Engineering Oxygen‐Terminated Hexagonal MBene for Accelerated Lithium Migration and Exceptional Lithium‐Ion Battery Performance

Abstract Ultrathin 2D hexagonal transition metal borides ( h ‐MBenes) hold significant promise for advancing energy storage technologies. Herein, with cost‐effective methods and earth‐abundant metals, the experimental feasibility of atomically thin Ti‐based 2D h ‐MBenes (TiBT x ) for lithium‐ion battery application is reported for the first time. These thin‐layer nanosheets are synthesized by using ZnCl 2 molten salt as Ti 2 InB 2 etchant, followed with a delaminated intercalation of tetrabutylammonium hydroxide (denoted as d‐TiBT x ). The formation of disorderly low‐boiling‐point Zn‐In intermediate phase is revealed to significantly reduce the In migration energy barrier and accelerate the lattice‐In release from parent Ti 2 InB 2 under low‐temperature. Moreover, in‐depth analyses reveal that the formation of O‐termination on the atomic d‐TiBT x surface endows d‐TiBT x h ‐MBene with exceptional lithium‐ion migration, achieving an impressive specific capacity of 530 mAh g −1 at 0.1 A g −1 and an exceptional rate capability of 120 mAh g −1 at 10 A g −1 . Notably, a lithium full‐cell paired with a LiFePO 4 cathode achieves an impressive energy density of 425 Wh kg −1 and retains 94.3% of its capacity after 100 cycles, sufficient to power a toy car under normal operation. This work confirms the usefulness of ultrathin Ti‐based 2D MBenes, paving the way for innovatively harnessing the potential application of h ‐MBenes.