Electrochemical deposition of lead di:oxide onto substrate - using direct current with superimposed alternating current to prevent defect formation

摘要

PbO2 is deposited electrochemically onto a support from aq. Pb(NO3)2 with the support connected as anode, and the soln. at 40 plus-or-minus 2 degrees C. The depositing voltage consists of a with a superimposed ac. of frequency 1.25 Hz of value 1/10. of the dc. Specifically parasitic nitrite ions produced by the electrolysis are eliminated by oxidn. by dissolving in the soln. PbO2, PbO or PbCO3 with regeneration in the bath of Pb2+ ions. The electrolyte pref. consists of 150 g/l. Pb(NO3)2. Used in mfr. of electrodes for batteries of the PbO2/HBF4/Pb type. Process avoids the heating step required when PbO2 is applied to a substrate by screen printing as in prior art. It avoids the need for separate bath compsn. maintenance in order to reduce fissuring and other defects in the finished deposit as experienced previously.