Method and electrochemical device for low environmental impact lithium recovery from aqueous solutions

Abstract

An efficient and low environmental impact method is disclosed for the recovery of lithium from aqueous solution, for example, brines from high altitude salt lakes. The method comprises the use of an electrochemical reactor with electrodes which are highly selective for lithium, where lithium ions are inserted in the crystal structure of manganese oxide in the cathode, and extracted from the crystal structure of manganese oxide in the anode. Also disclosed are three-dimensional carbon electrodes embedded in manganese oxides formed by impregnating a porous support, for example a carbon felt, with a manganese oxide/carbon black slurry.

1 . An electrochemical method for extracting lithium from an aqueous solution containing lithium ions comprising:
 (a) contacting two electrodes with an aqueous solution containing lithium ions, wherein the electrodes are a battery-type electrode and a chloride or polypyrrole reversible electrode;   (b) applying a voltage or circulating a current between the two electrodes, wherein the lithium ions are captured by the battery-type electrode; and,   (c) exchanging the aqueous solution containing lithium ions with a dilute solution of lithium chloride or potassium chloride and reversing the electrical polarity,   wherein the reversal of polarity releases lithium ions from the battery-type electrode into the dilute solution.   
     
     
         2 . The method according to  claim 1 , wherein the aqueous solution is selected from the group consisting of sea water, lake water, underground water, hot-springs water, geothermal brine, oilfield brine, relict hydrothermal brine, or high altitude salt lake brine. 
     
     
         3 . The method according to  claim 1 , wherein the aqueous solution is sea water. 
     
     
         4 . The method according to  claim 1 , wherein the aqueous solution is a high-altitude salt lake brine. 
     
     
         5 . The method according to  claim 1 , wherein the aqueous solution comprises lithium ions and contaminant non-lithium metal ions. 
     
     
         6 . The method according to  claim 1 , wherein the battery-type electrode is a lithium insertion battery-type electrode comprising a porous or high surface substrate and a lithium insertion compound. 
     
     
         7 . The method according to  claim 6 , wherein the substrate is a carbon substrate. 
     
     
         8 . The method according to  claim 7 , wherein the carbon substrate is a conductive substrate. 
     
     
         9 . The method according to  claim 6 , wherein the battery-type electrode comprises a conductive additive material. 
     
     
         10 . The method according to  claim 9 , wherein the conductive additive material is carbon black. 
     
     
         11 . The method according to  claim 6 , wherein the lithium insertion compound comprises a manganese oxide. 
     
     
         12 . The method according to  claim 11 , wherein the manganese oxide comprises γ-MnO 2 . 
     
     
         13 . The method according to  claim 11 , wherein the manganese oxide has a spinel crystal structure. 
     
     
         14 . The method according to  claim 11 , wherein the manganese oxide comprises LiMn 2 O 4 . 
     
     
         15 . The method according to  claim 6 , wherein the lithium insertion compound comprises lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, or combinations thereof. 
     
     
         16 . The method according to  claim 15 , wherein the lithium cobalt oxide comprises LiCoO 2 . 
     
     
         17 . The method according to  claim 15 , wherein the lithium iron phosphate comprises LiFePO 4 . 
     
     
         18 . The method according to  claim 6 , wherein the battery-type electrode is prepared by electrolytical delithiation of a porous or high surface substrate coated with lithium cobalt oxide (LiCoO 2 ), lithium iron phosphate (LiFePO 4 ), lithium manganese oxide (LiMn 2 O 4 ), or combinations thereof. 
     
     
         19 . The method according to  claim 6 , wherein the carbon substrate is selected from the group consisting of carbon felt, carbon cloth, carbon paper, graphite granules, granite foam, high surface area graphite fiber, and combinations thereof. 
     
     
         20 . The method according to  claim 6 , wherein the carbon substrate is a carbon felt. 
     
     
         21 . The method according to  claim 1 , wherein the chloride reversible electrode comprises a porous or high surface carbon substrate and silver metal particles. 
     
     
         22 . The method according to  claim 21 , wherein the silver metal particles are nanoparticles. 
     
     
         23 . The method according to  claim 1 , wherein the chloride reversible electrode further comprises an electrically conductive polymer. 
     
     
         24 . The method according to  claim 23 , wherein the electrically conductive polymer is a polypyrrole. 
     
     
         25 . The method according to  claim 1 , wherein the lithium ions in the aqueous solution are captured by insertion in the crystal structure of the battery-type electrode. 
     
     
         26 . An electrochemical device for extracting lithium from an aqueous solution containing lithium ions comprising at least one battery-type electrode comprising a porous or high surface substrate coated with a lithium insertion compound, wherein said device does not comprise a counter-electrode. 
     
     
         27 . The electrochemical device according to  claim 26 , wherein the device further comprises a chloride or polypyrrole reversible electrode. 
     
     
         28 . The electrochemical device according to  claim 26 , wherein the substrate is a carbon substrate. 
     
     
         29 . The electrochemical device according to  claim 28 , wherein the carbon substrate is a conductive substrate. 
     
     
         30 . The electrochemical device according to  claim 26 , wherein the battery-type electrode comprises a conductive additive material. 
     
     
         31 . The electrochemical device according to  claim 30 , wherein the conductive additive material is carbon black. 
     
     
         32 . The electrochemical device according to  claim 26 , wherein the lithium insertion compound comprises a manganese oxide. 
     
     
         33 . The electrochemical device according to  claim 32 , wherein the manganese oxide comprises γ-MnO 2 . 
     
     
         34 . The electrochemical device according to  claim 32 , wherein the manganese oxide has a spinel crystal structure. 
     
     
         35 . The electrochemical device according to  claim 32 , wherein the manganese oxide comprises LiMn 2 O 4 . 
     
     
         36 . The electrochemical device according to  claim 26 , wherein the lithium insertion compound comprises lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, or combinations thereof. 
     
     
         37 . The electrochemical device according to  claim 36 , wherein the lithium cobalt oxide comprises LiCoO 2 . 
     
     
         38 . The electrochemical device according to  claim 36 , wherein the lithium iron phosphate comprises LiFePO 4 . 
     
     
         39 . The electrochemical device according to  claim 26 , wherein the battery-type electrode is prepared by electrolytical delithiation of a porous or high surface substrate coated with lithium cobalt oxide (LiCoO 2 ), lithium iron phosphate (LiFePO 4 ), lithium manganese oxide (LiMn 2 O 4 ), or combinations thereof. 
     
     
         40 - 58 . (canceled) 
     
     
         59 . The electrochemical device according to  claim 26 , wherein the carbon substrate is selected from the group consisting of carbon felt, carbon cloth, carbon paper, graphite granules, granite foam, high surface area graphite fiber, and combinations thereof. 
     
     
         60 . The electrochemical device according to  claim 26 , wherein the carbon substrate is a carbon felt. 
     
     
         61 . The electrochemical device according to  claim 27 , wherein the chloride reversible electrode comprises a porous or high surface carbon substrate and silver metal particles. 
     
     
         62 . The electrochemical device according to  claim 61 , wherein the silver metal particles are nanoparticles. 
     
     
         63 . The electrochemical device according to  claim 27 , wherein the chloride reversible electrode further comprises an electrically conductive polymer. 
     
     
         64 . The electrochemical device according to  claim 63 , wherein the electrically conductive polymer is a polypyrrole. 
     
     
         65 . The electrochemical device according to  claim 26 , wherein the lithium ions in the aqueous solution are captured by insertion in the crystal structure of the battery-type electrode. 
     
     
         66 . The electrochemical device according to  claim 27 , wherein the battery-type electrode and chloride reversible electrode are positioned in separate half-cells. 
     
     
         67 . The electrochemical device according to  claim 66 , wherein the half-cell comprising the battery-type electrode and the half-cell comprising the chloride reversible electrode are separated by a semi-permeable electrolysis membrane. 
     
     
         68 . The electrochemical device according to  claim 67 , wherein the electrolysis membrane is an ionomer membrane. 
     
     
         69 . The electrochemical device according to  claim 68 , wherein the ionomer membrane is a N AFION ® membrane. 
     
     
         70 . The electrochemical device according to  claim 69 , wherein the N AFION ® membrane is N AFION ® 324. 
     
     
         71 . An lithium extraction plant for extracting lithium from an aqueous solution containing lithium ions comprising at least one electrochemical device according to  claim 26 . 
     
     
         72 . The lithium extraction plant according to  claim 71 , wherein the aqueous solution containing lithium ions is a brine. 
     
     
         73 . The lithium extraction plant according to  claim 72 , wherein the brine is obtained from a high-altitude salt lake. 
     
     
         74 . The lithium extraction plant according to  claim 71 , wherein the plant is controlled by a clean energy voltage source. 
     
     
         75 . The lithium extraction plant according to  claim 74 , wherein the clean energy voltage source is a solar power source. 
     
     
         76 . A method to manufacture high purity lithium comprising using the method of  claim 1 . 
     
     
         77 . The method according to  claim 1 , in which steps (a)-(c) are repeated at least twice using the aqueous solution containing lithium ions resulting from step (c) as the aqueous solution containing lithium ions of step (a), wherein the aqueous solution from each successive step (c) is used as the aqueous solution containing lithium ions of the next step (a). 
     
     
         78 . The method according to  claim 77 , in which steps (a)-(c) are repeated at least three times, wherein the aqueous solution from each successive step (c) is used as the aqueous solution containing lithium ions of the next step (a).