Lithium/sulfur dioxide cell

Abstract

The lithium/carbon/SO 2 energy cell is disclosed wherein the electrolyte includes lithium tetrachloroaluminate. In order to increase the electrical capacity of the cell, the concentration of lithium tetrachloroaluminate in the electrolyte is increased .[.to.]. .Iadd.and .Iaddend.calcium tetrachloroaluminate .[.and.]. .Iadd.is .Iaddend.added to the solution to aid the mass transport as well as .[.the.]. .Iadd.to .Iaddend.lower .Iadd.the .Iaddend.freezing point of the electrolyte. In order to eliminate any corrosive effect of the calcium .[.added.]. .Iadd.additive .Iaddend.to on the lithium anode, this disclosure provides a teaching of the use of an electrolyte solution .[.and.]. .Iadd.that .Iaddend.is essentially free of any .[.moist.]. .Iadd.moisture .Iaddend.content.

I claim: 
     
       1. A substantially moisture free electrochemical cell comprising a lithium anode, an inorganic electrolyte including sulfur dioxide that provides a solvent for lithium tetrachloroaluminate and at least one alkaline earth tetrachloroaluminate and that functions in conjunction with dissolved aluminum and lithium to produce a discharge product and in which solution there is a mole equivalent ratio of lithium to alkaline earth to sulfur dioxide within the range of from 1 to 1 to 9, to .[.lb 2.]. .Iadd.2 to 1 .Iaddend.to 12, said cell having a cathode supported on a current collector, and said cathode consisting of a porous carbon for supporting the discharge product. 
     
     
       2. A substantially moisture free electrochemical cell as in claim 1 wherein said at least one tetrachloroaluminate is calcium tetrachloroaluminate. 
     
     
       3. A substantially moisture free electrochemical cell as in claim 2 wherein said lithium tetrachloroaluminate, said calcium tetrachloroaluminate, and said sulfur dioxide are present in a mole equivalent ratio of 2 to 1 to 12. 
     
     
       4. A substantially moisture free electrochemical cell as in claim 1 wherein said at least one tetrachloroaluminate is magnesium tetrachloroaluminate. 
     
     
       5. A substantially moisture free electrochemical cell as in claim 1 wherein said at least one tetrachloroaluminate is strontium tetrachloroaluminate. 
     
     
       6. A substantially moisture free electrochemical cell as in claim 1 wherein said at least one tetrachloroaluminate is barium tetrachloroaluminate.