First-principles study of Fe- and Mn-doping in MoS 2 : structural modulation and enhanced Li/Na/K ion storage

Abstract In this study, we systematically studied the mechanism of Fe/Mn doping regulating the electronic structure of MoS 2 and the storage performance of Li + /Na + /K + by first-principles calculation. First, phonon spectra and ab initio molecular dynamics (AIMD) simulations confirmed the dynamic stability of the Fe–MoS 2 and Mn–MoS 2 structures. The mechanical properties show that Fe–MoS 2 (256 N m −1 ) and Mn–MoS 2 (240 N m −1 ) exhibit higher Young’s modulus and Poisson’s ratio than MoS 2 (210 N m −1 ), which enhances the deformation resistance of the materials. The DOS results reveal that doping significantly narrows the 1.83 eV band gap of pristine MoS 2 to 0.75 eV (Fe–MoS 2 ) and 0.98 eV (Mn–MoS 2 ), thereby boosting its intrinsic electrical conductivity. Migration energy calculations further reveal that Fe- and Mn-doping optimizes the diffusion pathways for Li/Na/K ions and reduces diffusion barriers. Differential charge density and Bader charge analyses confirm that the charge transfer efficiency between the doped materials and alkali metal ions is significantly enhanced, thereby improving electrochemical activity. In addition, both Fe–MoS 2 and Mn–MoS 2 exhibit strong adsorption stability toward Li/Na/K ions and possess high average open-circuit voltages, suggesting high energy density potential. Finally, AIMD and Young’s modulus simulations confirm that MoS 2 -based materials remain structurally stable upon full Li/Na/K intercalation, and Fe/Mn doping effectively suppresses the lattice distortion and volume expansion induced by alkali metal insertion. This study provides a theoretical basis for the rational design of MoS 2 -based anode materials for alkali metal ion batteries.