[3Ep01-07] Surface Science and Energy Storage: Electrode Surface Science Division's Session

[3Ep05] Overpotential of Co electrodeposition in an ionic liquid: mechanistic study using surface enhanced infrared absorption spectroscopy

*Kenta Motobayashi¹, Hyato Nakagawa¹, Yuhei Shibamura¹, Katsuyoshi Ikeda¹ (1. Graduate School of Engineering, Nagoya Institute of Technology)

Room temperature ionic liquids (RTILs), one of the promising electrolyte materials show characteristic electrochemical features in metal electrodeposition: significant overpotentials ~1 V at RT which decrease at higher temperatures. A possible origin of such characteristic behaviors is a RTIL/electrode interfacial structure consisting of multiply-ordered layers of ions. This structure is so rigid that suspected to inhibit electrochemical reactions. However, the origin of such a characteristic behavior is still unclear. Thus, we performed in-situ observation of RTIL/electrode interfaces under reaction condition by using surface-enhanced infrared absorption spectroscopy (SEIRAS). Simultaneous observation of interfacial structure and electrodeposition reaction revealed that interfacial restructuring is a trigger of electrodeposition, and overpotential required for the interfacial restructuring corresponds to the overpotetintial of the electrodeposition reaction.