Achieving Dendrite‐Free Lithium Metal Batteries by Constructing a Dense Lithiophilic Cu_1.8Se/CuO Heterojunction Tip

Abstract Lithium (Li) metal batteries (LMBs) have garnered widespread attention due to their high specific capacity. However, the growth of lithium dendrite severely limits their practical applications. Herein, a novel strategy is proposed to regulate the overall potential strength and lithium ions (Li⁺) concentration on the surface of the current collector by utilizing densely distributed tip effects. This concept is exemplified through the construction of lithiophilic Cu_1.8Se/CuO heterojunction needle array on the Cu foil, ultimately achieving dendrite‐free lithium deposition. Based on the simulation in COMSOL multiphysics and experimental research, this design is demonstrated to enrich Li⁺ on the current collector surface, delay the formation of space charge regions, and mitigate the growth of lithium dendrites. Additionally, a built‐in electric field (BIEF) triggered by the heterointerface between Cu_1.8Se and CuO further alleviates the Li⁺ concentration gradient on the electrode surface, achieving uniform bottom‐up deposition of Li within the array structure. Consequently, the symmetrical cell exhibits an ultra‐long cycle life of 2400 h (1 mA cm⁻², 1 mAh cm⁻²) with an extremely low overpotential of 13 mV. Furthermore, full batteries using LiFePO₄ as the cathode exhibit superior cycle stability and rate performance. This study presents a promising approach for designing dendrite‐free current collectors in LMBs.