Method for making a nickel positive electrode for an alkaline battery

Claim 1

In a method of making low-nickel-content nickel electrodes for use in secondary alkaline batteries which includes the step of impregnating a porous, conductive support with a coagulum comprising a mixture of nickel hydroxide and graphite particles in a polyvinylidene fluoride binder the improvement comprising: mechanically suspending said mixture in a liquid medium which is not a solvent for said binder, said mixture comprising up to about 30 percent by weight graphite particles which vary in size from about 0.5 microns to about 5.0 microns and the balance substantially nickel hydroxide having a particle size of less than about 200 mesh; preparing a viscous solution of said binder dissolved in a solvent which is sufficiently slowly soluble in said medium that, with agitation, said viscous solution will freely mix with said suspension before any substantial dissolution of said solvent in said medium occurs; intimately blending said viscous solution with said suspension and thereafter forming said coagulum by allowing said binder to slowly precipitate and coagulate substantially uniformly throughout the solution-suspension mixture and to entrain said particles therein; forcing the solution from the previous step through said support to separate the coagulum from the solution and to impregnate said support with said coagulum, the binder portion of which has an open-celled reticulated structure the cells of which are filled with said particles; compressing the thusly impregnated support with sufficient pressure to pack the particles together so as to enhance the electrical contact therebetween and maximize the percentage utilization of the nickel hydroxide therein; and drying the thus impregnated and compressed support.