Borophene, the lightest two-dimensional (2D) metallic material, exhibits many outstanding physical and chemical properties and holds great potential in the energy storage domain. However, the high surface activity and strong electronic interactions between borophene and Ag substrate raise a great challenge in its exfoliation, restricting its practical applications. Herein, halogen atoms (X = F, Cl, and Br) are used to passivate the surface of triangular borophene (t-borophene), which could not only increase its structural stability but also decrease their interfacial bonding. The halogenation of t-borophene on Ag substrate gives rise to B₃X, a corrugated 2D Janus material as determined by the unbiased structure search. Compared with the pristine t-borophene, B₃X exhibits weaker binding to the Ag(1 1 1) substrate. Interestingly, the obtained B₃F and B₃Cl exhibit isotropic mechanical properties and linear Dirac band, resembling the well-known 2D graphene. However, as an anode material in Na- and K-ion batteries, B₃F demonstrates degenerated theoretical capacity of 695 and 347 mAh/g, respectively. Nevertheless, the extreme shallow ion-hopping barriers on the X side of B₃F and B₃Cl were determined, which are typically smaller than 0.11 eV, indicating high ionic conductivity were retained. These results provide a steady path towards borophene functionalization, exfoliation, and utilization.

硼烯是最轻的二维 (2D) 金属材料，具有许多优异的物理和化学性质，在储能领域具有巨大潜力。然而，硼烯与银基底之间的高表面活性和强电子相互作用对其剥离提出了巨大挑战，限制了其实际应用。在此，卤素原子（X = F、Cl 和 Br）用于钝化三角硼烯（t-borophene）的表面，这不仅可以增加其结构稳定性，还可以减少它们的界面键合。t-硼烯在 Ag 基材上的卤化产生 B ₃ X，这是一种由无偏结构搜索确定的波纹二维 Janus 材料。与原始叔硼烯相比，B ₃X 与 Ag(1  1  1) 底物的结合较弱。有趣的是，获得的 B ₃ F 和 B ₃ Cl 表现出各向同性的机械性能和线性狄拉克带，类似于众所周知的二维石墨烯。然而，作为钠离子和钾离子电池的负极材料，B ₃ F 的理论容量分别为 695 和 347 mAh/g。然而，确定了 B ₃ F 和 B ₃ Cl的 X 侧极浅的离子跳跃势垒，它们通常小于 0.11 eV，表明保留了高离子电导率。这些结果为硼烯功能化、剥离和利用提供了稳定的途径。