基于“树状”聚苯胺/掺氮取向碳纳米管复合纤维的高性能可穿戴超级电容器电极的结构设计及相关机制研究

Wearable energy storage device is the “heart” of wearable electronics. To satisfy the practical application，the energy storage properties of reported wearable energy storage devices are highly requested to be improved, especially achieveing higher specific capacitance without loss of rate capability. To solve this challenging problem, it is critical to develop electrodes with both excellent conductivity and high electrochemical activity. Herein, a tree-like composite fiber supercapacitor electrode is designed as follows. As a wearable substrate and current collector, ultra-aligned carbon nanotube fiber is employed as trunk to support the electrode and facilitate the transfer of charge due to its excellent comprehensive physical properties including high conductivity, strong mechanical property, outstanding flexibility and weavability. Then, nitrogen-doped carbon nanotubes (N-CNT) which is in-situ grown on aligned CNT fiber plays a role of branch to increase the amount of active sites for the deposition of “leaves”. N-CNT is also highly conductive and can ensure the quick transfer of charges so as to ensure high rate capability. As the most important step to improve the specific capacitance and energy density of the wearable electrode, polyaniline (PANI) with high pseudocapacitance is introduced as leaf and in-situ deposited on N-CNT. In this project, for N-CNT and PANI, the dependences of structures and properties on in-situ growth conditions will be deeply researched. And the mechanism of PANI in-situ polymerization on N-CNT will be revealed. Furthermore, the dependences of produced composite fiber’s properties on the synergetic effects between PANI, N-CNT and aligned CNT fiber will be studied. Based on these works, the specific capacitance and energy density of supercapacitor will be highly improved without obvious loss of rate capability and power density. Therefore, this project can fully provide theoretic and experimental support for the improving of wearable supercapacitor’s energy storage properties. Moreover, it can also be extended to the development of other wearable energy storage devices, such as wearable lithium ion battery and lithium-sulfur battery.

可穿戴储能器件是可穿戴设备的“心脏”，目前可穿戴储能器件的导电性和储能活性亟待提高，难以兼顾高比容量和高倍率性能，为克服这一关键问题，本项目设计了一种树状结构超级电容器电极，其“树干”采用电导率高、柔性好、可编织的取向碳纳米管纤维，起电荷传输和柔性基底作用；“树枝”采用原位生长的掺氮碳纳米管，增加电荷附着活性位点、承托活性储能成分，并便于电荷传输、提高倍率性能；“树叶”为高赝电容活性的聚苯胺，是提高电极比容量和能量密度的关键。本项目将深入研究掺氮碳纳米管和聚苯胺在特定基底上的原位生长条件对结构和性能的影响规律，揭示聚苯胺的原位聚合机制，并进一步探明三者间的协同作用对复合纤维性能的影响规律和机制，同时实现比容量高、能量密度高和倍率性能好、功率密度高的超级电容器。本项目将为可穿戴超级电容器的高性能化提供理论和实验支撑，并对锂离子电池、锂硫电池等其他可穿戴储能器件的高性能化研究具有重要参考价值。

目前可穿戴储能器件的导电性和储能活性亟待提高，难以兼顾高比容量和高倍率性能，为克服这一关键问题，本项目设计了一种树状结构的超级电容器纤维电极，其“树干”采用电导率高、柔性好、可编织的取向碳纳米管纤维，起电荷传输和柔性基底作用；“树枝”采用原位生长的掺氮碳纳米管，增加电荷附着活性位点、承托活性储能成分，并便于电荷传输、提高倍率性能；“树叶”为高赝电容活性的聚苯胺，是提高电极比容量和能量密度的关键。本项目研究了掺氮碳纳米管和聚苯胺的原位生长条件对结构和性能的影响规律，揭示了掺氮碳纳米管和聚苯胺的原位生长机制，并进一步探明了三者间的协同作用对复合纤维性能的影响规律和机制。研究表明，通过该“树状”结构设计和原位生长条件控制，可有效提升纤维电极的导电性、有效表面积、亲水性、聚苯胺均匀性及其在纤维基底上的结合力，由此发展出了同时具有高比容量、高能量密度和优异倍率性能、高功率密度的纤维状超级电容器，并大幅提升了纤维状超级电容器的循环稳定性。本项目将为可穿戴超级电容器的高性能发展提供理论和实验支撑，并对其他可穿戴储能器件的发展具有重要参考价值。