Li⁺-Desolvation Dictating Lithium-Ion Battery's Low-Temperature Performances

Area of Science:

• Electrochemistry
• Materials Science

Background:

• Lithium-ion batteries are crucial for modern technology but face performance challenges in extreme environments, particularly at subzero temperatures.
• Low temperatures impede the kinetic processes essential for energy delivery in lithium-ion batteries.
• Understanding Li+ migration rate-determining steps is vital for optimizing battery performance in cold conditions.

Purpose of the Study:

• To identify the rate-determining process for lithium-ion (Li+) migration at subzero temperatures.
• To guide the design of optimal electrolyte formulations for enhanced low-temperature battery performance.
• To improve the energy output and stability of lithium-ion batteries in extreme cold.

Main Methods:

• Investigated graphite∥LiNi0.80Co0.15Al0.05O2 battery chemistry at temperatures down to -40 °C.
• Analyzed the effect of solvent molecules on Li+ desolvation energy barriers.
• Correlated electrolyte composition with observed changes in battery capacity and performance.

Main Results:

• Achieved substantial increases in available capacity for graphite∥LiNi0.80Co0.15Al0.05O2 cells at -40 °C.
• Demonstrated that reducing tightly binding solvent molecules lowers the Li+ desolvation energy barrier.
• Identified electrolyte solvent properties as key to overcoming low-temperature kinetic limitations.

Conclusions:

• Optimizing electrolyte solvent composition is critical for enhancing lithium-ion battery performance at subzero temperatures.
• Lowering the Li+ desolvation energy barrier through electrolyte design significantly boosts low-temperature energy output.
• The findings provide a fundamental understanding applicable to various electrochemical devices operating in extreme environments.