Two-dimensional 1T-PS2 as a promising anode material for sodium-ion batteries with ultra-high capacity, low average voltage and appropriate mobility

As electrodes,two-dimensio nal materials show special advantages including the infinite planar lengths,broad electrochemical window,large surface-volume ratio,and much exposed active sites.In theory,the two-dimensional materials consist of the elements with high electronegativity may absorb more Na atoms,resulting in a high battery storage capacity.Based on the above idea,we selected the two dimensional metallic PS2 with 1 T-Type structure as an anode material,and explored its potential applications as an electrode material for Na-ion battery through first-principle calculations.As we expected,when two dimensional PS2 is used as an anode in Na-ion battery,it can adsorb maximum three layers of sodium atoms on both sides of the monolayer,resulting in a maximum theoretical capacity of 1692 mAh/g.Furthermore,it also possesses a rather small sodium diffusion barrier of 0.17 eV,a low average open-circuit voltage of 0.18 V,and a relatively small lattice changes within 13% during the intercalation of Na.These results suggested that the two dimensional PS2 is a potentially excellent Na-ion battery anode.Our idea of designing two-dimensional anode materials with high storage capacity may provide some references for designing the next generation anode materials of metal-ion batteries.