Controelettrodo

Controelettrodo, in electrochemistry, is the electrode that completes the electrical circuit in a cell and carries the current flowing through the system. In a three-electrode arrangement, it works alongside the working electrode and the reference electrode; the counter electrode accepts the current produced at the working electrode and helps maintain charge balance. Its potential is not controlled directly by the measurement system; it adjusts to maintain the necessary redox reactions at the working electrode.

Materials commonly used for a counter electrode include chemically inert and conductive substances such as platinum, graphite, and carbon-based materials. Other metals can be used depending on the electrolyte and the desired stability, but the key requirement is chemical inertness with respect to the electrolyte to minimize unwanted side reactions. The counter electrode is typically designed with a large surface area to reduce polarization and ensure uniform current distribution.

Design considerations and configurations: in a three-electrode cell, the counter electrode should be separate from the working region to avoid interference with measurements, sometimes in a divided cell or separated by a salt bridge. Its primary function is to provide a path for current rather than to dictate potential. In two-electrode setups, the counter electrode acts as the second electrode, but the overall cell potential is governed by the combined behavior of both electrodes and the electrolyte. For high-current or demanding applications, material choice and surface treatment help reduce dissolution and polarization effects.

Applications: the counter electrode is used in cyclic voltammetry, chronoamperometry, impedance spectroscopy, battery and supercapacitor testing, corrosion studies, and electrochemical synthesis. In Italian literature, controelettrodo is often referred to as the auxiliary electrode.