室温自修复液态金属/红磷复合电极的界面调控与协同储钠机理研究

Red phosphorus (P) is considered as the most promising anode material for sodium ion batteries because of its high capacity and low cost. However, its practical application is hindered by its severe volumetric change and low electronic/ionic conductivities. In this project, we proposed that the above shortcomings could be simultaneously addressed by compositing P with self-healing GaInSn liquid metal (LM) and various carbon structures (C). The large volumetric change of P during cycling will lead to deformation and fluxion of the LM, which helps maintain integrity of the conductive network and synergistically regulates the sodium ion transport. The influence of preparation methods and reaction conditions on the interfacial properties, dispersibility and microstructures of the LM/P/C will be systematically studied by SEM, TEM, XPS, etc., to establish a controllable fabrication method. In-situ XRD, electrochemical atomic force microscope (EC-AFM) combined with molecular dynamics simulation, will be used to explore the change of crystal structure, internal stress and volumetric effect during the soudium ion alloying/dealloying process. As a result, the relationship between structure parameters (composition, interface, morphology) and electrochemical performances of the LM/P/C will be established. The success of this project will provide guidance for the design and optimization of high-capacity alloy materials for sodium ion batteries.

红磷（P）因其高容量和低成本被认为是最具潜力的钠离子电池负极材料，然而其实际应用却受制于导电性差、反应动力学缓慢和合金化体积膨胀严重等问题。针对此，本项目拟利用室温自修复导电合金镓铟锡液态金属（LM）与P复合，构建具有不同维度和界面结构的LM/P/C复合电极，实现LM流动性和红磷合金化效应对钠离子传输的协同调控，以及高容量和高循环稳定性磷基钠离子电池负极材料的制备。通过SEM、TEM、XPS等技术系统研究制备方法、反应条件等对LM/P/C复合材料表界面性质、分散性和微观结构的影响，建立复合材料的可控制备方法。通过原位XRD、电化学原子力显微镜并结合分子动力学模拟，系统研究晶相结构、体积效应和内应力等在嵌脱钠过程中的演变规律及其对钠离子传输的影响，揭示LM/P/C复合材料组分间的协同作用机制和储钠机理。项目成果将为高容量合金类材料的设计和优化及其在钠离子电池中的应用提供理论指导。

红磷（P）因其高容量和低成本被认为是最具潜力的钠离子电池负极材料，然而其实际应用却受制于导电性差、反应动力学缓慢和合金化体积膨胀严重等问题。针对此，本项目将室温自修复导电合金镓铟锡液态金属（LM）与P复合，利用LM流动性和高导电性解决红磷合金化过程中的体积膨胀问题，并针对性的对隔膜进行改性以抑制液态金属的穿梭，从而制备了高性能磷基复合负极。研究了液态金属尺寸、界面和复合负极组分对钠离子电池性能的影响。在此基础上，将液态金属扩展到钠硫电池体系，合成了具有自修复功能、超稳定的Ga2S3@S-rGO钠离子电池负极材料。得益于材料的可逆性以及Ga和S之间的强相互作用力，Ga2S3@S-rG在钠离子电池中表现出了优异的循环性能和倍率性能，电池的首次放电容量为798.2 mAh·g−1，充电比容量为617.3 mAh·g−1，初始库伦效率达到77.3%。项目成果将为高容量合金类材料的设计和优化及其在钠离子电池中的应用提供理论指导。