Definition - What does Concentration Overpotential mean?
Concentration overpotential refers to the equilibrium potential difference across a diffusion layer given a particular electrode reaction and density. The greater the potential difference, the greater the rate of corrosion experienced with a corresponding electrolyte. Concentration overpotential is used to describe the electrolyte of a cell.
Corrosionpedia explains Concentration Overpotential
An electrolytic solution is divided into three core parts: the bulk solution and the two diffusion layers at electrode surfaces. The bulk solution is assumed to be well mixed, allowing uniform species distribution. Similar distribution occurs in the diffusion layers by mass diffusion.
Electrolytic cells operate by pushing electrical currents throughout the system. The process of electrolysis serves as the driving force of the redox reaction towards a direction that will not happen at the same time. Overvoltage can occur within an electrolytic cell. The overvoltage or overpotential can be increased to reduce the corrosion rate, or manipulated as required for a given application.