Numerical Modeling of Fracture-Resistant Sn Micropillars as Anode for Lithium Ion Batteries

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• 作者：Nadeem Qaiser ; Yong Jae Kim ; Chung Su Hong ; Seung Min Han
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：April 7, 2016
• 年：2016
• 卷：120
• 期：13
• 页码：6953-6962
• 全文大小：607K
• ISSN：1932-7455

文摘

Sn possesses three times higher capacity in comparison to graphite anode (372 mAhg^–1) that makes it a promising candidate for enhanced performance Li ion batteries. Contrary to Si, Sn is compliant and ductile in nature and thus is expected to readily relax the Li diffusion-induced stresses. The low melting point of Sn additionally allows for stress relaxations from time-dependent or creep deformations even at room temperature. In this study, numerical modeling is used to reveal the significance of plasticity and creep-based stress relaxations in the Sn working electrode. The maximum elastic tensile hoop stresses for 1 μm micropillar size with 1C charging rate conditions reduces down from ∼1 GPa to ∼200 MPa when Sn is allowed to plastically deform at a yield strength of ∼150 MPa. After experimentally determining the creep response of Sn micropillars, creep deformations are incorporated in numerical modeling to show that the maximum tensile hoop stress is further reduced to ∼0.45 MPa under the same conditions. Lastly, the Li-induced stresses are analyzed for different micropillar sizes to evaluate the critical size to prevent fracture, which is determined to be ∼5.3 μm for C/10 charging rate, which is significantly larger than that in Si.