Binder-assisted electroplating of porous copper: formation of an interconnected network with enhanced electrolyte-accessible interfacial area

Abstract

A binder-assisted electroplating process is reported for the fabrication of porous copper electrodes in a room-temperature aqueous sulfate bath. A precursor layer composed of copper powder and a sodium alginate binder was deposited on an electroless-Cu-coated substrate, and electrolytic copper plating was carried out at room temperature in a sulfate bath. Cross-sectional scanning electron microscopy revealed that, in the early stage of plating, electrodeposited copper formed bridges at interparticle contact points, producing an interconnected three-dimensional network _dl) obtained from cyclic voltammetry in the non-Faradaic region in 0.1 mol L^− 1 Na₂SO₄ (pH 4). The C_dl values were 1.09 × 10^− 2, 2.32, and 1.94 mF cm^− 2 for a flat Cu plate, the 5 min porous Cu, and the 30 min porous Cu, respectively, corresponding to relative increases of approximately 213-fold and 178-fold over the flat reference. These results are consistent with the formation of an electrolyte-accessible porous Cu network by binder-assisted electroplating; quantitative comparison with other porous Cu fabrication routes is beyond the scope of this communication. Linear sweep voltammetry and impedance measurements in 0.1 mol L^− 1 Na₂SO₄ (pH 4) showed a negatively shifted anodic dissolution onset for the porous electrode and a distributed, porous-electrode impedance response. 

Graphical Abstract