High-Performance Lithium-Sulfur Batteries With an IPA/AC Modified Separator.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but suffer from polysulfide shuttle effect.
• Polysulfide diffusion leads to capacity decay and poor cycle life in Li-S batteries.
• Effective strategies are needed to confine polysulfides and improve Li-S battery performance.

Purpose of the Study:

• To develop a facile method for inhibiting polysulfide diffusion in Li-S batteries.
• To enhance the electrochemical properties and cycling stability of Li-S batteries.
• To explore the potential of active carbon-coated polypropylene separators for practical Li-S battery applications.

Main Methods:

• Commercial polypropylene (PP) separators were coated with active carbon (AC).
• The AC coating was functionalized with electronegative oxygenic groups (-OH).
• Electrochemical performance of Li-S batteries with modified separators was evaluated.

Main Results:

• The AC coating effectively adsorbed polysulfides via strong adsorption and electrostatic repulsion.
• Li-S batteries exhibited a high initial discharge capacity of 1,656 mAh g^-1 (99% sulfur utilization).
• Stable capacity of 830 mAh g^-1 was maintained after 100 cycles at 0.2 C, with 1,143 mAh g^-1 at 1 C.

Conclusions:

• The active carbon coating successfully restrains the polysulfide shuttle effect.
• The modified PP separators significantly improve the electrochemical performance and cycling stability of Li-S batteries.
• This approach offers a promising pathway for the practical application of high-performance Li-S batteries.