Upgrading Ester-Based Electrolyte with LiNO₃ and GPE to Realize Dendrite-Free Lithium Deposition

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Interfacial degradation at lithium metal anodes (LMAs) hinders high-energy-density lithium metal batteries (LMBs) in ester-based electrolytes.
• Improving lithium nitrate (LiNO3) solubility is crucial for stable solid electrolyte interphase (SEI) formation.

Purpose of the Study:

• Investigate multivalent acrylates as co-solvents to enhance LiNO3 solubility.
• Develop a gel polymer electrolyte (GPE) for improved interfacial stability in LMBs.
• Enhance the performance and cycle stability of NCM622|Li cells.

Main Methods:

• Employed molecular dynamic simulations to understand Li+ solvation sheath modification.
• Synthesized a gel polymer electrolyte (GPE-7.5) using neopentyl glycol diacrylate and LiNO3.
• Utilized X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS) for SEI analysis.

Main Results:

• A positive correlation was found between carbonyl group number and LiNO3 dissolution.
• The GPE-7.5 facilitated the formation of an inorganic-rich SEI (LiF, Li3N) on LMAs.
• NCM622|GPE-7.5|Li cells exhibited exceptional cycle stability and high Coulombic efficiency.

Conclusions:

• Multivalent acrylates effectively improve LiNO3 solubility and promote stable SEI formation.
• The developed GPE strategy mitigates interfacial degradation and enables dendrite-free lithium deposition.
• This approach offers new insights for designing advanced high-energy-density lithium metal batteries.