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

Abstract

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.