Modification of Nitrate Ion Enables Stable Solid Electrolyte Interphase in Lithium Metal Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• High-energy-density lithium metal batteries (LMBs) face lifespan limitations due to heterogeneous solid electrolyte interphase (SEI) formation.
• Uniform SEI is crucial for stable cycling and longevity in LMBs.
• Current electrolyte designs often fail to achieve homogeneous SEI layers.

Purpose of the Study:

• To develop a novel electrolyte additive for improving SEI homogeneity in LMBs.
• To investigate the impact of modified nitrate ions on SEI formation and lithium deposition.
• To enhance the performance and stability of practical lithium-sulfur batteries.

Main Methods:

• Modification of nitrate ions (NO3-) by connecting to an ether-based moiety to form isosorbide dinitrate (ISDN).
• Analysis of ISDN's effect on breaking the resonance structure of NO3- and improving reducibility.
• Evaluation of SEI composition, including LiNxOy enrichment, using ISDN.
• Testing of lithium-sulfur batteries and pouch cells with ISDN additives for capacity retention and specific energy.

Main Results:

• ISDN effectively breaks the resonance structure of NO3-, leading to improved reducibility.
• The decomposition of non-resonant NO3- in ISDN enriches the SEI with LiNxOy, promoting uniform lithium deposition.
• Lithium-sulfur batteries with ISDN additives showed 83.7% capacity retention over 100 cycles, outperforming LiNO3.
• Lithium-sulfur pouch cells with ISDN achieved a specific energy of 319 Wh/kg and completed 20 cycles.

Conclusions:

• Isosorbide dinitrate (ISDN) is a promising additive for stabilizing lithium metal batteries.
• ISDN facilitates the formation of a uniform SEI layer, enhancing lithium deposition and battery cycle life.
• This approach offers a viable strategy for designing advanced electrolytes for high-performance energy storage systems.