Efficient Polysulfide Redox Enabled by Lattice-Distorted Ni₃Fe Intermetallic Electrocatalyst-Modified Separator for...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but face challenges in polysulfide conversion.
• Efficient electrocatalysts are crucial for managing the multiphase redox reactions in Li-S batteries.

Purpose of the Study:

• To investigate nickel-iron intermetallic (Ni3Fe) as a novel electrocatalyst for Li-S batteries.
• To understand the mechanism by which Ni3Fe enhances polysulfide surface reactions and redox kinetics.

Main Methods:

• Synthesis and characterization of Ni3Fe intermetallic compound.
• Electrochemical performance testing of Li-S cells with Ni3Fe-modified separators.
• Kinetics investigations of polysulfide redox reactions.

Main Results:

• Ni3Fe exhibits strong electronic interactions and lattice distortion, activating catalytic activity.
• Ni3Fe promotes the redox kinetics of Li-S electrochemistry, leading to high initial capacities (1310.3 mAh g⁻¹ at 0.1 C).
• Cells demonstrate excellent rate capability (598 mAh g⁻¹ at 4 C) and long cycle life (1000 cycles at 1 C with 0.034% fading per cycle).
• Ni3Fe-catalyzed cells perform well under high sulfur loading and lean electrolyte conditions.

Conclusions:

• Ni3Fe is a highly effective electrocatalyst for promoting polysulfide surface reactions in Li-S batteries.
• This intermetallic catalyst offers a new strategy for developing high-rate, long-life Li-S batteries.
• The findings pave the way for advanced intermetallic catalysts in next-generation energy storage.