Theoretical understanding of SnS monolayer as Li ion battery anode material

Ideal Li-ion battery materials should have a low Li-ion diffusion barrier and a suitable binding energy. Here, first-principles calculations were performed to investigate the potential of SnS monolayer as a Li-ion battery material. Our study reveals that Li ions can be strongly bonded on the SnS monolayer with a binding energy of around 2 eV, and donate electrons into the SnS monolayer. Consequently, Li intercalation of SnS monolayer gives rise to a semiconducting to metallic transition, and leads to a good electrical conductivity. Interestingly, in spite of the existence of strong chemical interaction, the energy barrier (0.45 eV) of Li diffusion on the SnS monolayer is quite low. Moreover, the estimated open circuit voltage is about 1.98 V, which is much better than that of commercial graphite. Thus, given these advantages, it is expected that SnS monolayer will be a promising anode material for Li ion batteries.