The nickel–iron battery (NiFe battery) is a rechargeable battery having nickel(III) oxide-hydroxide positive plates and iron negative plates, with an electrolyte of potassium hydroxide. The active materials are held in nickel-plated steel tubes or perforated pockets. It is a very robust battery which is tolerant of abuse,. Many railway vehicles use NiFe batteries. Some examples are and. The technology has regained popularity for applications. Swedish inventor invented the in 1899. Jungner experimented with substituting iron for the cadmium in varying proportions, including 100% iron. Jungner discovered that the main advantage over the. Charge/discharge involves the transfer of oxygen from one electrode to the other (from one group of plates to the other). Hence this type of cell is sometimes called an oxygenlift cell. In a charged cell the active material of the positive plates is superoxidized, and that. The ability of these batteries to survive frequent cycling is due to the low solubility of the reactants in the electrolyte. The formation of metallic iron during charge is slow because of the low solubility of the. While the slow formation of iron crystals. The at the positive plate from black NiO(OH) to green Ni(OH)2 : and at the negative plate: (Discharging is read left to right, charging is from right to left.) The active material of the battery plates is contained in a number of filled tubes or pockets, securely mounted in a supporting and conducting frame or grid. The support is in good electrical contact with the tubes. The grid is a light skeleton frame, stamped from thin sheet steel,. Under discharge the positive plates are reduced ("deoxidized"); the oxygen, with its natural affinity for iron, goes to the negative plates, oxidizing them. It is permissible to discharge continuously at any rate up to 25% above normal, and for short periods at up to six.
