The electrodes are made from stainless steel and carbon. The most advanced electrolytic system maintains the cathode potential at or upward (more positive) of -0.55V with reference to saturated calomel electrode. It's also best to adjust the pH to about 7 to 8 range before starting silver recovery (the pH of Clearfix is ideal for silver recovery system without any adjustment, and most color fixers are not far from it either).Also, are there any gasses produced in the reaction that I would need to be concerned about, such as hydrogen?
A recent report on electrolytic silver recovery system was published by Mina and Chang of Kodak Rochester Lab in 1982. Mina, R. and Chang, J. C. 1982. Electrolytic silver recovery from spent fixing solutions---an electroanalytical study. Photo. Sci. Engr., 26, 223-7.