First-principles study of pristine and transition metal (Fe/Co/Ti)-doped layered MoS2 as anode materials for sodium-ion batteries

Abstract

In this work, we apply first-principles density functional theory (DFT) calculations to study the intercalation of Na atoms into the pristine and transition metal (TM) doped MoS₂ ⁠(M_xMo_1-xS₂) layers. Our results show that TM atom doping enhances the binding of the Na atoms between the M_xMo_1-xS₂⁠ (M: Fe/Co/Ti) layers. Moreover, we find that Na intercalation facilitates the transition from the 2H phase to the 1T phase of the MoS₂ in agreement with previous findings. However, Fe and Co doping is found to promote such transition; conversely, Ti doping is found to delay this transition. M_xMo_1-xS₂⁠ have metallic properties, and the doping increases the average open-circuit voltage (OCV) of the 1T and 2H phase M_xMo_1-xS₂. This work provides a new perspective on the phase change mechanism of transition metal dichalcogenide and valuable theoretical insights for the development of doped MoS₂ nanomaterials in Na-ion battery applications.