Process for producing manganese dioxide
AssigneeDuracell Inc.
InventorsEnoch I. Wang, Lifun Lin, William L. Bowden
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Abstract
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 the is particularly suitable for use as a cathode active material in electrochemical cells.
Claims17
A process for manufacture of gamma manganese dioxide comprising the steps of:
- a) reacting MnSO.sub.4 and Na.sub.2 S.sub.2 O.sub.8 in an aqueous solution heated to a temperature below 100.degree. C. to produce a reaction product mixture comprising a precipitate of gamma MnO.sub.2 ;
- b) removing the gamma MnO.sub.2 precipitate from said reaction product mixture;
- and
- c) drying said precipitate.
A process for the manufacture of a cathode for an electrochemical cell comprising the steps of:
- a) reacting MnSO.sub.4 and Na.sub.2 S.sub.2 O.sub.8 in an aqueous solution to produce a reaction product mixture comprising a precipitate of gamma MnO.sub.2 ;
- b) removing the gamma MnOz precipitate from said reaction product mixture;
- c) drying said precipitate;
- and
- d) compacting said precipitate.
A process for the manufacture of gamma MnO.sub.2 comprising reacting a manganese salt with Na.sub.2 S.sub.2 O.sub.8.
Dependencies are inferred from the claim text.