A battery comprises an ion-conducting polymeric composition comprising a copolymer of styrene and vinylbenzyl-R.sub.s, where R.sub.s is a positively charged cyclic amine group. The ion-conducting polymeric composition can be in the form of a membrane. The ion-conducting polymeric composition can comprise a terpolymer of styrene, vinylbenzyl-R.sub.s and vinylbenzyl-R.sub.x, in which R.sub.s is a positively charged cyclic amine group, R.sub.x is at least one constituent selected from the group consisting of Cl, OH, and a reaction product between an OH or a Cl and a species other than a cyclic amine or a simple amine, the total weight of the vinylbenzyl-R.sub.x groups is greater than 1% of the total weight of the membrane, and the total weight of the vinylbenzyl-R.sub.s groups is 15% or more of the total weight of the membrane.

A lithium ion secondary battery in which the positive electrode active material is predominantly composed of olivine type lithium phosphorus oxide, the positive electrode contains a binder predominantly composed of a resin containing polyamic acid and polyimide, and a carbon material is contained in the positive electrode as a conductive agent. A ratio A/B of a peak intensity A of an aromatic ring to a peak intensity B of an imide ring of the positive electrode by FTIR is 0.20 or more.

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 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.

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 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.

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.

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.

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.

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.

Provided is a NiFe battery comprising an iron electrode which is preconditioned prior to any charge-discharge cycle. The preconditioned iron electrode used in the NiFe battery is prepared by first fabricating an electrode comprising an iron active material, and then treating the surface of the electrode with an oxidant to thereby create an oxidized surface.

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 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.