Lithiated manganese dioxide

A process for treating manganese dioxide comprising the steps of:

• (a) forming a mixture of manganese dioxide and a liquid;
• and
• (b) adding a sufficient amount of a basic lithium salt to said mixture to adjust the pH of said mixture to between about 7.5 and 9;
• and
• (c) allowing said mixture to soak at a temperature between about 15 and 35° C. at said pH to neutralize surface acidic sites on said manganese dioxide;
• and
• (d) adding a sufficient amount of basic lithium salt to said mixture after said soaking to raise the pH of said mixture to between about 10 and 13;
• and
• (e) allowing said mixture to soak at a temperature between about 15 and 100° C. at said raised pH to form a lithiated manganese dioxide intermediate product having the formula LixMnO2, wherein 0.05≦x≦0.125;
• and
• (f) separating said lithiated manganese dioxide intermediate product from said mixture;
• and
• (g) heating said lithiated manganese dioxide intermediate product at a temperature between about 300 and 420° C. to form a heat-treated lithiated manganese dioxide product having the formula LiyMnO2−δ, wherein 0.075≦y≦0.175 and 0.01≦δ≦0.06, and a predominantly gamma(γ)-MnO2-type crystal structure;
• and
• (h) inserting said heat-treated lithiated manganese dioxide into a primary lithium electrochemical cell as an active cathode material for said cell.

A process for treating manganese dioxide comprising the steps of:

• (a) forming a reaction precursor comprising a blended, dry mixture of manganese dioxide and a low melting point lithium salt mixture, said lithium salt mixture having a melting point less than about 350° C.;
• and
• (b) heating said reaction precursor in a first step at a temperature between the melting point of said low melting point lithium salt mixture and 350° C. to form a lithiated manganese dioxide intermediate product having the formula LixMnO2, wherein 0.05≦x≦0.175;
• and
• (c) heating said intermediate product in a second step at a temperature between about 350 and 420° C. to form heat-treated lithiated manganese dioxide product having the formula LiyMnO2−δ, wherein 0.05≦y≦0.175 and 0.01≦δ≦0.06, and a predominantly gamma(γ)-MnO2-type crystal structure;
• and
• (d) inserting said heat-treated lithiated manganese dioxide into a primary lithium electrochemical cell as an active cathode material of said cell.