Effect of Electrolytic Properties of a Magnesium Organohaloaluminate Electrolyte on Magnesium Deposition
Effect of Electrolytic Properties of a Magnesium Organohaloaluminate Electrolyte on Magnesium Deposition
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DOI：
10.1021/jp4077068
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发表时间：
2013-12-26
影响因子：
3.7
通讯作者：
Prakash, Jai
中科院分区：
文献类型：
--
作者：
Benmayza, Aadil;Ramanathan, Mayandi;Prakash, Jai
采用电化学输运测量和原位电化学/X射线吸收光谱研究了有机卤铝酸镁复合电解质。采用循环伏安法研究了电化学沉积镁的可逆性。为了更好地理解该电解质系统的作用，在不同浓度下测量了Mg离子种类的离子传输性质，例如迁移数、离子电导率和扩散系数。迁移数通过原子吸收光谱法通过量化Pt电极上的电位Mg沉积量来确定。尽管显示出100%的库仑效率的Mg沉积和溶解，电解质显示出低的离子电导率和迁移数在中等和更高的浓度。为了进一步研究所观察到的传输性质，用Mg K边的原位/操作中X射线吸收光谱监测镁从[Mg-2（μ-Cl）（3）中心点6（OC 4 H8）]（+）的电化学沉积。扩展的X射线吸收精细结构（EXAFS）分析表明，在低于镁电镀电位的非二聚体和界面镁中间体的存在下。从电化学传输的结果和在原位/在operando X-射线吸收测量相结合，镁沉积在有机卤铝酸盐电解质的机制提出。
Complex magnesium organohaloaluminate electrolytes were studied by electrochemical transport measurements and in-situ electrochemical/X-ray absorption spectroscopy. Cyclic voltammetry was employed to examine the reversibility of electrochemical magnesium deposition. To better understand the role of this electrolyte system, ionic transport properties such as transference number, ionic conductivity, and diffusion coefficient of Mg-ion species were measured at different concentrations. Transference number was determined by atomic absorption spectroscopy by quantifying the amount of potentiometric Mg deposition on Pt electrode. Despite exhibiting 100% Coulombic efficiency for Mg deposition and dissolution, the electrolyte showed low ionic conductivity and transference number at moderate and higher concentrations. To further investigate the observed transport properties, electrochemical deposition of magnesium from [Mg-2(mu-Cl)(3)center dot 6(OC4H8)](+) was monitored with in-situ/in-operando X-ray absorption spectroscopy of the Mg K-edge. Extended X-ray absorption fine structure (EXAFS) analysis revealed the presence of a nondimeric and interfacial Mg intermediate at potentials below Mg plating. From a combination of the electrochemical transport results and in-situ/in-operando X-ray absorption measurements, a mechanism for Mg deposition in organohaloaluminate electrolyte is proposed.