Achieving long cycle life for all-solid-state rechargeable Li-I₂ battery by a confined dissolution strategy

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Rechargeable lithium-iodine (Li-I2) batteries offer high capacity and eco-friendliness.
• Liquid electrolytes in Li-I2 batteries suffer from polyiodide shuttle effects.
• Solid-state Li-I2 batteries face challenges with insoluble discharge products, hindering performance.

Purpose of the Study:

• To develop a rechargeable all-solid-state Li-I2 battery with enhanced stability and cycle life.
• To address the sluggish electrochemical reactions and poor rechargeability in conventional solid-state Li-I2 systems.
• To introduce a novel polyiodide chemistry through a hybrid electrolyte design.

Main Methods:

• Designed a hybrid electrolyte featuring a dispersion layer and a blocking layer.
• Localized polyiodide dissolution within a confined space near the cathode.
• Investigated the electrochemical performance and long-term cycling stability of the all-solid-state Li-I2 battery.

Main Results:

• Successfully promoted a new polyiodide chemistry.
• Localized polyiodide dissolution effectively mitigated shuttle effects.
• Achieved a rechargeable and highly reversible all-solid-state Li-I2 battery.
• Demonstrated a long-term cycle life exceeding 9000 cycles at 1C with 84.1% capacity retention.

Conclusions:

• The confined dissolution strategy using a hybrid electrolyte is effective for improving Li-I2 battery performance.
• This approach overcomes key limitations of previous solid-state Li-I2 battery designs.
• The developed battery shows significant promise for long-term, stable energy storage applications.