Alloy-Regulated Heterointerface Engineering for Kinetics-Driven Sulfur Redox in Li-S Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries possess high theoretical energy density but face challenges.
• Key limitations include slow sulfur redox kinetics and polysulfide shuttle effect.
• These issues hinder practical application and long-term stability.

Purpose of the Study:

• To engineer Mo2C/MoC heterostructures for improved Li-S battery performance.
• To develop a quantitative heterointerface strategy using NiMo-alloy.
• To enhance sulfur electrochemistry and address polysulfide shuttling.

Main Methods:

• NiMo-alloy assisted quantitative heterointerface engineering.
• Controlled Mo2C→MoC phase reconstruction by tuning Ni/Mo ratio.
• In situ/ex situ characterizations and density functional theory (DFT) calculations.

Main Results:

• Maximized density and accessibility of catalytically active Mo2C/MoC heterointerfaces.
• NiMo domains acted as structural modulators and electron pathways.
• Achieved high reversible capacity (1477.8 mAh g⁻¹ at 0.1 C) and long-term cycling stability (0.032% decay per cycle over 1000 cycles at 0.5 C).
• Enabled high areal capacity (15.2 mAh cm⁻²) at high sulfur loading.

Conclusions:

• The Mo2C/MoC heterointerfaces exhibit optimal polysulfide adsorption and low energy barriers for sulfur conversion.
• The NiMo-alloy strategy provides a quantitative paradigm for designing advanced Li-S batteries.
• Heterostructure engineering offers general insights for metal-sulfur battery catalysis.