Aqueous rechargeable batteries show great application prospects in large‐scale energy storage because of their reliable safety and low cost. However, a key challenge in developing this battery system lies in its low energy density. Herein, a high‐energy manganese–metal hydride (Mn–MH) hybrid battery is reported in which a Mn‐based cathode operated by the Mn²⁺/MnO₂ deposition–dissolution reactions, a hydrogen‐storage alloy anode that absorbs and desorbs hydrogen in an alkaline solution, and a proton‐exchange membrane separator are employed. Given the benefit derived from the high solubility and high specific capacity of the Lewis acidic MnCl₂ in the cathode and the low electrode potential of the MH anode, this aqueous Mn–MH hybrid battery exhibits impressive electrochemical properties with admirable discharge voltage plateaus up to 2.2 V, a competitive energy density of about 240 Wh kg⁻¹ (based on the total mass of the 5.5 m MnCl₂ solution and the hydrogen storage alloy electrode system), good cycling stability over 130 cycles, and a desirable rate capability. This work demonstrates a new strategy for achieving high‐performance and low‐cost aqueous rechargeable batteries.

中文翻译：

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高能锰水金属氢化物混合电池。

水性充电电池由于其可靠的安全性和低成本而在大规模储能中显示出广阔的应用前景。然而，开发这种电池系统的关键挑战在于其低能量密度。本文报道了一种高能锰-金属氢化物（Mn-MH）混合电池，其中通过Mn ²⁺ / MnO ₂沉积-溶解反应操作的Mn基阴极，吸收和解吸氢存储合金的阳极使用碱性溶液中的氢气和质子交换膜分离器。得益于路易斯酸性MnCl ₂的高溶解度和高比容量在正极和MH阳极的低电极电位下，这种Mn-MH混合水电池表现出令人印象深刻的电化学性能，具有令人赞叹的高达2.2 V的放电电压平台，竞争能量密度约为240 Wh kg ^-1（基于总5.5 m MnCl ₂溶液和储氢合金电极系统的质量），在130个循环中具有良好的循环稳定性以及理想的倍率能力。这项工作展示了实现高性能和低成本水性可充电电池的新策略。