On the Role of Mechanics in the Design and Performance of Electrode Materials for Energy Storage
Event details
| Date | 22.05.2012 |
| Hour | 13:15 › 14:15 |
| Speaker | Prof. Pradeep Guduru, Brown University, USA |
| Location | |
| Category | Conferences - Seminars |
The increasing interest in employing alternative energy sources, especially for transportation applications, led to a large scale national effort in recent years towards developing electrochemical energy storage systems (batteries) with significantly higher energy density and cycle-life compared to the prevailing technologies. The performance of the new classes of materials being developed/considered is severely limited by the mechanical degradation that accumulates during operation, which is a main impediment that needs to be overcome. This talk focuses on the mechanics issues in silicon, which is considered to be a promising anode material to increase the specific energy of lithium-ion batteries by as much as 30%. For accurate modeling of battery performance, cycle life and reliability, there is a need to understand the failure modes and how mechanical fields influence electrochemical response. Our experiments show that lithiated silicon is capable of undergoing large plastic deformation in constrained geometries; the ability to undergo plastic deformation underpins the failure behavior in all silicon anode architectures. An analysis of the dependence of electric potential on the state of stress of a lithiated-silicon electrode is also presented. Based on the Larche and Cahn chemical potential for a solid solution, a thermodynamic argument is made for the existence of a stress-potential coupling in lithiated-silicon, the magnitude of which is estimated to be ~ 60 mV/GPa. The analysis was validated by an accompanying experimental investigation that measured the coupling to be around 100 mV/GPa. The implications of the stress-potential coupling to Li plating and safety are discussed. We also present an experimental method to measure average stress fields in practical electrode microstructures during electrochemical cycling.
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Practical information
- General public
- Free
Organizer
- IGM