Mo₃S₁₃ Chalcogel: A High-Capacity Electrode for Conversion-Based Li-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Metal-sulfide electrodes offer high theoretical energy densities but face practical limitations in energy storage systems.
• Developing stable and high-performance electrode materials is crucial for advancing battery technology.

Purpose of the Study:

• To synthesize and characterize a sulfur-rich Mo3S13 chalcogel for use as a conversion-based electrode in lithium-sulfide batteries (LiSBs).
• To investigate the local structure and electrochemical performance of the Mo3S13 chalcogel.
• To demonstrate the potential of this material for sustainable and high-capacity energy storage.

Main Methods:

• Solution-processable, room temperature (RT) synthesis of the Mo3S13 chalcogel.
• Operando Raman spectroscopy, synchrotron X-ray pair distribution function (PDF), X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) analyses.
• Ab initio molecular dynamics (AIMD) simulations.
• Electrochemical testing of Li/Mo3S13 half-cells.

Main Results:

• The amorphous Mo3S13 chalcogel exhibits a 3D network structure with S-S bonds connecting Mo3S13 units.
• Initial discharge capacity reached 1013 mAh g-1.
• Stable capacity of 312 mAh g-1 was maintained at a C/3 rate after 140 cycles.
• High capacity and stability are attributed to abundant (poly)sulfide bonds and stable Mo-S coordination.

Conclusions:

• The Mo3S13 chalcogel is a promising conversion-based electrode material for LiSBs.
• The unique structure and composition contribute to its excellent electrochemical performance.
• This work highlights the potential of chalcogels for next-generation energy storage solutions.