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Fluorine-Rich Electrolyte Additive for Achieving Dendrite-Free Lithium Anodes at Low Temperatures
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2024-08-30 , DOI: 10.1021/acsami.4c10028
Yan Wang 1 , Longtao Ren 1 , Qiaoli Zhang 1 , Abdul Hameed Pato 1 , Jun Liu 1 , Xiwen Lu 1 , Wen Liu 1
Affiliation  

The practical application of lithium metal anodes is significantly impeded by poor interfacial stability and uncontrolled dendrite growth. Herein, we introduce methyl trifluoroacetate (MTFA), a low-melting-point small molecule, as an electrolyte additive in an ether-based electrolyte. This additive facilitates the formation of an in situ composite solid electrolyte interphase (SEI) layer that is rich in LiF and features an ester-based flexible matrix. The resulting composite layer exhibits high ionic conductivity and mechanical stability, effectively regulating the lithium deposition behavior over a broad temperature range and inhibiting dendrite formation. Based on MTFA, the Li||Li symmetrical cell achieves a lifespan exceeding 5000 h at room temperature and 800 h at −20 °C, both with ultralow overpotential and exceptional cycling stability. In Li||LiFePO4 full cells with a high-area loading (10.52 mg cm–2) and an N/P ratio of 1.68, an average capacity decay of merely 0.096% per cycle is observed over 200 cycles. Even at −20 °C, the Li||LiFePO4 cell shows a CE of over 99% and maintains stable cycling performance. This work provides an innovative approach for optimizing lithium metal anode interfaces and enhancing low-temperature operation capabilities through the use of electrolyte additives.

中文翻译:


用于在低温下实现无枝晶锂阳极的富氟电解质添加剂



界面稳定性差和枝晶生长失控严重阻碍了锂金属负极的实际应用。在这里,我们引入了低熔点小分子三氟乙酸甲酯(MTFA)作为醚基电解液中的电解液添加剂。这种添加剂有助于原位复合固体电解质中间相 (SEI) 层的形成,该层富含 LiF,并具有酯基柔性基质。所得复合层表现出高离子电导率和机械稳定性,可在较宽的温度范围内有效调节锂沉积行为并抑制枝晶形成。基于MTFA,Li||Li对称电池在室温下的寿命超过5000小时,在-20℃下的寿命超过800小时,同时具有超低的过电位和出色的循环稳定性。在具有高面积负载(10.52 mg cm –2 )和N/P比为1.68的Li||LiFePO 4全电池中,在200个循环中观察到每个循环的平均容量衰减仅为0.096%。即使在-20°C下,Li||LiFePO 4电池的CE也超过99%,并保持稳定的循环性能。这项工作为优化锂金属阳极界面并通过使用电解质添加剂增强低温运行能力提供了一种创新方法。
更新日期:2024-08-30
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