Modeling the delamination of amorphous-silicon thin film anode for lithium-ion battery Siladitya Pal a , Sameer S. Damle b, e , Siddharth H. Patel c , Moni K. Datta a, e , Prashant N. Kumta a, b, d, e , Spandan Maiti a, b, e, * a Department of Bioengineering, University of Pittsburgh, PA 15261, USA b Department of Chemical Engineering, University of Pittsburgh, PA 15261, USA c Department of Mechanical Engineering, MichiganTechnological University, MI 49931, USA d Mechanical Engineering and Materials Science, University of Pittsburgh, PA 15261, USA e Center for Complex Engineered Multifunctional Materials, University of Pittsburgh, PA 15261, USA highlights  Computational study of electrochemical cycling induced film delamination has been undertaken.  Current collector mechanical properties significantly influence cycling response.  Elasto-plastic current collectors show partial delamination of the thin film.  Absence of interfacial delamination in thin Si film on low modulus elastic substrate. article info Article history: Received 4 January 2013 Received in revised form 13 June 2013 Accepted 14 June 2013 Available online 25 June 2013 Keywords: Li-ion battery a-Si thin film anode Diffusion induced stress (DIS) Interfacial delamination Current collector Mechanical properties abstract Sputter-deposited amorphous silicon thin films on metallic copper current collectors are widely studied as lithium-ion anode systems. Electrochemical results indicate these electrodes exhibit near theoretical capacity for first few cycles; however delamination at the thin filmecurrent collector interface causes rapid capacity fade leading to poor cycling performance. Primary reason for this interfacial delamination is the mechanical stress generated due to colossal volume expansion of silicon during lithiation. The focus of the current study is to present a mechanistic understanding of the role of mechanical properties of the current collector on this characteristic delamination behavior during electrochemical cycling. Toward this end, we have developed a computational framework that accounts for the coupled diffusion induced large deformation in silicon, elasto-plastic deformation of the current collector, as well as the nucleation and propagation of interfacial delamination. We have also performed a detailed parametric study to investigate the effect of mechanical properties of the current collector on the delamination of the thin filmecurrent collector interface. We have accordingly determined that current collectors with low elastic modulus such as graphite can completely suppress interfacial delamination. Our analysis thus provides a sound mechanistic approach for designing next generation Si thin film anodes with improved capacity retention. Ó 2013 Elsevier B.V. All rights reserved. 1. Introduction Lithium-ion batteries (LIBs) at present are widely considered as the flagship energy storage system for a variety of portable con- sumer electronic devices and transportation systems. Sony intro- duced first commercial LIB based on LiCoO 2 and carbon anode in 1991 to be used primarily in portable consumer electronic devices. Since then, the LIB system and the area in general, has witnessed tremendous research activity focused at primarily improving the capacity and cycling performance to support the increasing energy storage demands of new and emerging portable and consumer electronic devices, while extending its application to transportation systems. Accordingly, the application of LIBs today extends exclu- sively not only to laptops, camcorders and cameras but also to smart cellular phones, hybrid and plug-in electric vehicles (HEV’s, PHEVs), all electric vehicles (EVs), as well as several advanced aerospace applications. The current universally accepted energy * Corresponding author. Department of Bioengineering, University of Pittsburgh, Pittsburgh PA 15261, USA. Tel.: þ1 412 624 4240; fax: þ1 412 383 8788. E-mail address: spm54@pitt.edu (S. Maiti). Contents lists available at SciVerse ScienceDirect Journal of Power Sources journal homepage: www.elsevier.com/locate/jpowsour 0378-7753/$ e see front matter Ó 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jpowsour.2013.06.089 Journal of Power Sources 246 (2014) 149e159