Confinement-Induced In Situ Cl^-/Cl₂ Conversion in a Cathode Enables a Lean Electrolyte Sodium-Chlorine Battery.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Rechargeable metal-chlorine (Li/Na-Cl2) batteries offer high energy density potential.
• High electrolyte consumption for active metal chloride formation limits performance.
• Sacrificial electrolyte use is a major drawback for practical applications.

Purpose of the Study:

• To develop a novel cathode structure for metal-chlorine batteries.
• To reduce electrolyte consumption and improve electrochemical performance.
• To enhance the cycling stability and energy density of Li/Na-Cl2 batteries.

Main Methods:

• Utilizing a cathode with precast metal chloride confined within graphene layers.
• Implementing a lean electrolyte strategy for battery operation.
• Investigating in situ conversion of confined metal chloride with gaseous chlorine.

Main Results:

• Demonstrated a new start-up operation mode for metal-chlorine batteries.
• Achieved substantially improved cathode kinetics due to graphene confinement.
• Obtained high areal capacity (3 mAh cm-2) and over 300 stable cycles for Na-Cl2 batteries under lean electrolyte conditions.

Conclusions:

• Graphene interlayers effectively confine metal chlorides as initial active materials.
• This approach significantly improves kinetics and reduces electrolyte needs.
• The strategy shows practical significance for advanced rechargeable alkali-metal-Cl2 batteries.