Understanding dynamic fluctuations in complex multi-physics fields at the electrolyte/electrode interface is crucial for explaining the lithium deposition mechanism and developing efficient interface structures, but there are significant challenges. Here, we introduce an internal standard substance (1,1,2, 2-tetrafluoroethyl-2,2,3, 3-tetrafluoropropyl ether (TTE)) to propose a quantitative in-situ Raman spectroscopy method to disclose the variation of interfacial concentration filed. It is proved that the formation of anion depletion layer at the electrolyte/electrode interface during lithium deposition leads to the formation of space charge layer (SCL) with local electric field, which can accelerate dendrite growth and is closely related to the withdrawth of anion from interface. Further, a high anion-concentration interface (HACI) with immobilized anions is proposed. This HACI can effectively prevents the anion depletion at interface and enhance the interfacial Li+ transference number from 0.30 to 0.57, thus alleviating formation of SCL and facilitating uniform lithium deposition. Hence, the full cell with high-load NCM523 cathode (~14 mg cm-2) and limited HACI@Li anode (~50 μm) delivers excellent cycling over 200 cycles with a high discharge capacity retention of 77.6 % (~125.7 mAh g-1). This offers critical insights for designing lithium battery systems from the perspective of multi-physics field.

中文翻译：

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优化界面浓度和电场以增强锂金属阳极的锂沉积行为


了解电解质/电极界面复杂多物理场的动态波动对于解释锂沉积机制和开发有效的界面结构至关重要，但也存在重大挑战。在这里，我们引入内标物质（1,1,2,2-四氟乙基-2,2,3,3-四氟丙醚（TTE）），提出一种定量的原位拉曼光谱方法来揭示界面浓度的变化提交。事实证明，锂沉积过程中电解质/电极界面处阴离子耗尽层的形成导致具有局域电场的空间电荷层（SCL）的形成，可以加速枝晶的生长，并且与阴离子从电极中的撤出密切相关。界面。此外，还提出了一种固定阴离子的高阴离子浓度界面（HACI）。这种HACI可以有效防止界面阴离子耗尽，并将界面Li+迁移数从0.30提高到0.57，从而减轻SCL的形成并促进均匀的锂沉积。因此，具有高负载 NCM523 阴极 (~14 mg cm-2) 和有限 HACI@Li 阳极 (~50 μm) 的全电池可提供超过 200 个循环的优异循环性能，放电容量保持率为 77.6 % (~125.7 mAh g) -1）。这为从多物理领域的角度设​​计锂电池系统提供了重要的见解。