Enhancing the mechanical stability of composite electrodes by regulating the volume of active material using a prelithiation strategy
Enhancing the mechanical stability of composite electrodes by regulating the volume of active material using a prelithiation strategy
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DOI：
10.1016/j.est.2022.104390
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发表时间：
2022
影响因子：
9.4
通讯作者：
Xu Song;Yongjun Lu;Chao Li;Fenghui Wang;Xiang Zhao
中科院分区：
文献类型：
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作者：
Xu Song;Yongjun Lu;Chao Li;Fenghui Wang;Xiang Zhao
在锂/脱硫化循环过程中，合金和转换型负极材料的体积变化很大，这增加了组装具有高机械稳定性的复合电极的挑战。本文从理论上研究了在复合电极组装中应用预锂化化策略的可能性，通过控制活性物质的预体积膨胀来提高复合电极的机械稳定性。建立了一个包含描述不可逆体膨胀的内变量的化学-力学耦合模型来分析复合电极的微单元。模拟结果表明，边缘预硫化不能有效缓解高应力，而过度预硫化会增加损伤风险。最佳的预锂范围主要取决于活性物质在循环过程中的不可逆体积膨胀。对于不可逆体积膨胀为~40%的硅电极，最佳预锂化合成化学计量比数为0.3-0.6，理论预测与实验结果一致。理论模型和研究结果为基于力学方面的预硫化策略提供了更深层次的见解。
Significant volume variations in alloy-type and conversion-type anode materials during lithiation/delithiation cycling increase the challenge of assembling a composite electrode with high mechanical stability. This paper theoretically investigated the possibility of applying a prelithiation strategy to the assembly of a composite electrode to improve the mechanical stability of the composite electrode by controlling the pre-volume expansion of the active material. A chemo-mechanical coupled model containing an internal variable describing the irreversible volume dilation is developed to analyze a microunit of the composite electrode. Simulation results indicate that whereas a marginal prelithiation cannot effectively alleviate the high stress, and an excessive prelithiation increases the risk of damage. The optimal prelithiation range mainly depends on the irreversible volume dilation of the active material during cycling. For Si electrodes with the irreversible volume dilation of ~40%, the preferred prelithiation stoichiometric number is 0.3–0.6, the theoretical predictions are consistent with previous experimental results. The theoretical model and findings provide deeper insights on the prelithiation strategy based on the mechanical aspects.