Synthesis, Crystal Structure, and Electrochemical Properties of a Simple Magnesium Electrolyte for Magnesium/Sulfur Batteries

• Published in: Angewandte Chemie 2016-05, Vol.128 (22), p.6516-6520
• Main Authors: Li, Wanfei, Cheng, Shuang, Wang, Jian, Qiu, Yongcai, Zheng, Zhaozhao, Lin, Hongzhen, Nanda, Sanjay, Ma, Qian, Xu, Yan, Ye, Fangmin, Liu, Meinan, Zhou, Lisha, Zhang, Yuegang
• Format: Article
• Language: eng ; ger
• Subjects: Anodic; Batteries; Battery cycles; Chemistry; Conductivity; Conversion; Crystal structure; Cycles; Efficiency; Electrochemical analysis; Electrochemistry; Electrodes; Electrolytes; Electrolytic cells; Elektrochemie; Elektrolyte; Ion currents; Magnesium; Metals; Passivity; Salts; Schwefel; Stability; Sulfur; Wiederaufladbare Batterien
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.201600256

Most simple magnesium salts tend to passivate the Mg metal surface too quickly to function as electrolytes for Mg batteries. In the present work, an electroactive salt [Mg(THF)6][AlCl4]2 was synthesized and structurally characterized. The Mg electrolyte based on this simple mononuclear salt showed a high Mg cycling efficiency, good anodic stability (2.5 V vs. Mg), and high ionic conductivity (8.5 mS cm−1). Magnesium/sulfur cells employing the as‐prepared electrolyte exhibited good cycling performance over 20 cycles in the range of 0.3–2.6 V, thus indicating an electrochemically reversible conversion of S to MgS without severe passivation of the Mg metal electrode surface. Einfach und effektiv: Das einfache Magnesiumsalz [Mg(THF)6][AlCl4]2 eignet sich als Elektrolyt mit hoher reversibler Mg‐Zykleneffizienz, guter Anodenstabilität und guter Ionenleitfähigkeit. Mg‐S‐Batterien mit diesem Elektrolyt durchliefen 20 Zyklen, was auf eine elektrochemisch reversible Umwandlung von Schwefel in MgS hindeutet.