▎ 摘　　要

Understanding electrochemical behavior of the alkaline metal cation-graphene interface in electrolyte is essential for understanding the fundamental electrochemical interface and development of graphene-based technologies. However, most studies have been mainly conducted based on typical electrochemical analysis and computational evaluation, and the fundamental properties of both cations and graphene at the electrified interface by the experimental approach still remain poorly understood. Here, we report comprehensive analysis of the electrochemical behavior of both alkaline metal cations and graphene using electrochemical surface X-ray diffraction (EC-SXRD) and Raman (EC-Raman) spectroscopic techniques in which the interfacial structure of cations and the charging state and mechanical strain of the graphene can be elucidated. EC-SXRD and cyclic voltammetry demonstrated electrochemically driven specific adsorption and desorption of cations on the graphene surface involved in the dehydration and hydration process. Under the cation adsorption condition, EC-Raman spectroscopy revealed that graphene becomes a highly electron doped state with lattice expansion, which is a similar feature of the potassium-graphite intercalation compound. This study provides new insight for understanding fundamental electrochemical behavior of the alkaline metal cation-graphene interface and contributes to the development of carbon-based novel applications.