Electrochemically and Thermally Stable Inorganics-Rich Solid Electrolyte Interphase for Robust Lithium Metal...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium metal batteries offer high energy density but suffer from dendrite growth and poor safety, limiting their practical use.
• The lithium anode's high activity and dendrite formation are critical challenges for battery lifespan and safety.

Purpose of the Study:

• To develop a stable solid electrolyte interphase (SEI) on lithium metal anodes.
• To improve the electrochemical and thermal stability of lithium metal batteries.
• To enhance the safety and cycle life of high-energy-density lithium metal batteries.

Main Methods:

• Constructed an F-/N-containing inorganics-rich SEI using a trisalt electrolyte design.
• Investigated the electrochemical and thermal stability of the modified lithium anode.
• Fabricated and tested coin-type and pouch-type full cells with LiNi0.5Co0.2Mn0.3O2 cathodes.
• Performed thermal runaway tests on cycled pouch cells.

Main Results:

• The trisalt electrolyte enabled a stable, inorganic-rich SEI on the lithium anode.
• Maintained high Coulombic efficiency (>98.98%) over 400 cycles.
• Achieved 85.0% capacity retention in full cells after 200 cycles (coin) and 72 cycles (1.0 Ah pouch).
• Significantly enhanced thermal safety, increasing onset and triggering temperatures of thermal runaway by over 30°C.

Conclusions:

• The trisalt electrolyte and resulting SEI effectively suppress dendrite growth and improve lithium anode stability.
• This approach significantly enhances both the cycle life and thermal safety of lithium metal batteries.
• The findings provide a promising strategy for developing practical, high-performance, and safe lithium metal batteries.