Claims
- 1. An electrochemical cell comprising a lithium anode, an electrolyte, and a cathode comprising manganese dioxide, said manganese dioxide made by a process for treating gamma electrolytic manganese dioxide (EMD) wherein the gamma EMD is prepared by subjecting a solution of manganese sulfate to electrolysis in a sulfuric acid solution, the improvement comprising:
- a) treating the EMD in a solution comprising sodium hydroxide to neutralize residual surface acidity of the EMD resulting from said electrolysis in sulfuric acid solution,
- b) mixing the neutralized EMD in an aqueous acid solution to replace ion-exchangeable sodium in the EMD with hydrogen to produce an intermediate treated EMD having reduced sodium content,
- c) treating said intermediate treated EMD with an aqueous basic solution including a lithium compound selected from the group consisting of lithium hydroxide, lithium carboxylate, lithium carbonate, lithium benzoate, lithium sulfate, lithium nitrate and mixtures thereof, to replace the hydrogen introduced into the EMD in step (b) with lithium to produce an EMD product containing lithium.
- 2. An electrochemical cell comprising a lithium anode, an electrolyte, and a cathode comprising manganese dioxide, said manganese dioxide made by a process for treating gamma electrolytic manganese dioxide (EMD) wherein the gamma EMD is prepared by subjecting a solution of manganese sulfate to electrolysis in a sulfuric acid solution, the improvement comprising:
- a) treating the EMD in a solution comprising sodium hydroxide to neutralize residual surface acidity of the EMD resulting from said electrolysis in sulfuric acid solution,
- b) mixing the neutralized EMD in an aqueous acid solution to replace ion-exchangeable sodium in the EMD with hydrogen to produce an intermediate treated EMD having reduced sodium content,
- c) treating said intermediate treated EMD with an aqueous basic solution comprising lithium hydroxide to replace the hydrogen introduced into the EMD in step (b) with lithium to produce an EMD product containing lithium.
- 3. An electrochemical cell comprising a lithium anode, an electrolyte, and a cathode comprising manganese dioxide, said manganese dioxide made by a process for treating gamma electrolytic manganese dioxide (EMD) wherein the gamma EMD is prepared by subjecting a solution of manganese sulfate to electrolysis in a sulfuric acid solution, the improvement comprising:
- a) treating the EMD in a solution comprising sodium hydroxide to neutralize residual surface acidity of the EMD resulting from said electrolysis in sulfuric acid solution,
- b) mixing the neutralized EMD in an aqueous acid solution to replace ion-exchangeable sodium in the EMD with hydrogen to produce an intermediate treated EMD having reduced sodium content,
- c) treating said intermediate treated EMD with an aqueous basic solution including a lithium compound selected from the group consisting of lithium hydroxide, lithium carboxylate, lithium carbonate, lithium benzoate, lithium sulfate, lithium nitrate and mixtures thereof, to replace the hydrogen introduced into the EMD in step (b) with lithium to produce an EMD product containing lithium, wherein the sodium content of said EMD product is less than 1000 ppm.
- 4. An electrochemical cell comprising a lithium anode, an electrolyte, and a cathode comprising manganese dioxide, said manganese dioxide made by a process for treating gamma electrolytic manganese dioxide (EMD) wherein the gamma EMD is prepared by subjecting a solution of manganese sulfate to electrolysis in a sulfuric acid solution, the improvement comprising:
- a) treating the EMD in a solution comprising sodium hydroxide to neutralize residual surface acidity of the EMD resulting from said electrolysis in sulfuric acid solution,
- b) mixing the neutralized EMD in an aqueous acid solution to replace ion-exchangeable sodium in the EMD with hydrogen to produce an intermediate treated EMD having reduced sodium content,
- c) treating said intermediate treated EMD with an aqueous basic solution including a lithium compound selected from the group consisting of lithium hydroxide, lithium carboxylate, lithium carbonate, lithium benzoate, lithium sulfate, lithium nitrate and mixtures thereof, to replace the hydrogen introduced into the EMD in step (b) with lithium to produce an EMD product containing lithium,
- d) thermally treating said manganese dioxide containing lithium at a temperature of at least about 350.degree. C. for a time sufficient to convert at least about 30% by weight of said manganese dioxide from the gamma to the beta form.
Parent Case Info
This application is a division of application Ser. No. 08/474,871, filed Jun. 7, 1995, now U.S. Pat. No. 5,698,176.
US Referenced Citations (11)
Foreign Referenced Citations (2)
Number |
Date |
Country |
5273328 |
Jun 1977 |
JPX |
52-73328 |
Jun 1977 |
JPX |
Divisions (1)
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Number |
Date |
Country |
Parent |
474871 |
Jun 1995 |
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