Herein, first-principles calculations were carried out to investigate the mechanism of metal-ion, such as K, Li, Na, Mg and Al, adsorption and diffusion on the SnCo (0 0 1) surface. Our results demonstrated that K, Li, and Na are more readily adsorbed on the pristine SnCo (0 0 1) surface than Mg and Al. Based on the calculations of migration barriers for metal atom on SnCo (0 0 1) surface, we identified the most energetically favorable metal atom diffusion pathway. The influence of vacancies on the K and Li storage capabilition of the SnCo (0 0 1) surface was also investigated. Our calculations show that Sn vacancies (VSn) tend to improve Li adsorption, but have no effect on K adsorption. Unfortunately, the Co vacancy (VCo) tends to inhibit the adsorption of Li and K on the SnCo (0 0 1) surface.