  Two dimensional materials as electrodes have shown unique advantages such as
the infinite planar lengths, broad electrochemical window, and much exposed
active sites. In this work, by means of density functional theory computations,
we demonstrate that two dimensional PS2 with the 1T-Type structure as many two
dimensional disulfides is a promising anode material for sodium ion batteries
application. Different from many two dimensional disulfides (e.g. MoS2, TiS2,
CrS2) compounds that are semiconducting, PS2 monolayer exhibits metallic
character with considerable electronic states at the Fermi level, which can
provide good electrical conductivity during the battery cycle and also suggest
the potential superconductivity. Remarkably, PS2 monolayer has a considerably
high theoretical capacity of 1692 mAh/g, a rather small sodium diffusion
barrier of 0.17 eV, and a low average open circuit voltage of 0.18 V. These
results suggest that PS2 monolayer can be utilized as a promising anode
material for the application in sodium ion batteries with high power density
and fast charge/discharge rates. In addition, estimated by first principle
calculations, PS2 is found to be an intrinsic phonon-mediated superconductor
with a relatively high critical superconducting temperature of about ~10 K.
