Nitrogen-doped carbon embedded with Ag nanoparticles for bidirectionally-promoted polysulfide redox electrochemistry

The advances of lithium-sulfur (Li-S) batteries have long been challenged by the polysulfides shuttling and the intrinsically sluggish sulfur redox kinetics. Herein, Ag-decorated N-doped carbon (Ag-CNx) is prepared through magnesiothermic reduction followed by a "silver mirror" reaction. Attributed to the high conductivity, porous architecture, strong absorbability, and catalytic effect, the as-developed Ag-CNx, as an interlayer material in Li-S configuration, well confines active species within the cathodic side and simultaneously promotes the sulfur conversions bidirectionally to the final S/Li2S product. As a result, fast and durable Li-S electrochemistry can be realized, exhibiting excellent cyclability over 550 cycles, superb rate capability up to 5C, and decent areal capacity of 4.8 mAh cm-2 under raised sulfur loading of 4.1 mg cm-2. This work provides a facile and effective pathway toward multifunctional that combines chemical binding and electrocatalysis, holding great promise in future development of high-performance Li-S batteries.