Search

US-12623932-B2 - Direct production of lithium hydroxide from brine by electrochemical flow cells

US12623932B2US 12623932 B2US12623932 B2US 12623932B2US-12623932-B2

Abstract

Disclosed are a system and methods for producing lithium hydroxide directly from natural brine by an electrochemical approach. In one example version of the system, an electrochemical cell operates in two states. In one state, lithium cations (Li + ) intercalate into a first electrode from the brine, and sodium cations (Na + ) deintercalate from a second electrode into the brine. In another state, lithium cations deintercalate from the first electrode into a dilute lithium hydroxide (LiOH) solution, and sodium cations intercalate to the second electrode from a concentrated sodium hydroxide (NaOH) solution. Hydroxide anions (OH − ) transport through an anion exchange membrane to combine with lithium cations (Li + ) to form LiOH, continuously increasing its concentration.

Inventors

  • Wei Lu
  • TIANHAN GAO

Assignees

  • THE REGENTS OF THE UNIVERSITY OF MICHIGAN

Dates

Publication Date
20260512
Application Date
20220829

Claims (19)

  1. 1 . A system for recovery of a first cation from a liquid containing the first cation, the system comprising: a first electrode comprising a first cation host material; a second electrode comprising a second cation host material, the first electrode and the second electrode being spaced apart to define a flow channel between the first electrode and the second electrode; an anion exchange membrane including an openable portion for shifting the anion exchange membrane into a first state and a second state, wherein in the first state, the flow channel is separated into a first subchannel of the flow channel and a second subchannel of the flow channel such that the first subchannel and the second subchannel are not in fluid communication, wherein in the first state, the first subchannel is in fluid communication with the first electrode, and wherein in the first state, the second subchannel is in fluid communication with the second electrode, and wherein in the second state, the first subchannel and the second subchannel are in fluid communication; a first tank in fluid communication with an inlet and an outlet of the first subchannel, the first tank storing a first solution containing the first cation, the first solution being transported through the first subchannel; a second tank in fluid communication with an inlet and an outlet of the second subchannel, the second tank storing a second solution containing a second cation, the second solution being transported through the second subchannel; and an electrical device in electrical communication with the first electrode and the second electrode to supply a current to the first electrode and the second electrode, wherein the first cation and the second cation are different.
  2. 2 . The system of claim 1 wherein: the liquid is brine.
  3. 3 . The system of claim 1 wherein: the liquid is a geothermal brine.
  4. 4 . The system of claim 1 wherein: the first cation is lithium, and the first cation host material is a lithium host material.
  5. 5 . The system of claim 4 wherein: the lithium host material comprises lithium manganese oxide or lithium titanium oxide.
  6. 6 . The system of claim 4 wherein: the second cation is sodium, and the second cation host material is a sodium host material.
  7. 7 . The system of claim 6 wherein: the sodium host material comprises sodium manganese oxide or sodium titanium oxide.
  8. 8 . The system of claim 1 wherein: the first solution is lithium hydroxide.
  9. 9 . The system of claim 1 wherein: the second solution is sodium hydroxide.
  10. 10 . A system for recovery of a first cation from a liquid containing the first cation, the system comprising: a first electrode comprising a first cation host material; a second electrode comprising a second cation host material, the first electrode and the second electrode being spaced apart to define a flow channel between the first electrode and the second electrode; an anion exchange membrane including an openable portion for shifting the anion exchange membrane into a first state and a second state, wherein in the first state, the flow channel is separated into a first subchannel of the flow channel and a second subchannel of the flow channel such that the first subchannel and the second subchannel are not in fluid communication, wherein in the second state, the first subchannel and the second subchannel are in fluid communication, wherein the first subchannel is in fluid communication with the first electrode, and wherein the second subchannel is in fluid communication with the second electrode, a first tank in fluid communication with an inlet and an outlet of the first subchannel, the first tank storing a first solution containing the first cation, the first solution being transported through the first subchannel when the anion exchange membrane is in the first state; a second tank in fluid communication with an inlet and an outlet of the second subchannel, the second tank storing a second solution containing a second cation, the second solution being transported through the second subchannel when the anion exchange membrane is in the first state; a third tank in fluid communication with an inlet and an outlet of the flow channel, the third tank storing the liquid containing the first cation, the liquid containing the first cation being transported through the flow channel when the anion exchange membrane is in the second state; and an electrical device in electrical communication with the first electrode and the second electrode to supply a current to the first electrode and the second electrode.
  11. 11 . The system of claim 10 further comprising: a fourth tank in fluid communication with the first electrode, the second electrode, the flow channel, the first subchannel, and the second subchannel, the fourth tank storing a wash fluid, the wash fluid being transported through the first electrode, the second electrode, the flow channel, the first subchannel, and the second subchannel after the liquid containing the first cation is transported through the flow channel.
  12. 12 . The system of claim 10 wherein: the openable portion comprises a door in the anion exchange membrane.
  13. 13 . The system of claim 10 wherein: the anion exchange membrane allows hydroxide anions to pass though the anion exchange membrane.
  14. 14 . The system of claim 10 wherein: the system generates electricity when the liquid containing the first cation is transported through the flow channel, and the system consumes electricity when the first solution is transported through the first subchannel, and the second solution is transported through the second subchannel.
  15. 15 . The system of claim 10 wherein: the electrical device comprises a storage battery, the system generates electricity that is stored in the storage battery when the liquid containing the first cation is transported through the flow channel, and the system consumes electricity from the storage battery when the first solution is transported through the first subchannel, and the second solution is transported through the second subchannel.
  16. 16 . The system of claim 10 wherein: the electrical device comprises a resistive load and a power supply to supply the current to the first electrode and the second electrode, the system generates electricity that is provided to the resistive load when the liquid containing the first cation is transported through the flow channel, and the system consumes electricity from the power supply when the first solution is transported through the first subchannel, and the second solution is transported through the second subchannel.
  17. 17 . A system comprising a plurality of systems according to claim 10 .
  18. 18 . The system of claim 17 wherein: one of the plurality of systems generates electricity during a time period, and another of the plurality of systems consumes electricity generated by the one of the plurality of systems during the time period.
  19. 19 . The system of claim 1 wherein: the openable portion comprises a door in the anion exchange membrane.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS This application is based on, claims benefit of, and claims priority to U.S. Application No. 63/237,626 filed on Aug. 27, 2021, which is hereby incorporated by reference herein in its entirety for all purposes. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH Not Applicable. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an electrochemical flow cell system for producing lithium hydroxide directly from natural brine by an electrochemical approach. 2. Description of the Related Art It is expected that the global demand for lithium will increase dramatically by 2050 to meet the needs for lithium ion batteries. With the widespread adoption and growth of electric vehicles, consumer electronics, and grid-scale battery storage, lithium will become a crucial element in the clean energy supply chain [Ref. 1-4]. Lithium hydroxide NOM is widely used as raw material for manufacturing ternary nickel-rich battery cathodes such as NCA, NMC 622, NMC 811, as well as other chemical products. A major global lithium source is natural geothermal brine, which takes up to 90% of the world's proven lithium reserves. It is vital to produce lithium hydroxide with high purity, and low energy and water consumption from natural geothermal brine, to meet the increasing demand for battery manufacturing. Traditionally, lithium hydroxide is primarily produced by lithium carbonate [Ref. 5-6], which can be further generated through natural geothermal brine, or through spodumene by sulfuric acid or heating (some typical reactions are shown in Eqs. (1)-(3)) [Ref. 6-8]. However, this method incurs high cost and energy consumption [Ref. 9]. This method also involves many steps so that various middle products are generated, which increases the consumption of resources, generation of waste species, and reduces the purity of produced lithium hydroxide. Li2O·Al2O3·4SiO2+H2SO4→H2O·Al2O3·4SiO2+Li2SO4  (1) Li2SO4+Na2CO3→Li2CO3+Na2SO4  (2) Li2CO3+Ca(OH)2→2LiOH+CaCO3  (3) Lithium hydroxide, a key material in the production of lithium ion battery, is receiving ever increasing demands. The current approaches for producing lithium hydroxide from natural geothermal brine have major limitations such as need producing lithium carbonate as a middle step, high energy consumption and pollution, resource waste, and low efficiencies. Electrodialysis combining with membrane ion-exchange, or the membrane electrodialysis process, has received attention in the last decade since this technology requires fewer steps in producing lithium hydroxide, and can increase efficiency and reduce cost compared with lithium hydroxide production through lithium carbonate. The mechanism of membrane electrodialysis is to generate hydroxide anion by electrolyzing the water solvent, and pass lithium ions in the brine through the membrane to form lithium hydroxide with the generated hydroxide anion. To explore generating lithium hydroxide by this process, Grageda et al. [Ref. 9] investigated the effect of current density, electrode material, electrolyte concentration, temperature, and cationic membrane on the generation performance. They found that the specific energy consumption can be reduced to 7.25 kWh/kg-LiOH at a current density of 1200 A/m2 and a temperature between 75-85° C. When the temperature is below 75° C., the product purity can be improved with the Nafion 117 membrane and at a lower electrolyte concentration. Zhao et al. [Ref. 10] used bipolar membrane electrodialysis (BMED) to acquire lithium hydroxide. They investigated the effect of ion properties on the mass transfer behavior of BMED, and the effect of coexisting ions on lithium migration and current efficiency. Chen et al. [Ref. 11] used BMED to generate lithium hydroxide and sulfate acid based on lithium sulfate. They found that the energy consumption can be reduced to ˜7 kWh/kg-LiOH when maintaining a low concentration of H2SO4. These investigations all show that electrodialysis combining with membrane ion-exchange is feasible in generating lithium hydroxide without going through lithium carbonate. However, a major challenge with the electrodialysis procedure is huge water consumption, since the amount of decomposed water needs to be large enough in order to generate sufficient hydroxide anions, which undergo the reactions in Eqs. (4) and (5) or (6). Besides, the energy consumption is still large since the electricity consumed during electrodialysis cannot be recovered within the process itself. Additionally, the electrodialysis procedure often requires the concentration of species in brine to remain in a certain range, which poses higher requirement on brine pre-processing and causes the cost of the whole procedure to be high. 2H2O+2e−→2OH−+H2  (4) 2H2O−4e−→O2+4H+  (5) 2Cl−−2e−→Cl2  (6) Nowadays, electrochemical flow cells are receiving increasing interest for potential use in the area of ion adsorption/desorption and deionization, also