Multilayer Load and Fast Diffusion of Metal Ions on a Ti2CS2/Blue Phosphorene Heterostructure Anode

Developing electrode materials with better storage performances is currently one of the hotspots in the field of battery storage. Though monolayer materials such as Ti2CS2 and blue phosphorene (BlueP) monolayers have some excellent storage properties as anode materials, the re-stacking of Ti2CS2 and poor conductivity of BlueP may limit their application prospects. Considering that the heterostructure may retain/avoid the advantages/disadvantages of monolayer anodes, we study the load and diffusion of Li/Na/K ions on a Ti2CS2/BlueP heterostructure to explore the feasibility of it as an anode via density functional theory. We find that this heterostructure not only retains the stability characteristics of Ti2CS2 and the high capacity of BlueP but also avoids the re-stacking of Ti2CS2 and poor conductivity of BlueP. Moreover, 4/8/3 layers (nine atoms per layer) of Li/Na/K are loaded into this heterostructure, far exceeding the 2/2/2 layers loaded into the pristine BlueP and 2/6/2.67 layers into the pristine Ti2CS2 due to the interfacial synergy. In addition, the Ti2CS2/BlueP anode material shows high capacity (344–917 mA h/g), low average open-circuit voltage (OCV) (0.32–0.78 V), and low diffusion barrier (0.10–0.37 eV). Furthermore, Ti2CS2/BlueP presents better prospects for Na-ion batteries among three batteries owing to the highest capacity and lowest average OCV.