纤维状可编织高性能锂硫电池研究

To prepare woven fiber-like functional devices is an important approach to make wearable equipments more flexible, light-weighted and integrated. Lithium sulfur (Li-S) batteries with sulfur cathode and lithium metal anode possess higher theoretical capacity (1675 mAh g-1) than traditional lithium ion batteries, however, the low conductivity and the dissolution of intermediate polysulfide limits the real capacity and cycle life of Li-S batteries. To make a fiber-like Li-S battery, it has to not only address the issues of sulfur itself, but also make the electrode as fiber shape with continuous process, which consequently become a large challenge. In this research, we propose to develop wet-spinning continuous process to make fiber-like sulfur cathode, with carbon nanotubes substrate and pre-decorated sulfur nanomaterials which are blended in the precursor solution. MXene is used to decorate hollow sulfur nanoparticles to improve the capacity and charge-discharge cycle life of sulfur electrode, due to the enhanced chemisorption between polar sites of MXene and sulfur that can enhance the confinement of sulfur and polysulfide. Besides, the hollow structure of sulfur nanoparticles can accommodate the volume expansion strength of sulfur electrode during charge-discharge process. This research benefits to address the key scientific and technological issues of fiber-like batteries, and paves a road to the real application of wearable devices.

将功能器件制备成可编织的纤维状，是实现可穿戴设备柔性化、轻质化和可集成化的重要途径。以单质硫为正极、金属锂为负极的锂硫电池具有比传统锂离子电池高数倍的理论容量（1675 mAh g-1），但是硫的低导电率以及中间产物易溶等问题严重制约了其容量和循环寿命。研制纤维状锂硫电池正极既要有效克服上述硫自身问题，还要将电极制备成可连续化生产的纤维，因此成为一个研究难点与重要挑战。本研究提出发展湿法纺丝技术，以碳纳米管作为纤维基体，通过在前驱液中合并预修饰的硫复合纳米材料，制备连续化的纤维状碳纳米管/硫复合正极以及纤维状锂硫电池。采用新型二维材料MXene纳米片修饰中空的硫纳米粒子，通过MXene表面极性位点与硫的价键作用增强对硫和多硫化物的限域效应，利用中空纳米结构克服硫充放电过程的体积膨胀，以此提高硫的容量和循环寿命。该研究将有助于解决该领域的关键科学和技术问题，为柔性可穿戴器件的应用奠定基础。

开发高性能柔性储能器件是实现可穿戴设备柔性化、轻质化和可集成化的重要途径。纤维状器件能够实现三维方向上的柔性，可以像传统化学纤维一样，通过纺织技术将不同的纤维功能器件编织成可穿戴性能良好的织物，从而实现将多种器件的智能集成。本项目围绕纤维状电化学储能器件及关键材料开展研究，掌握了连续化制备碳基复合纤维的技术，获得复合纤维形貌、电化学和力学性能调控方法，研制了纤维状电化学储能器件。开展的研究工作包括：（1）长纤维电极与纤维状器件：研究了干法/湿法技术连续化制备碳纳米管长纤维及其与复合纤维，开发了可拉伸纤维电池、柔性纤维状锂硫电池、长纤维锌电池、柔性聚合物纤维电池；（2）关键材料：研制了基于纳米锂镧锆钽氧（LLZTO）的高离子导电固态电解质、三维结构石墨烯正极、柔性聚合物正极等关键材料；（3）界面设计：深入研究了锂硫电池的界面设计与性能调控。这些研究有助于解决该领域的关键科学和技术问题，为柔性可穿戴器件的工程化应用奠定理论基础。基于上述研究，在Adv. Mater., Energy Storage Mater., J. Mater. Chem A, Journal of Energy Chemistry等国际期刊发表SCI论文14篇，申报国家发明专利3项，已授权2项；并参加国内外学术会议15次。通过本项目，培养博士后1名、研究生4名。