Huang Dan, Tan Shuangshuang, Li Maosheng, Wang Dandan, Han Chunhua, An Qinyou, Mai Liqiang
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, Hubei, China.
Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States.
ACS Appl Mater Interfaces. 2020 Apr 15;12(15):17474-17480. doi: 10.1021/acsami.0c00196. Epub 2020 Apr 3.
The application of high-energy Mg/S batteries was obstructed by the insufficiency of low-cost and non-nucleophilic electrolyte. In this work, a non-nucleophilic electrolyte was prepared by facilely dissolving Mg(CFSO), MgCl, and AlCl in 1,2-dimethoxyethane (DME). The equilibrium species of the MTB electrolyte mainly comprise [Mg(μ-Cl)(DME)] and [(CFSO)AlCl], which are generated by dehalodimerization reaction and Lewis acid-base reaction, respectively. The electrolyte exhibits a highly efficient reversible Mg deposition/dissolution, low overpotential of around 250 mV, and good oxidative stability up to 3.5 V after conditioning. The conditioning process that the active [Mg(μ-Cl)(DME)] species transforms into [Mg(μ-Cl)(μ-Cl)(DME)] was demonstrated, owing to the irreversible deposition of Al on Mg foil. More importantly, this electrolyte exhibited good compatibility and kinetics for reversible Mg/MgS redox, resulting in a high specific capacity of 866 mAh g at 200 mA g and high power density of 550 W kg. This work offers a new direction for low-cost, non-nucleophilic electrolyte and paves the way to explore high-power Mg/S batteries.
低成本且非亲核性电解质的不足阻碍了高能镁/硫电池的应用。在这项工作中，通过将Mg(CFSO)、MgCl和AlCl轻松溶解于1,2 - 二甲氧基乙烷（DME）中制备了一种非亲核性电解质。MTB电解质的平衡物种主要包括[Mg(μ-Cl)(DME)]和[(CFSO)AlCl]，它们分别通过脱卤二聚反应和路易斯酸碱反应生成。该电解质表现出高效的可逆镁沉积/溶解、约250 mV的低过电位以及在预处理后高达3.5 V的良好氧化稳定性。证明了由于铝在镁箔上的不可逆沉积，活性[Mg(μ-Cl)(DME)]物种转变为[Mg(μ-Cl)(μ-Cl)(DME)]的预处理过程。更重要的是，这种电解质对于可逆镁/硫化镁氧化还原表现出良好的兼容性和动力学，在200 mA g下具有866 mAh g的高比容量以及550 W kg的高功率密度。这项工作为低成本、非亲核性电解质提供了新方向，并为探索高功率镁/硫电池铺平了道路。
