overpotential

This term is a specialized technical expression used almost exclusively in electrochemistry and materials science. It describes the energy penalty or additional voltage required to overcome kinetic barriers at an electrode surface, meaning the system must be pushed beyond its equilibrium state to achieve a practical reaction rate.

In a laboratory or industrial context, the goal is typically to minimize overpotential to increase energy efficiency. It is distinct from thermodynamic potential, as it focuses on the kinetic limitations of the reaction rather than the theoretical energy difference between reactants and products.