Carbon-based artificial SEI layers for aqueous lithium-ion battery anodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous electrolytes in lithium-ion batteries (LIBs) offer enhanced safety over organic electrolytes.
• Water-in-salt (WIS) electrolytes extend the electrochemical stability window, improving LIB performance.
• High salt concentrations in WIS electrolytes are limited by salt solubility, impacting kinetic protection.

Purpose of the Study:

• To develop anode structure design strategies for improving the cycle life of LIBs utilizing WIS electrolytes.
• To mitigate issues related to anode surface exposure and water electrolysis in WIS LIBs.
• To enhance charge transfer kinetics and overall battery performance.

Main Methods:

• Introduction of partially graphitic protective carbon layers onto anode particles via a versatile coating method.
• Characterization of anode structure and electrochemical performance.
• Testing of modified TiO2 anodes in WIS electrolytes.

Main Results:

• The protective carbon layer improved charge transfer kinetics.
• Minimized anode surface exposure reduced water electrolysis.
• TiO2 anodes with the developed structure showed an 11-fold improvement in cycle performance and a 29% increase in coulombic efficiency compared to base anodes.

Conclusions:

• Anode structure modification with protective carbon layers is an effective strategy for enhancing WIS LIB performance.
• This approach significantly improves cycle life and coulombic efficiency.
• The developed method offers a pathway for safer and more durable next-generation energy storage systems.