Patent ID: 8088270

Claim:
A process for oxidizing alkali metal polysulfides electrochemically comprising: obtaining an electrolytic cell comprising an alkali ion conductive membrane configured to selectively transport alkali ions, the membrane separating an anolyte compartment configured with an anode and a catholyte compartment configured with a cathode; introducing into the anolyte compartment an anolyte solution comprising an alkali metal polysulfide and an anolyte solvent that dissolves elemental sulfur; introducing into the catholyte compartment a catholyte; applying an electric current to the electrolytic cell thereby: i. oxidizing sulfur in the anolyte compartment to form elemental sulfur; ii. causing alkali metal ions to pass through the alkali ion conductive membrane from the anolyte compartment to the catholyte compartment; and iii. reducing the alkali metal ions in the catholyte compartment to form elemental alkali metal; removing at least a portion of the anolyte solution from the anolyte compartment and cooling the removed anolyte solution to precipitate solid phase sulfur from the anolyte solution.