Wang Yingli, Liu Fangming, Fan Guilan, Qiu Xiaoguang, Liu Jiuding, Yan Zhenhua, Zhang Kai, Cheng Fangyi, Chen Jun
College of Chemistry, Nankai University, Tianjin 300071, P. R. China.
Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Research Center of High-Efficiency Energy Storage (Ministry of Education), College of Chemistry, Nankai University, Tianjin 300071, P. R. China.
J Am Chem Soc. 2021 Feb 24;143(7):2829-2837. doi: 10.1021/jacs.0c12051. Epub 2021 Feb 15.
Engineering a stable solid electrolyte interphase (SEI) is one of the critical maneuvers in improving the performance of a lithium anode for high-energy-density rechargeable lithium batteries. Herein, we build a fluorinated lithium/sodium hybrid interphase via a facile electroless electrolyte-soaking approach to stabilize the repeated plating/stripping of lithium metal. Jointed experimental and computational characterizations reveal that the fluorinated hybrid SEI mainly consisting of NaF, LiF, LiPOF, and organic components features a mosaic polycrystalline structure with enriched grain boundaries and superior interfacial properties toward Li. This LiF/NaF hybrid SEI exhibits improved ionic conductivity and mechanical strength in comparison to the SEI without NaF. Remarkably, the fluorinated hybrid SEI enables an extended dendrite-free cycling of metallic Li over 1300 h at a high areal capacity of 10 mAh cm in symmetrical cells. Furthermore, full cells based on the LiFePO cathode and hybrid SEI-protected Li anode sustain long-term stability and good capacity retention (96.70% after 200 cycles) at 0.5 C. This work could provide a new avenue for designing robust multifunctional SEI to upgrade the metallic lithium anode.
构建稳定的固体电解质界面（SEI）是提高高能密度可充电锂电池锂负极性能的关键措施之一。在此，我们通过一种简便的化学镀电解液浸泡方法构建了一种氟化锂/钠混合界面，以稳定锂金属的反复镀覆/剥离。联合实验和计算表征表明，主要由NaF、LiF、LiPOF和有机成分组成的氟化混合SEI具有镶嵌多晶结构，晶界丰富，对Li具有优异的界面性能。与不含NaF的SEI相比，这种LiF/NaF混合SEI表现出更高的离子电导率和机械强度。值得注意的是，在对称电池中，氟化混合SEI能够使金属Li在10 mAh cm的高面积容量下实现超过1300 h的无枝晶循环。此外，基于LiFePO正极和混合SEI保护的Li负极的全电池在0.5 C下保持长期稳定性和良好的容量保持率（200次循环后为96.70%）。这项工作可为设计坚固的多功能SEI以升级金属锂负极提供一条新途径。
