Asymmetric Polarization Modulation of d-p Hybridization-Enhanced Bidirectional Sulfur Redox Kinetics with...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Lithium-sulfur batteries (LiSBs) offer high energy density but face challenges due to slow sulfur redox reaction (SRR) kinetics.
• Efficient catalysts are crucial for overcoming these kinetic limitations and enabling practical LiSB applications.

Purpose of the Study:

• To design and investigate a heteronuclear dual-atom catalyst (hetero-DAC) for enhancing LiSB performance.
• To elucidate the mechanism by which hetero-DACs modulate sulfur intermediate adsorption and conversion dynamics.

Main Methods:

• Development of a heteronuclear dual-atom catalyst (CoFe DACs) with surface charge polarization.
• Investigation of d-p orbital hybridization between the catalyst and sulfur intermediates.
• Electrochemical testing to evaluate capacity, rate performance, and cycling stability.

Main Results:

• The CoFe hetero-DAC demonstrated enhanced asymmetric adsorption of sulfur intermediates via modulated d-p orbital hybridization.
• Dynamic switching between adsorption sites fine-tuned orbital hybridization, boosting rate-determining steps in the SRR.
• The CoFe DACs cathode achieved a high initial specific capacity (703.9 mA h g⁻¹ at 3 C) and excellent long-term cycling stability (0.031% decay over 1000 cycles).

Conclusions:

• The study successfully linked catalyst geometric and electronic structures to improved LiSB performance.
• Hetero-DACs offer a promising strategy for designing advanced catalysts by enabling asymmetric trapping and conversion of sulfur species.
• This work provides new insights for developing efficient catalysts for LiSBs and other energy storage systems.