A three-ions model of electrodiffusion kinetics in a nanochannel

Highlights: • Three or more exponential time periods of different rate constants were identified. • Complex dynamics with oscillations in electric potential was observed. • Ion currents exhibit significant transient spatial nonuniformity. • The system shows considerable ion current rectification. • The steady state obeys the constant field condition. Nanoscale electrodiffusion transport is involved in many electrochemical, technological and biological processes. Developments in computer power and numerical algorithms allow for solving full time-dependent Nernst-Planck and Poisson equations without simplifying approximations. We simulate spatio-temporal profiles of concentration and electric potential changes after a potential jump in a 10 nm channel with two cations (with opposite concentration gradients and different mobilities) and one anion (of uniform concentration). The temporal dynamics shows three exponential phases and damped oscillations of the electric potential. Despite the absence of surface charges in the studied model, an asymmetric current-voltage characteristic was observed.