Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States.
Langmuir. 2017 Sep 19;33(37):9426-9433. doi: 10.1021/acs.langmuir.7b01111. Epub 2017 Jul 6.
Magnesium batteries are a promising alternative to lithium-ion batteries due to the widespread abundance of magnesium and its high specific volumetric energy capacity. Ethereal solvents such as tetrahydrofuran (THF) are commonly used for magnesium-ion electrolytes due to their chemical compatibility with magnesium metal, but the volatile nature of THF is a concern for practical application. Herein, we investigate magnesium bis(hexamethyldisilazide) plus aluminum chloride (Mg(HMDS)-AlCl) electrolytes in THF, diglyme, and tetraglyme at varying temperature. We find that, despite the higher thermal stability of the glyme-based electrolytes, THF-based electrolytes have better reversibility at room temperature. Deposition/stripping efficiency is found to be a strong function of temperature. Diglyme-based Mg(HMDS)-AlCl electrolytes are found to not exchange as quickly as THF and tetraglyme, stabilizing AlCl and facilitating undesired aluminum deposition. Raman spectroscopy, Al NMR, and mass spectrometry are used to identify solution speciation.
镁电池作为锂离子电池的替代品具有广阔的前景，因为镁在自然界中储量丰富，且具有较高的比体积能量容量。由于与镁金属具有化学兼容性，四氢呋喃（THF）等醚类溶剂通常被用于镁离子电解质，但 THF 的挥发性是实际应用中的一个关注点。在此，我们研究了在不同温度下，THF、二甘醇和四甘醇中双（六甲基二硅氮烷）镁加氯化铝（Mg（HMDS）-AlCl）电解质。我们发现，尽管甘醇基电解质具有更高的热稳定性，但基于 THF 的电解质在室温下具有更好的可逆性。沉积/剥离效率被发现是温度的强函数。基于二甘醇的 Mg（HMDS）-AlCl 电解质的交换速度不如 THF 和四甘醇快，这稳定了 AlCl 并促进了不希望的铝沉积。拉曼光谱、Al NMR 和质谱用于确定溶液形态。
