# US 2021/0277529 A1 · Production of sodium metal by dual temperature electrolysis processes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0277529 A1 - Document ID: US20210277529A1 - Status: Published application - Kind: A1 - Application number: 17/192,799 - Filed: 2021-03-04 - Published: 2021-09-09 - Earliest claimed: 2020-03-04 - Assignees: Enlighten Innovations Inc. - Applicants: Enlighten Innovations Inc. - Inventors: Sai Venkata Bhavaraju; Roger Marc Flinders; Thomas Ray Hinklin; Steven William Hughes; Mykola Makowsky; Mathew Richard Robins - Web page: https://patentgrep.com/patent/US20210277529A1 ## CPC - C25C 1/02: of light metals - C25C 3/02: of alkali or alkaline earth metals - C01B 17/06: from non-gaseous sulfides or materials containing such sulfides, e.g. ores - C25C 7/005: {of cells for the electrolysis of melts (C25C7/02 - C25C7/06 take precedence)} - C25C 7/04: Diaphragms; Spacing elements - C25C: PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} ## Abstract New dual temperature electrochemical methods and systems for the production of sodium metal from sodium polysulfides have been discovered. The technology provides high conductivity for sodium ions and extended service life for the electrochemical cell. ## Claims ### Claim 1 A method comprising: introducing an anolyte at a first temperature into an anolyte compartment of an electrochemical flow cell, wherein the anolyte comprises an effective amount of a sodium salt dissolved in a temperature-sensitive solvent; the anolyte compartment comprises an anode, wherein the anode comprises the sodium salt; the electrochemical flow cell further comprises a catholyte compartment and a ceramic sodium ion conductive membrane that separates the anolyte compartment from the catholyte compartment; and the catholyte compartment comprises a molten sodium cathode; causing sodium ions from the sodium salt to pass through the ceramic sodium ion conductive membrane from the anolyte compartment to the catholyte compartment; reducing the sodium ions to sodium metal at the molten sodium cathode; and cooling the anolyte outside the anolyte compartment to a second temperature; wherein the second temperature causes degradation of the temperature-sensitive solvent at a rate less than 20% of the rate that occurs at the first temperature. ### Claim 2 (depends on 1) The method of claim 1, wherein the sodium salt comprises, consists of, or consists essentially of a sodium sulfide, a sodium polysulfide, a mixture of sodium sulfide and one or more sodium polysulfides. ### Claim 3 (depends on 2) The method of claim 2, wherein the polysulfide has the formula Na2Sx wherein x is an integer from 1 to 32. ### Claim 4 (depends on 1) The method of claim 1, wherein the amount of sodium in the anolyte ranges from about 1 wt % to about 10 wt %. ### Claim 5 (depends on 1) The method of claim 1, wherein the amount of sodium in the anolyte ranges from about 3 wt % to about 7 wt %. ### Claim 6 (depends on 1) The method of claim 1, wherein the anolyte further comprises sulfur. ### Claim 7 (depends on 6) The method of claim 6, further comprising recovering the sulfur from the anolyte. ### Claim 8 (depends on 1) The method of claim 1, wherein the temperature-sensitive solvent comprises, consists of, or consists essentially of an alkyl diol, alkyl triol, cycloalkyl diol, cycloalkyl triol, lactam, cyclic urea, C1-6 alkyl amide, carbonate, ether, mixtures of any two or more thereof, or mixtures of any of the foregoing with water. ### Claim 9 (depends on 1) The method of claim 1, wherein the temperature-sensitive solvent is selected from the group consisting of ethylene glycol, propylene glycol, butane-1,4-diol, diethylene glycol, triethylene glycol, tetraethylene glycol, glycerol and mixtures of two or more thereof. ### Claim 10 (depends on 1) The method of claim 1, wherein the temperature-sensitive solvent comprises, consists of, or consists essentially of ethylene glycol. ### Claim 11 (depends on 1) The method of claim 1, wherein an anode current collector in electrical contact with the anode is disposed in the anolyte compartment of the electrochemical cell. ### Claim 12 (depends on 11) The method of claim 11, wherein the anode current collector comprises, consists of, or consists essentially of one or more of nickel, various carbon types, steel, Kovar, or cobalt. ### Claim 13 (depends on 12) The method of claim 12, wherein the anode current collector comprises, consists of, or consists essentially of nickel. ### Claim 14 (depends on 1) The method of claim 1, wherein the electrochemical flow cell further comprises a cathode current collector. ### Claim 15 (depends on 14) The method of claim 14, wherein the cathode current collector comprises, consists of, or consists essentially of nickel. ### Claim 16 (depends on 1) The method of claim 1, wherein the ceramic sodium ion conductive membrane comprises, consists of, or consists essentially of a sodium ion conducting garnet-like ceramic, Na-conducting ceramic glass, NaSiCON or Na-β″-alumina. ### Claim 17 (depends on 1) The method of claim 1, wherein the first temperature ranges from about 115° C. to about 150° C. ### Claim 18 (depends on 1) The method of claim 1, wherein the second temperature ranges from 80° C. to less than 115° C. ### Claim 19 (depends on 1) The method of claim 1, wherein the ceramic sodium ion conductive membrane or the ceramic sodium ion conductive membrane and anolyte compartment are heated to the first temperature. ### Claim 20 (depends on 1) The method of claim 1, wherein the ceramic sodium ion conductive membrane or the ceramic sodium ion conductive membrane and anolyte compartment are heated to the first temperature by a thermal enclosure. ### Claim 21 (depends on 1) The method of claim 1, wherein the ceramic sodium ion conductive membrane has a conductivity of at least 10 mS cm−1 when anolyte is in the anolyte compartment. ### Claim 22 (depends on 1) The method of claim 1, wherein the ceramic sodium ion conductive membrane has a conductivity of at least 50 mS cm−1 when anolyte is in the anolyte compartment. ### Claim 23 (depends on 1) The method of claim 1, wherein the ceramic sodium ion conductive membrane has a conductivity of 10 mS cm−1 to 100 mS cm−1. ### Claim 24 A system for the production of sodium metal by dual temperature electrolysis comprising: an anolyte source comprising anolyte; at least one pump for pumping anolyte within the system; a heater for heating anolyte to a first temperature; a chiller for cooling anolyte to a second temperature, lower than the first temperature; and an electrolytic flow cell comprising an anolyte compartment and a catholyte compartment separated by a sodium ion conductive ceramic membrane; an anode comprising a sodium salt, disposed in the anolyte compartment; a molten sodium cathode disposed in the catholyte compartment; and a power supply electrically connected to the anode and cathode; wherein the anolyte compartment further comprises an anolyte inlet and an anolyte outlet; and the catholyte compartment comprises an opening through which molten sodium may flow; and wherein the anolyte source is in fluid connection with the pump and the anolyte inlet of the anolyte compartment; the heater is adapted to heat the anolyte from the anolyte source before or upon entering the anolyte compartment; and the chiller is adapted to cool the anolyte upon exiting the anolyte compartment.