Single-Atom Yttrium Engineering Janus Electrode for Rechargeable Na–S Batteries

The development of rechargeable Na–S batteries is very promising, thanks to their considerably high energy density, abundance of elements, and low costs and yet faces the issues of sluggish redox kinetics of S species and the polysulfide shuttle effect as well as Na dendrite growth. Following the theory-guided prediction, the rare-earth metal yttrium (Y)–N4 unit has been screened as a favorable Janus site for the chemical affinity of polysulfides and their electrocatalytic conversion, as well as reversible uniform Na deposition. To this end, we adopt a metal–organic framework (MOF) to prepare a single-atom hybrid with Y single atoms being incorporated into the nitrogen-doped rhombododecahedron carbon host (Y SAs/NC), which features favorable Janus properties of sodiophilicity and sulfiphilicity and thus presents highly desired electrochemical performance when used as a host of the sodium anode and the sulfur cathode of a Na–S full cell. Impressively, the Na–S full cell is capable of delivering a high capacity of 822 mAh g–1 and shows superdurable cyclability (97.5% capacity retention over 1000 cycles at a high current density of 5 A g–1). The proof-of-concept three-dimensional (3D) printed batteries and the Na–S pouch cell validate the potential practical applications of such Na–S batteries, shedding light on the development of promising Na–S full cells for future application in energy storage or power batteries.