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Limiting anode utilization: A strategy to increase Si content and useable capacity in Si/C composite anode without compromising cycle life
Electrochimica Acta ( IF 5.5 ) Pub Date : 2023-02-26 , DOI: 10.1016/j.electacta.2023.142105
M.K.S. Verma , R.S. Patil , S. Bharathraj , S.P. Adiga , K.S. Mayya

Despite having a high theoretical capacity, silicon-based anodes fall short in providing practical and cycle-stable specific capacity close to the theoretical potential. The main challenge, namely particle pulverization and loss of mechanical integrity due to a large volume expansion, is commonly addressed by nano-structuring and blending with graphite in a Si/C composite anode. However, a maximum Si content of 15% in Si/C composite anodes has been realized, leaving scope for much improvement. Herein we discuss and theoretically benchmark a new strategy to increase Si content and achievable specific capacity by limiting anode utilization to minimize degradation. Through careful consideration to differential rates of lithiation of Si and C, particle fracture, and electrode swelling limit, our physical analysis suggests that this strategy could provide specific capacities of greater than 1100 Ah/Kg while eliminating degradation. These benchmarks are arrived at though a comprehensive analysis of lithiation of Si and C on an individual component level and the associated propensity for Si particle fracture as well as reduction in electrode porosity due to volume expansion and arriving at safe lithiation limits for a given set of electrode parameters under consideration. Since this safe range of operation is dependent on particle size, we show that we can optimize the Si% in Si/C to achieve maximum utilizable specific capacity for a given particle size.



中文翻译:

限制阳极利用率:一种在不影响循环寿命的情况下增加 Si/C 复合阳极中 Si 含量和可用容量的策略

尽管具有很高的理论容量,但硅基负极在提供接近理论潜力的实用和循环稳定的比容量方面存在不足。主要挑战,即由于大体积膨胀导致的颗粒粉碎和机械完整性损失,通常通过纳米结构化和在 Si/C 复合阳极中与石墨混合来解决。然而,Si/C 复合阳极中的最大 Si 含量已达到 15%,还有很大的改进空间。在这里,我们讨论并从理论上对一种新策略进行基准测试,该策略通过限制阳极利用率以最大程度地减少退化来增加 Si 含量和可实现的比容量。通过仔细考虑 Si 和 C 的不同锂化速率、颗粒断裂和电极溶胀极限,我们的物理分析表明,这种策略可以提供大于 1100 Ah/Kg 的比容量,同时消除降解。这些基准是通过对单个组分水平上的 Si 和 C 的锂化和相关的 Si 颗粒断裂倾向以及由于体积膨胀导致的电极孔隙率降低和达到给定组的安全锂化极限的综合分析得出的。正在考虑的电极参数。由于此安全操作范围取决于粒径,我们表明我们可以优化 Si/C 中的 Si%,以实现给定粒径的最大可利用比容量。这些基准是通过对单个组分水平上的 Si 和 C 的锂化和相关的 Si 颗粒断裂倾向以及由于体积膨胀导致的电极孔隙率降低和达到给定组的安全锂化极限的综合分析得出的。正在考虑的电极参数。由于此安全操作范围取决于粒径,我们表明我们可以优化 Si/C 中的 Si%,以实现给定粒径的最大可利用比容量。这些基准是通过对单个组分水平上的 Si 和 C 的锂化和相关的 Si 颗粒断裂倾向以及由于体积膨胀导致的电极孔隙率降低和达到给定组的安全锂化极限的综合分析得出的。正在考虑的电极参数。由于此安全操作范围取决于粒径,我们表明我们可以优化 Si/C 中的 Si%,以实现给定粒径的最大可利用比容量。

更新日期:2023-02-26
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