So, we have established that oxides (hydroxides) are used to form the electrodes of a NiFe battery. We have established Nickel II hydroxide (the green one) as the positive electrode of the battery. This is confirmed in the Edison Patent #1,488,480, page 1, line 39. However, Nickel II is a very poor conductor. To make it work, Edison needed to find a way to force the Nickel II to transfer charges to and from the iron oxides.

To accomplish this, he took a length of small diameter steel pipe, and perforated it with 88 holes per square centimeter. Each tiny hole is 0.25mm X 0.40mm. He then gave this tube a heavy plating of nickel to protect it from the KOH.

The nickel tube was filled with alternating layers of nickel flake and Nickel II hydroxide. There were 32 layers per centimeter in Edison’s design. Each layer was tamped firmly in place with a ram rod to ensure a tight packing and good contact.

The best results are obtained when twice as many positive as negative plates are employed, and his standard cells were made up on this basis. Makes sense right? After all, half of each positive tube was filled with inert nickel flakes.