A homogeneous manganese dioxide composition having on a microscopic scale domains of alpha and delta manganese dioxide is manufactured by reacting a manganese-oxygen containing composition with a sodium containing composition at elevated temperature followed by acid treatment.
The invention relates to the manufacture of manganese dioxide by a chemical process. The resulting manganese dioxide product takes the form of particles characterized by filament-like protrusions jutting out from its surface. The manganese dioxide particles having such surface features can be manufactured by reacting manganese sulfate with sodium peroxodisulfate in an aqueous solution. The process can be controlled to yield high density manganese dioxide. The manganese dioxide formed in the process can be deposited directly onto the surface of electrolytic manganese dioxide (EMD). The manganese dioxide product is particularly suitable for use as a cathode active material in electrochemical cells.
A process of synthesizing synthetic manganese oxide hydrates having various structures including hollandite and todorokite structure by hydrothermal synthesis. The products have a high degree of crystallinity, and thermal stability.
The invention relates to the manufacture of manganese dioxide by a chemical process. The resulting product takes the form of gamma manganese dioxide particles characterized by filament-like protrusions of ramsdellite manganese dioxide jutting out from the surface of the particles. The manganese dioxide particles having such features can be manufactured by reacting manganese sulfate with sodium peroxodisulfate in an aqueous solution. The process can be controlled to yield high density manganese dioxide. The manganese dioxide formed in the process can be deposited directly onto the surface of electrolytic manganese dioxide (EMD). The manganese dioxide product is particularly suitable for use as a cathode active material in electrochemical cells.
A process of synthesizing synthetic manganese oxide hydrates having various structures including hollandite and todorokite structure by hydrothermal synthesis. The products have a high degree of crystallinity, and thermal stability.
The invention provides a manganese dioxide-based material which is highly crystalline and chemically prepared. The material has a predominantly ramsdellite structure, and has a powder X-ray diffraction pattern (CuK.sub..alpha. radiation) in which the ratio of a [110] peak height to a [201] peak height is at least 0,6:1,0. The material can be used as an electrode material in an electrochemical cell 10.
