Fast polysulfide catalytic conversion and self-repairing ability for high loading lithium-sulfur batteries using a...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but suffer from the polysulfide shuttle effect and sluggish redox kinetics, hindering performance.
• These issues lead to electrode degradation and poor cycling stability, limiting practical applications of Li-S technology.

Purpose of the Study:

• To develop a high-performance and stable Li-S battery by modifying a separator coating.
• To address the shuttle effect and sluggish electrochemical kinetics in Li-S batteries through advanced material design.

Main Methods:

• A separator was coated with organo-polysulfide chain modified acetylene black (ABPS).
• The ABPS coating was designed to provide permselectivity for lithium ions, electrocatalytic activity, and self-repairing properties.
• Performance was evaluated by comparing ABPS-coated separators with standard acetylene black (AB) and Celgard separators in Li-S cells.

Main Results:

• The ABPS-coated separator demonstrated excellent cycling performance (970 mA h g⁻¹ at 0.2 C after 100 cycles) and rate capability (805 mA h g⁻¹ at 2 C).
• Li-S batteries with ABPS coating showed stable cycling over 500 cycles at 1 C with low degradation (0.04% per cycle) and high coulombic efficiency (~100%).
• High sulfur loading (6.8 mg cm⁻²) was achieved with a low electrolyte/sulfur ratio (E/S = 4), yielding a high areal capacity of 6.03 mA h cm⁻² after 170 cycles.

Conclusions:

• Organo-polysulfide chain modified acetylene black (ABPS) is an effective coating material for enhancing and stabilizing Li-S batteries.
• The ABPS coating successfully mitigates the shuttle effect and improves electrochemical kinetics, leading to superior battery performance.
• This approach offers a promising strategy for developing practical, high-energy-density Li-S batteries.