Cobalt‐Mediated Defect Engineering Endows High Reversible Amorphous VS₄ Anode for Advanced Sodium‐Ion Storage

Abstract

Metal sulfides are promising anode materials for sodium‐ion batteries (SIBs) due to their structural diversity and high theoretical capacity, but the severe capacity decay and inferior rate capability caused by poor structural stability and sluggish kinetics impede their practical applications. Herein, a cobalt‐doped amorphous VS4 wrapped by reduced graphene oxide (i.e., Co0.5‐VS4/rGO) is developed through a Co‐induced defect engineering strategy to boost the kinetics performances. The as‐prepared Co0.5‐VS4/rGO demonstrates excellent rate capacities over 10 A g−1 and superior cycling stability at 5 A g−1 over 1600 cycles, which is attributed to the defects formed by Co doping, the formed amorphous structure and the robust rGO substrate. The great features of Co0.5‐VS4/rGO anode are further confirmed in sodium‐ion capacitors when the active carbon cathode is used. Additionally, the relationships between metal doping, the derived defects, the amorphous structure, and the sodium storage of VS4 are uncovered. This work provides deep insights into preparing amorphous functional materials and also probes the potential applications of metal sulfide‐based electrode materials for advanced batteries.

Yolk–Shell MoS2 Nanosphere-Doped Electron-Rich Iron Heteroatoms for Ultralong Lifespan Na-Ion Batteries

“…Recently, heteroatom-induced engineering has achieved considerable success in semiconductors and brought interesting characteristics, including polymorphism transformation, regulation of ion/electron conductivity, and reduction of diffusion barrier. − Chen et al reported a Mn-doped FeS multicore nanoparticle with enhanced reversible capacity and rate performance due to the high concentration of Mn-heteroatoms doping, which manipulates the electronic structure and improves the charge carrier transport. Meanwhile, Zhang et al fabricated a cobalt-doped amorphous VS 4 with tailored electronic structure, sufficient defects, and abundant active adsorption sites, which may responsible for its improved electronic conductivity as well as accelerated ion mobility. Our previous research has also demonstrated that by rationally introducing vanadium heteroatoms, the intrinsic electronic texture, the charge transfer, and the reversibility of electrode reactions of pristine MoS 2 phase can be modulated synchronously, thus endowing superior Na-storage performances .…”