3D打印高安全、高性能全固态可自修复三维锂离子电池

The project targets at the urgent call for the rapid advancement of the currently sluggish development in the field of 3D printed three dimensional lithium ion battery. By harnessing the research specialty of Polymer Research Institute and State Key Laboratory of Polymer Materials Engineering of Sichuan University in 3D printing of functional materials, this project intends to design and fabricate 3D printable conductive hydrogel ink with desired rheology properties and to fabricate active battery electrodes embedded in self-healable elastic polymer solid electrolyte by means direct ink writing 3D printing. The self-healable polymer solid electrolyte is endowed with dual advantages of both high ionic conductivity and self-healing property. This obviates the shortcomings of liquid electrolyte while proving a facile transportation path for lithium ions; It restricts the volume of expansion of the active electrode material and restores the damaged structure for improved cycling stability. Besides, the kinetic bonding established at the solid state electrolyte/electrode interface as well as the interface between printed layers of the electrode results in reduction of interfacial impedance and more efficient utilization of the active electrode material, which contribute to high energy density and enhanced cycling stability. Benefiting from this project, novel theories, approaches and electrode materials for the next generation solid state lithium ion battery constructed by 3D printing could be realized.

本项目针对目前3D打印三维锂离子电池需求迫切但发展缓慢的现状，结合四川大学高分子研究所、高分子材料工程国家重点实验室在3D打印功能材料方面的研究特色，拟设计和制备适于直接墨水式3D打印加工的导电凝胶电极以及弹性自修复聚合物固体电解质，实现基于弹性自修复聚合物固体电解质的具有高能量密度和优异循环性能的全固态锂离子电池的3D打印。自修复聚合物固体电解质具有高离子电导性和可自修复的双重特性，可提供必要的锂离子传输通道但同时克服液体电解质的缺点；其可限制电极材料体积膨胀并修复循环过程中造成的破损，提高其循环稳定。此外，通过建立动态键改善打印层间以及电解质/电极间的界面问题，可降低全固态电池界面电阻/阻抗，并充分发挥各层活性负载物质的作用，提高能量密度，改善循环性能。本项目的开展将为发展新一代全固态锂离子电池的3D打印技术提供新理论、新方法、新材料。

先进增材制造技有望突破传统二维锂离子电池构架的局限因素，全面推动新型构架锂离子电池在高安全、高容量、高能量密度、高功率密度、高柔性方面的发展，为三维锂离子电池以及其他重要电化学储能体系应对高电能消耗应用环境提供重要解决方案。本项目瞄准了目前三维锂离子电池这个前沿研究中存在的一些重要挑战。通过首次实施自修复功能引导实时打印界面修复，本项目在超高厚度、超大负载、高能量密度电化学储能应用方向取得了重要的突破。同时，通过超分子组装引导强化相形成以及固态弹性聚合物电解质的研发，我们可赋予打印器件极佳的机械柔性，为锂离子电池的高安全、致密储能应用提供了重要思路。此外，通过实施结构工程以及电极表界面调控，本项目也在高能量密度电极体系快速充放电应用方向取得了一系列进展。本项目的研究结果与发现具备非常良好的普适性与先进性，有望在除了锂离子电池外的其他重要电化学储能应用中发挥重要应用，推动超高能量密度三维电化学储能技术的发展。