Computational insight of monolayer SnS2 as anode material for potassium ion batteries

There is a great challenge to design anode materials for rechargeable batteries with large capacity, excellent cyclic stability and high rate performance. Using first principle calculations, we have calculated electronic properties of monolayer SnS2 which reveal that it is an indirect-gap semiconductor with a band gap of 1.56 eV. The SnS2 becomes metallic after the insertion of small amount of K content, and the electronic conductivity increases by increasing the concentration of K. Also, our predictions show that there is a proper binding energy between K ion and monolayer SnS2 with a low average open circuit voltage (0.84 V) which is in the range of commercial anode materials. The energy surface for the diffusion of K ion on the surface of SnS2 monolayer is analyzed and a very low energy barrier (0.054 eV) is found for the K diffusion. These results indicate that SnS2 is very suitable to be use as a high performance anode material for KIBs.