Metal-N Coordination in Lithium-Sulfur Batteries: Inhibiting Catalyst Passivation

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries are promising next-generation energy storage devices.
• Catalysts accelerate polysulfide conversion reactions, but catalyst passivation hinders performance.
• The role of metal-N coordination in preventing catalyst passivation is underexplored.

Purpose of the Study:

• To investigate the role of metal-N coordination in preventing catalyst passivation in Li-S batteries.
• To demonstrate the effectiveness of Ni-N4 coordination in enhancing Li-S battery performance.

Main Methods:

• Investigated the interaction between sulfur and nickel catalysts.
• Studied the effect of Ni-N4 coordination on sulfur stability and polysulfide conversion kinetics.
• Evaluated the electrochemical performance of Li-S batteries with Ni-N4 modified sulfur cathodes.

Main Results:

• Uncoordinated nickel catalysts passivate due to NiSx formation.
• Ni-N4 coordination stabilizes sulfur and prevents passivation.
• Ni-N4 catalysts exhibit rapid polysulfide conversion kinetics.
• Sulfur cathodes with Ni-N4 show high rate capability (604.11 mAh g⁻¹ at 3 C) and excellent cycling stability (0.046% decay per cycle over 1000 cycles at 2 C).
• The passivation inhibition effect is applicable to various transition metals and coordination numbers.

Conclusions:

• Metal-N coordination is a crucial factor in inhibiting catalyst passivation in Li-S batteries.
• Ni-N4 coordination offers a promising strategy for developing stable and high-performance Li-S batteries.
• This study advances the understanding of catalyst mechanisms in Li-S systems.