# US 10,872,705 B2 · Electrochemical cells for direct oxide reduction, and related methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,872,705 B2 - Document ID: US10872705B2 - Status: Granted - Kind: B2 - Application number: 15/886,041 - Filed: 2018-02-01 - Published: 2019-08-01 - Granted: 2020-12-22 - Earliest claimed: 2018-02-01 - Assignees: Battelle Energy Alliance, LLC - Applicants: Battelle Energy Alliance, LLC - Inventors: Prabhat K. Tripathy - Web page: https://patentgrep.com/patent/US10872705B2 ## CPC - G21C 19/48: Non-aqueous processes - C25C 3/34: of metals not provided for in groups C25C3/02 - C25C3/32 - C25C 3/36: Alloys obtained by cathodic reduction of all their ions - C25C 7/025: {used in cells for the electrolysis of melts} - G21C 19/50: of irradiated fluid fuel {, e.g. regeneration of fuels while the reactor is in operation} - Y02E 30/30: Nuclear fission reactors - Y02W 30/50: Reuse, recycling or recovery technologies - G21C: NUCLEAR REACTORS (fusion reactors, hybrid fission-fusion reactors G21B; nuclear explosives G21J) - C25C: PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT ## Abstract A method of direct oxide reduction includes forming a molten salt electrolyte in an electrochemical cell, disposing at least one metal oxide in the electrochemical cell, disposing a counter electrode comprising a material selected from the group consisting of osmium, ruthenium, rhodium, iridium, palladium, platinum, silver, gold, lithium iridate, lithium ruthenate, a lithium rhodate, a lithium tin oxygen compound, a lithium manganese compound, strontium ruthenium ternary compounds, calcium iridate, strontium iridate, calcium platinate, strontium platinate, magnesium ruthenate, magnesium iridate, sodium ruthenate, sodium iridate, potassium iridate, and potassium ruthenate in the electrochemical cell, and applying a current between the counter electrode and the at least one metal oxide to reduce the at least one metal oxide. Related methods of direct oxide reduction and related electrochemical cells are also disclosed. ## Claims ### Claim 1 An electrochemical cell, comprising: a counter electrode including at least one inert material consisting of lithium ruthenate or a lithium rhodate; a working electrode comprising a metal oxide to be reduced in the electrochemical cell; and a molten salt electrolyte comprising a molten salt comprising at least one of an alkali halide salt and an alkaline earth metal halide salt. ### Claim 2 (depends on 1) The electrochemical cell of claim 1, further comprising a reference electrode comprising nickel, nickel/nickel oxide, glassy carbon, silver/silver chloride, one or more platinum group metals, one or more precious metals, or combinations thereof and configured to control a cell potential between the counter electrode and the working electrode. ### Claim 3 (depends on 1) The electrochemical cell of claim 1, wherein the working electrode comprises uranium oxide. ### Claim 4 (depends on 3) The electrochemical cell of claim 3, wherein the molten salt electrolyte comprises at least one mixture comprising lithium chloride and lithium oxide, calcium chloride and calcium oxide, or calcium chloride, sodium chloride, and calcium oxide. ### Claim 5 (depends on 1) The electrochemical cell of claim 1, wherein the working electrode comprises at least one of titanium monoxide, nickel oxide manganese oxide, and tantalum pentoxide. ### Claim 6 (depends on 1) The electrochemical cell of claim 1, wherein the counter electrode further comprises a substrate substantially surrounded by the at least one inert material of the counter electrode, the substrate comprising a material selected from the group consisting of high density graphite, molybdenum, tantalum, titanium, chromium, tungsten, nickel, and combinations thereof. ### Claim 7 (depends on 1) The electrochemical cell of claim 1, wherein the working electrode comprises enriched uranium oxide. ### Claim 8 (depends on 1) The electrochemical cell of claim 1, wherein the molten salt electrolyte comprises at least one of lithium chloride, lithium oxide, calcium chloride, calcium oxide, and sodium chloride. ### Claim 9 (depends on 1) The electrochemical cell of claim 1, wherein the counter electrode further comprises a substrate material selected from the group consisting of high density graphite, molybdenum, tantalum, titanium, nickel, chromium, tungsten, and combinations thereof, wherein the substrate material is coated with the at least one inert material. ### Claim 10 (depends on 1) The electrochemical cell of claim 1, wherein the working electrode comprises at least one of uranium oxide, tantalum pentoxide, titanium monoxide, titanium dioxide, zirconium oxide, hafnium oxide, tungsten oxide, chromium oxide, molybdenum oxide, iron oxide, nickel oxide, samarium oxide, and silicon oxide. ### Claim 11 (depends on 1) The electrochemical cell of claim 1, wherein the working electrode comprises at least one of at least one lanthanide oxide and at least one actinide oxide. ### Claim 12 (depends on 1) The electrochemical cell of claim 1, wherein the molten salt comprises one or more of at least one chloride salt and at least one bromide salt. ### Claim 13 (depends on 1) The electrochemical cell of claim 1, wherein the metal oxide comprises selenium, tellurium, or iodine. ### Claim 14 (depends on 1) The electrochemical cell of claim 1, wherein the at least one inert material consists of lithium ruthenate. ### Claim 15 A method of direct oxide reduction, the method comprising: forming a molten salt electrolyte in an electrochemical cell comprising at least one of an alkali halide salt and an alkaline earth metal halide salt; disposing a working electrode comprising at least one metal oxide in the electrochemical cell; disposing a counter electrode consisting of lithium ruthenate or a lithium rhodate in the electrochemical cell; and applying a current between the counter electrode and the working electrode to reduce the at least one metal oxide. ### Claim 16 (depends on 15) The method of claim 15, wherein forming a molten salt electrolyte in the electrochemical cell comprises forming the molten salt electrolyte from one or more of at least one chloride salt and at least one bromide salt. ### Claim 17 (depends on 15) The method of claim 15, wherein disposing a working electrode comprising at least one metal oxide in the electrochemical cell comprises forming the working electrode of the electrochemical cell from at least one of uranium oxide, tantalum pentoxide, titanium monoxide, titanium dioxide, zirconium oxide, hafnium oxide, tungsten oxide, chromium oxide, molybdenum oxide, iron oxide, nickel oxide, neodymium oxide, samarium oxide, and silicon oxide. ### Claim 18 (depends on 15) The method of claim 15, wherein disposing a working electrode comprising at least one metal oxide in the electrochemical cell comprises forming the working electrode of the electrochemical cell from at least one of at least one lanthanide oxide and at least one actinide oxide. ### Claim 19 (depends on 15) The method of claim 15, wherein: disposing a working electrode comprising at least one metal oxide in the electrochemical cell comprises disposing more than one metal oxide in the electrochemical cell; and reducing the at least one metal oxide comprises reducing the more than one metal oxide to form a metal alloy. ### Claim 20 An electrochemical cell, comprising: a counter electrode consisting of a lithium tin oxygen compound or Li2MnO3; a working electrode comprising a metal oxide to be reduced in the electrochemical cell; and a molten salt electrolyte comprising a molten salt comprising at least one of an alkali halide salt and an alkaline earth metal halide salt.