Instability at the Electrode/Electrolyte Interface Induced by Hard Cation Chelation and Nucleophilic Attack,Chemistry of Materials

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Instability at the Electrode/Electrolyte Interface Induced by Hard Cation Chelation and Nucleophilic Attack
Chemistry of Materials ( IF 7.2 ) Pub Date : 2017-10-02 00:00:00 , DOI: 10.1021/acs.chemmater.7b03404
Yi Yu _{1,

2} , Artem Baskin _{3,

4} , Carlos Valero-Vidal _{1,

4} , Nathan T. Hahn _{4,

5} , Qiang Liu _{1,

6} , Kevin R. Zavadil _{4,

5} , Bryan W. Eichhorn ₂ , David Prendergast _{3,

4} , Ethan J. Crumlin _{1,

4}

Affiliation

Electrochemistry is necessarily a science of interfacial processes, and understanding electrode/electrolyte interfaces is essential to controlling electrochemical performance and stability. Undesirable interfacial interactions hinder discovery and development of rational materials combinations. By example, we examine an electrolyte, magnesium(II) bis(trifluoromethanesulfonyl)imide (Mg(TFSI)₂) dissolved in diglyme, next to the Mg metal anode, which is purported to have a wide window of electrochemical stability. However, even in the absence of any bias, using in situ tender X-ray photoelectron spectroscopy, we discovered an intrinsic interfacial chemical instability of both the solvent and salt, further explained using first-principles calculations as driven by Mg²⁺ dication chelation and nucleophilic attack by hydroxide ions. The proposed mechanism appears general to the chemistry near or on metal surfaces in hygroscopic environments with chelation of hard cations and indicates possible synthetic strategies to overcome chemical instability within this class of electrolytes.

中文翻译：

硬阳离子螯合和亲核攻击引起的电极/电解质界面的不稳定性

电化学必定是一门界面工艺的科学，了解电极/电解质界面对于控制电化学性能和稳定性至关重要。不良的界面相互作用阻碍了合理材料组合的发现和发展。例如，我们检查了一种电解质，即溶解在二甘醇二甲醚中的二甲基三（三氟甲磺酰）亚胺镁（Mg（TFSI）₂），紧挨着Mg金属阳极，据称它具有宽的电化学稳定性窗口。然而，即使在没有任何偏差的情况下，我们也使用原位嫩X射线光电子能谱法发现了溶剂和盐的固有界面化学不稳定性，这是由Mg ²⁺驱动的第一性原理计算进一步解释的。氢氧根离子的螯合和亲核攻击。所提出的机理似乎对具有吸湿性环境的金属表面附近或表面上的化学物质具有螯合硬阳离子的化学作用是通用的，并表明了克服此类电解质中化学不稳定性的可能的合成策略。

更新日期：2017-10-03

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