锂离子电池用多孔纳米硅/金属/碳三元复合负极材料的结构设计和性能研究

项目名称： 锂离子电池用多孔纳米硅/金属/碳三元复合负极材料的结构设计和性能研究

项目编号： No.51504032

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 矿业工程

项目作者： 于冰

作者单位： 有研工程技术研究院有限公司

项目金额： 21万元

中文摘要： 项目设计一种多孔纳米硅/金属/碳三元复合材料，拟结合熔盐电解法和表面碳修饰实现，该材料主要解决硅作为锂离子电池负极材料存在的循环差问题。该材料保留硅的高比容量的同时，具有稳定的结构和高导电性。在熔盐电解过程中，金属起到催化硅纳米结构生长的作用，同时还与还原的硅原位复合，形成活性物质和导电相均匀分布的多孔结构。这种结构可以降低硅体积变化带来的应力，缓解硅的体积变化对负极材料的破坏，保证整个导电网络的稳定。表面碳修饰工艺可以增加材料的电子和离子导电性，隔绝硅与电解液的直接接触，避免不稳定SEI膜的不断生成。本项目重点研究金属在纳米硅的熔盐电解过程中的作用机理，找到制备高容量和结构稳定的多孔纳米硅/金属的制备工艺；研究表面碳修饰技术在纳米硅表面均匀完整的进行碳包覆的工艺；研究纳米硅基材料在锂离子电池应用中的电化学行为。项目的研究可为高容量、长寿命和高安全性的锂离子电池研究奠定理论基础和实践指导。

中文关键词： 熔盐电解；锂离子电池负极；纳米复合材料；熔盐电化学；多孔结构

英文摘要： Silicon is of great interest since it has 10 times higher specific capacity than traditional carbon anodes. However, the poor cyclability due to the large volume change of silicon upon insertion and extraction of lithium has been an impediment to its deployment. To solve this issue, electrochemical approaches in molten salts and carbon modification method for producing nano silicon/metal/carbon porous materials have been studied. These silicon materials with large capacity have stable structure and high conductivity. In the electrochemical process, the porous structure is formed with uniform electrochemical activity and conductive phases. Stress induced by large changes in the volume of silicon anodes is limited in small range, which leads to the stable conductive network. The electronic conductivity and ion conductivity are enhanced by the carbon modification method. This method can shut off the silicon contact with electrolyte. And the unstable solid electrolyte interphases (SEI) are prevented by this method. The catalytic mechanisms of metals are focused on to obtain the porous silicon/metals structure with high capacity and good stability. Research are studied to obtain the uniform and whole carbon coating by the carbon modification method. The electrochemical processes of the lithium ion batteries anodes with nano silicon materials are studied. The work in this project will put forward on theoretical basis of the design and application of new lithium ion batteries with the large capacity, the long cycle life and the high security.

英文关键词： molten salt electrolysis;lithium ion batteries anode;nano composite materials;molten salt electrochemistry;porous structure