Mg-ion batteries represent a promising alternative to Li-ion batteries but face challenges with Mg dendrite formation on Mg metal anodes. Conventional solid alloy anodes prevent Mg dendrite formation but are prone to failure due to significant volume changes during (de)magnesiation. “Self-healing” electrodes composed of liquid alloys can undergo reversible liquid–solid phase transformations during (de)magnesiation, thereby “healing” themselves from the volume expansion-induced material degradation, offering a promising solution. Here, we employ a liquid eutectic Ga–In alloy as a conceptual “self-healing” Mg-ion battery anode with a 246 mA h g_GaIn⁻¹ theoretical capacity. This anode demonstrates an unprecedented cycle life of 2000 cycles at the C-rate of 1C, retaining 91% capacity (225 mA h g⁻¹ post-cycled capacity) at 25 °C. We elucidate the morphology evolution and storage mechanism during (de)magnesiation using in situ wide-angle X-ray scattering and cryogenic focused ion beam scanning electron microscopy. These results pave the way for developing high-performance electrodes for next-generation Mg-ion batteries.

中文翻译：

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液态共晶镓-铟作为镁离子电池阳极，通过室温（去）镁化过程中的液-固相变实现超长循环寿命


镁离子电池是锂离子电池的一种有前途的替代品，但面临着镁金属阳极上镁枝晶形成的挑战。传统的固体合金阳极可以防止镁枝晶的形成，但由于镁化（去）镁过程中体积发生显着变化，很容易发生故障。由液态合金组成的“自愈”电极可以在（去）镁化过程中经历可逆的液固相变，从而从体积膨胀引起的材料降解中“自我修复”，提供了一种有前途的解决方案。在这里，我们采用液态共晶 Ga-In 合金作为概念性的“自愈”镁离子电池阳极，理论容量为 246 mA hg _GaIn ^-1 。该阳极在 1C 倍率下表现出前所未有的 2000 次循环寿命，在 25 °C 时保留 91% 的容量（225 mA hg ^-1循环后容量）。我们利用原位广角 X 射线散射和低温聚焦离子束扫描电子显微镜阐明了（去）磁化过程中的形貌演变和存储机制。这些结果为开发下一代镁离子电池的高性能电极铺平了道路。