Controllably Designed "Vice-Electrode" Interlayers Harvesting High Performance Lithium Sulfur Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but suffer from short cycle life due to the polysulfide shuttle effect.
• Interlayers are explored to mitigate polysulfide migration and improve Li-S battery performance.
• Understanding the precise role and placement of interlayers is crucial for optimizing battery design.

Purpose of the Study:

• To investigate the working mechanism of interlayers in Li-S batteries.
• To evaluate the impact of interlayer placement (cathode vs. anode side) on electrochemical performance.
• To explore the relationship between interlayer properties (conductivity, polysulfide absorbability) and battery function.

Main Methods:

• Design and fabrication of various interlayers for Li-S batteries.
• Electrochemical testing of Li-S cells with interlayers placed on the cathode and anode sides.
• Comparative analysis with non-conductive interlayers (glass fibers).
• Investigation of polysulfide adsorption and electrochemical behavior.

Main Results:

• Cathodic interlayers significantly improved the electrochemical performance of sulfur electrodes compared to pristine cells.
• Anodic interlayers resulted in poorer performance than pristine cells.
• Non-conductive interlayers led to substantial capacity fading due to polysulfide adsorption, acting as a 'dead zone'.
• Conductive interlayers with good polysulfide absorbability showed promising results.

Conclusions:

• Optimized interlayers with both electrical conductivity and polysulfide absorbability can act as 'vice-electrodes'.
• Conductive cathodic interlayers enhance Li-S battery performance.
• Conductive anodic interlayers may be beneficial for designing protective 3D networks for lithium metal anodes.