Electrochemical

Electrochemistry is a branch of chemistry that studies chemical processes driven by or producing electrical energy. It focuses on redox reactions at interfaces between electrodes and electrolytes, and on the transport of ions in conductive media. The central idea is that electrons can be transferred between chemical species through an external circuit, linking chemical change to electrical power.

Key concepts include electrochemical cells, electrodes (anode and cathode), electrolytes, and reference electrodes. The potential difference between electrodes drives or halts reactions. Faraday's laws relate the amount of substance transformed to the electric charge passed, while standard electrode potentials and the Nernst equation describe the driving force under varying conditions. Overpotential, kinetics, and mass transport influence reaction rates at interfaces.

Common electrochemical techniques include voltammetry, amperometry, potentiometry, and chronoamperometry, often performed with potentiostats or galvanostats. Electrochemical impedance spectroscopy measures impedance as a function of frequency to study interfaces and reaction mechanisms.

Applications span energy storage and conversion (batteries, fuel cells, and supercapacitors), electroplating and metal finishing, electrosynthesis of chemicals, corrosion protection and mitigation, and sensors including biosensors. Electrochemical methods are also used in manufacturing, such as electrochemical machining and surface modification.

Historically, electrochemistry emerged from the work of Volta, Galvani, and Faraday, who linked electricity and chemical change. Today the field integrates materials science, physics, and environmental science to address energy, synthesis, and analytical challenges.