In situ measurements of stress evolution in silicon thin films during electrochemical lithiation and delithiation
In situ measurements of stress evolution in silicon thin films during electrochemical lithiation and delithiation
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DOI：
10.1016/j.jpowsour.2010.02.013
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发表时间：
2010-08-01
影响因子：
9.2
通讯作者：
Guduru, Pradeep R.
中科院分区：
文献类型：
--
作者：
Sethuraman, Vijay A.;Chon, Michael J.;Guduru, Pradeep R.
我们报告在硅薄膜电极电化学锂化和脱锂过程中的应力演化的原位测量，通过使用多光束光学传感器（MOS）技术。在锂化时，由于衬底约束，硅电极最初经历弹性变形，导致压缩应力的快速上升。电极在压缩应力约为0.5MPa时开始塑性变形。-1.75 GPa;随后的锂化导致持续的塑性应变，耗散机械能。在脱锂时，电极首先在相反方向上经历弹性应变，导致约100的拉伸应力。1 GPa;随后，它在脱锂的其余部分中塑性变形。塑性流动应力随锂含量的增加而不断变化。因此，在锂化和脱锂过程中，机械能在塑性变形中耗散，并且可以从应力测量中计算：我们表明它与极化损耗相当。在电流中断时，薄膜应力和电极电位都以相似的时间常数松弛，表明应力对锂化硅的化学势有显著贡献。(C)2010 Elsevier B. V.保留所有权利。
We report in situ measurements of stress evolution in a silicon thin-film electrode during electrochemical lithiation and delithiation by using the multi-beam optical sensor (MOS) technique. Upon lithiation, due to substrate constraint, the silicon electrode initially undergoes elastic deformation, resulting in rapid rise of compressive stress. The electrode begins to deform plastically at a compressive stress of ca. -1.75 GPa; subsequent lithiation results in continued plastic strain, dissipating mechanical energy. Upon delithiation, the electrode first undergoes elastic straining in the opposite direction, leading to a tensile stress of ca. 1 GPa; subsequently, it deforms plastically during the rest of delithiation. The plastic flow stress evolves continuously with lithium concentration. Thus, mechanical energy is dissipated in plastic deformation during both lithiation and delithiation, and it can be calculated from the stress measurements: we show that it is comparable to the polarization loss. Upon current interruption, both the film stress and the electrode potential relax with similar time constants, suggesting that stress contributes significantly to the chemical potential of lithiated silicon. (C) 2010 Elsevier B.V. All rights reserved.