Positive electrode active material, method for producing the same, and electrochemical device

摘要

The invention provides a high-capacity positive electrode active material capable of sufficiently exploiting the excellent characteristics of magnesium metal or the like as a negative electrode active material, such as high energy capacity; a method for producing the same; and an electrochemical device using the positive electrode active material. A positive electrode 11 includes a positive electrode can 1, a positive pole pellet 2 having a positive electrode active material and the like, and a metal mesh support 3. A negative electrode 12 includes a negative electrode cap 4 and a negative electrode active material 5 such as magnesium metal. The positive electrode pellet 2 and the negative electrode active material 5 are disposed so as to sandwich a separator 6, and an electrolyte 7 is injected into the separator 6. The positive electrode active material, which provides the feature of the invention, is synthesized by a step of reacting a permanganate, such as potassium permanganate, with hydrochloric acid preferably having a concentration of 3 to 4 mol/l to produce a precipitate, and a step of filtering the precipitate, thoroughly washing the filtered precipitate with water, and then subjecting the washed precipitate to heat treatment preferably at a temperature of 300 to 400° C. for not less than 2 hours, thereby giving a manganese oxide.

主权项

1. A positive electrode active material comprising:
a manganese oxide having an ion diffusion channel comprising a tunnel structure or a layered structure, the ion diffusion channel being substantially free of water, obtained by filtering a precipitate resulting from a reaction of a permanganate with hydrochloric acid and subjecting the precipitate to heat treatment, wherein the manganese oxide has, as only one diffraction peak, a broad diffraction peak that appears at a diffraction angle 2θ of about 38° in a powder X-ray diffraction pattern.