Lithium dendrite growth is one of the most challenging problems affecting the safety performance of lithium‐ion batteries (LIBs). It causes low Coulombic efficiency as well as safety hazards for LIBs. Understanding the evolution process of Li‐dendrite growth at the nanoscale is critical for solving this problem. Herein, an in situ electrochemical atomic force microscopy (EC‐AFM) investigation of the initial Li deposition in ethylene carbonate (EC)‐based and fluoroethylene carbonate (FEC)‐based electrolytes on graphite anodes is reported. These results show that the solid electrolyte interphase (SEI) formed from the FEC‐based electrolyte can suppress Li‐dendrite growth. The FEC‐based electrolyte induces formation of LiF‐rich SEI films, which are harder and denser than those formed in an EC‐based electrolyte. Due to its better mechanical properties and larger resistance, the SEI layer formed from the FEC‐based electrolyte is sufficient to prevent reduction of Li⁺ ions and deposition of Li⁺ ions on the anode surface. These results demonstrate that EC‐AFM is a powerful in situ technique for the study of lithium‐dendrite growth.

中文翻译：

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通过Operando EC‐AFM直接观察石墨阳极上锂树枝状晶体的生长

锂枝晶的生长是影响锂离子电池（LIB）安全性能的最具挑战性的问题之一。它会导致库仑效率低下，并给LIB带来安全隐患。了解纳米尺度下锂树枝状晶体生长的演化过程对于解决该问题至关重要。本文报道了原位电化学原子力显微镜（EC-AFM）对石墨阳极上碳酸亚乙酯（EC）和碳酸氟亚乙酯（FEC）电解质中初始Li沉积的研究。这些结果表明，由基于FEC的电解质形成的固体电解质中间相（SEI）可以抑制Li-树突的生长。基于FEC的电解质会诱导形成富含LiF的SEI膜，该膜比在基于EC的电解质中形成的膜更硬，更致密。⁺离子和Li ⁺离子在阳极表面的沉积。这些结果表明，EC‐AFM是研究锂树枝状晶体生长的强大原位技术。