First-principles predictions of Co/V-doped MoS₂ for alkali metal ion storage: Electronic structure modulation and...

This study systematically investigated the effects of Co- and V-doping on the structural stability, mechanical properties, electronic structure, and electrochemical performance of MoS₂ using first-principles calculations. Phonon dispersion spectrum analysis confirmed that both Co-MoS₂ and V-MoS₂ exhibit excellent dynamic stability. Mechanical property tests demonstrated that doping significantly enhances the Young's modulus (Co-MoS₂: 220 N/m; V-MoS₂: 238 N/m) and maintaining an appropriate Poisson's ratio, effectively mitigating stress concentration. DOS calculations revealed that Co- and V-doping markedly improve the intrinsic electronic conductivity of MoS₂, with band gaps reduced to 0.39 eV and 0.98 eV for Co-MoS₂ and V-MoS₂, respectively. In terms of electrochemical performance, the study yielded breakthrough findings: the doped systems significantly lowered the migration barriers for Li⁺/Na⁺/K⁺ (Co-MoS₂: 0.06 eV/0.09 eV/0.09 eV, V-MoS₂: 0.27 eV/0.24 eV/0.21 eV), achieving fast ion transport kinetics. Charge density difference and adsorption energy analyses showed that Co- and V-doping strengthens the interactions between MoS₂ and Li⁺/Na⁺/K⁺. Additionally, doped significantly increased the average open-circuit voltage of MoS₂ for Li⁺/Na⁺/K⁺ (Co-MoS₂: 0.76 V/0.68 V/0.44 V, V-MoS₂: 0.83 V/0.71 V/0.51 V), providing a crucial theoretical basis for designing electrode materials with high energy density. These findings provide new design strategies and theoretical guidance for developing high-performance MoS₂ materials for alkali metal-ion batteries.