Influence of the configuration in planar interdigitated electrochemical micro-capacitors
Résumé
We have investigated the influence of the geometric configuration of planar interdigitated microsupercapacitors
on their specific energy and specific power. The theoretical values of the Equivalent
Series Resistance (ESR) were deduced from an analytical expression of the cell constant L, and compared
with experimental Electrochemical Impedance Spectroscopy (EIS) measurements performed on gold
current collectors with different interdigitated patterns (varying the interspace, width, length and
number of interdigitated fingers). It is shown that the configuration plays a key-role on the electrochemical
performances of the device, and that the specific power is enhanced by a reduction of the
interspace.
Based on these results, we have realized hydrous RuO2-based thin films electrochemical capacitors
integrated on silicon with an optimized configuration, using conventional photolithography techniques
and electrodeposition from an aqueous chloride solution. The micro-supercapacitor is characterized by
a cell capacitance of 0.2 mF cm2 per footprint area, and was able to cycle at a scan rate of 100 V s1.