= Butler-Volmer equation
{c}
{title2=$j=j_0(e^{\alpha_anF\eta/(RT)}-e^{-\alpha_cnF\eta/(RT)})$}
A kinetic model for the net <electrode> current near and away from equilibrium. For a single effective reaction with consistent activities and $\alpha_a+\alpha_c=1$, $j=j_0[\exp(\alpha_anF\eta/RT)-\exp(-\alpha_cnF\eta/RT)]$. Near equilibrium it gives $j\simeq j_0nF\eta/(RT)$; at sufficiently large <overpotential> one exponential gives the <Tafel equation>. Multistep reactions can require a different kinetic interpretation.
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