Details

Autor(en) / Beteiligte

• Yang, Yangyuchen
• Davies, Daniel M.
• Yin, Yijie
• Borodin, Oleg
• Lee, Jungwoo Z.
• Fang, Chengcheng
• Olguin, Marco
• Zhang, Yihui
• Sablina, Ekaterina S.
• Wang, Xuefeng
• Rustomji, Cyrus S.
• Meng, Y. Shirley

Titel

High-Efficiency Lithium-Metal Anode Enabled by Liquefied Gas Electrolytes

Ist Teil von

• Joule, 2019-08, Vol.3 (8), p.1986-2000

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2019

Quelle

EZB-FREE-00999 freely available EZB journals

Beschreibungen/Notizen

• Among the several challenges to enable next-generation batteries is the development of an electrolyte that maintains a dendrite-free and high Coulombic efficiency lithium-metal anode over extended cell cycling. A new electrolyte solvation structure and transport mechanism is demonstrated in fluoromethane-based liquefied gas electrolytes with the introduction of additive amounts of tetrahydrofuran, which is shown to fully coordinate with the lithium cations and greatly enhance salt dissociation and transport. The resulting electrolyte shows a high conductivity and transference number (t+ > 0.79), which leads to a dramatic improvement of the cycling performance of the lithium-metal anode. Systems using the enhanced liquefied gas electrolytes demonstrate a long-term high average Coulombic efficiency of 99.6%, 99.4%, and 98.1% (± 0.3%) at capacities of 0.5, 1, and 3 mAh·cm−2, respectively, with dendrite-free morphology and remarkable rate capability. Both the rate and cycling performance are well maintained from +20°C to −60°C. [Display omitted] •Unique properties and solvation structures of liquefied gas electrolytes are shown•Compact Li-metal deposition with fluorinated interfaces are demonstrated•Electrolytes enable dendrite-free cycling with outstanding Coulombic efficiency•Excellent Li-metal cyclability and rate performance are shown down to −60°C The practical applications of lithium-metal batteries are hampered by incompatibilities between the lithium-metal anode and conventional electrolytes, resulting in dendrite growth and low Coulombic efficiency. With a new solvation mechanism, liquefied gas electrolytes with additive amounts of a fully coordinated cosolvent show improved salt solubility, high lithium transference numbers, and good conductivity. Because of the superior physical and chemical properties of this system, dendrite-free lithium-metal cycling with a high average Coulombic efficiency over 500 cycles of 99.6% was demonstrated. The lithium-metal cycling and rate performance is well maintained down to −60°C. Combining dendrite-free cyclability at high rates and over a wide temperature range, this study opens a promising avenue toward the applications of high-energy rechargeable lithium-metal batteries. A modified liquefied gas electrolyte with the addition of fully coordinated cosolvent enables unique Li solvation structures. Their favorable properties lead to dendrite-free high Coulombic efficiency Li-metal anode cycling and enable low-temperature operation even down to −60°C with high Li-metal efficiency. The system shows potential for improved energy density and low-temperature operation of Li-metal batteries.