基于SEI膜演化动力学和理化性质研究高电位正极材料LiNi0.5Mn1.5O4表面改性作用机理

项目名称： 基于SEI膜演化动力学和理化性质研究高电位正极材料LiNi0.5Mn1.5O4表面改性作用机理

项目编号： No.51272051

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 方海涛

作者单位： 哈尔滨工业大学

项目金额： 80万元

中文摘要： 对高压正极材料LiNi0.5Mn1.5O4尖晶石（LNMO）进行表面包覆改性，是提高其充放电循环稳定性和倍率性能的有效方法之一。鉴于电解液氧化分解所生成的电极/电解液界面膜层(SEI膜)是影响正极材料电化学性能的关键，本项目以多种金属氧化物和石墨烯电极对电解液电化学氧化行为的比较为研究切入点，从表面改性对LNMO表面SEI膜演化动力学及其理化性质影响的角度，研究几种典型金属氧化物和石墨烯改性的作用机理，分析改性层材料化学性质与表面改性LNMO电化学性能之间的内在联系规律。将采用电化学石英微晶天平技术（EQCM），实现SEI膜演化动力学的定量研究；使用同步辐射光谱学技术精确表征SEI膜的成分及沿厚度的分布状态。 研究结果将为以LNMO为代表的高电位正极材料在新一代先进锂离子电池中的应用奠定材料科学基础，还为LNMO和其他正极材料表面改性的设计提供理论依据。

中文关键词： 锂离子电池；LiNi0.5Mn1.5O4；SEI膜；表面改性；高电位

英文摘要： Surface modification of high-potential LiNi0.5Mn1.5O4 (LNMO) spinel is one of effective method to improve its cycling performance and rate capability. Electrode/electrolyte interfacial layer, or called solid/electrolyte interphase layer (SEI layer), formed during the decomposition of electrolyte, plays a key role in the electrochemical performance of cathodes. Starting with a comparison on electrochemical oxidation behaviors of electrolyte by various metal oxide and graphene electrodes, the mechanism for the improvement on the performance after surface modification by several typical metal oxides and graphene will be studied in depth especially based on the kinetics of forming and stripping SEI layer and physicochemical characteristics of SEI layer. The inherent relationship between chemical properties of modification layers and electrochemical performance of corresponding surface-modified LNMO will be investigated. Electrochemical quartz crystal microbalance (EQCM) is used to quantitatively investigate the kinetics, and synchrotron radiation spectroscopy is applied to preciously characterize the composition and distribution along depth of the SEI layer. The results of this study can lay a scientific material foundation for the application of LNMO and other 5V class cathodes in new generation advanced Li-ion ba

英文关键词： lithium ion battery；LiNi0.5Mn1.5O4；solid-electrolyte interphase layer；surface modification；high potential