P-016

Ermo Leuska

ermo.leuska@ut.ee

Heigo Ers, Piret Pikma, Enn Lust, Liis Siinor

Institute of Chemistry, University of Tartu, Estonia

The role of experimental conditions on EDL formation at the glassy carbon electrode and EMImBF4 interface

The development of supercapacitors mostly relies on studying the processes occurring at the interface between various carbon materials and electrolytes. This is quite a challenge, as carbon material, besides its chemical composition, also has a porous nature. Typically, the electrolyte used is either organic or aqueous, often with an added adsorbable component (organic or inorganic) to improve the supercapacitor's properties.[1-3] From fundamental electrochemical studies, it is known that the adsorption of organic molecules onto the electrode surface occurs due to various interactions.[4,5] By manipulating these interactions through the applied electric field or electrode material, energy can be stored or reactions catalyzed. Therefore, the use of such compounds in the field of supercapacitors holds great potential benefits in terms of both efficiency and sustainability.

The current work aims to study the properties of the interface between an ionic liquid and the glassy carbon electrode by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).

The electrochemical behavior of the glassy carbon and 1-Ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) interface is characterized by CV and EIS measurements. Capacitance is estimated after altering the measurement duration, number of cycles applied, and EIS time delay periods. All these parameters change capacitance values considerably. Stable values of current density are observed within the potential region −1.9 V < E < 1.9 V, which is in accordance with earlier results.[6,7] Narrower potential range (−1.2 V < E < 0.8 V), where the current density values are low (j < −10 µA cm-2), are selected for characterization of the effect of experimental conditions.

Acknowledgments:

This work was supported by the Estonian Research Council grant PRG2677, by the Estonian Ministry of Education and Research (TK210), and by the project ""Increasing the knowledge intensity of Ida-Viru entrepreneurship"" (ÕÜF12) co-funded by the European Union.

References:

1.        Zhong, C. et al. Chem. Soc. Rev. 44, 7484–7539 (2015).

2.        Tooming, T. et al. J. Electrochem. Soc. 161, A222–A227 (2014).

3.        Arulepp, M. et al. J. Power Sources 133, 320–328 (2004).

4.        Kühnle, A. Curr. Opin. Colloid Interface Sci. 14, 157–168 (2009).

5.        Grozovski, V. et al. Electrochimica Acta 120, 86–95 (2014).

6.        Zheng, J. et al. J. Phys. Chem. C 115 (15), 7527–7537 (2011)

7.         Romann, T. et al. Electrochim. Acta 125, 183–190 (2014)