Effects of electrochemical reaction and surface morphology on electroactive surface area of porous copper manufactured by Lost Carbonate Sintering

Porous metals are potentially excellent electrode materials because of their high specific surface areas. The electroactive surface area is dependent on the electrochemical reaction and can be affected by the surface morphology. This work measured the electroactive surface area of porous Cu manufactured by the Lost Carbonate Sintering process, using the cyclic voltammetry (CV) peak current method and employing two reactions with different Nernst diffusion layer thicknesses. The real surface area was also measured by the double layer capacitance method. The effects of Cu particles size, sintering temperature and chemical treatment on the surface morphology and therefore surface areas were investigated. Cu particle size had a modest effect, with the medium particle sizes, 20-45 mm or 45-75 mm, showing the highest surface areas. Increasing the sintering temperature from 850 degrees C to 950 degrees C or etching the samples by 5 M nitric acid for 5 minutes reduced the electroactive and real surface areas by 31-61% or 9-25%, respectively. The electroactive surface area was increased by up to 2 times when the diffusion layer thickness was decreased from 50 mu m to 1 mu m.