The present invention provides one with an iron electrode employing a binder comprised of polyvinyl alcohol (PVA) binder. In one embodiment, the invention comprises an iron based electrode comprising a single layer of a conductive substrate coated on at least one side with a coating comprising an iron active material and a binder, wherein the binder is PVA. This iron based electrode is useful in alkaline rechargeable batteries, particularly as a negative electrode in a Ni—Fe battery.

Provided is a process for preparing an electrode comprising an iron active material. The process comprises first fabricating an electrode comprising an iron active material, and then treating the surface of the electrode with water to thereby create an oxidized surface. The resulting iron electrode is preconditioned prior to any charge-discharge cycle to have the assessable surface of the iron active material in the same oxidation state as in discharged iron negative electrodes active material.

In an aspect, provided is an alkaline rechargeable battery comprising: i) a battery container sealed against the release of gas up to at least a threshold gas pressure, ii) a volume of an aqueous alkaline electrolyte at least partially filling the container to an electrolyte level; iii) a positive electrode containing positive active material and at least partially submerged in the electrolyte; iv) an iron negative electrode at least partially submerged in the electrolyte, the iron negative electrode comprising iron active material; v) a separator at least partially submerged in the electrolyte provided between the positive electrode and the negative electrode; vi) an auxiliary oxygen gas recombination electrode electrically connected to the iron negative electrode by a first electronic component, ionically connected to the electrolyte by a first ionic pathway, and exposed to a gas headspace above the electrolyte level by a first gas pathway.

The invention provides a method of storing varying or intermittent electrical energy and one or more of hydrogen (H.sub.2) and oxygen (O.sub.2) with an energy apparatus, the method comprising: providing the first cell aqueous liquid, the second cell aqueous liquid, and electrical power from an external power source to the functional unit thereby providing an electrically charged functional battery unit and one or more of hydrogen (H.sub.2) and oxygen (O.sub.2) stored in said storage system, wherein during at least part of a charging time the functional unit is charged at a potential difference between the first cell electrode and the second cell electrode of more than 1.37 V.

Provided is an aqueous battery configured to use hydroxide ions (OH.sup.−) as carrier ions. The aqueous battery is an aqueous battery comprising a cathode layer, an anode layer and an aqueous liquid electrolyte, wherein the cathode layer contains, as a cathode active material, a graphite having a rhombohedral crystal structure; wherein the anode layer contains, as an anode active material, at least one selected from the group consisting of an elemental Zn, an elemental Cd, an elemental Fe, a Zn alloy, a Cd alloy, an Fe alloy, ZnO, Cd(OH).sub.2, Fe(OH).sub.2 and a hydrogen storage alloy; and wherein, as an electrolyte, at least one selected from the group consisting of KOH and NaOH is dissolved in the aqueous liquid electrolyte.

The present invention provides one with an iron electrode employing a binder comprised of polyvinyl alcohol (PVA) binder. In one embodiment, the invention comprises an iron based electrode comprising a single layer of a conductive substrate coated on at least one side with a coating comprising an iron active material and a binder, wherein the binder is PVA. This iron based electrode is useful in alkaline rechargeable batteries, particularly as a negative electrode in a Ni-Fe battery.

A rechargeable battery includes an iron electrode comprising carbonyl iron composition dispersed over a fibrous electrically conductive substrate. The carbonyl iron composition includes carbonyl iron and at least one additive. A counter-electrode is spaced from the iron electrode. An electrolyte is in contact with the iron electrode and the counter-electrode such that during discharge. Iron in the iron electrode is oxidized with reduction occurring at the counter-electrode such that an electric potential develops. During charging, iron oxides and hydroxides in the iron electrode are reduced with oxidation occurring at the counter-electrode (i.e., a nickel electrode or an air electrode).

In an aspect, provided is an alkaline rechargeable battery comprising: i) a battery container sealed against the release of gas up to at least a threshold gas pressure, ii) a volume of an aqueous alkaline electrolyte at least partially filling the container to an electrolyte level; iii) a positive electrode containing positive active material and at least partially submerged in the electrolyte; iv) an iron negative electrode at least partially submerged in the electrolyte, the iron negative electrode comprising iron active material; v) a separator at least partially submerged in the electrolyte provided between the positive electrode and the negative electrode; vi) an auxiliary oxygen gas recombination electrode electrically connected to the iron negative electrode by a first electronic component, ionically connected to the electrolyte by a first ionic pathway, and exposed to a gas headspace above the electrolyte level by a first gas pathway.

Provided is a high quality and high performance nickel-iron battery comprising an iron electrode which is prepared by a continuous process. The process comprises preparing a formulation comprising an iron active material and a binder, and continuously coating a continuous substrate material on at least one side with the formulation. The coated continuous substrate material is dried, compacted and blanked. In one embodiment, the iron electrode comprises a PVA binder.

Provided is a Ni—Fe battery comprising a high quality, high performance iron electrode. In one embodiment the iron electrode comprises a polyvinyl alcohol binder. The iron electrode of the Ni—Fe battery comprises a single conductive substrate coated on one or both sides with an iron active material.