Method of making sintered plaque cadmium electrodes

摘要

The improved method of the invention comprises electrochemically depositing cadmium hydroxide into the pores of a sintered nickel plaque cathode from a heated electrolyte at acid pH and at controlled density in a treating zone containing an anode, at least periodically contacting the electrolyte during the electro chemical deposition with neutralizing agent selected from cadmium oxide and cadmium hydroxide to neutralize acid generated at the anode, and continuing the electrochemical deposition until an improved loading level of cadmium hydroxide within the cathode is obtained. The acid pH preferably is between 2 - 5 and the electrolyte preferably is in a concentration of 2 - 3 M and at an average temperature of about 85 DEG - 105 DEG C. Preferably, the current density is maintained at a level of less than one ampere per square inch in order to improve the loading level, which may be as high as about 2.6 grams of cadmium hydroxide per cubic centimeter of void volume in the cathode. The neutralizing agent may be disposed in a porous container in a separate reservoir zone connected to the treating zone so that the electrolyte can circulate therebetween and into direct contact with the neutralizing agent. The method results in a loading level of cadmium hydroxide in the sintered nickel plaque cathode as high as or higher than previously obtained and in a shorter period of time. The method is simple, inexpensive and efficient.