Two-dimensional silicether: A promising anode material for sodium-ion battery.

[Display omitted] Sodium-ion batteries (SIBs) are expected to replace lithium-ion batteries as the next generation of commercial secondary batteries. However, the large-scale commercial use is hindered by the lack of suitable anode materials. Based on first-principles calculations, we systematically investigate the electrochemical performance of 2D silicether as an anode material for SIBs. It could turn to the metallic state from semiconductor after being intercalated with a low Na concentration of 0.056. Owing to the special groove-like structure of silicether, Na atom crosses a low energy barrier of 0.40 eV along the armchair direction. The theoretical storage capacity (418 mA h/g), the average electron potential (2.22 V), and no significant volume expansion suggest that silicether has a great potential in SIBs. Moreover, bilayer silicether could preserve the performances of silicether monolayer, such as strong Na adsorption capability and fast ionic mobility. The above-mentioned appealing results make silicether a high-performance anode material for SIBs. [ABSTRACT FROM AUTHOR]