Synergistic Cu/Se Substitution and Dual Carbon Encapsulation in ZnS Enabling High-Rate Sodium Storage.

ZnS possesses an elevated theoretical capacity, a feature that makes it an exceptionally promising anode option for sodium-ion batteries (SIBs), yet its electrochemical performance is severely hindered by sluggish electron and ion migration kinetics, along with structural deterioration upon repeated cycling. Here, a synergistic Cu/Se dual-doped and dual carbon encapsulated ZnS (CuZnSSe@DC) anode is rationally designed. The incorporated Cu cation and Se anion not only boost charge transfer kinetics but also create rapid Na+ diffusion channels. Meanwhile, the conductive dual carbon encapsulation efficiently accommodates volume variation during electrochemical processes. As expected, CuZnSSe@DC demonstrates excellent sodium storage properties, delivering a high-rate capability (193.1 mAh g-1 at 100 A g-1) and a long lifespan of 2500 cycles at 20 A g-1. This work highlights the great potential of cation/anion dual-doping engineering in developing high-capacity, durable anodes suitable for SIBs.