Ti₂PTe₂ monolayer: a promising two-dimensional anode material for sodium-ion batteries

Developing efficient anode materials with a good electrochemical performance has been a key scientific issue in the development of sodium ion batteries (SIBs). In this work, by means of density functional theory (DFT) computations, we demonstrate that two-dimensional (2D) Ti₂PTe₂ monolayer is a promising candidate for this application. The exfoliation of Ti₂PTe₂ monolayer from its experimentally known layered bulk phase is feasible due to the moderate cohesive energy. Different from many binary 2D transitions metal chalcogenides (TMCs) that are semiconducting, Ti₂PTe₂ monolayer is metallic with considerable electronic states at the Fermi level. Remarkably, Ti₂PTe₂ monolayer has a considerably high theoretical capacity of 280.72 mA h g^-1, a rather small Na diffusion barrier of 0.22 eV, and a low average open circuit voltage of 0.31 eV. These results suggest that Ti₂PTe₂ monolayer can be utilized as a promising anode material for SIBs with high power density and fast charge/discharge rates.