Customized Solvation Structures for Long-Term Stable Lithium Metal Batteries.

Area of Science:

• Electrochemistry
• Materials Science

Background:

• Lithium metal batteries (LMBs) face challenges like lithium dendrite growth and side reactions in carbonate electrolytes, leading to low coulombic efficiency and poor cycling stability.
• Electrolyte engineering is crucial for enhancing the reversibility and performance of lithium anodes.

Purpose of the Study:

• To improve the interfacial chemistry of lithium metal anodes in LMBs.
• To enhance the stability and cycling life of lithium metal anodes through electrolyte modification.

Main Methods:

• Improving the solubility of lithium nitrate (LiNO3) in carbonate electrolytes by adding zinc trifluoroacetate (Zn(TFA)2).
• Constructing a competitive solvation structure with an anion-enriched Li+ solvation structure.
• Evaluating the performance of the modified electrolyte in lithium metal anodes and full cells.

Main Results:

• The modified electrolyte facilitated uniform lithium deposition and extended cycle life, achieving high reversibility over 640 hours of plating/stripping.
• Li||LFP full cells demonstrated stable operation for over 300 cycles at 1 C.
• Improved compatibility of the lithium anode with high-voltage NCM811 cathodes was observed.

Conclusions:

• The addition of Zn(TFA)2 to LiNO3 effectively enhances the stability of the solid electrolyte interphase (SEI) and suppresses side reactions.
• This electrolyte engineering strategy provides a feasible approach for developing dependable interfacial chemistry in lithium metal anodes.
• The findings contribute to the advancement of high-performance and long-lasting lithium metal batteries.