Zirconia-based hollow anodes for improved molten regolith electrolysis

Abstract

This disclosure provides an electrochemical system and method for in situ resource utilization for the production of molecular oxygen and cathodic products from molten regolith. The regolith may be derived from resources on the moon, Mars, asteroids, and other destinations in outer space. The electrochemical system and method utilizes a novel hollow anode design. The disclosure provides an electrochemical system and method comprising a hollow anode comprising: an active anode material; and a solid state electrolyte in ionic communication with the active anode material; wherein the solid state electrolyte is conductive to oxygen anions; a cathode in ionic communication with the hollow anode; a liquid electrolyte comprising molten regolith; wherein the molten regolith establishes ionic communication between the cathode and the hollow anode; and an electronic unit configured to apply an electrical signal across the hollow anode and the cathode to generate molecular oxygen.

1 . An electrochemical system for producing molecular oxygen from regolith comprising:
 a hollow anode comprising:
 an active anode material; and 
 a solid state electrolyte in ionic communication with the active anode material; 
   wherein the solid state electrolyte is conductive to oxygen anions;   a cathode in ionic communication with the hollow anode;   a liquid electrolyte comprising molten regolith; wherein the molten regolith establishes ionic communication between the cathode and the hollow anode; and   an electronic unit configured to apply an electrical signal across the hollow anode and the cathode to generate molecular oxygen.   
     
     
         2 . The electrochemical system of  claim 1 , wherein the solid state electrolyte comprises a shell that shields the active anode material from the liquid electrolyte, and wherein the solid state electrolyte conducts oxygen anions from the liquid electrolyte to the active anode material. 
     
     
         3 . (canceled) 
     
     
         4 . The electrochemical system of  claim 1 , wherein the solid state electrolyte has a thickness of between 1 mm to 10 mm, and is at least partially in contact with the active anode material. 
     
     
         5 . (canceled) 
     
     
         6 . (canceled) 
     
     
         7 . The electrochemical system of  claim 1 , wherein the solid state electrolyte is selectively conductive to oxygen anions, has an oxygen anion conductivity of at least 0.1 S/cm at 1600° C., and does not react with oxide species in the molten regolith. 
     
     
         8 . (canceled) 
     
     
         9 . The electrochemical system of  claim 1 , wherein the solid state electrolyte comprises a refractory ceramic, and is selected from the group consisting of doped zirconia, doped hafnia, doped ceria, doped thoria, doped urania, or any combination thereof. 
     
     
         10 . (canceled) 
     
     
         11 . The electrochemical system of  claim 1 , wherein the solid state electrolyte comprises yttria stabilized zirconia. 
     
     
         12 . The electrochemical system of  claim 1 , wherein the solid state electrolyte comprises a dopant with a concentration of 5 mol % to 15 mol %, and the dopant comprises MgO, CeO 2 , CaO, La 2 O 3 , Y 2 O 3 , SC 2 O 3 , Gd 2 O 3 , or any combination thereof. 
     
     
         13 . (canceled) 
     
     
         14 . The electrochemical system of  claim 1 , wherein the active anode material comprises a porous solid metal, a metal oxide, or any combination thereof, and the porous solid metal or metal oxide comprises Ir, Pt, Cr 2 O 3 , an alloy thereof, or any combination thereof. 
     
     
         15 . (canceled) 
     
     
         16 . The electrochemical system of  claim 1 , wherein the active anode material comprises a liquid metal, and the liquid metal comprises Pd, Pt, Au, Ag, Ir, Ru, Rh, Os, an alloy thereof, or any combination thereof. 
     
     
         17 . (canceled) 
     
     
         18 . The electrochemical system of  claim 1 , wherein the active anode material comprises a metallic core at least partially enclosed by the solid state electrolyte, and the active anode material is permeable to oxygen anions, molecular oxygen, or any combination thereof. 
     
     
         19 . (canceled) 
     
     
         20 . The electrochemical system of any of  claim 1 , wherein the active anode material comprises carbon, carbon coated with a solid metal, or any combination thereof. 
     
     
         21 . The electrochemical system of  claim 1 , wherein the cathode comprises a refractory metal selected from the group consisting of Mo, Nb, Ta, W, Re, an alloy thereof, or any combination thereof, and the cathode is solid at temperatures between 1,500° C. and 2,000° C. 
     
     
         22 . (canceled) 
     
     
         23 . The electrochemical system of  claim 1 , wherein the electrical signal comprises a current, a voltage, or any combination thereof, and the voltage is at least 1.0 V. 
     
     
         24 . (canceled) 
     
     
         25 . The electrochemical system of  claim 1 , wherein the molten regolith comprises lunar regolith, Martian regolith, terrestrial regolith, or any combination thereof, and wherein the lunar regolith comprises mare regolith, highlands regolith, or any combination thereof. 
     
     
         26 . (canceled) 
     
     
         27 . The electrochemical system of  claim 1 , wherein the molten regolith comprises Al 2 O 3 , CaO, Cr 2 O 3 , FeO, Fe 2 O 3 , K 2 O, MgO, MnO, Na 2 O, P 2 O 5 , SiO 2 , TiO 2 , or any combination thereof. 
     
     
         28 . The electrochemical system of  claim 1 , wherein the molten regolith comprises FeO, Fe 2 O 3 , SiO 2 , or any combination thereof. 
     
     
         29 . The electrochemical system of  claim 1 , wherein the molten regolith comprises at least 35% oxygen by weight, at least 40% SiO 2  by weight, from 2% to 25% FeO by weight, or any combination thereof. 
     
     
         30 . (canceled) 
     
     
         31 . (canceled) 
     
     
         32 . The electrochemical system of  claim 1 , wherein the molten regolith is characterized by a viscosity of 0.1 Pa·s to 50 Pa·s at 1,600° C., and a surface tension of 10 N/m to 1,000 N/m at 1,600° C. 
     
     
         33 . (canceled) 
     
     
         34 . The electrochemical system of  claim 1 , wherein the faradaic efficiency for molecular oxygen is greater than or equal to 30%. 
     
     
         35 . (canceled) 
     
     
         36 . The electrochemical system of  claim 1 , wherein one or more metal, non-metal, or metalloid cations selected from the group consisting of Al 3+ , Ca 2+ , Cr 3+ , Fe 2+ , Fe 3+ , K + , Mg 2+ , Mn 2+ , Na + , P 5+ , Si 4+ , or Ti +4  is reduced at the cathode and wherein Fe, Si, an alloy thereof, or any combination thereof is generated at the cathode. 
     
     
         37 . (canceled) 
     
     
         38 . The electrochemical system of  claim 1  further comprising a module for collecting the molecular oxygen, and a container for holding the liquid electrolyte. 
     
     
         39 . The electrochemical system of  claim 1 , wherein the electrochemical system is configured to heat and maintain the molten regolith at a temperature greater than or equal to 1,500° C. and less than or equal to 2,000° C. 
     
     
         40 . (canceled) 
     
     
         41 . A process for producing molecular oxygen from regolith, the process comprising:
 providing an electrochemical system comprising:
 a hollow anode comprising:
 an active anode material; and 
 a solid state electrolyte in ionic communication with the active anode material; wherein the solid state electrolyte is conductive to oxygen anions; 
 
 a cathode in ionic communication with the hollow anode; 
 a liquid electrolyte comprising molten regolith; wherein the liquid electrolyte establishes ionic communication between the hollow anode and the cathode; and 
   applying an electrical signal across the hollow anode and the cathode to produce molecular oxygen at the hollow anode.   
     
     
         42 . The process of  claim 41 , wherein the process is carried out via mobile operation. 
     
     
         43 . (canceled) 
     
     
         44 . The process of  claim 41 , further comprising operating the electrochemical system at a temperature greater than or equal to 1,500° C. and less than or equal to 2000° C. and wherein a hollow anode product comprises molecular oxygen and a cathode product comprises Si, Fe, an alloy thereof, or any combination thereof. 
     
     
         45 . (canceled)