Synthetic Sweeteners as Novel CEI-Stabilizing Electrolyte Additives for Li-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Next-generation lithium-ion batteries require cost-effective electrolyte additives for stable high-rate cycling.
• Electrode/electrolyte interface stabilization is crucial for battery longevity and performance.

Purpose of the Study:

• To investigate the efficacy of food-grade synthetic sweeteners, lithium acesulfame (AceLi) and lithium saccharinate (SachLi), as electrolyte additives for LCO cathodes.
• To evaluate the impact of these additives on the stability and high-rate performance of lithium-ion batteries.

Main Methods:

• Galvanostatic cycling at variable C-rates and long-term cycling under stable C-rates.
• Electrochemical impedance spectroscopy (EIS) to analyze interfacial properties.
• X-ray photoelectron spectroscopy (XPS) to characterize the cathode-electrolyte interphase (CEI).

Main Results:

• Low to moderate concentrations (optimal near 0.2 wt.%) of AceLi and SachLi significantly improved discharge capacity retention at high C-rates.
• XPS analysis revealed additive-specific decomposition products in the CEI, including sulfur, nitrogen, and lithium carbonate species.
• The formation of a protective CEI layer was confirmed, correlating with enhanced high-rate performance.

Conclusions:

• Synthetic sweeteners AceLi and SachLi are effective, inexpensive electrolyte additives for enhancing lithium-ion battery performance.
• These additives promote the formation of a stable and protective cathode-electrolyte interphase, crucial for high-rate cycling.
• The use of readily available, food-grade materials offers a promising pathway for developing advanced lithium-ion battery electrolytes.