Mg‐ion batteries (MIBs) possess promising advantages over monovalent Li‐ion battery technology. However, one of the myriad obstacles in realizing highly efficient MIBs is a limited selection of cathode materials that can enable reversible, stable Mg²⁺ intercalation at a high operating voltage. Here, a scalable method is showcased to synthesize a hydrated Mg_xV₅O₁₂ cathode, which shows a high capacity of ≈160 mAh g⁻¹ with a high voltage of 2.1 V, a decent rate capability, and an outstanding cycling life (e.g., 81% capacity retention after 10 000 cycles). The combination of in situ and ex situ characterizations and first‐principles calculations provides evidence of reversible, facile topochemical Mg²⁺ intercalation into the expanded 2D channels of the hydrated Mg_xV₅O₁₂ cathode, which results from the synergistic effects of Mg²⁺ pillars and structural H₂O. The findings underscore the advantage of the rich but controllable chemistry of vanadium oxide bronzes in achieving practical multivalent cation mobility.

中文翻译：

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具有改进的Mg2 +存储性能的水合MgxV5O12阴极

镁离子电池（MIB）优于单价锂离子电池技术。但是，实现高效MIB的众多障碍之一是有限的阴极材料选择，这些材料可以在高工作电压下实现可逆，稳定的Mg ²⁺嵌入。在这里，展示了一种可扩展的方法来合成水合Mg _x V ₅ O ₁₂阴极，该阴极表现出≈160mAh g ^-1的高容量，2.1 V的高电压，良好的倍率能力和出色的循环寿命（例如，在1万次循环后，容量保留率为81％）。原位和异位表征与第一性原理计算的结合提供了可逆的，易制的拓扑化学镁的证据²⁺嵌入到水合Mg _x V ₅ O ₁₂阴极的扩展2D通道中，这是由于Mg ²⁺柱和结构H ₂ O的协同作用^所致。这些发现强调了钒氧化物化学丰富但可控的优点。青铜在实现实用的多价阳离子迁移率方面。