Cathode active material (higher oxides of silver)
View Patent ↗The present invention provides novel cathodes having a reduced resistivity and electrochemical cells using these cathodes. Furthermore, this invention also presents methods of manufacturing novel electrochemical cells and novel cathodes.
1. A method of producing cathode active material comprising:
providing a silver compound, wherein the silver of the compound has +1 oxidation state;
dissolving the silver compound in a solvent comprising at least about 95% water by weight to form a mixture; and
oxidizing the silver of the silver compound with ozone to generate a silver oxide, wherein the silver of the silver oxide has an oxidation state of +2 or more and wherein the silver oxide comprises at least 95 wt % of Ag 2 O 3 .
2. The method of claim 1 , wherein the silver compound comprises Ag—X, wherein X is a counter anion.
3. The method of claim 2 , wherein counter anion is hydride, nitrate, fluoride, nitrite, chloride, perchlorate, bromide, chlorate, iodide, chlorite, cyanide, hypochlorite, cyanate, iodate, thiocyanate, bromate, hydroxide, hypobromite, amide, permanganate, acetate, dihydrogen phosphate, formate, hydrogen sulfate, hydrogen carbonate or bicarbonate, periodate, iodate, perbromate, hexafluorophosphate, tetrafluoro borate, azide, aluminate, hydrogen sulfide, hexafluoroarsinate, bromite, iodite, metaborate, hydrogen carbide, or any combination thereof.
4. The method of claim 3 , wherein the silver compound comprises silver nitrate.
5. The method of claim 1 , wherein the silver compound is dissolved in the solvent at a temperature of from about 10° C. to about 60° C. to form the mixture.
6. The method of claim 5 , wherein the mixture is substantially liquid.
7. The method of claim 6 , wherein the silver compound is dissolved under stirring.
8. The method of claim 1 , wherein the solvent has a pH of less than about 8.
9. The method of claim 1 , wherein the ozone is diffused through the mixture at a rate of at least about 3 g per hour.
10. The method of claim 1 , wherein the silver oxide has an ionic conductivity of less than about 5 microOhms.
11. The method of claim 10 , wherein the silver oxide has an ionic conductivity of less than about 1 microOhms.
12. The method of claim 11 , further comprising drying the silver oxide.
13. The method of claim 12 , wherein the silver oxide is dried in an environment having a pressure of less than about 0.5 atm.
14. The method of claim 13 , wherein the silver oxide is dried at a temperature of at least about 30° C.
15. A method of producing cathode active material comprising:
providing a silver compound, wherein the silver of the compound comprises silver nitrate;
dissolving the silver compound in an aqueous solvent comprising at least about 95% water by weight to form a mixture at a temperature and pressure wherein the aqueous solvent is liquid; and
diffusing ozone through the mixture to generate a silver oxide comprising Ag 2 O 3 .