Positive electrode material and nickel-zinc battery

#The present invention relates to beta-type nickel oxyhydroxide and a method of producing thereof, and yet, also relates to a positive electrode active material composed of beta nickel oxyhydroxide. Further, the present invention relates to a nickel-zinc battery incorporating a positive electrode comprising beta nickel oxyhydroxide as a positive electrode active material and a negative electrode comprising zinc as a negative electrode active material.

#In recent years, compact-size portable electronic apparatuses, especially portable game players, digital cameras and digital video-camera recorders, or the like, have been propagated very significantly. It is expected that these compact-size portable electronic apparatus will be propagated furthermore from now on, and thus, demand for compact-size battery serving as a power-supply source for these compact-size portable electronic apparatuses will also be promoted quickly. Generally, any of those compact-size portable electronic apparatuses utilizes a high operating voltage and requires a large amount of current, and thus, a usable power source must be distinguished in discharge characteristic under heavy load.

#Of those batteries satisfying the above requirements, such a alkaline-manganese battery has already been propagated most widely, which comprises manganese dioxide for composing the positive electrode and zinc for the negative electrode, and yet, it also comprises highly concentrated alkaline aqueous solution for composing electrolytic solution. Inasmuch as manganese dioxide and zinc are respectively inexpensive, and yet, because of high energy density per weight, not only for the power-supply source of compact-size portable electronic apparatuses, but the alkaline-manganese battery is also utilized extensively.

#FIG. 1 is a vertical cross-sectional view of a nickel-zinc battery according to a practical form for embodying the present invention;

#FIG. 2 is explanatory of substantially spherical beta nickel oxyhydroxide (A) realized by the present invention and conventional non-spherical beta nickel oxyhydroxide (B);

#FIG. 3 exemplifies grading distribution of the beta nickel oxyhydroxide according to a practical form for embodying the present invention;

#Practical forms for implementing the present invention in relation to beta nickel oxyhydroxide and method of producing the nickel oxyhydroxide, a positive electrode active material, and a nickel-zinc battery, are described below.

#FIG. 1 is a vertical cross-sectional view of a nickel-zinc battery 1 as an example of a battery according to an embodiment of the present invention. The nickel-zinc battery 1 comprises the following: a battery can 2, a positive electrode 3, a separator 4, a negative electrode mixture 5, a sealing member 6, a washer 7, a negative electrode terminal plate 8, and a current collecting pin 9.

#The battery can 2 is made of iron plated with nickel, for example, which constitutes an external positive electrode terminal of the nickel-zinc battery 1.