Degradation Mechanisms of Magnesium Metal Anodes in Electrolytes Based on (CF3SO2)2N– at High Current Densities

• DOI: 10.1021/acs.langmuir.7b01051
• Publication Date: 2017-06-21T22:54:58Z
• Authors: Hyun Deog Yoo; Sang-Don Han; Igor L. Bolotin; Gene M. Nolis; Ryan D. Bayliss; Anthony K. Burrell; John T. Vaughey; Jordi Cabana
• Keywords: Degradation

The energy density of rechargeable batteries utilizing metals as anodes surpasses that Li ion batteries, which employ carbon instead. Among possible metals, magnesium represents a potential alternative to the conventional choice, lithium, in terms storage density, safety, stability, and cost. However, major obstacle for metal-based is identification electrolytes show reversible deposition/dissolution metal anode support intercalation ions into cathode. Traditional Grignard-based Mg are excellent with respect deposition Mg, but their limited anodic stability compatibility oxide cathodes hinder applicability higher voltage. Non-Grignard electrolytes, consist ethereal solutions magnesium(II) bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2), remain fairly stable near deposition. slight reactivity these toward can be remedied by addition surface-protecting agents, such MgCl2. Hence, Mg(TFSI)2 salt MgCl2 an additive have been suggested representative non-Grignard electrolyte. In this work, degradation mechanisms TFSI-based electrolyte were studied using current 1 mA cm-2 areal capacity ∼0.4 mAh cm-2, close those used practical applications. identified include corrosion metal, causes loss electronic pathways mechanical integrity, nonuniform decomposition TFSI- anions. This study not only assessment behavior at also details outcomes interfacial passivation, was detected simple cyclic voltammetry experiments. points out absolute absence any passivation electrode-electrolyte interface premise developing compatible anode.