Metal-air battery is an environmental friendly energy storage system with unique open structure. Magnesium (Mg) and its alloys have been extensively attempted as anodes for air batteries due to high theoretical energy density, low cost, and recyclability. However, the study on Mg-air battery (MAB) is still at the laboratory level currently, mainly owing to the low anodic efficiency caused by the poor corrosion resistance. In order to reduce corrosion losses and achieve optimal utilization efficiency of Mg anode, the design strategies are reviewed from microstructure perspectives. Firstly, the corrosion behaviors have been discussed, especially the negative difference effect derived by hydrogen evolution. Special attention is given to the effect of anode micro-structures on the MAB, which includes grain size, grain orientation, second phases, crystal structure, twins, and dislocations. For further improvement, the discharge performance, long period stacking ordered phase and its enhancing effect are considered. Meanwhile, given the current debates over Mg dendrites, the potential risk, the impact on discharge, and the elimination strategies are discussed. Microstructure control and single crystal would be promising ways for MAB anode.

中文翻译：

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先进镁空气电池负极微结构设计

金属空气电池是一种具有独特开放式结构的环保型储能系统。镁（Mg）及其合金由于理论能量密度高、成本低和可回收性而被广泛尝试作为空气电池的阳极。然而，目前对镁空气电池（MAB）的研究仍处于实验室水平，主要是由于耐腐蚀性差导致阳极效率低。为了减少镁阳极的腐蚀损失并实现最佳利用效率，从微观结构角度对设计策略进行了综述。首先，讨论了腐蚀行为，特别是析氢引起的负差异效应。特别关注阳极微结构对 MAB 的影响，包括晶粒尺寸、晶粒取向、第二相、晶体结构、孪晶和位错。为了进一步改进，考虑了放电性能、长周期堆垛有序相及其增强效果。同时，针对目前关于镁枝晶的争论，讨论了其潜在风险、对排放的影响以及消除策略。微观结构控制和单晶将是 MAB 阳极的有前途的方法。