Prediction of S-functionalized double-metal TiNbC MXene monolayer as a promising anode material for superior high-capacity mono- and multivalent ion batteries

Abstract

In search of new electrode materials that improve rechargeable metal-ion batteries’ performance, S-functionalized double-metal TiNbC MXene monolayer (TiNbCS2) is designed, and its properties as an anode material for Li-, Na-, K-, Mg-, Ca-, and Al-ion batteries are investigated employing density functional theory. Due to technical issues during the preparation process, the surface of MXenes is mostly terminated by –O, –OH, and –F functional groups. It is possible to modify the surface by other terminal groups to improve MXenes’ energy storage performance. According to our findings, the TiNbCS2 monolayer, thanks to its metallic behavior, high chemical stability, low diffusion energy barriers, and low open-circuit voltages of these metal cations, is a promising anode material for rechargeable metal-ion batteries. Notably, the adsorption of multilayers of Na+ and Mg2+ cations on the surface of TiNbCS2 provides excellent capacities of 494 mA h g−1 and 988 mA h g−1 for Na- and Mg-ion batteries, respectively. Although the trivalent Al ion may offer a higher energy density, our calculations show that Al3+ ions are not adsorbed onto the surface of the TiNbCS2 monolayer effectively.