Claims
- 1. In a secondary lithium cell susceptible to over-charging or overdischarging, the improvement being:
- a cathode additive for incorporating into a cathode of the cell, the cathode having a charge cutoff voltage and a discharge cutoff voltage, the cathode additive yielding an upper voltage plateau within the cell upon the application of an overcharge voltage to the cell, said upper voltage plateau being slightly higher than the charge cutoff voltage of the cathode and yielding a lower voltage plateau within the cell upon the application of an overdischarge voltage to the cell, said lower voltage plateau being slightly lower than the discharge cutoff voltage plateau of the cathode.
- 2. The improvement of claim 1, wherein the additive is a transition metal oxide.
- 3. The improvement of claim 1, wherein the additive is a sulfide.
- 4. The improvement of claim 2, wherein the cathode additive is selected from a group consisting of Li.sub.x Mn.sub.2 O.sub.4, Li.sub.x MoO.sub.2, Li.sub.x CoO.sub.2, Li.sub.x NiO.sub.2, and Li.sub.x M.sub.y Mn.sub.(2-y) O.sub.4, wherein M is Co, Cr, or Fe.
- 5. The improvement of claim 1, wherein the cathode additive is a mixture of Li.sub.2 Mn.sub.2 O.sub.4 and Li.sub.0.1 MoO.sub.2.
- 6. The improvement of claim 1, wherein the secondary lithium cell is selected from a group consisting of Li--TiS.sub.2, Li--MoS.sub.2, Li--NbSe.sub.3, Li--V.sub.2 O.sub.5, Li--MnO.sub.2, and Li.sub.x C--Li.sub.x CoO.sub.2.
- 7. The improvement of claim 1, wherein the secondary lithium cell is a liquid electrolyte cell.
- 8. The improvement of claim 1, wherein the secondary lithium cell is a solid state cell.
- 9. The improvement of claim 8, wherein the secondary lithium cell is a polymeric electrolyte cell.
- 10. The improvement of claim 1, wherein the upper and lower plateaus are separated by at least 1000 millivolts.
- 11. The improvement of claim 1, wherein the additive is an electron and lithium ion conductor.
- 12. The improvement of claim 1, wherein the additive is a single compound additive which creates a sharp transition between the upper and lower voltage plateaus.
- 13. The improvement of claim 1, wherein the additive is incorporated into the cathode to a concentration of less than 15% by weight.
- 14. In a multicell rechargeable lithium battery susceptible to over-charging and overdischarging, the improvement being:
- a cathode additive for incorporating into a cathode of each cell of the multicell battery, said cathode additive selected from a group consisting of Li.sub.x Mn.sub.2 O.sub.4, Li.sub.x MoO.sub.2, Li.sub.x CoO.sub.2, Li.sub.x NiO.sub.2, and Li.sub.x M.sub.y Mn.sub.(2-y) O.sub.4, wherein M is Co, Cr, or Fe, said secondary lithium cell being of a type selected from a group consisting of Li--TiS.sub.2, Li--MOS.sub.2, Li--NbSe.sub.3, Li--V.sub.2 O.sub.5, Li--MnO.sub.2, and Li.sub.x C--Li.sub.x CoO.sub.2, each cathode having a charge cutoff voltage and a discharge cutoff voltage, the cathode additive yielding an upper voltage plateau within each respective cell upon the application of an overcharge voltage to the respective cell, said upper voltage plateau being slightly higher than the charge cutoff voltage of the cathode of the respective cell and yielding a lower voltage plateau within each respective cell upon the application of an over-discharge voltage to the respective cell, said lower voltage plateau being slightly lower than the discharge cutoff voltage plateau of the cathode of the respective cell.
- 15. The improvement of claim 14, wherein the cathode additive is a mixture of Li.sub.2 Mn.sub.2 O.sub.4 and Li.sub.0.1 MoO.sub.2.
- 16. The improvement of claim 14, wherein the secondary lithium cell is a solid state cell.
- 17. The improvement of claim 16, wherein the secondary lithium cell is a polymeric electrolyte cell.
- 18. The improvement of claim 14, wherein the upper and lower plateaus are separated by at least 1000 millivolts.
- 19. The improvement of claim 14, wherein the additive is an electron and lithium ion conductor.
- 20. The improvement of claim 14, wherein the additive is a single compound additive which creates a sharp transition between the upper and lower voltage plateaus.
- 21. The improvement of claim 14, wherein the additive is incorporated into the cathode to a concentration of less than 15% by weight.
- 22. In a multicell rechargeable solid state lithium battery susceptible to over-charging and overdischarging, the improvement being:
- a cathode additive for incorporating into a cathode of each cell of the multicell battery, said cathode additive being a mixture of Li.sub.2 Mn.sub.2 O.sub.4 and Li.sub.0.1 MoO.sub.2, said secondary lithium cell being a Li--TiS.sub.2 cell, each cathode having a charge cutoff voltage of about 2.7 volts and a discharge cutoff voltage of about 1.7 volts, the cathode additive yielding an upper voltage plateau of about 2.9 volts within each respective cell upon the application of an overcharge voltage to the respective cell, and yielding a lower voltage plateau of about 1.6 volts within each respective cell upon the application of an overdischarge voltage to the respective cell.
ORIGIN OF THE INVENTION
The invention described herein was made in the performance of work under a NASA contract, and is subject to the provisions of Public Law 96-517 (35 U.S.C. Section 202) in which the Contractor has elected not to retain title.
US Referenced Citations (11)