红磷镶嵌多孔碳纤维柔性自支撑电极的构筑及其储锂(钠)性能研究

Research on flexible power sources is now actively pursued worldwide for flexible portable electronics，which need to explore new flexible Li (Na)-ion batteries. Red phosphorous (P) have been considered as one of the most promising anode material for both lithium-ion batteries (LIBs) and Na-ion batteries (NIBs), because of its high theoretical capacity (2595 mAh/g) than commercial graphite.anode. However，the practical application using Red phosphorous (P) are prevented by their poor cycling stability, which is attributed to the significant volume changes during charge/discharge and low electronic conductivity of P. The proposed research plan will focus on develop electrospinning process to fabricate red phosphorus embedded in self-support flexible porous carbon nanofiber (P@PCNFs).thin film with controllable morphology to overcome these challenges and develop high performance flexible LIBs (NIBs). This project will significantly help us clarifying the following fundamental and practical issues: the intrinsic principle of structure change during charging/discharging process, the mechanism of P as anodes for LIBs (NIBs). The technology developed under this grant will help fill.the need for next generation high energy density and high power density flexible power sources.

可穿戴电子设备的迅速发展，迫切需要发新型高性能柔性锂(钠)离子电池电极材料。红磷作为锂(钠)离子电池负极具有2595 mAh/g的理论容量，已成为替代传统石墨类材料(理论容量372 mAh/g)的最佳负极材料之一。然而，红磷本身的低电子电导特性和储锂(钠)过程中的巨大体积变化导致其循环寿命和倍率性能不佳，限制了其应用。本项目着眼于抑制红磷的体积效应、提高材料电子电导率、发展柔性电极，从纳米化、多孔化、柔性可折叠、自支撑(避免使用对电池容量无贡献的粘结剂，金属集流体)等方向对其进行改性。发展静电纺丝法，可控制备红磷镶嵌纳米多孔碳纤维的柔性自支撑薄膜电极（直径、壁厚、孔径、红磷负载量均分别可控），同时利用CNT，TiN等高电子电导材料修饰碳纤维，筛选兼具高容量、长寿命和高倍率性能的柔性锂(钠)离子电池电极材料。明晰材料脱、嵌锂(钠)的反应机理，为探索柔性锂(钠)离子电池奠定理论与实际操作基础。

磷基电极材料因具有高的理论比容量而受到广泛关注，但其在充放电过程中存在体积膨胀大、颗粒易破碎等问题，导致电池循环稳定性和倍率性能较差。本项目针对磷基电极材料的关键问题开展了深入系统的研究，主要研究内容包括：1）利用静电纺丝技术制备了自支撑的红磷镶嵌的氮掺杂多孔中空碳纳米纤维负极材料，有效缓解了电极的体积膨胀问题，获得了高性能钠离子电池负极；2）设计制备了多孔碳嵌入超细红磷纳米粒子复合电极材料，将红磷包封于独立式氮掺杂多孔空心碳纳米纤维，增强了电子和离子传输效率，实现了优异的储钾性能；3）采用商品纳米红磷作为界面保护层修饰钠/钾金属负极，提高了界面离子传输速率，并抑制了金属枝晶的生长，取得了长寿命的钠/钾金属电池。此外，还将上述电极材料的设计策略拓展至其他材料体系中，为发展新型高性能电极材料提供了指导。在项目执行过程中，负责人共发表 SCI 论文 79 篇，其中 IF＞10的 72 篇, 主要包括：Adv. Mater. 19 篇， Angew. Chem. Int. Ed. 1 篇，Energy Environ. Sci. 1篇，Adv. Energy Mater. 7 篇，Nano Lett. 5 篇， Adv. Funct. Mater. 11 篇， ACS Nano 7 篇， ACS Energy Lett. 2 篇，Nano Energy 4篇，Small 7 篇。这些成果对于发展高性能储能材料、阐明材料结构与电化学性能之间的关系，提供了坚实的实验基础。