A Non-Expendable Leveler as Electrolyte Additive Enabling Homogenous Lithium Deposition.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium metal anodes offer high energy density for batteries.
• Lithium dendrite growth poses significant safety risks, hindering practical applications.

Purpose of the Study:

• To investigate 4,6-dimethyl-2-mercaptopyrimidine (DMP) as a functional additive to suppress lithium dendrite formation.
• To evaluate the performance and protective mechanism of DMP in lithium metal batteries.

Main Methods:

• Systematic investigation of various lithium-metal-based battery configurations (Li||Li and Li||Cu cells).
• Electrochemical performance testing including cycling stability and coulombic efficiency measurements.
• Analysis of the protective mechanism of DMP on the lithium anode surface.

Main Results:

• DMP additive demonstrated excellent cycling stability (>800 h at 3 mA cm⁻²) in Li||Li cells.
• Li||Cu cells exhibited stable performance for 400 cycles with high coulombic efficiencies (>98%).
• DMP modifies Li⁺ solvation structure and forms a planar molecular layer on the Li anode, inducing homogeneous deposition via steric hindrance.

Conclusions:

• DMP effectively suppresses lithium dendrites and improves the safety and stability of lithium metal batteries.
• The mechanism involves altering the Li⁺ solvation and surface deposition behavior without participating in solid electrolyte interphase formation.
• DMP offers a promising strategy for developing high-performance lithium metal batteries using non-depleting electrolyte additives.