Thesis presented July 07, 2020

Abstract:
Electrolytic capacitors are key components in energy storage via electrochemical charge in electronics, with domains of application ranging from aerospace to home appliance. With the uprising of numerical tools and the growing demand of autonomous and mobile technologies, more efficient capacitors are needed, which lead to an evolution in electrochemical etching technics. Electrolytic capacitor capacitance is given by the area developed on 4N (99,99% Al) aluminum sheet, which form the final capacitor anode. This tunnel micrometric etching, perpendicular to the surface of the foil, is realized by electrochemical etching, using strong mineral acid as electrolyte.
In this PhD work, we produced high purity aluminum foil (99,99%) pit etching, by avoiding excessive etching of the aluminum. The goal is to enhance the specific area developed​ on the foil. To achieve this, a method of directing the propagation of the tunnel during its growth is studied. It is also studied alongside a new electrolyte used to optimize the capacitance developed on the aluminum foil. By the first method, an increase by 8% of the foil capacitance is achieved, further increasing to 27% while using both this method and the new electrolyte. Finally, a solution is studied regarding the treatment of the aluminum polluted etching solution post-etching.

Keywords:
Electrochemistry, capacitors, energy           

On-line thesis. ​