Stable Harsh-Temperature Lithium Metal Batteries Enabled by Tailoring Solvation Structure in Ether Electrolytes

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• High operating temperatures in lithium metal batteries (LMBs) cause capacity fade and safety concerns due to unstable interfaces and electrolyte structures.
• Developing advanced electrolytes is critical for stable LMB operation under demanding conditions.

Purpose of the Study:

• To design a stable localized high-concentration electrolyte (LHCE) using diethylene glycol dimethyl ether (DGDME) for high-temperature LMBs.
• To investigate the electrolyte's ability to form stable electrode-electrolyte interphases and improve battery performance.

Main Methods:

• Computational modeling and experimental validation were used to characterize the DGDME-LHCE.
• Electrochemical testing of Li||Li and Li||NCM523 cells at elevated temperatures (60 °C) and high voltages (4.5 V).

Main Results:

• The DGDME-LHCE exhibits high Li+-binding stability, electro-oxidation resistance, thermal stability, and nonflammability.
• A tailored solvation structure promotes stable interphases on both cathode and Li anode, ensuring uniform Li plating/stripping and high-voltage tolerance.
• Li||Li cells demonstrated over 1900 hours of lifespan, while Li||NCM523 cells showed 95.59% capacity retention over 250 cycles with >99.88% Coulombic efficiency.

Conclusions:

• The DGDME-LHCE offers a promising solution for high-temperature LMBs by enhancing interfacial stability and electrochemical performance.
• This ether electrolyte strategy provides a pathway for developing robust LMBs that can withstand stringent high-temperature operational challenges.