Abstract

Graphite as a positive electrode material of dual ion batteries (DIBs) has attracted tremendous attentions for its advantages including low lost, high working voltage and high energy density. However, very few literatures regarding to the real-time observation of anion intercalation behavior and surface evolution of graphite in DIBs have been reported. Herein, we use in situ atomic force microscope (AFM) to directly observe the intercalation/de-intercalation processes of PF₆⁻ in graphite in real time. First, by measuring the change in the distance between graphene layers during intercalation, we found that PF₆⁻ intercalates in one of every three graphite layers and the intercalation speed is measured to be 2 µm·min⁻¹. Second, graphite will wrinkle and suffer structural damages at high voltages, along with severe electrolyte decomposition on the surface. These findings provide useful information for further optimizing the capacity and the stability of graphite anode in DIBs.

中文翻译：

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通过原位原子力显微镜揭示双离子电池中石墨的阴离子嵌入行为和表面演化

摘要

石墨作为双离子电池（DIB）的正极材料，因其低损耗，高工作电压和高能量密度等优点而备受关注。但是，关于DIB中石墨的阴离子嵌入行为和石墨表面演变的实时观察的文献很少。在此，我们使用原位原子力显微镜（AFM）直接观察到PF的嵌入/脱嵌过程₆ ^-石墨的实时性。首先，通过测量在插层中的石墨烯层之间的距离的变化，我们发现，PF ₆ ^-在每三个石墨层中的一个和所述插入速度插层被测量为2μm·分钟^-1。其次，石墨将起皱并在高压下遭受结构性损坏，同时电解质在表面上会严重分解。这些发现为进一步优化DIB中石墨阳极的容量和稳定性提供了有用的信息。