Mo-doped induced amorphous phase and sulfur vacancy healing in VS4 for enhancing the storage of lithium ions

To ameliorate the inherent issues of the huge volume expansion and low conductivity of vanadium tetrasulfide (VS4) as an anode material for lithium ion batteries, the structural design must be significantly effective. Therefore, we prepared various Mo-doped VS4 materials for the first time, and found that Mo impacted the VS4 structure. It was confirmed that Mo-doping not only could repair the sulfur vacancies of VS4, but also introduce the formation of local amorphous structure. Because the intrinsic sulfur vacancies in VS4 were repaired, the electrical conductivity of Mo-doped VS4 was improved and the Mo-doped VS4 electrode showed a superior rate performance. Moreover, the amorphous structure of Mo-doped VS4 provided more sites for the storage of lithium ions, more channels for the transportation of lithium ions, and a stable buffer to accommodate the volume change of VS4. Based on the synergistic effect between the repaired sulfur vacancies and introduction of local amorphous structure after Mo-doping, both the electrochemical performance and kinetics of Mo-VS4 electrode were enhanced distinctly.