Magnesium as a promising alloy‐type anode material for lithium‐ion batteries features both high theoretical specific capacity (2150 mAh g⁻¹) and stack energy density (1032 Wh L⁻¹). However, the poor cycling performance of Mg‐based anodes severely limits their application, mainly because high‐impedance films can grow easily on the surface of Mg and cause diminished electrochemical activity. As a result, the capacities of reported Mg anodes fade quickly in less than 100 cycles. To improve the stability of Mg anodes, 3D Cu@Mg@C structures are prepared by depositing Mg/C composite on 3D Cu current collectors. The resulting 3D Cu@Mg@C anodes can deliver an initial capacity of 1392 mAh g⁻¹. With a second‐cycle capacity of 1255 mAh g⁻¹, 91% can be retained after 1000 cycles at 0.5 C. When cycled at 2 C, the initial capacity can be maintained for 4000 cycles. This remarkably improved cycling performance can be attributed to both the 3D structure and the embedded carbon layers of the 3D Cu@Mg@C electrodes that facilitate electrical contact and prevent the growth of high‐impedance films during cycling. With 3D Cu@Mg@C anodes and LiFePO₄ cathodes, full cells are assembled and charging by a rotating triboelectric nanogenerator that can harvest mechanical energy is demonstrated.

中文翻译：

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锂离子电池循环稳定性增强的镁阳极

镁作为锂离子电池的有希望的合金型负极材料，具有很高的理论比容量（2150 mAh g ^-1）和堆能量密度（1032 Wh L ^-1）。但是，镁基阳极的不良循环性能严重限制了它们的应用，这主要是因为高阻抗膜很容易在镁表面上生长并导致电化学活性降低。结果，所报道的镁阳极的容量在不到100个循环内迅速衰减。为了提高Mg阳极的稳定性，通过在3D Cu集电器上沉积Mg / C复合材料来制备3D Cu @ Mg @ C结构。所得的3D Cu @ Mg @ C阳极可提供1392 mAh g ^-1的初始容量。第二循环容量为1255 mAh g ^-1在0.5 C下循环1000次后，可保留91％。在2 C下循环时，初始容量可维持4000个循环。这种显着改善的循环性能可归因于3D结构和3D Cu @ Mg @ C电极的嵌入式碳层，它们有助于电接触并防止循环过程中高阻抗膜的生长。借助3D Cu @ Mg @ C阳极和LiFePO ₄阴极，可以组装完整的电池，并演示了可以旋转的摩擦电纳米发电机可产生机械能的充电方式。