Rechargeable aluminum-ion batteries have attracted increasing attention owing to the advantageous multivalent ion storage mechanism thus high theoretical capacity as well as inherent safety and low cost of using aluminum. However, their development has been largely impeded by the lack of suitable positive electrodes to provide both sufficient energy density and satisfactory rate capability. Here we report a candidate positive electrode based on ternary metal oxides, Fe2(MoO4)3, which assembled by cross-stacking of porous nanosheets, featuring superior rate performance and cycle stability, and most importantly a well-defined discharge voltage plateau near 1.9 V. Specifically, the positive electrode is able to deliver reversible capacities of 239.3 mAh g-1 at 0.2 A g-1 and 73.4 mAh g-1 at 8.0 A g-1, and retains impressively 126.5 mAh g-1 at 1.0 A g-1 after 2000 cycles. Furthermore, the aluminum-storage mechanism operating on Al3+ intercalation in this positive electrode is demonstrated for the first time via combined in-situ and ex-situ characterizations and density functional theory calculations. This work not only explores potential positive electrodes for aluminum-based batteries but also sheds light on the fundamental charge storage mechanism within the electrode.

中文翻译：

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通过交叉堆叠多孔纳米片组装的 Fe2(MoO4)3 可实现高性能铝离子电池


可充电铝离子电池由于有利的多价离子存储机制、高理论容量以及固有的安全性和使用铝的低成本而引起了越来越多的关注。然而，由于缺乏合适的正极来提供足够的能量密度和令人满意的倍率性能，它们的发展在很大程度上受到阻碍。在此，我们报告了一种基于三元金属氧化物 Fe2(MoO4)3 的候选正极，该正极通过交叉堆叠多孔纳米片组装而成，具有优异的倍率性能和循环稳定性，最重要的是具有接近 1.9 V 的明确放电电压平台具体来说，正极能够在 0.2 A g-1 时提供 239.3 mAh g-1 的可逆容量，在 8.0 A g-1 时提供 73.4 mAh g-1 的可逆容量，并在 1.0 A g-1 时保留令人印象深刻的 126.5 mAh g-1。 1 2000 次循环后。此外，通过结合原位和异位表征以及密度泛函理论计算，首次证明了该正极中 Al3+ 插层的铝储存机制。这项工作不仅探索了铝基电池的潜在正极，而且还揭示了电极内基本的电荷存储机制。