Avoiding Fracture in a Conversion Battery Material through Reaction with Larger Ions
Avoiding Fracture in a Conversion Battery Material through Reaction with Larger Ions
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DOI：
10.1016/j.joule.2018.05.015
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发表时间：
2018-09-19
期刊：
影响因子：
39.8
通讯作者：
McDowell, Matthew T.
中科院分区：
文献类型：
--
作者：
Boebinger, Matthew G.;Yeh, David;McDowell, Matthew T.
转化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，但与锂反应相比，较大的体积变化被认为限制了循环能力。然而，许多材料与Na+和K+的反应机制是未知的，这一知识是工程机械弹性材料的关键。在这里，原位透射电子显微镜用于揭示FeS2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+的转化反应期间体积变化较大，但FeS2晶体仅在锂化期间断裂。反应诱导变形的建模表明，两相反应前沿的形状影响应力演化，锂化过程中的独特行为导致应力集中和断裂。因此，Na离子和K离子电池材料中较大的体积变化可以通过理解和控制反应机制来管理，最终导致更好的碱离子电池。
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.