t₂ occupancy as a descriptor for polysulfide conversion on spinel oxides

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Transition metal oxides are crucial catalysts for polysulfide conversion in lithium-sulfur batteries.
• A predictive descriptor for their structure-activity relationship is needed.

Purpose of the Study:

• Investigate t2 orbital occupancy as a descriptor for spinel oxide polysulfide conversion activity.
• Establish a structure-activity relationship for enhanced lithium-sulfur battery performance.

Main Methods:

• Electrochemical characterization of spinel oxides.
• Theoretical calculations to understand catalytic mechanisms.
• Design and synthesis of Mn0.5Co0.5Cr2O4 with optimized t2 occupancy.

Main Results:

• A volcano relationship was observed between t2 occupancy and polysulfide conversion activity.
• t2 occupancy influences S-S bond cleavage and Li-S bond formation.
• Mn0.5Co0.5Cr2O4 exhibited promising catalytic activity.

Conclusions:

• t2 orbital occupancy is an effective descriptor for spinel oxide polysulfide conversion.
• The findings guide the design of advanced catalysts for lithium-sulfur batteries.
• This descriptor may apply to other catalytic systems beyond spinel structures.