overpotential

Etymology

over- + potential

noun

1. (physics) The difference between the electric potential of an electrode or cell under the passage of a current and the thermodynamic value of the electrode or cell potential in the absence of electrolysis
   One of the factors that limits their development and use is that known anode and cathode electrocatalysts produce useful current densities only at high overpotentials. June 12, 1998, Erik Reddington et al., “Combinatorial Electrochemistry: A Highly Parallel, Optical Screening Method for Discovery of Better Electrocatalysts”, in Science, volume 280, number 5370, →DOI, pages 1735–1737