Electrolytic manganese dioxide, and method for its production and its application

Abstract

To provide electrolytic manganese dioxide to be used as a cathode active material for an alkali-manganese dry cell, which has a high alkali potential and is provided with a high reactivity and packing efficiency as a cathode for the cell. Electrolytic manganese dioxide having an alkali potential of at least 310 mV, FWHM of at least 2.2 DEG and at most 3.0 DEG , and a (110) / (021) peak intensity ratio in the X-ray diffraction peaks of at least 0.50 and at most 0.80, is used. The (110) interplanar spacing of the electrolytic manganese dioxide is preferably at least 4.00 AA and at most 4.06 AA. Particularly when the alkali potential is at least 350 mV and at most 400 mV, the molar ratio of structural water contained (H 2 O / MnO 2 ) is preferably at least 0.20. It can be produced by electrolysis at a low sulfuric acid concentration at the initial stage of the electrolysis and at a high sulfuric acid concentration at a later stage. It is preferred to further carry out sulfuric acid treatment.

Description

technical field [0001] The present invention relates to electrolytic manganese dioxide used as a positive electrode active material in, for example, manganese dry batteries, particularly alkaline manganese dry batteries, a method for producing the same, and uses thereof. Background technique [0002] Manganese dioxide is known as, for example, a positive electrode active material for manganese dry batteries and alkaline manganese dry batteries, and has advantages of excellent storage stability and low cost. In particular, alkaline manganese dry batteries using manganese dioxide as a positive electrode active material are widely used in digital cameras, portable recorders, portable information devices, and even game machines and toys due to their excellent discharge characteristics under heavy loads. Its demand expanded rapidly. [0003] However, as the discharge current increases, the utilization rate of manganese dioxide as the positive electrode active material decreases,...

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Problems solved by technology

[0003] However, as the discharge current increases, the utilization rate of manganese dioxide as the positive electrode active material decreases, and since the alkaline manganese dry battery cannot be used in a state where the discharge voltage is lowered, there is a problem that the actual discharge capacity is greatly impaired.

That is, if an alkaline manganese dry battery is used in a device using a large current (high rate discharge), there is a disadvantage that the filled manganese dioxide as a positive electrode active material cannot be fully utilized, and the usable time is short.

However, the discharge characteristics of the manganese dioxide disclosed here are effective at a discharge capacity of 30mA at a low load, but exhibit almost the same characteristics as conventional products at a constant current discharge of 500mA.

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