Metallic magnesium is a promising high-capacity anode material for energy storage technologies beyond lithium-ion batteries. However, most reported Mg metal anodes are only cyclable under shallow cycling (≤1 mAh cm^–2) and thus poor Mg utilization (<3%) conditions, significantly compromising their energy-dense characteristic. Herein, composite Mg metal anodes with high capacity utilization of 75% are achieved by coating magnesiophilic gold nanoparticles on copper foils for the first time. Benefiting from homogeneous ionic flux and uniform deposition morphology, the Mg-plated Au–Cu electrode exhibits high average Coulombic efficiency of 99.16% over 170 h cycling at 75% Mg utilization. Moreover, the full cell based on Mg-plated Au–Cu anode and Mo₆S₈ cathode achieves superior capacity retention of 80% after 300 cycles at a low negative/positive ratio of 1.33. This work provides a simple yet effective general strategy to enhance Mg utilization and reversibility, which can be extended to other metal anodes as well.

中文翻译：

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由亲镁涂层实现的复合镁金属阳极的高利用率

金属镁是一种很有前途的高容量负极材料，可用于锂离子电池以外的储能技术。然而，大多数报道的 Mg 金属阳极只能在浅循环 (≤1 mAh cm ^–2 ) 下循环，因此 Mg 利用率低 (<3%) 条件下，显着损害了它们的能量密度特性。在此，首次通过在铜箔上涂覆亲镁金纳米粒子，实现了容量利用率高达 75% 的复合镁金属负极。得益于均匀的离子通量和均匀的沉积形态，镀镁的 Au-Cu 电极在 75% 的 Mg 利用率下，在 170 小时的循环中表现出 99.16% 的高平均库仑效率。此外，基于镀镁 Au-Cu 阳极和 Mo ₆ S _{8的全电池}正极在 1.33 的低负/正比下在 300 次循环后实现了 80% 的出色容量保持率。这项工作提供了一种简单而有效的通用策略来提高镁的利用率和可逆性，也可以扩展到其他金属阳极。