Pressurized Alloying Assisted Synthesis of High Quality Antimonene for Capacitive Deionization

Abstract Mono‐elemental antimonene as a new member of the 2D material family has recently attracted huge attention, whereas the higher chemical activity and narrower interlayer gallery have impinged the quality of product upon exfoliation from the bulk counterpart. To overcome the intrinsic drawbacks, along with the line of the liquid‐phase exfoliation (LPE) method, here, a pressurized alloying approach introduces a Li 3 Sb alloy intermediate at the edge region of bulk β‐phase antimony by pre‐lithiation in the presence of n‐butyllithium and internal pressure is put forward. A protonation process converts the Li 3 Sb to gaseous stibine (SbH 3 ) in a liquid solution, enabling an upward buoyancy together with the endothermic opening of the galleries that facilitate the subsequent LPE. As a result, the β‐phase antimony is efficiently exfoliated into antimonene nanosheets with perfect retention of basal plane texture (lateral size of ≈3 µm and thickness of less than 2 nm). Finally, the high‐quality antimonene being simply treated with HCl enables great Na + diffusion along the basal plane to deliver excellent capacitive deionization performance with a salt adsorption capacity of 31.4 mg g –1 at an ultra‐low NaCl concentration (135 mg L –1 ).