be enhanced by hydrophilic treatment of active electrodes, through which highly stretchable supercapacitors can be realized. (2) By using aligned carbon nanotubes with large aspect ratio as active electrodes, high stretchability can be achieved because carbon nanotubes will be slipping in electrodes or devices but damaged under high tensile strain. Furthermore, highly pseudocapacitive materials can be easily incorporated into the aligned carbon nanotubes electrode to enhance the energy storage efficiency of the resulting supercapacitors.

可拉伸超级电容器在柔性、可穿戴电子设备领域具有广阔的应用前景，但是，目前报道的可拉伸超级电容的可拉伸性（30%-200%）和能量储存效率并不理想，主要瓶颈在于可拉伸基底、电解质和电极材料，尤其是它们之间弱的界面结合力较为突出。基于申请人前期的研究积累，本项目提出基于高分子水凝胶可拉伸基底和电解质以及取向碳纳米管构筑超高可拉伸的高性能全固态超级电容器。本项目的基本构想和主要创新点在于：（1）器件中使用含有相同组分的高分子水凝胶基底和电解质，将有效避免器件在拉伸过程中基底与电解质发生脱离；同时，通过活性电极材料的亲水处理优化电极材料与基底和电解质的界面相互作用，实现超级电容器的高度可拉伸；（2）采用基于取向碳纳米管的活性电极材料，具有大的长径比的碳纳米管在被拉伸时首先发生位置的相对滑移而不是断裂，实现高度可拉伸性能；取向碳纳米管膜中能够方便地引入高赝电容材料，从而实现较高的能量储存效率。

可拉伸超级电容器在可穿戴电子领域具有广泛的应用前景。凝胶电解质和电极作为超级电容器中的两个关键组成，其拉伸性和离子电导率对可拉伸超级电容器的性能具有决定性影响。为实现高性能可拉伸超级电容器，本项目主要从以下三个方面展开工作：1）设计合成新型高分子凝胶电解质；2）设计制备新型纳米碳基电极材料；3）探索提升柔性超级电容器性能的新策略。.通过本项目的实施，取得了以下重要研究结果：1）从分子层面设计合成一系列拉伸性能好、离子电导率高的新型高分子水（或离子）凝胶，实现了具有超高可拉伸（1000%）的超级电容器，为其它柔性电子器件的构筑提供了一定借鉴；2）发展了基于CVD生长的石墨烯构筑超轻超强导电石墨烯纤维的新方法，设计合成了一系列新型石墨烯/碳纳米管杂化电极材料，在柔性可拉伸电子器件中表现出重要的应用价值；3）首次提出异质结聚电解质抑制超级电容器快速自放电的新思路，揭示并阐明了该新型结构超级电容器的工作机制，为实现长续航、高性能柔性超级电容器提供了重要的理论和实践支撑。相关研究成果发表SCI论文13篇，其中包括Sci. Bull.、Adv. Mater.、Nat. Commun.等国内外知名期刊；授权中国发明专利9项；受邀为两部英文专著撰写各一个章节。.总结言之，本项目均按计划实施，已经完成研究目标。在新型高分子凝胶电解质、新型电极材料、新机制等方面取得了一些重要突破，对于推动柔性可拉伸超级电容器在柔性电子领域中的应用具有重要意义。