Numerical investigation on structural evolution and mechanical behaviour of amorphous silicon Li ion battery anodes

Sitinamaluwa, Hansinee and Wang, Mingchao and Will, Geoffrey and Senadeera, Wijitha and Ling, Ming and Zhang, Shanqing and Yan, Cheng (2015) Numerical investigation on structural evolution and mechanical behaviour of amorphous silicon Li ion battery anodes. In: 9th International Mesostructured Materials Symposium (IMMS-9), 17-20 Aug 2015, Brisbane, Australia.

Abstract

Silicon (Si) is widely regarded as one of the most promising anode materials for Li ion battery (LIB) due to its high theoretical specific capacity. However, the volume change (~300%) during lithiation/delithiation results in poor mechanical integrity, which impedes its commercialization. To address this issue, a better understanding of the atomistic mechanisms behind lithiation is necessary. In this work, the atomic structure and stress evolution during lithiation/delithiation was investigated on an amorphous silicon film (2.7 nm) using molecular dynamics. Steep stress gradients were observed when the lithium content in the anode is very low (<Li0.5Si). Plastic flow and stress relaxation are dominant in higher Li concentrations. The microstructure evolution during lithiation process is associated with the break of covalent amorphous structure into small clusters, when Li concentration exceeds ~Li0.5Si. At a low Li concentration, the sharp stress increase is due to the elastic deformation of the covalent Si lattice. The Radial Distribution Function (RDF) analysis revealed a defective amorphous structure in silicon film after a complete lithiation/delithiation cycle, which is attributed to breaking down of covalent silicon network and subsequent plastic flow. These results are believed to be able to help improve the materials selection and design of next generation Li ion battery.


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Item Type: Conference or Workshop Item (Commonwealth Reporting Category E) (Poster)
Refereed: Yes
Item Status: Live Archive
Additional Information: Poster. c. 2016 QUT.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering
Date Deposited: 06 Oct 2017 05:55
Last Modified: 14 Nov 2017 02:49
Uncontrolled Keywords: Li ion battery, anode, mechanical behaviour
Fields of Research : 09 Engineering > 0913 Mechanical Engineering > 091305 Energy Generation, Conversion and Storage Engineering
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
URI: http://eprints.usq.edu.au/id/eprint/33174

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