There is provided a positive electrode for an alkaline secondary battery and an alkaline secondary battery having good output properties and cycle life. To that end, a positive electrode (10) for alkaline secondary battery is obtained by laminating a flexible metal substrate (11) having flexibility; a primer layer (12) having conductivity provided on one or both surfaces of the substrate (11); and a positive electrode composite material layer (13) provided on the primer layer (12) and containing a positive electrode active material, a binder resin, and a first conductive material.

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.

A negative electrode for an alkaline battery cell which includes zinc-based particles, wherein less than 20% of the zinc-based particles, by weight relative to the total zinc in the electrode, have a particle size of greater than about 150 micrometers, is provided. An alkaline electrochemical cell that includes the negative electrode and a method for reducing the gassing of the electrochemical cell is also provided.

An alkaline battery has a positive electrode mixture containing manganese dioxide and a conductive material filling a tubular positive electrode can that is closed at one end. A negative electrode mixture containing a zinc powder filling on an inner peripheral side of a separator is disposed on an inside of the positive electrode mixture. The negative electrode mixture contains zinc particles with a granularity of 75 μm or less at 25 to 40 mass %. The positive electrode mixture has a plurality of tubular pellets stacked inside the positive electrode can coaxially with the positive electrode can. A sum s of lengths of gaps between the pellets is set at 1 to 14% with respect to a sum d of lengths of the pellets. Thus, a sufficient amount of the electrolyte is held in the gaps and between the pellets in the positive electrode.

An alkaline battery has a positive electrode mixture containing manganese dioxide and a conductive material filling a tubular positive electrode can that is closed at one end. A negative electrode mixture containing a zinc powder filling on an inner peripheral side of a separator is disposed on an inside of the positive electrode mixture. The negative electrode mixture contains zinc particles with a granularity of 75 μm or less at 25 to 40 mass %. The positive electrode mixture has a plurality of tubular pellets stacked inside the positive electrode can coaxially with the positive electrode can. A sum s of lengths of gaps between the pellets is set at 1 to 14% with respect to a sum d of lengths of the pellets. Thus, a sufficient amount of the electrolyte is held in the gaps and between the pellets in the positive 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 method for producing a composite alloy for use in an electrode for an alkaline storage battery, including a powder preparation step of preparing a hydrogen storage alloy powder containing Ti and Cr and having a BCC structure, an etching step of applying an acid to the hydrogen storage alloy powder prepared in the powder preparation step, a Pd film forming step of coating the surface of the hydrogen storage alloy powder subjected to the etching step with Pd using a substitution plating method, and a heat treatment step of heating the hydrogen storage alloy powder having a Pd film formed, at said heating being a temperature of 500° C. or less, wherein in the Pd coating forming step, the hydrogen storage alloy powder is coated with Pd under the condition that the Pd element weight ratio of the composite alloy to be produced is 0.47% or more.

A rechargeable zinc metal battery cell includes a zinc metal anode, a cathode, a porous separator between them, and an electrolyte composition absorbed by the porous separator and in contact with both anode and cathode. The electrolyte composition includes (i) an aqueous solution of zinc chloride at a concentration greater than 15 molal, and (ii) dimethyl carbonate present at a mass ratio between 0.1:1.0 and 1.0:1.0 with respect to water in the aqueous solution. In some examples: the anode includes zinc metal foil stacked on titanium metal foil; the cathode includes vanadium(V) phosphate; the porous separator includes glass fibers and is less than 200 μm thick; or the electrolyte composition includes (i) an aqueous solution of 30 molal zinc chloride, 5 molal lithium chloride, and 10 molal trimethyl ammonium chloride, and (ii) dimethyl carbonate present at a mass ratio of 1.0:1.0 with respect to water in the aqueous solution.

The nickel-containing hydroxide particle covered with cobalt, wherein in a volume-based particle size distribution, the nickel-containing hydroxide particle covered with cobalt has the maximum peak with a height a, one peak at a height of (½)a or higher, and has a value A of formula (1) calculated from a width b of the maximum peak at a height of (½)a, and in a volume-based particle size distribution after compression treatment, the nickel-containing hydroxide particle covered with cobalt has the maximum peak with a height c, and has a value B of formula (2) calculated from a width d of the maximum peak at a height of (½)c, and wherein the value B and the value A have a relation represented by formula (3):

A=[(b×(½)a]/2  (1)

B=[(d×(½)c]/2  (2)

−1.50≤[(B−A)/A]×1005.00  (3)