Details

Autor(en) / Beteiligte

• Liu, Haodong
• Holoubek, John
• Zhou, Hongyao
• Chen, Amanda
• Chang, Naijen
• Wu, Zhaohui
• Yu, Sicen
• Yan, Qizhang
• Xing, Xing
• Li, Yejing
• Pascal, Tod A.
• Liu, Ping

Titel

Ultrahigh coulombic efficiency electrolyte enables Li||SPAN batteries with superior cycling performance

Ist Teil von

• Materials today (Kidlington, England), 2021-01, Vol.42 (C), p.17-28

Ort / Verlag

United Kingdom: Elsevier Ltd

Erscheinungsjahr

2021

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• This novel electrolyte stabilizes both lithium metal anode and SPAN cathode for high energy density batteries with low cost. [Display omitted] Raising the coulombic efficiency of lithium metal anode cycling is the deciding step in realizing long-life rechargeable lithium batteries. Here, we designed a highly concentrated salt/ether electrolyte diluted in a fluorinated ether: 1.8 M LiFSI in DEE/BTFE (diethyl ether/bis(2,2,2-trifluoroethyl)ether), which realized an average coulombic efficiency of 99.37% at 0.5 mA cm−2 and 1 mAh cm−2 for more than 900 cycles. This electrolyte also maintained a record coulombic efficiency of 98.7% at 10 mA cm−2, indicative of its ability to provide fast-charging with high cathode loadings. Morphological studies reveal dense, dendrite free Li depositions after prolonged cycling, while surface analyses confirmed the formation of a robust LiF-rich SEI layer on the cycled Li surface. Moreover, we discovered that this ether-based electrolyte is highly compatible with the low-cost, high-capacity SPAN (Sulfurized polyacrylonitrile) cathode, where the constructed Li||SPAN cell exhibited reversible cathode capacity of 579 mAh g−1 and no capacity decay after 1200 cycles. A cell where a high areal loading SPAN electrode (>3.5 mAh cm−2) is paired with only onefold excess Li was constructed and cycled at 1.75 mA cm−2, maintaining a coulombic efficiency of 99.30% for the lithium metal. Computational simulations revealed that at saturation, the Li-FSI complex forms contact ion pairs, with a first solvation shell comprising DEE molecules, and a second solvation shell with a mix of DEE/BTFE. This study provides a path to enable high energy density Li||SPAN batteries with stable cycling.