Aliphatic saturated sulfones C8-C10 as new electrolyte solvents for Li batteries

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Development of advanced electrolytes is critical for next-generation lithium batteries.
• Sulfone solvents offer high electrochemical and thermal stability, making them attractive candidates.
• Existing sulfones like sulfolane have limitations, necessitating exploration of alternatives.

Purpose of the Study:

• To investigate aliphatic non-cyclic sulfones (C8-C10) as novel electrolyte solvents for lithium batteries.
• To evaluate their physical properties, electrochemical stability, ionic conductivity, and thermal stability.
• To understand the oxidation mechanisms and Li+ solvation using computational methods.

Main Methods:

• Synthesis and characterization of C8-C10 aliphatic sulfones.
• Experimental determination of phase diagrams and eutectic points.
• Electrochemical stability window, ionic conductivity, and thermal stability measurements.
• Density functional theory (DFT) calculations for oxidation stability and solvation analysis.

Main Results:

• Synthesized sulfones (e.g., (i-C4H9)2SO2, (i-C5H11)2SO2) exhibit eutectic melting points below 0 °C.
• Experimental phase diagrams align with ideal solution models, enabling prediction for similar compounds.
• Electrolytes demonstrate good electrochemical stability, ionic conductivity, and thermal stability.
• DFT calculations provide insights into oxidation mechanisms and Li+ solvation shells.
• LiFePO4//Li cells show stable cycling at 75 °C with these electrolytes.

Conclusions:

• Aliphatic C8-C10 sulfones are viable candidates for lithium battery electrolytes due to favorable properties.
• The studied sulfones offer improved low-temperature performance compared to traditional sulfolane.
• These findings contribute to the development of safer and more efficient lithium battery systems.