Engineering Bilayer MoS2 with Moiré–Dopant Synergy for Advanced Supercapacitor Electrodes

Synergistic integration of atomic-scale doping and Moiré superlattices opens up new possibilities for manipulating the electrical characteristics of two-dimensional (2D) ma- terials. Here, we report the first thorough first-principles investigation of site-specific chemical doping-based quantum capacitance (CQ ) modulation in Moiré-patterned bi- layer MoS2 (mBL-MoS2 ). Periodic potential fluctuations caused by a 21.79◦ interlayer twist change the density of states close to the Fermi level. By performing transition- metal-site substitution (Mo→Nb) and chalcogen-site substitution (S→Se), further im- provements are achieved. Nb doping, which induces a semiconductor-to-metal transi- tion, greatly enhances electronic delocalization and quantum capacitance, whereas Se doping has a comparatively smaller impact owing to its isoelectronic nature with S. The structural and electronic tunability of these systems is confirmed by a comprehensive analysis that includes electronic structure, differential and integral CQ calculations, electron localization function (ELF) mapping, Bader charge analysis, phonon stabil- ity, and work function evaluation. The superior charge storage capacity of Nb-doped mBL-MoS2 in the low-bias domain is demonstrated by benchmarking against other 2D materials. These results show how Moiré engineering and chemical doping can work together to create a new design framework for CQ -dominated supercapacitor electrodes.