Gibbs Free Energy Regulation to Decrease Desolvation Barrier for Ultralow-Temperature Lithium Metal Batteries at...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium metal batteries (LMBs) suffer from poor lifespan at ultralow temperatures due to sluggish lithium-ion (Li) desolvation kinetics.
• Efficient Li-ion transport and uniform deposition are critical for stable LMB operation, especially under demanding thermal conditions.

Purpose of the Study:

• To enhance the desolvation kinetics of Li ions at electrode-electrolyte interfaces for improved LMB performance at low temperatures.
• To reduce the Gibbs free energy barrier for Li-ion desolvation by manipulating enthalpy and entropy changes.

Main Methods:

• Designed a Gibbs free energy-driven electrolyte with multiple anions to create complex solvation structures.
• Engineered weak ion-dipole interactions between Li ions and solvents to lower enthalpy change.
• Investigated the formation of inorganic-rich solid electrolyte interphase (SEI) induced by anions.

Main Results:

• Achieved rapid Li-ion desolvation by increasing entropy change (△S) and decreasing enthalpy change (△H).
• Demonstrated anion-induced SEI formation, promoting uniform Li deposition and enhanced plating kinetics at low temperatures.
• Maintained 95.5% capacity retention in Li||LiNi0.5Co0.2Mn0.3O2 cells after 210 cycles at -20°C with high cathode loading.
• Achieved 87.7% capacity retention after 220 cycles at -40°C.

Conclusions:

• The Gibbs free energy regulation strategy effectively lowers the desolvation barrier for Li ions.
• The developed electrolyte enables rapid interfacial kinetics and uniform Li deposition, significantly improving LMB performance at ultralow temperatures.
• This approach provides a novel perspective for designing advanced low-temperature electrolytes for energy storage applications.