现场表面增强红外光谱法研究离子液体中锌电沉积过程:水的影响

In-situ Surface Enhanced Infrared Absorption Spectroscopic(SEIRAS)Study of Zinc Electrodeposition in Ionic Liquid:Effect of Water

利用离子液体[Emim]BF4作为电解液,研究了不同锌盐种类对提高锌电沉积过程效率的影响.分别将4种锌盐Zn(BF4)2、ZnCl2、ZnSO4、Zn(NO3)2添加到离子液体中,循环伏安结果表明引入ZnCl2可以达到较高的电流密度以及较好的反应可逆性.在此基础上,进一步研究了微量水对锌电沉积过程的影响,发现体积比为5%的水的引入可以使锌的沉积电位正移,提高反应电流密度,并同时提高体系可逆性.综合考虑电极反应电流密度、可逆性及锌盐溶解度,本文选择较为理想的ZnCl2作为锌盐,对其在无水离子液体体系及有水体系分别进行了现场表面增强红外光谱法研究,对锌电沉积过程中的电极界面结构进行了分析,得到了不同电位下电极的界面结构示意图.

The electrochemical efficiency of zinc electrodeposition in ionic liquid[Emim]BF4 with different zinc salt has been investigated.By comparing the cyclic voltammetry results of four zinc salts including Zn（BF4）2,ZnCl2,ZnSO4 and Zn（NO3）2 in ionic liquid,it has been found that ZnCl2 system presents relatively higher current density and better reversibility.The effect of the addition of water has also been studied,the potential of zinc deposition shifts positively and the reaction current density as well as the reversibility has been improved upon the addition of5%（V/V）water.The electrochemical deposition processes of Zn in [Emim]BF4＋ ZnCl2 with water or without water has been monitored by using in-situ surface enhanced infrared absorption spectroscopy（SEIRAS）,and the interfacial structure during Zn deposition processes has been discussed,and the structure models at different potential has been presented.