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.