Speaker
Description
Due to the increased demand for electric vehicles with a longer range, lithium-ion batteries have been developed to increase the energy density. For the same reason, a higher proportion of silicon is gradually being introduced into the anode. However, only a small amount of silicon has been commercialized so far due to serious drawbacks such as initial lithium loss and drastic volume expansion upon cycling.
In order to overcome the downsides, pre-lithiation is regarded as an effective way especially to compensate for initial lithium loss. This is a strategy to store additional lithium in the electrode before the battery cell is assembled. For Si/graphite composite anodes, during the anode is pre-lithiated, it is critical to analyze which material intakes more lithium because it can influence the deterioration of the anode from a long-term perspective. Although it can play a critical role in the electrochemical performance of the battery, there are few systematic approaches to determine the ratio of the lithiation state between silicon and graphite.
Therefore, in this study, the lithium state of silicon and graphite of a composite electrode during pre-lithiation is investigated according to three different parameters: State of Charge (SoC), charge rate, and silicon content. The task includes the prediction of the lithium state of Si and graphite based on modeling after measuring the main parameters from the electrochemical experiments. Appropriate analytical methods (e.g., Raman, NMR, or XRD) will then be applied to investigate the results from the modeling. After modeling, a real experiment for verification will be tried as well.
While working on the project, a deep understanding of LIB operating mechanisms, modeling skills, and analytical methods is expected. In addition, practical laboratory skills and the ability to plan the design of experiments (DoE) will be increased.
References
[1] PEREIRA, Drew J., et al. A Mechano-Electrochemical Battery Model that Accounts for Preferential Lithiation Inside Blended Silicon Graphite (Si/C) Anodes. Journal of The Electrochemical Society, 2022, 169. Jg., Nr. 2, S. 020577.
| Keywords | Lithium-Ion battery, anode, silicon, modeling, pre-lithiation |
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