Theoretical investigation on potassium storage performance of MoSe₂ with single/dual-element doping of vanadium and niobium

Potassium-ion batteries (PIBs) offer the advantages of low cost and relatively high operating voltage and have emerged as promising energy-storage systems. Layered molybdenum diselenide (MoSe₂) is considered an attractive anode material for PIBs due to its high theoretical specific capacity and large interlayer spacing. In this work, based on first-principles calculations, single V-doped, single Nb-doped and V/Nb co-doped 1 T’-phase MoSe₂ systems were constructed to systematically investigate the modulation mechanisms of these dopants on potassium storage behaviors. The calculation results demonstrate that all the doped systems exhibit metallic characteristics, and their K adsorption strengths are significantly enhanced compared with the pristine MoSe₂. Notably, the V/Nb co-doped configuration exhibits strong K adsorption (−3.13 eV) together with an intermediate diffusion barrier of 0.28 eV between those of V-MoSe₂ (0.29 eV) and Nb-MoSe₂ (0.27 eV). Furthermore, compared with the single-doped counterparts, the V/Nb co-doped system not only preserves the preferential adsorption of K atoms at V sites but also boosts the K adsorption strength at Nb sites. This study provides valuable theoretical guidance for the rational design of high-performance MoSe₂-based anode materials for potassium-ion batteries.