A Weakly Solvating Ether Electrolyte Enables Fast-Charging and Wide-Temperature Lithium-Ion Pouch Cells

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Graphite anodes in lithium-ion batteries face performance issues during fast charging and low temperatures.
• Traditional carbonated ester electrolytes exhibit slow desolvation kinetics, limiting charge rates.

Purpose of the Study:

• To design a novel ether electrolyte using tetrahydropyran (THP) for improved lithium-ion battery performance.
• To enable fast and reversible lithium-ion intercalation in graphite anodes.

Main Methods:

• Development of a weakly solvating ether electrolyte with THP as the solvent.
• Investigation of lithium-ion (Li+) desolvation kinetics and intercalation behavior with graphite.
• Electrochemical testing of lithium iron phosphate/graphite pouch cells with the THP electrolyte.

Main Results:

• The THP-based electrolyte demonstrates fast Li+ desolvation and efficient intercalation into graphite anodes.
• Cells with THP electrolyte show significantly improved capacity retention (80.3% after 500 cycles at 2C) compared to ester electrolytes (7.6% after 200 cycles).
• Enhanced discharging capacity (2.96 Ah vs 2.29 Ah at 4C) and stable operation across wide temperatures (-20 to 60 °C) were achieved.

Conclusions:

• The THP electrolyte design overcomes limitations of traditional electrolytes for fast charging and wide temperature applications.
• Weak Li+-THP interaction promotes an inorganic-rich interface, suppressing detrimental side reactions.
• This work offers insights into advanced electrolyte design for high-performance lithium-ion batteries.