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Avoiding Fracture in a Conversion Battery Material through Reaction with Larger Ions
Joule ( IF 39.8 ) Pub Date : 2018-06-19 , DOI: 10.1016/j.joule.2018.05.015
Matthew G. Boebinger , David Yeh , Michael Xu , B. Casey Miles , Baolin Wang , Marc Papakyriakou , John A. Lewis , Neha P. Kondekar , Francisco Javier Quintero Cortes , Sooyeon Hwang , Xiahan Sang , Dong Su , Raymond R. Unocic , Shuman Xia , Ting Zhu , Matthew T. McDowell

Conversion and alloying electrode materials offer high specific capacity for emerging sodium- and potassium-ion batteries, but the larger volume changes compared to reaction with lithium are thought to limit cyclability. The reaction mechanisms of many materials with Na+ and K+ are unknown, however, and this knowledge is key for engineering mechanically resilient materials. Here, in situ transmission electron microscopy is used to uncover the nanoscale transformations during the reaction of FeS2 electrode materials with Li+, Na+, and K+. Surprisingly, despite larger volume changes during the conversion reaction with Na+ and K+, the FeS2 crystals only fracture during lithiation. Modeling of reaction-induced deformation shows that the shape of the two-phase reaction front influences stress evolution, and unique behavior during lithiation causes stress concentrations and fracture. The larger volume changes in Na- and K-ion battery materials may therefore be managed through understanding and control of reaction mechanisms, ultimately leading to better alkali-ion batteries.



中文翻译:

避免与更大离子发生反应而导致转换电池材料破裂

转换和合金化电极材料为新兴的钠离子和钾离子电池提供了高比容量,但是与与锂反应相比,更大的体积变化被认为限制了可循环性。但是,许多材料与Na +和K +的反应机理尚不清楚,因此,该知识对于工程机械弹性材料至关重要。在这里,原位透射电子显微镜用于揭示FeS 2电极材料与Li +,Na +和K +反应期间的纳米级转变。令人惊讶的是,尽管在与Na +和K的转化反应过程中体积发生了较大变化+,FeS 2晶体仅在锂化过程中破裂。反应诱发变形的建模表明,两相反应前沿的形状会影响应力的演化,而锂化过程中的独特行为会导致应力集中和断裂。因此,可以通过了解和控制反应机理来控制Na和K离子电池材料的较大体积变化,最终导致更好的碱离子电池。

更新日期:2018-06-19
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