Graphite anodes with a solvent co-intercalation mechanism exhibit excellent kinetics and cycling stability in sodium-ion batteries. However, the dramatic volume changes caused by solvent participation are challenging for interphasial conformality. Herein, we reveal the intercalation compound degradation and solid electrolyte interphase (SEI) evolution of graphite at different sodiated states via capacity loss and fluctuation of Coulombic efficiency (CE) induced by calendar aging. Abnormal calendar aging dependent on sodiated states is found, and it appears as more severe capacity loss and lower CE in partially sodiated graphite anodes. The deteriorated performance results from its high-staged intercalated phase transition accompanied by huge volume shrinkage. Under the effect of intercalation degradation, the growth and destruction of SEI coexist on the partially sodiated graphite, whereas growth-dominated SEI is found on fully sodiated graphite. Using X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) spectroscopy, we distinguished that the evolution of ether-derived SEI is dominated by alkoxides. These findings reveal the abnormal calendar aging of a graphite anode in an ether system, providing new insights into its interphasial stability.

中文翻译：

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日历老化过程中石墨阳极上钠共插化学和醚衍生界面的降解

具有溶剂共插机制的石墨负极在钠离子电池中表现出优异的动力学和循环稳定性。然而，溶剂参与引起的剧烈体积变化对相间共形性提出了挑战。在此，我们通过日历老化引起的容量损失和库仑效率（CE）波动揭示了不同钠化状态下石墨的插层化合物降解和固体电解质界面（SEI）演变。发现了依赖于钠化状态的异常日历老化，并且在部分钠化的石墨阳极中表现为更严重的容量损失和更低的CE。性能恶化是由于其高阶段插层相变伴随着巨大的体积收缩。在插层降解的影响下，部分钠化石墨上SEI的生长和破坏同时存在，而全钠化石墨上SEI以生长为主。使用 X 射线光电子能谱 (XPS) 和核磁共振 (NMR) 光谱，我们发现醚衍生的 SEI 的演化主要是醇盐。这些发现揭示了醚体系中石墨阳极的异常日历老化，为其间相稳定性提供了新的见解。