Bismuthene Arrays Harvesting Reversible Plating‐Alloying Electrochemistry Toward Robust Lithium Metal Batteries

3D lithiophilic skeletons have attracted enormous attention in homogenizing local current distribution and optimizing metal deposition in the pursuit of robust Li metal anodes. Nonetheless, their practicability is markedly plagued by the cumbersome production routes and mediocre Coulombic efficiency (CE) of Li plating/stripping. Herein, scalable in situ growth of uniform bismuthene arrays over commercial Cu foam via spontaneous galvanic replacement reaction is demonstrated. Exhaustive structural/electrochemical measurements in combination with theoretical calculations collectively disclose the reversible plating‐alloying mechanism, wherein the formed Li₃Bi alloy interphase aids to lower the Li nucleation overpotential and elevate the CE performance. The thus‐designed Li metal electrode sustains a stable cyclic operation at 1 mA cm⁻²/1 mAh cm⁻² for 1600 h. When paired with LiFePO₄ and sulfur cathodes, the Li metal batteries enable gratifying rate capability and cycling durability. This straightforward maneuver opens a new frontier in the scalable manufacturing of pragmatic current collectors in an economic fashion.