A secondary electrochemical cell includes a negative electrode including as an output conductor, a metallic or metal-coated open-pore form or a metallic or metal-coated nonwoven, as a carbon-based storage material that enables storage of electrical charge in the electrode through formation of an electrical double layer (Helmholtz double layer), activated carbon having a BET surface area of at least 800 m.sup.2/g, a non-carbon-based H2 storage material that can chemisorb hydrogen and/or store it as a metal hydride, a positive electrode including as an output conductor, a metallic or metal-coated open-pore form or a metallic or metal-coated nonwoven, and nickel hydroxide and/or nickel oxyhydroxide, a porous separator that separates the negative electrode and the positive electrode from one another, an aqueous alkaline electrolyte with which the electrodes and the separator are soaked, and a housing that encases the electrodes, the separator and the electrolyte.

A secondary electrochemical cell includes a negative electrode including an output conductor, activated carbon having a BET surface area of at least 800 m.sup.2/g as a carbon-based storage material that enables storage of electrical charge in the electrode through formation of an electrical double layer (Helmholtz double layer), a positive electrode including an output conductor, and nickel hydroxide and/or nickel oxyhydroxide, a porous separator that separates the negative electrode and the positive electrode from one another, an aqueous alkaline electrolyte with which the electrodes and the separator are soaked, and a housing that encases the electrodes, the separator and the electrolyte.

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, a polyvinyl alcohol binder and sulfur, and then treating the electrode with a gaseous oxidant to thereby create an oxidized surface. The resulting iron electrode is treated 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.

A secondary battery includes an alkaline electrolyte and a negative electrode in contact with the alkaline electrolyte. The negative electrode includes a conductive metal substrate having thereon a metal alloy coating including nickel and an amorphous phase containing phosphorous.

An electrolyte for iron-air batteries, which is able to increase the discharge capacity of iron-air batteries without concentration control, and an iron-air battery using the electrolyte. The electrolyte for iron-air batteries having an anode containing an iron element may comprise an aqueous solution comprising a discharge reaction promoter containing at least one kind of anion selected from the group consisting of SCN.sup. anions, S.sub.2O.sub.3.sup.2 anions and (CH.sub.3).sub.2NCSS.sup. anions.

Systems and methods of the various embodiments may provide metal electrodes for electrochemical cells. In various embodiments, the electrodes may comprise iron. Various methods may enable achieving high surface area with low cost for production of metal electrodes, such as iron electrodes.

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 an oxidant solution to thereby create an oxidized surface. The resulting iron electrode is thereby 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 au 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 some pathway, and exposed to a gas headspace above the electrolyte level by a first gas pathway.

An electrode, including a first iron material and a second iron material. The first iron material is a first reduced iron and the second iron material is different from the first iron material. Also provided is an electrochemical cell comprising an electrode including a first iron material and a second iron material. Further provided is a method of making an electrode.

In an aspect, provide 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.