纳米多孔硅/凝胶电解质互贯网络结构的可控制备、异质界面特性及储锂性能研究

Silicon is a promising high capacity alternative to graphite anodes, which is also one of the key materials for the next generation high-power lithium-ion batteries. The main disadvantages that restrict the application of Si include poor intrinsic conductivity, the large volume changes during lithiation, and the continuous growth of the SEI layer. This project intends to solve the above problems through the controlled preparations and efficient compounding of silicon and polyaniline as follows: (1) synthesizing nanoporous Si crystals via selective-dealloying and alkali-corrosion two chemical synthesis methods; (2) in the controllable preparation of polyaniline, the construction of an interlinked conductive network structure of nanoporous Si/gel electrolytes will be completed synchronously; (3) study the crystal structure, ion conduction, and the growth of SEI film of the heterogeneous interfaces within the composite structures. In this project, nanoporous Si/gel electrolyte interlinked networks are used to obtain excellent high-rate long-cycle battery performance. The pore formation mechanism of silicon crystals will be studied. The influence of anion and cation groups to polyaniline on its ion/electron conduction, infiltration, self-healing, and electrochemical stability will also be explored. Based on the above investigations, the rational relations will be constructed of material preparation, structural adjustment, performance optimization. These fundamental researches are significant for the development of Si-based anodes with high energy and application value.

硅是一种有望替代石墨的高容量负极材料，也是开发下一代高能动力电池的关键材料。限制硅应用的主要问题包括较低的本征导电率、硅在锂化过程中的体积膨胀、和不断生长的SEI膜。本项目拟通过对硅和聚苯胺的可控制备与高效复合，最终解决上述问题。具体包括：(1)发展选择性脱合金和碱腐蚀两种化学合成方法来制备纳米多孔Si；(2)在可控制备聚苯胺时，同步完成纳米多孔硅-凝胶电解质互贯网络结构的构建；(3)研究复合结构里异质界面的晶体结构、离子传导、SEI膜生长。本项目通过纳米多孔硅-凝胶电解质互贯网络材料来获得优异的高倍率长循环电池性能；研究硅晶体的孔道形成机制；探索聚苯胺引入阴阳离子基团对材料离子/电子传导、浸润性、自愈性、电化学稳定性的影响规律；基于上述研究，建立“材料制备-结构调整-性能优化”的研究关系，为开发具有应用前景的高能硅负极奠定技术基础。

限制硅应用的主要问题包括较低的本征导电率、硅在锂化过程中的体积膨胀、和不断生长的SEI 膜。本项目拟通过对纳米硅和导电物的可控制备与高效复合，最终解决上述问题。具体包括：(1)发展了“选择性脱合金”和“草酸铜还原热解”两种化学方法制备硅基的纳米多孔结构；(2)开发聚苯胺原位聚合技术得到纳米多孔硅-凝胶电解质互贯网络结构，并深入探索了硼掺杂对硅-碳互贯网络负极的影响；(3)通过开发新型粘结剂来优化研究硅负极里内在结构、离子传导、SEI膜生长；(4)将固态电解质和SEI研究思路拓展到包覆型高镍正极材料开发。综上，本项目通过纳米多孔硅-导电物互贯网络材料来获得优异的高倍率长循环电池性能；并研究了多孔硅结构的孔道构建；探索聚苯胺引入阴阳离子基团及硼掺杂引入石墨包覆层对负极材料离子/电子传导、浸润性、电化学稳定性的影响规律；为开发具有应用前景的高能硅负极奠定技术基础。

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