[en] Recently, the atom intercalation method has been developed and applied to two-dimensional (2D) materials to regulate their pristine physical properties. However, as it is an important factor in the hydrogen evolution reaction (HER), the influence of alkali-metal-intercalated technology upon the electronic structure and catalytic activity of 2D materials needs to be investigated systematically. In this work, layered ReS₂ crystals with charge decoupling are chosen as a model for exploring changes in the electronic structure and Gibbs free energy induced by alkali-metal-intercalated compounds and external strain. The calculated results show that the structural transformation induced by intercalated alkali-metal atoms and external strain not only leads to a decrease in the band gap of ReS₂ but also makes the Gibbs free energy of adsorbed hydrogen close to zero. Our calculations provide an insight to improve the performance of the HER by a simple alkali-metal-intercalated technology. (paper)