Controlled dopant engineering in Mo8S16/W8S16 heterostructures for enhanced Li+ adsorption, reaction kinetics, electronic conductivity and structural stability toward energy storage devices

Designing advanced anode materials for lithium-ion batteries requires a careful balance between electronic conductivity, favorable Li + adsorption characteristics, and structural stability. In this work, first-principles density functional theory (DFT) calculations were employed to systematically investigate pristine and transition-metal-doped M − W (0,0) layered heterostructures (where 0 denotes the absence of a dopant at the corresponding substitution site), including single (V,0), (Nb,0), (Ta,0), (W,0), (0,Cr), double (V,Cr), (Nb,Cr), (Ta,Cr), and multi-doped (VNb,Cr) and (VTa,Cr) systems, as potential lithium-ion battery anode materials. All substituted systems retained the original layered framework, exhibiting only minimal variation in the c/a ratio (−1.60 to +0.42%, corresponding to c/a = 4.232-4.319), while slight interlayer expansion in selected doped configurations contributed to more accessible Li + adsorption sites. The electronic properties were significantly modified, with the band gap decreasing from 1.58 eV for the pristine structure to 0.73 eV for the (Ta,Cr) system, corresponding to a 54% reduction, suggesting the potential for improved electronic conductivity. Mechanical analysis revealed improved toughness (bulk modulus >111 GPa) and a 15% increase in ductility, indicating enhanced mechanical robustness during lithiation and delithiation. Among the investigated systems, the (Li*Nb,0)-substituted heterostructure exhibited the most favorable theoretical characteristics, achieving 25% stronger Li + adsorption (−2.98 to −3.72 eV), more favorable reaction energetics (−1.20 to −4.06 eV), and 20-25% stronger binding energies than the pristine material, indicating stronger Li-host interactions and enhanced structural stability according to the present DFT calculations. Furthermore, phonon and thermodynamic analyses suggested dynamical stability and 2.2% improvements in heat capacity and entropy from a theoretical perspective. This work presents a comprehensive first-principles computational screening of transition-metal-doped M − W layered heterostructures, identifying promising theoretical anode candidates with favorable energy storage applications.