Dual‐gradient Engineering of Urchin‐like Silver@Copper Oxide Heterostructures for Highly Stable Lithium Metal Anodes

Abstract Lithium‐metal anodes with excellent theoretical specific capacities (3680 mAh g⁻¹) have attracted considerable attention for overcoming the capacity bottleneck of conventional graphite anodes. However, they often suffer from uncontrolled dendrite growth and undesirable side reactions, considerably limiting their practical application in lithium‐metal batteries. In this study, urchin‐like silver@copper oxide (Ag@CuO) heterostructures with gradient electrical conductivity and lithiophilicity are prepared using a facile liquid‐phase reduction method. The unique amphiphilic lithium mechanism of the alloying and conversion reactions effectively reduces the nucleation overpotential of the lithium metal anode and promotes a uniform lithium deposition process. Meanwhile, the in situ‐generated Li₂O‐rich solid electrolyte interphase (SEI) film can further induce uniform and reversible lithium plating/stripping. All these characteristics endow the Ag@CuO anode with a high Coulombic efficiency of 98.89%, even after 1200 cycles, and long cycle life of 2800 h at a current density of 0.2 mA cm⁻², thus demonstrating that such modified Li metal anodes exhibit superior compatibility with major commercial cathode materials, such as LiCoO₂ (LCO) and LiNi_0.8Co_0.1Mn_0.1O₂ (NCM‐811). Hence, this study provides an effective strategy for developing practical lithium metal anodes.