Efficient Polysulfide Trapping and Conversion on N-Doped CoTe₂ via Enhanced Dual-Anchoring Effect

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries face challenges in cyclability and rate capability due to polysulfide shuttling and slow sulfur redox kinetics.
• The performance of sulfur cathodes is critically dependent on the interaction between catalysts and sulfur species.

Purpose of the Study:

• To develop an effective dual-anchoring electrocatalyst for enhancing Li-S battery performance.
• To investigate the role of nitrogen doping in cobalt telluride (CoTe2) for improved lithium and sulfur binding.

Main Methods:

• Synthesis and characterization of N-doped CoTe2 as a dual-anchoring electrocatalyst.
• Experimental studies and computational modeling to understand the binding mechanisms of lithium and sulfur species.
• Fabrication and testing of Li-S batteries utilizing N-doped CoTe2 as a catalytic interlayer.

Main Results:

• N-doped CoTe2 demonstrates simultaneous binding of Li and S atoms through ionic Te-Li/N-Li and coordinate covalent Co-S bonds.
• Nitrogen doping enhances lithiophilicity and the sulfiphilicity of cobalt sites.
• Li-S batteries with N-doped CoTe2 interlayer exhibit a rate capability of 758 mAh g-1 at 4 C and a low capacity decay of 0.021% per cycle over 1000 cycles.

Conclusions:

• N-doped CoTe2 serves as a highly effective dual-anchoring electrocatalyst for Li-S batteries.
• The developed material and strategy offer a promising pathway for creating advanced electrocatalysts for next-generation Li-S batteries.