2D MoN-VN Heterostructure To Regulate Polysulfides for Highly Efficient Lithium-Sulfur Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but suffer from rapid capacity fading.
• Poor theoretical understanding of sulfur host and polysulfide interactions hinders Li-S battery development.

Purpose of the Study:

• To investigate a novel 2D heterostructured MoN-VN as a sulfur host for Li-S batteries.
• To elucidate the atomic-level chemical interactions between the sulfur host and polysulfides.

Main Methods:

• Fabrication of a 2D heterostructured MoN-VN material.
• Theoretical calculations to study electronic structure and polysulfide adsorption.
• In situ synchrotron X-ray diffraction and electrochemical measurements.

Main Results:

• Theoretical calculations showed tunable electronic structure of MoN by V incorporation, enhancing polysulfide adsorption.
• MoN-VN demonstrated effective regulation and utilization of polysulfides.
• MoN-VN based Li-S batteries achieved 708 mAh g⁻¹ at 2 C with extremely low capacity decay (0.068% per cycle over 500 cycles).

Conclusions:

• The 2D MoN-VN heterostructure serves as an effective sulfur host for high-performance Li-S batteries.
• Tailoring electronic structure is crucial for enhancing polysulfide management in Li-S systems.
• This work provides a new model for designing advanced sulfur hosts to overcome capacity fading.