Cheng Yingwen, Stolley Ryan M, Han Kee Sung, Shao Yuyan, Arey Bruce W, Washton Nancy M, Mueller Karl T, Helm Monte L, Sprenkle Vincent L, Liu Jun, Li Guosheng
Energy Processes & Materials Division, Energy and Environmental Directorate, Richland, WA 99352, USA.
Phys Chem Chem Phys. 2015 May 28;17(20):13307-14. doi: 10.1039/c5cp00859j.
A novel Mg2(μ-Cl)2 cation complex, which is highly active for reversible Mg electrodeposition, was identified for the first time in this work. This complex was found to be present in electrolytes formulated in dimethoxyethane (DME) through dehalodimerization of non-nucleophilic MgCl2 by reacting with either Mg salts (such as Mg(TFSI)2, TFSI = bis(trifluoromethane)sulfonylimide) or Lewis acid salts (such as AlEtCl2 or AlCl3). The molecular structure of the cation complex was characterized by single crystal X-ray diffraction, Raman spectroscopy and NMR. The electrolyte synthesis process was studied and rational approaches for formulating highly active electrolytes were proposed. Through control of the anions, electrolytes with an efficiency close to 100%, a wide electrochemical window (up to 3.5 V) and a high ionic conductivity (>6 mS cm(-1)) were obtained. The understanding of electrolyte synthesis in DME developed in this work could bring significant opportunities for the rational formulation of electrolytes of the general formula [Mg2(μ-Cl)2][anion]x for practical Mg batteries.
在本工作中首次鉴定出一种对可逆镁电沉积具有高活性的新型Mg2(μ-Cl)2阳离子配合物。通过与镁盐（如Mg(TFSI)2，TFSI = 双（三氟甲烷）磺酰亚胺）或路易斯酸盐（如AlEtCl2或AlCl3）反应，使非亲核性MgCl2进行脱卤二聚反应，发现该配合物存在于在二甲氧基乙烷（DME）中配制的电解质中。通过单晶X射线衍射、拉曼光谱和核磁共振对阳离子配合物的分子结构进行了表征。研究了电解质合成过程，并提出了配制高活性电解质的合理方法。通过控制阴离子，获得了效率接近100%、宽电化学窗口（高达3.5 V）和高离子电导率（>6 mS cm(-1)）的电解质。这项工作中对DME中电解质合成的理解可为实际镁电池合理配制通式为[Mg2(μ-Cl)2][阴离子]x的电解质带来重大机遇。
