锂离子电池电极表面钝化膜的扫描探针研究

项目名称： 锂离子电池电极表面钝化膜的扫描探针研究

项目编号： No.21273273

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 卢威

作者单位： 中国科学院苏州纳米技术与纳米仿生研究所

项目金额： 80万元

中文摘要： 锂离子电池电极表面的钝化层（SEI膜）的结构与性能对电极材料的化学及电化学稳定性、锂离子的传输能力起到决定性的作用，进而会影响锂离子电池的循环效率、容量、高低温特性、倍率特性等关键性能。但是，因为SEI膜的生长过程与结构复杂，其生长机理、结构模型以及输运性能等方面仍然存在许多有待解决的基础科学问题。申请人在国际上首创利用扫描探针技术的力谱模式，直观地测得SEI膜的介观结构与成分分布情况，并通过对SEI膜杨氏模量的测量与统计，证明了SEI膜中存在着无机/有机的双层SEI膜结构，为揭示SEI膜的介观结构信息提供了有力的检测手段。在将来的工作中，申请人拟将力谱、电子电导、离子电导等模式应用于SEI膜研究，采用原位与非原位结合的方法重点研究石墨、硅以及过渡金属氧化物负极材料在不同电解液体系、充放电条件下表面SEI膜的结构成分分布以及机械强度、电子电导、离子电导，稳定性等关键性能。

中文关键词： 扫描探针显微镜；锂离子电池；钝化膜；界面；SEI

英文摘要： Solid electrolyte interphase (SEI) is known as an electronic insulating but ionic conducting film formed on the surface of the anode and cathode in Li-ion batteries. It is widely accepted that the physical and chemical properties of the SEI film have significant impacts on the safety, power capability, morphology of lithium deposits, shelf life, and cycle life of lithium-ion battery. It is very important that there be uniform morphology and chemical composition in order to ensure homogeneous current distribution. The SEI must be both mechanically stable and flexible and good adhesion to the electrode. However, the distribution of structure and chemical composition in SEI films are not uniform, which make it difficult to study the structure and properties of SEI films. In our recently work, we have proposed a force spectroscopy method to study the structure and mechanical properties of SEI films in nanometer scale. By this method, we firstly elucidate the double-layers structure of SEI film on MnO electrode, where an inner-hard inorganic layer and outer-soft organic layer. Furthermore, we also observed the evolution of SEI thickness/structure with voltage. There is not significant SEI film formed at voltage above 0.3 V, when the electrode was discharged to 0.1 V, the hard inorganic film start to form. The thickne

英文关键词： scanning probe microscopy；lithium-ions battery；solid electrolyte interphase film；interface；SEI