Abstract: An alkaline secondary battery which is characterized in that it comprises, a positive electrode containing nickel hydroxide having a value of 0.8° or more in the half-width of a peak in the (101) plane thereof as measured by X-ray powder diffraction (2?) using Cu—K? ray, and 4.0 to 15% by weight of at least one material selected from the group consisting of zinc and zinc compounds, and an alkali electrolyte, the ratio of which to theoretical capacity of the positive electrode being 0.7 to 2.0 cm3/Ah, the weight of the at least one material being one calculated as zinc element and based on the weight of the nickel hydroxide.

Abstract: An alkaline secondary battery which is characterized in that it comprises, a positive electrode containing nickel hydroxide having a value of 0.8° or more in the half-width of a peak in the (101) plane thereof as measured by X-ray powder diffraction (2&thgr;) using Cu—K&agr; ray, and 4.0 to 15% by weight of at least one material selected from the group consisting of zinc and zinc compounds, and an alkali electrolyte, the ratio of which to theoretical capacity of the positive electrode being 0.7 to 2.0 cm3/Ah, the weight of the at least one material being one calculated as zinc element and based on the weight of the nickel hydroxide.

Abstract: Provided is a active material for positive electrode for an alkaline secondary cell, which advantageously exhibits improved overdischarge characteristics, improved utilization of the active material and an improved effect of suppressing the rise in cell internal pressure, a method for producing the same, and an alkaline secondary cell using the above active material for positive electrode, especially a nickel-hydrogen secondary cell. The above active material comprises nickel hydroxide particles each having a surface to which a cobalt oxide sticks, wherein the cobalt oxide contains 20 to 40% by mole of cobalt(II) oxide, wherein the nickel hydroxide particles form an eutectic together with Co and Zn or/and Y, and the Co content of the eutectic is 2% by mass or less, and the nickel hydroxide particles have a value of a half width of the peak ascribed to the (101) crystal face diffraction of 0.8°/2&thgr;(Cu—K&agr;) or more as measured by powder X-ray diffractometry.

Abstract: A nickel-metal hydride secondary battery comprising electrode group comprising positive electrode comprised mainly of nickel hydroxide, negative electrode comprised mainly of a hydrogen storage alloy, and separator being disposed between the positive electrode and the negative electrode, wherein the electrode group is sealed in battery casing, together with an alkali electrolyte liquid, wherein, in the battery, a W element and an Na element are present simultaneously. The nickel-metal hydride secondary battery of the present invention is advantageous not only in that it exhibits high utilization of the active material and excellent self-discharge characteristics in a high temperature storage as well as high charging efficiency in a high temperature environment, but also in that it has excellent large current discharge characteristics.

Abstract: Provided is a active material for positive electrode for an alkaline secondary cell, which advantageously exhibits improved overdischarge characteristics, improved utilization of the active material and an improved effect of suppressing the rise in cell internal pressure, a method for producing the same, and an alkaline secondary cell using the above active material for positive electrode, especially a nickel-hydrogen secondary cell.

Abstract: The present invention is to provide a production method of an active material for an alkaline secondary battery comprising: a step of mixing particles comprising particles mainly containing nickel hydroxide and particles of a metal cobalt or a cobalt compound in a mixer with a sealed structure comprising a heating means in the presence of oxygen and an alkaline aqueous solution while heating. An active material produced by the method allows a high utilization. And a battery assembled with a positive electrode using the active material has an excellent high ratio discharge characteristic, and hardly causes the capacity decline even at the time of recharging after leaving in the over discharge state for a long time.

Abstract: An alkaline secondary battery comprising a positive electrode, a negative electrode, and an alkaline electrolyte, wherein the positive electrode comprises a conductive substrate and a mixture held by the conductive substrate, the mixture containing nickel hydroxide and a conductive cobalt compound, and the positive electrode has pores, substantially all of the pores each having a diameter with a range of 0.0001 .mu.m to 10 .mu.m.