Compact Ion-Pair Aggregates Dominated Electrolytes Enable High-Performance Low-Temperature Lithium-Ion Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium-ion batteries (LIBs) face operational challenges at sub-zero temperatures due to poor electrolyte ion transport and charge transfer polarization.
• Degraded performance at low temperatures limits the application of LIBs in cold environments.

Purpose of the Study:

• To develop a novel electrolyte strategy for enhancing lithium-ion battery performance at sub-zero temperatures.
• To improve lithium-ion transference and reduce de-solvation energy barriers in electrolytes.

Main Methods:

• Designed solvation structures dominated by compact ion-pair aggregates (CIPAs) using weak lithium-solvent interactions.
• Investigated the formation of anion-derived solid electrolyte interfaces.
• Evaluated electrochemical performance with natural graphite and LiNi0.8Co0.1Mn0.1 (NCM811) electrodes in full cells.

Main Results:

• Achieved significantly improved lithium-ion transference numbers and reduced de-solvation energy barriers.
• Demonstrated the formation of a robust anion-derived solid electrolyte interface enabling rapid ion transport at low temperatures.
• NCM811||graphite full cells retained 84.7% capacity at -20°C (0.5C) and showed stable cycling over 200 cycles at -40°C.

Conclusions:

• The proposed electrolyte strategy enables high-performance lithium-ion batteries at extremely low temperatures.
• This work offers an innovative approach for overcoming temperature limitations in LIBs.
• The developed electrolyte is suitable for practical applications requiring reliable cold-weather operation.