Lithium adsorption and diffusion on Janus Mo/WXY (X,Y = S, Se, Te)

One of the most important factors in improving the efficiency of anode materials for Li-ion batteries is the mobility of Lithium atoms in these materials. On the basis of first-principles plane-wave calculations, we examined the adsorption and diffusion of lithium atoms on the hexagonal Janus Mo/WXY (X,Y=S, Se and Te) monolayers. We found the lowest energy adsorption positions of the Li adatom to be on the top site of the transition metal atom, on both sides of all considered Janus monolayers. Due to electronegativity differences of the chalcogenides in the Janus structures and induced dipole moment, both the Li adatom adsorption and the diffusion barrier energies on the surfaces of Janus structures differ from the bare Mo/WX2 monolayers. For instance, Li diffusion barrier energy for the Tellurium sides of the Mo-Janus structures are about 0.09-0.12 eV lower than that of MoTe2 monolayers which is 0.23 eV. Also, Li diffusion barrier energy on the Sulfur sides of the Mo-Janus monolayer is about 0.04-0.08 eV larger than its MoS2 energy value. All considered structures turn to metal after Li atom absorption. Our electronic transport calculations concluded inn an increase in conductivity. This makes them superb candidate materials for the electrodes of Li-ion batteries.