Charge Storage Mechanisms of Single-Layer Graphene in Ionic Liquid

Jianglin Ye (1, 2) , Yih-Chyng Wu (2, 3) , Kui Xu (2, 3) , Kun Ni (1) , Na Shu (1) , Pierre-Louis Taberna (2, 3) , Yanwu Zhu (1) , Patrice Simon (2, 3)

1 USTC - University of Science and Technology of China [Hefei]
2 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
3 RS2E - Réseau sur le stockage électrochimique de l'énergie

Graphene-based carbon materials are promising candidates for electrical double-layer (EDL) capacitors, and there is considerable interest in understanding the structure and properties of the graphene/electrolyte interface. Here, electrochemical impedance spectroscopy (EIS) and electrochemical quartz crystal microbalance (EQCM) are used to characterize the ion fluxes and adsorption on single-layer graphene in neat ionic liquid (EMI-TFSI) electrolyte. It is found that a positively charged ion-species desorption and ion reorganization dominate the double-layer charging during positive and negative polarizations, respectively, leading to the increase in EDL capacitance with applied potential.

Mots clés: Interfaces; Two dimensional materials; Electrical properties; Electrodes; Ions

Domaines: Matériaux; Energie électrique

Jianglin Ye, Yih-Chyng Wu, Kui Xu, Kun Ni, Na Shu, et al.. Charge Storage Mechanisms of Single-Layer Graphene in Ionic Liquid. Journal of the American Chemical Society, 2019, 141 (42), pp.16559-16563. ⟨10.1021/jacs.9b07134⟩. ⟨hal-02519714⟩