Lithium Nitrate-Mediated Low-Volatile Deep Eutectic Electrolyte for Highly Stable Lithium-Oxygen Batteries.

Area of Science:

• Electrochemistry and Materials Science
• Advanced energy storage solutions

Background:

• Lithium-oxygen batteries (LOBs) offer high theoretical energy density but face challenges in semiopen systems.
• Issues include electrolyte volatilization, lithium metal anode instability (passivation/dendrites), and slow oxygen redox reactions.

Purpose of the Study:

• To propose a solvation structure regulated deep eutectic electrolyte (DEE) for LOBs.
• To address critical operational issues hindering the long-lasting performance of lithium-oxygen batteries.

Main Methods:

• Development of a deep eutectic electrolyte (DEE) with modulated LiNO3 content for interface stabilization.
• Fabrication and testing of Li/NMA-2.0/Li symmetric cells.
• Investigation of electrolyte properties, including high-temperature conductivity and solvation structure.
• Utilized systematic experiments and theoretical simulations to elucidate reaction mechanisms.

Main Results:

• Achieved over 700 hours of cycling stability in a Li/NMA-2.0/Li symmetric cell under a semiopen O2 atmosphere.
• Demonstrated stable operation in real air and over 100 cycles at 60 °C due to high-temperature electrolyte conductivity.
• Realized superlong cyclability of 779 cycles at 500 mA g-1 by lowering Li2O2 nucleation energy and forming nanoscale discharge products.

Conclusions:

• The proposed DEE effectively stabilizes the lithium metal anode and facilitates oxygen redox reactions in LOBs.
• This electrolyte design offers a promising pathway for developing stable and high-performance alkali-metal batteries in semiopen systems.
• The findings provide valuable guidance for designing advanced electrolytes for next-generation energy storage.