Controlling Interfacial Ion-Transport Kinetics Using Polyelectrolyte Membranes for Additive- and Effluent-free, High-Performance Electrodeposition.

ABSTRACT

The development of high-performance, environmentally friendly electrodeposition processes is critical for emerging coating technologies because current technologies use highly complex baths containing metal salts, supporting electrolytes, and various kinds of organic additives, which are problematic from both environmental and cost perspectives. Here, we show that a 200 µm-thin polyelectrolyte membrane sandwiched between electrodes effectively concentrates metal ions through interfacial penetration, which increases the conductance between the electrodes to 0.30 S and realizes solid-state electrodeposition that produces no mist, sludge, or even waste effluent. Both, experimental results and theoretical calculations, reveal that electrodeposition is controlled by ion penetration at the solution/polyelectrolyte interface, providing an intrinsically different ion-transport mechanism to that of conventional diffusion-controlled electrodeposition. The setup, which includes 0.50 mol L-1 copper sulfate and no additives, delivers a maximum current density of 300 mA cm-2, which is nearly fivefold higher than that of a current commercial plating bath containing organic additives.