Functionalizing Janus-structured Ti2B2 unveils exceptional capacity and performance in lithium-ion battery anodes.

[Display omitted] With the ever-growing demand for high-capacity energy storage technologies, lithium-ion batteries (LIBs) have drawn increasing attention. Ti 2 B 2 , a typical two-dimensional MBenes material, has been considered as a strong contender for anode materials of LIBs with significant performance. However, the limited Li storage capacity of MBenes has hindered its wide applications. To address this issue, we have functionalized Janus-structured MBenes, denoted as Ti 2 B 2 X a X b (X a /X b = N, O, S, Se). Employing first-principles simulations based on density functional theory, we have investigated the geometric characteristics and electrochemical properties of Ti 2 B 2 X a X b. Our results reveal that Ti 2 B 2 NO exhibits an exceptionally large theoretical specific capacity of 1091.17 mAh·g−1, improved by 2.4 times compared with the pristine Ti 2 B 2 (456 mAh·g−1). Li atoms on the O side of Ti 2 B 2 NO possess a low diffusion barrier of 0.33 eV, which is conducive to the rapid charging and discharging of the battery. Moreover, the open-circuit voltage of Ti 2 B 2 NO within the safe voltage range of 0–1 V ensures the safety of battery operation. Overall, our study sheds light on understanding the underlying mechanism of surface functionalization on the Li storage properties of Janus-structured MBenes from atomic-scale, laying the groundwork for future design of high-performance anode materials. [ABSTRACT FROM AUTHOR]