New technics

A more complete understanding of the mechanisms of charge storage in supercapacitors requires the physical modeling of the associated phenomena and their quantification by fine experiments.

Theme: Microcalorimetry (PhD thesis)

In order to demonstrate the energetic phenomena accompanying the adsorption of ions in the pores of supercapacitor electrodes and to quantify these phenomena, a thermal and thermodynamic approach is used in support of a fine and original microcalorimetry experiment.

Description of the entire microcalorimetry installation

Theme: Electrochemical modeling

The heat transport equations are coupled to charge and mass transfer equations to model electrochemical behaviors, particularly impedance spectroscopy. The modeling technique makes it possible, for example, to investigate in detail the problems associated with the presence of resistive / capacitive interfaces between the various elements constituting a supercapacitor.

Simultaneous modeling of an impedance spectrum and
Voltamogram of the same electrode (1F) with or without
Presence of a collector-active material interface

Theme: Cavity Microelectrode (CME)

In order to better understand the mechanisms of storage in an active material and to demonstrate the role of each constituent of a composite electrode in electrochemical performances, the technique of the cavity microelectrode is used for the electrochemical characterization of a material powder Active, in very small quantity, alone, with or without the addition of binder and / or conductive additive.

Left: Diagram of a conventional composite electrode and a cavity microelectrode;
Right: Electrochemical characterization of MnO2, powder alone and mixed with acetylene black
(Cryptomelane (a), birnessite (b), 0.5M Na2SO4, 20 mV / sec)

Références

Guillemet, P., Brousse, T., Crosnier, O., Dandeville, Y., Athouël, L., Scudeller, Y., Modeling pseudo capacitance of manganese dioxide (2012) Electrochimica Acta, 67, pp. 41-49.

Athouël, L., Arcidiacono, P., Ramirez-Castro, C., Crosnier, O., Hamel, C., Dandeville, Y., Guillemet, P., Scudeller, Y., Guay, D., Bélanger, D., Brousse, T., Investigation of cavity microelectrode technique for electrochemical study with manganese dioxides (2012) Electrochimica Acta, 86, pp. 268-276.

Dandeville, Y., Guillemet, P., Scudeller, Y., Crosnier, O., Athouël, L., Brousse, T., Measuring time-dependent heat profiles of aqueous electrochemical capacitors under cycling (2011) Thermochimica Acta, 526 (1-2), pp. 1-8.

Pascot, C., Dandeville, Y., Scudeller, Y., Guillemet, P., Brousse, T., Calorimetric measurement of the heat generated by a Double-Layer Capacitor cell under cycling (2010) Thermochimica Acta, 510 (1-2), pp. 53-60.