Modeling the delamination of amorphous-silicon thin film anode for lithium-ion battery

• Published in: Journal of power sources Vol. 246; pp. 149 - 159
• Main Authors: PAL, Siladitya, DAMLE, Sameer S, PATEL, Siddharth H, DATTA, Moni K, KUMTA, Prashant N, MAITI, Spandan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 2014
• Subjects: Accumulators; Anodes; Applied sciences; Collectors; Delaminating; Delamination; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Lithium-ion batteries; Materials; Mechanical properties; Silicon; Thin films; Lithium ion batteries; Amorphous thin film; Anode; Li-ion battery; Mechanical properties; Diffusion induced stress (DIS); Secondary cell; Electrode material; Modeling; Stress; Transport process; Interfacial delamination; Current collector; Current collection; Thin layer electrode; a-Si thin film anode; Silicon; Diffusion; Delamination
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.06.089

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 film-current 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 film-current 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.