Discharge Performance of Li鈥揙2 Batteries Using a Multiscale Modeling Approach

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• 作者：Jie Bao ; Wu Xu ; Priyanka Bhattacharya ; Mark Stewart ; Ji-Guang Zhang ; Wenxiao Pan
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：July 9, 2015
• 年：2015
• 卷：119
• 期：27
• 页码：14851-14860
• 全文大小：745K
• ISSN：1932-7455

文摘

To study the discharge performance of Li鈥揙₂ batteries, we propose a multiscale modeling framework that links models in an upscaling fashion from the nanoscale to mesoscale and finally to the device scale. We have effectively reconstructed the microstructure of a Li鈥揙₂ air electrode in silico, conserving the porosity, surface-to-volume ratio, and pore size distribution of the real air electrode structure. The mechanism of rate-dependent morphology of Li₂O₂ growth is incorporated into the mesoscale model. The correlation between the active-surface-to-volume ratio and averaged Li₂O₂ concentration is derived to link different scales. The proposed approach鈥檚 accuracy is first demonstrated by comparing the predicted discharge curves of Li鈥揙₂ batteries with experimental results at the high current density. Next, the validated modeling approach effectively captures the significant improvement in discharge capacity due to the formation of Li₂O₂ particles. Finally, it predicts the discharge capacities of Li鈥揙₂ batteries with different air electrode microstructure designs and operating conditions.