氧化及离子迁移反应应变的测试方法研究

化学反应产生的应力应变会导致材料功能减退和失效，研究电池中的反应力学问题是一个有意义的新课题。在电池材料中，我们发现氧化发生时，随着氧化程度增大，层中应力会重新分布进而导致膜系曲率改变，并有曲率反转出现；而锂离子电池充放电过程中，锂离子的嵌入和迁出改变了硅电极材料结构和性能，导致电极材料发生非弹性变形和塑性出现。本项目研究测试化学应变的方法和手段，拟用光学读出悬臂梁法测试氧化及离子嵌入过程电池类材料变形演化过程，实时测试多层膜氧化曲率反转过程，测试硅电极电池材料的反应塑性流动变形过程和机理。并弄清楚两个问题，1、氧化过程多层膜到底是中心环开裂还是层化开裂，2、离子嵌入性硅电极材料反应塑性流动的机理和引起变形的影响因素，建立描写反应塑性流动变形的非弹性和非平衡力学模型。这些研究对于化学反应应变测试方法研究和电池材料的失效机理都具有应用价值和科学意义。

Abstract：the strain induced by chemical reaction usually cause fading of the capacity and damage of electrinic cell material. The curvature reversal occurs when oxidazed anode of Solid Oxidation Fuel Cell,the reseason is that ther exist of oxdation layer will redistribute the stress in multlayers.furthmore,the charge and discharge of li-ion battery, lithiation-induced large deformation of silicon electrodes can be accommodated by plastic flow. Here we want to investigate a mothod to measure the deformation of multlayer film under oxidation in SOFC and reative flow in lithiation, a cantileverbeam with osicalate laser detecter is propose to set up for measurement. Through the experiment, two problems are to be solved, the first is that to understand which one is right responsful the crack of multlayer film of fuel cell, the center ring model or the oxidation layer evolution model ; the other is to understand the mechanism of plastic deformation of lithiated silicon, using continuum plasticity theory and nonequilibrium theory to formulate the lithium diffusion coupled to the elastic-plastic deformation of the silicon electrode.