Magnesium rechargeable batteries potentially offer high-energy density, safety, and low cost due to the ability to employ divalent, dendrite-free, and earth-abundant magnesium metal anode. Despite recent progress, further development remains stagnated mainly due to the sluggish scission of magnesium-chloride bond and slow diffusion of divalent magnesium cations in cathodes. Here we report a battery chemistry that utilizes magnesium monochloride cations in expanded titanium disulfide. Combined theoretical modeling, spectroscopic analysis, and electrochemical study reveal fast diffusion kinetics of magnesium monochloride cations without scission of magnesium-chloride bond. The battery demonstrates the reversible intercalation of 1 and 1.7 magnesium monochloride cations per titanium at 25 and 60 °C, respectively, corresponding to up to 400 mAh g^-1 capacity based on the mass of titanium disulfide. The large capacity accompanies with excellent rate and cycling performances even at room temperature, opening up possibilities for a variety of effective intercalation hosts for multivalent-ion batteries.Magnesium rechargeable batteries potentially offer high-energy density, safety, and low cost. Here the authors show a battery that reversibly intercalates magnesium monochloride cations with excellent rate and cycle performances in addition to the large capacity.

中文翻译：

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层间膨胀的二硫化钛可充电电池中一氯化镁阳离子的快速动力学。

镁可充电电池由于能够使用二价，无枝晶且富含地球的镁金属阳极而具有潜在的高能量密度，安全性和低成本。尽管最近取得了进展，但主要由于氯化镁键的断裂缓慢和二价镁阳离子在阴极中的缓慢扩散，导致进一步的发展停滞不前。在这里，我们报告了一种电池化学，该化学在膨胀的二硫化钛中利用了一氯化镁阳离子。理论建模，光谱分析和电化学研究相结合，揭示了单氯化镁阳离子的快速扩散动力学，而没有破坏氯化镁键。该电池在25°C和60°C下分别显示出每钛1和1.7个一氯化镁阳离子的可逆插入，相当于高达400 mAh g^-1容量基于二硫化钛的质量。大容量带来出色的倍率和循环性能，即使在室温下也是如此，这为多种有效的多价离子电池插层主机开辟了可能性。镁可充电电池潜在地提供了高能量密度，安全性和低成本。在这里，作者展示了一种电池，该电池除了具有大容量外，还具有出色的倍率和循环性能，可逆地嵌入一氯化镁阳离子。