Applied electrochemistry

Electricity was already known when Volta invented the electric battery. Indeed, electricity was already being used and studied as a laboratory curiosity: rubbing insulating materials created a few electric charges and stored them in capacitors. In 1800, when Volta stacked metal disks separated by non-metallic materials made conductive by impregnation with salt water, he created the first electric battery and, with this first application, also opened the door to electrochemistry.

Electrochemistry can be characterized as the set of phenomena involved in the passage of an electric current through an ionic conductor, irrespective of its direction. The passage of this current requires the use of an electrochemical system consisting of two electrodes in electrical contact with the ionic conductor. The material involved therefore comprises electronically conductive materials and a liquid medium made electrically conductive by the presence of ions. The physical characterization of electrochemical systems mainly involves measuring current or potential.

The passage of current is generally accompanied by chemical changes to the electrodes or the material on their surface. This coupling of chemical transformations with electricity is involved in two major electrochemical applications: batteries and electrolysis. The passage of current always involves a conversion of energy. In a battery, current and electrical energy are produced by the consumption of an oxidant and a reductant, respectively on a cathode and an anode. In electrolysis, electrical energy is consumed and transformed into products and heat.

Since Volta, electrochemistry has developed enormously, both fundamentally and in terms of applications in various sectors: energy, materials synthesis and processing, analysis and the living world. Depending on the nature and size of the electrodes, and the intensity of the current, electrochemistry has given rise to a wide variety of industrial applications, which are described in this article. These applications are still the subject of active research, particularly when they are in line with the objectives of sustainable development and better management of materials and energy. Indeed, the coupling of electricity with changes in matter is currently at the heart of the most credible processes for storing intermittent renewable energies.