Ion transport and deposit growth in spatially coupled bipolar electrochemistry

In spatially coupled bipolar electrochemistry, electrodissolution and elect rodeposition processes in an applied electric field are exploited to create directional growth of copper deposits between two copper discs, not physic ally linked to an external voltage source. Here, we study the electric fiel d in the whole cell through theoretical modeling, and ion transport in the interdisc region using optical and particle image velocimetry techniques. T heir combined effect on incubation time and deposit morphology is assessed. Both the electric field and ion transport in the interdisc region are cruc ial factors in the characteristics of the Interconnection. The model simula tions reveal that the electric field is almost an order of magnitude larger in the region between discs as compared with the mean field value. Measure ments and simulations show that the incubation time scales linearly with th e inverse of the electric field, an indication that in this period, migrati on is the dominant transport mode. Experiments reveal that after branching develops. convection plays a relevant role as well, the contact growing lin early in time, with a change of the time length slope at half the interdisc gap. (C) 1999 Elsevier Science S.A. All rights reserved.