SrCl_(2)-KCl-MgCl_(2)熔体中氯化镁的电化学行为和镁锶共沉积机理  

Electrochemical behavior of MgCl_(2) and co-deposition mechanisms of Mg and Sr in SrCl_(2)−KCl−MgCl_(2) melt

作　　者：赵佳 闫艺航 张皓 高华阳 张烨[1,2,3] 路贵民 Jia ZHAO;Yi-hang YAN;Hao ZHANG;Hua-yang GAO;Ye ZHANG;Gui-min LU(National Engineering Research Center for Integrated Utilization of Salt Lake Resource,East China University of Science and Technology,Shanghai 200237,China;Joint International Laboratory for Potassium and Lithium Strategic Resources,East China University of Science and Technology,Shanghai 200237,China;School of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]华东理工大学国家盐湖资源综合利用工程技术研究中心,上海200237 [2]华东理工大学钾锂战略资源国际联合实验室,上海200237 [3]华东理工大学化工学院,上海200237

出　　处：《Transactions of Nonferrous Metals Society of China》2024年第7期2381-2392,共12页中国有色金属学报（英文版）

基　　金：the financial support provided by the National Natural Science Foundation of China(No.U20A20147)。

摘　　要：采用循环伏安法、方波伏安法、开路电位等电化学手段评估SrCl_(2)-KCl共晶体系中MgCl_(2)的电化学行为和Mg、Sr共沉积机理。在SrCl_(2)-KCl体系中,Mg(Ⅱ)在钨电极的还原属于一步两电子的准可逆过程;Mg、Sr的电化学共沉积过程形成两种Mg-Sr金属间化合物。基于计时电流法探索共沉积过程的成核类型随过电位的演变关系,结果显示,电极表面的成核模式依赖于基体材料和电极反应产物。所有过电位下对应的前期成核归因于Mg(Ⅱ)的还原。当Mg和Sr共同沉积时,首先是Mg(Ⅱ)在电极表面还原,形成Mg核,随后同时进行Sr(Ⅱ)在Mg表面欠电位沉积和Mg的沉积。此外,随着SrCl_(2)-KCl体系中MgCl_(2)浓度的增加,Mg-Sr共沉积过程中的电流密度相应增加。The electrochemical behavior of MgCl_(2) and the co-deposition mechanisms of Mg and Sr in the SrCl_(2)−KCl eutectic system were evaluated using various electrochemical techniques,including cyclic voltammetry(CV),square wave voltammetry(SWV),and open-circuit potential(OCP)analysis.It was observed the Mg(II)reduction on the tungsten electrode in SrCl_(2)−KCl melt occurred in a single-step process involving the transfer of two electrons,exhibiting a quasi-reversible mode.The electrochemical co-deposition of Mg and Sr in the SrCl_(2)−KCl−MgCl_(2) melt involved the formation of two types of Mg−Sr intermetallic compounds.The evolution in the co-deposition mechanism of the nucleation type with changing overpotential was explored through chronoamperometry(CA).It is shown that the nucleation pattern on the electrode surface was depended on the substrate materials and the electrode reaction products.Early-stage nucleation was attributed to Mg(II)reduction under all overpotential conditions.With the co-deposition of Mg and Sr,Mg(II)was reduced to form the Mg nucleus on the electrode surface,followed by underpotential deposition of Sr(II)on the Mg surface accompanied by Mg deposition simultaneously.Additionally,increasing MgCl_(2) concentration in the SrCl_(2)−KCl melt resulted in a higher current density during the Mg−Sr co-deposition process.

关 键 词：氯化镁 电化学行为 扩散系数 成核机理 共沉积 

分 类 号：TF822[冶金工程—有色金属冶金]