A Homo-Triatomic Molybdenum Cluster Catalyst Enables Synergistic Optimization of Multi-Step Sulfur Reduction...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Single-atom catalysts (SACs) face challenges in managing multiple lithium polysulfide intermediates in Li-S batteries.
• Optimizing adsorption states is crucial for efficient sulfur redox reactions.

Purpose of the Study:

• To develop a novel catalyst that overcomes the limitations of SACs in Li-S batteries.
• To investigate the catalytic activity of homo-triatomic molybdenum clusters for improved Li-S battery performance.

Main Methods:

• Synthesis of a homo-triatomic molybdenum cluster catalyst (Mo3/ONC) with Mo3-O3N3 motifs in a carbon matrix.
• Electrochemical testing and in situ spectroscopic analysis to evaluate catalytic performance.
• Comparison with a single-atom molybdenum catalyst (Mo1/ONC).

Main Results:

• The Mo3-O3N3 motifs exhibit multi-active sites and interatomic synergies, enabling flexible Mo-S pathways for various sulfur intermediates.
• Optimized Mo-S interactions facilitate electron transfer, weaken S-S bonds, and reduce sulfur conversion energy barriers.
• Mo3/ONC demonstrates significantly improved sulfur redox kinetics compared to Mo1/ONC.
• The Li-S battery with Mo3/ONC achieves high rate capability (661.2 mAh g-1) and excellent cycling stability (0.027% decay per cycle at 10 C for 1200 cycles).

Conclusions:

• Homo-triatomic cluster catalysts offer a new design strategy for enhancing Li-S battery performance.
• The Mo3/ONC catalyst effectively addresses the challenges of polysulfide management in Li-S batteries.
• This work provides fundamental insights into catalyst design principles for advanced energy storage.