Boosting Polysulfide Conversion Reactions via Constructing RuCo Alloy Catalysts in Li-S Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• The shuttle effect of lithium polysulfides (LiPSs) and slow redox kinetics hinder practical lithium-sulfur (Li-S) battery applications.
• Developing efficient catalysts is crucial to mitigate these issues and enhance battery performance.

Purpose of the Study:

• To design and synthesize RuCo alloy nanoparticles supported on N-doped mesoporous carbon spheres (RuCo/NMCS) as effective catalytic sulfur hosts.
• To investigate the catalytic activity and mechanism of RuCo/NMCS for accelerating LiPS conversion in Li-S batteries.

Main Methods:

• Synthesis of RuCo alloy nanoparticles on N-doped mesoporous carbon spheres.
• Electrochemical characterization including cycling tests and rate capability measurements.
• Analysis of metal-LiPS interactions using in-situ/operando techniques (implied by dynamic changes).

Main Results:

• RuCo/NMCS demonstrated optimized adsorption and catalytic conversion of LiPSs due to electron transfer from Co to Ru.
• Strong Ru-S and Co-S interactions were observed, accelerating the conversion of Li2S2/Li2S to LiPSs and LiPSs to S8.
• The RuCo/NMCS electrode exhibited improved electrochemical performance with enhanced cycling capacity and stable reversible capacity.

Conclusions:

• RuCo/NMCS functions as an efficient catalytic sulfur host, effectively suppressing the shuttle effect and accelerating redox kinetics.
• This study presents a viable strategy for creating alloy electrocatalyst-supported cathode materials with bidirectional catalysis for high-performance Li-S batteries.