Reducing mass-transport limitations by application of special pulsed current modes

Current pulsing, unlike potential pulsing, is generally considered ineffective in enhancing mass transport. However, we show here, that by properly selecting the pulsed current parameters, the depletion of the reactant at the electrode during cathodic reduction, or its excess during anodic dissolution, can be reduced compared to the corresponding dc current application, while still passing the same amount of charge in an identical amount of time. The advantageous pulsed current modes include a sequence of decreasing current density amplitudes, or pulsing the current at the same amplitude, but with increasing relaxation intervals. By comparison, it is also shown that applying a sequence of constant-amplitude square current pulses at constant time intervals leads to an identical concentration profile as in dc. The application to the battery-charging process is briefly discussed. (c) 2005 The Electrochemical Society. All rights reserved.