Supersaturated bridge-sulfur and vanadium co-doped MoS₂ nanosheet arrays with enhanced sodium storage capability

The low specific capacity and sluggish electrochemical reaction kinetics greatly block the development of sodium-ion batteries (SIBs). New high-performance electrode materials will enhance development and are urgently required for SIBs. Herein, we report the preparation of supersaturated bridge-sulfur and vanadium co-doped MoS₂ nanosheet arrays on carbon cloth (denoted as V-MoS_2+x/CC). The bridge-sulfur in MoS₂ has been created as a new active site for greater Na⁺ storage. The vanadium doping increases the density of carriers and facilitates accelerated electron transfer. The synergistic dual-doping effects endow the V-MoS_2+x/CC anodes with high sodium storage performance. The optimized V-MoS_2.49/CC gives superhigh capacities of 370 and 214 mAh·g^-1 at 0.1 and 10 A·g^-1 within 0.4-3.0 V, respectively. After cycling 3,000 times at 2 A·g^-1, almost 83% of the reversible capacity is maintained. The findings indicate that the electrochemical performances of metal sulfides can be further improved by edge-engineering and lattice-doping co-modification concept.