In Situ Construction of Aramid Nanofiber Membrane on Li Anode as Artificial SEI Layer Achieving Ultra-High Stability,Small

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In Situ Construction of Aramid Nanofiber Membrane on Li Anode as Artificial SEI Layer Achieving Ultra-High Stability
Small ( IF 13.0 ) Pub Date : 2021-09-24 , DOI: 10.1002/smll.202102347
Shuai Zheng ₁ , HaiYan Zhang ₁ , JinChen Fan _{1,

2} , QunJie Xu _{1,

2} , YuLin Min _{1,

2}

Affiliation

Achieving uniform Li deposition is vital for the construction of a safe but also efficient Li-metal anode for Li-metal batteries (LMBs). Herein, a facile coating strategy is used for forming an ultra-thin aramid nanofiber (ANF) membrane, with a network structure, on a Li anode (ANF-Li) as an artificial layer inhibiting Li dendrite's growth. The results show that under an ultra-high current density of 50 mA cm⁻², the ANF-Li|ANF-Li symmetric cells can be kept stably cycled for a period exceeding 300 h. The ANF-Li|LiFePO₄ full cells exhibit a high-capacity retention of 80.1% after 1200 cycles at 1 C, showing a promising potential for LMBs application. Combined experimental results with theoretical calculations, the excellent performance of the ANF-Li anode is explored. Lithiophilic polar functional groups (CO, NH) appear in the surface and structure of ANF membrane, which offer high-concentration functional sites for the Li ions to realize an effective adhesion at the molecular level. This work also finds fiber-shaped lithium deposition for the first time. Furthermore, the nanoscale porosity of the ANF membrane not only provides fast pathways and channels for the diffusion of the electrolyte and Li transportation, but also eliminates the “weak links” of micron-scale Li dendrites penetrating the membrane.

中文翻译：

在锂阳极上原位构建芳纶纳米纤维膜作为人造SEI层实现超高稳定性

实现均匀的锂沉积对于构建安全且高效的锂金属电池 (LMB) 锂金属负极至关重要。在此，采用简便的涂层策略在锂负极 (ANF-Li) 上形成具有网络结构的超薄芳纶纳米纤维 (ANF) 膜，作为抑制锂枝晶生长的人工层。结果表明，在50 mA cm ^-2的超高电流密度下，ANF-Li|ANF-Li对称电池可以保持稳定循环超过300小时。ANF-Li|LiFePO ₄全电池在 1 C 下 1200 次循环后显示出 80.1% 的高容量保持率，显示出 LMB 应用的潜力。将实验结果与理论计算相结合，探索了 ANF-Li 负极的优异性能。Lithiophilic极性官能团（CO，N  1H）出现在ANF膜的表面和结构，其提供用于锂离子的高浓度的功能位点，实现在分子水平上有效的粘合性。这项工作还首次发现了纤维状锂沉积。此外，ANF 膜的纳米级孔隙率不仅为电解质的扩散和锂的运输提供了快速的途径和通道，而且消除了微米级锂枝晶穿透膜的“薄弱环节”。

更新日期：2021-11-04

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