Adsorption and diffusion of alkali atoms on FeX2 (X = Se, S) surfaces for potassium-ion battery applications

The adsorption and diffusion behaviors of alkali atoms on all stable surfaces of FeX2 (X = Se, S) were studied by DFT calculation to investigate its application potential as electrode material for potassium-ion battery applications. The surface energies of all possible surfaces of FeSe2 and FeS2 are calculated to identify the stable ones with Wulff construction, and these surfaces were FeS2(001), FeSe2(110), and the FeSe2(001) surface, and the stable adsorption sites on those surfaces were also identified. Based on the chosen positions, the diffusion paths of the alkali atoms on these surfaces were examined to obtain the diffusion energy barrier of all these surfaces. It turned out that the lowest energy barrier was only 0.06 eV which occurred on FeS2(001) surface and FeSe2(110) surface. According to this research, FeSe2 offered both suitable negative adsorption energy and a relatively small diffusion barrier, which made it a promising electrode material of potassium-ion batteries.

Automated summary

The research found that the FeSe2 surface has suitable negative adsorption energy and relatively small diffusion barriers, providing great potential as an electrode material for potassium-ion batteries.