Process for impregnating porous electrodes, and electrodes produced thereby

Claim 1

IN A PROCESS FOR FORMING POROUS ELECTRODES FOR STORAGE BATTERIES IN WHICH A POROUS ELECTRODE IS IMPREGNATED WITH ELECTROCHEMICALLY ACTIVE MATERIAL, THE IMPROVEMENT WHICH COMPRISES IMPREGNATING THE POROUS ELECTRODE WITH A SOLUTION CONTAINING AN AMMONIUM COMPLEX OF A METAL OF THE GROUP CONSISTING OF NICKEL, COBALT, CADMIUM, ZINC, SILVER, COPPER, AND MERCURY, SAID AMMONIUM COMPLEX HAVING BEEN PREPARED BY DISSOLVING A METALLIC COMPOUND WHICH IS A MEMBER OF THE GROUP CONSISTING OF NICKEL, COBALT, CADMIUM, ZINC, SILVER, COPPER, AND MERCURY COMPOUNDS, IN A NITROGEN CONTAINING SOLVENT WHICH IS A MEMBER OF THE GROUP CONSISTING OF ALIPHATIC AMINES, AROMATIC AMINES, AMINO ACIDS, AND AQUEOUS AMMONIACAL SOLUTIONS OF AMMONIA, AT A TEMPERATURE IN EXCESS OF ABOUT 25*C., BUT BELOW THE TEMPERATURE AT WHICH THE AMMONIUM COMPLEX OF THE METAL UNDERGOES DECOMPOSITION, REMOVING THE ELECTRODE FROM THE IMPREGNATING SOLUTION, DRYING THE ELECTRODE BY HEATING IT TO A TEMPERATURE SUFFICIENT TO DRIVE OFF WATER AND AMMONIUM SALTS AND TO DRY THE ELECTRODE, AND SAID STEPS OF IMPREGNATING AND HEATING ARE SUBSEQUENTLY REPEATED UNTIL THE ELECTRODE HAS ACCUMULATED THE REQUIRED AMOUNT OF ACTIVE MATERIAL, AND THEN LEACHING THE IMPREGNATED ELECTRODE IN A HOT AQUEOUS SOLUTION OF SODIUM HYDROXIDE, WASHING THE LEACHED ELECTRODE WITH HOT WATER TO REMOVE RESIDUAL ANIONS AND AMMONIUM SALTS, AND THEN HEATING THE WASHED ELECTRODE AT A TEMPERATURE IN THE RANGE BETWEEN 105*C. AND 140*C. TO DRY IT.