Toward Ultralong Lifespan Aqueous Zinc-Ion Batteries via Sulfur- Defect Vanadium Tetrasulfide Cathode

Vanadium sulfide has become one of the promising cathodes of aqueous rechargeable zinc-ion batteries (AZIBs); however, the further application of vanadium sulfides for AZIBs is severely restricted by the limited specific capacity and poor cycling stability. Herein, we synthesize the vanadium tetrasulfide nanosphere with S-defects and coated by an ultrathin carbon layer (D-VS4). The as-assembled Zn//D-VS4 cell delivers a high specific capacity of 295 mAh g-1 at 0.5 A g-1 and long-time cycling stability (a capacity retention of 72.0% after 8,000 cycles). The electrochemical reaction mechanism of D-VS4 is revealed. This work provides a significant supplement to the study of vanadium-based sulfides cathode for AZIBs.