In Situ Measurements of Stress-Potential Coupling in Lithiated Silicon
In Situ Measurements of Stress-Potential Coupling in Lithiated Silicon
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DOI：
10.1149/1.3489378
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发表时间：
2010-01-01
影响因子：
3.9
通讯作者：
Guduru, P. R.
中科院分区：
文献类型：
--
作者：
Sethuraman, V. A.;Srinivasan, V.;Guduru, P. R.
本文分析了锂硅电极的应力状态与电位的关系。基于固溶体的Larche和Cahn化学势，对锂化硅中存在的应力-势耦合进行了热力学论证;基于材料的已知性质，估计耦合的大小与薄膜几何形状中的60 mV/GPa相似。对硅薄膜电极进行了实验研究，在电化学锂化和脱锂过程中原位测量了应力。通过增量脱锂逐步改变应力，测得应力变化和电势变化之间的关系为100-120 mV/GPa，这与分析预测的数量级相同。耦合的重要性进行了讨论，在解释中观察到的滞后的电位与充电状态图和应力的作用，在修改的硅电极的最大充电容量的应力。(C)2010年电化学学会。[DOI：10.1149/1.3489378]保留所有权利。
An analysis of the dependence of electric potential on the state of stress of a lithiated-silicon electrode is presented. Based on the Larche and Cahn chemical potential for a solid solution, a thermodynamic argument is made for the existence of the stress-potential coupling in lithiated silicon; based on the known properties of the material, the magnitude of the coupling is estimated to be similar to 60 mV/GPa in thin-film geometry. An experimental investigation is carried out on silicon thin-film electrodes in which the stress is measured in situ during electrochemical lithiation and delithiation. By progressively varying the stress through incremental delithiation, the relation between stress change and electric-potential change is measured to be 100-120 mV/GPa, which is of the same order of magnitude as the prediction of the analysis. The importance of the coupling is discussed in interpreting the hysteresis observed in the potential vs state-of-charge plots and the role of stress in modifying the maximum charge capacity of a silicon electrode under stress. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3489378] All rights reserved.