Boosting Dual-Directional Polysulfide Electrocatalysis via Bimetallic Alloying for Printable Li-S Batteries

The rational design of electrocatalyst has readily stimulated a burgeoning interest in expediting polysulfide conversion and hence essentially restricting the shuttle effect in Li-S systems. Nevertheless, seldom efforts have been devoted to probing the dual-directional polysulfide electrocatalysis to date. Herein, a CoFe alloy decorated mesoporous carbon sphere (CoFe-MCS) serving as a promising mediator for Li-S batteries is reported. Such bimetallic alloying boosts dual-directional electrocatalytic activity toward effective polysulfide conversion throughout detailed electroanalytic characterization, theoretical calculation, and operando instrumental probing. Accordingly, the S@CoFe-MCS cathode harvests a stable cycling with a low capacity decay rate of 0.062% per cycle over 500 cycles at 2.0 C. More encouragingly, benefiting from the optimized redox kinetics and delicate grid architecture, printable S@CoFe-MCS cathode achieves an excellent rate performance at a sulfur loading of 4.0 mg cm(-2)and advanced areal capacity of 6.0 mAh cm(-2)at 7.7 mg cm(-2). This work explores non-precious metal alloy electrocatalysts in printable cathodes toward dual-directional polysulfide conversion, holding great potential in the pursuit of Li-S commercialization.

Automated summary

This study presents a mesoporous carbon sphere decorated with CoFe alloy as a promising catalyst for Li-S batteries, achieving dual-directional polysulfide conversion and excellent cycling stability and rate performance. The optimized redox kinetics and structure design of the catalyst help improve the cycling stability and rate performance of Li-S batteries.