导电纳米网络负载金属锂柔性电极的构建与储能性能

Lithium (Li) metal not only faces the intrinsic problems of “dendrites” and “dead Li”when directly used as anodes in flexible batteries, but also suffers the mechanical damages induced by external bending and stretching forces. In order to overcome these shortages, it is need to carry out a comprehensive study on the preparation of high-performance metallic Li flexible electrodes by simultaneously resolving the “stability” and “flexibility” issues. Some recently cut-edge works have demonstrated that Li metal supported by conductive nanonetworks (CNWs), such as metal nanowires or nanogrids could effectively eliminate the formation of Li dendrites. Taking the advantage of the outstanding property of CNWs used as building blocks in flexible electrodes, this project proposes an novel approach to prepare CNW supported Li metal (Li/CNW) flexible electrodes by combining the flexible features of CNWs and their inhibitive effect on Li-dendrite growth. The structure of Li/CNW composite electrodes will be tailored by tuning the CNW architectures and electrochemical deposition of Li metal. This project will systematically investigate the internal relation between the electrode structures and the involved interfacial reactions to illuminate the working mechanism of CNMs in stabilizing Li metal, and also carry out the research on the electrochemical behavior of the Li/CNW electrodes under deformation caused by external forces to reveal the new problems encountered and provide the corresponding solutions. On the basis of the optimized Li/CNW flexible electrodes, Li-S and Li-Air flexible prototype batteries will be developed in order to provide scientific evidence for the design and exploration of high-performance Li metal-based flexible batteries.

直接以金属锂作为柔性电池负极存在锂自身的“枝晶”和“死锂”等问题，还无法克服弯折和拉伸等外力引起的机械性损伤。为了克服这些缺点，需从金属锂的“稳定化”和“柔性化”两方面入手，开展新型高性能金属锂柔性电极的研究。近期文献报道，金属纳米线和网格等导电网络作为载体可有效地抑制锂枝晶生长。考虑到导电纳米网络是一类优秀的柔性电极构建单元，本项目提出将导电纳米网络抑制锂枝晶的作用与其柔性特点相结合，制备负载型金属锂柔性电极。拟从调变导电网络载体和电化学沉积金属锂两个方面调控复合电极的结构。系统研究电极结构与其界面反应的内在关系，阐明导电纳米网络稳定锂的作用机制。开展外力形变条件下金属锂复合电极的电化学性能研究，揭示柔性电极面临的新问题并提供解决方案。以所制备的高性能金属锂/导电纳米网络柔性电极为基础，研制Li-S和Li-Air柔性原型电池，为高性能金属锂基柔性电池的设计开发提供科学依据。

柔性电池是未来便携式、轻柔和可穿戴电子产品的重要功能器件。由于金属锂负极极高的理论容量和低的电势，发展柔性锂金属电池越来越引起了人们广泛的关注。然而，直接以金属锂作为柔性电池负极面临着不稳定化和非柔性两个关键问题。项目围绕柔性锂金属电池负极的制备、性能和原型电池器件开展系统研究，发展了柔性电极制备新方法，提出了金属锂负极稳定新策略，研制出柔性固态电解质新材料，展示了柔性锂金属电池原型器件。主要研究成果如下：. 1.提出了呼吸图法制备柔性导电薄膜，研制出可拉伸穿孔电极，应用于柔性电子和柔性电池等器件，获得美国化学化工新闻期刊（C&EN）专题报道。. 2.提出了动态自适应抑制锂枝晶生长新策略，研制出锂负载量达12 mAh cm-2、在10 mA cm-2下稳定循环1000 h以上的金属锂负极，为高容量锂负极的研制开辟新途径。. 3.研制出柔性聚合物固态电解质，其室温离子电导为0.51 mS cm-1，应用于全固态Li-LiFePO4电池稳定运行196圈，容量损失仅为9.3%，为开发柔性全电池研制提供材料支持。. 4.制备了柔性Li-S和柔性Li-LiFePO4全电池，它们在弯折条件下循环100圈的容量保持率高于80%，展示了柔性锂金属电池具有突出的机械和电化学性能。. 项目组在Nano Letters、Advanced Energy Materials、ACS Nano、Nano Energy、Nano Research等国内外期刊上发表高质量论文28篇；获批中国发明专利6件；培养博士生2名、硕士生10名；主办2018年低维材料应用与标准研讨会(LDMAS)暨低维纳米标准化工作组年会、2019无机材料化学前沿论坛等会议。“柔性电极的高效制备、功能调控及其储能器件”荣获2019年度中国电子学会科学技术奖自然科学一等奖（排名第三）。