Phase transformations with stress generations in electrochemical reactions of electrodes: Mechanics-based multiscale model for combined-phase reactions

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• 作者：Jin-Myoung Lim^a ; Kyeongjae Cho^a ; ^b ; ^c ; Maenghyo Cho^a ; ^{mhcho@snu.ac.kr}
• 关键词：Multiscale mechanics ; Combined-phase reaction ; First-principles ; Electrochemical phase transformation ; Stress generation
• 刊名：Extreme Mechanics Letters
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：11
• 期：Complete
• 页码：89-95
• 全文大小：1411 K
• 卷排序：11

文摘

Phase transformations in most electrodes used for electrochemical energy storages follow the conserved dynamics of combined one- and two-phase reactions, which leads to complicated charge–discharge processes with various voltage plateaus; this could affect an electrochemical performance as a generic phenomenon in electrochemical system. In order to fully describe the combined-phase reactions from the atomic scale to the mesoscale, we propose a multiscale-based phase transformation model that also considers electrochemical states and mechanical deformations. This model predicts the miscibility gap, spinodal region, voltage profile, phase transformation, and stress generations of the combined-phase electrodes in the electrochemical reactions. We apply this multiscale model to high-rate cathode material LixxFePO44 to fundamentally understand the experimental phase transformation behaviors (Yamada et al., 2006). This model is applicable to various electrodes for phase behaviors too complex to be detected experimentally due to combined-phase reactions.