Search

A new method for Li recovery from seawater by electrodialysis using a Li separation membrane with the ionic liquid PP13-TFSI was developed. Only Li ions can significantly permeate this membrane and thus pass from the anode side to the cathode side. Because the other ions (Na, Mg, Ca and K) in seawater are much less capable of permeating the membranes, Li becomes selectively concentrated on the cathode side. In the measurements of the ion concentration on the cathode side as a function of the duration of the applied dialysis voltage (2V), the Li concentration increased with time, reaching 24.5% after 2 h. The other ions in seawater did not permeate the membrane. This new recovery method shows good energy efficiency and is easily scalable. It should be suitable for use in seawater desalination plants and for the recycling of used Li-ion batteries.

As a means of addressing global warming, the world is increasingly turning to the use of Li-ion batteries in electric vehicles and as storage batteries in the home; therefore, there is a growing need for Li. I have developed a method for the recovery of Li from used Li-ion batteries using a Li ionic conductor functioning as a Li-ion separation membrane (LISM). This innovative method involves the use of an LISM whereby only Li ions in a solution of used Li-ion batteries permeate from the positive electrode side to the negative electrode side during electrodialysis; the other ions, including Co, Al, and F, do not permeate the membrane. Li0.29La0.57TiO3 was selected as the LISM. The positive side of the dialysis cell was filled with used Li-ion battery solution. Then the negative side was filled with distilled water. The applied dialysis voltage was 5 V, and electrode area was 16 cm2. The Li recovery ratio increased with electrodialysis time. Then, Co, Al, and F were not permeated (Fig.1). Measurements of the Li ion concentration at the negative electrode side as a function of dialysis duration showed that the Li recovery ratio increased to approximately 90% after 72 h. Moreover, other ions in the seawater did not permeate the LISM. With both ends of the LISM bound with a negative and positive electrode, hydrated Li ion was transformed to Li ion only because Li ion can permeate through the LISM [1]. After electrodialysis, CO2 gas was bubbled in the Li recovery water to produce lithium carbonate (Li2CO3) as a raw material for Li-ion batteries. The Li2CO3 deposition was easily generated by the reaction of CO2 gas and the Li recovery solution as a lithium hydroxide (LiOH) solution (Fig.2). Moreover, the purity of Li2CO3 is up to 99.99%. This new method for recycling Li-ion batteries shows good energy efficiency and is easily scalable. Thus, this electrodialysis method is suitable for the recycling of Li from used Li-ion batteries. Fig.1 Schematic of Li recovery from Li-ion battery solution using the proposed electrodialysis. Fig.2 Production of High-purity Li2CO3 by CO2 bubbling method. [1] T. Hoshino, Desalination, 359, 59-63 (2015). Figure 1

As a means of addressing global warming, the world is increasingly turning to the use of Li-ion batteries in electric vehicles and as storage batteries in the home; therefore, there is a growing need for Li. Furthermore, as a fuel for fusion reactors, tritium is produced by the reaction of lithium with neutrons in a tritium-breeding material. Li is primarily recovered from salt lakes in South America but is also present in seawater. Thus, I propose a method for recovering Li from seawater by using innovative dialysis, wherein Li only permeates from the negative electrode side to the positive electrode side through a Li ionic superconductor functioning as a Li separation membrane (LISM) (Fig.1). Measurements of the Li ion concentration at the positive electrode side as a function of dialysis duration showed that the Li recovery ratio increased to approximately 7% after 72 h with no applied electric voltage, and an electrical power of 0.04 V and 0.1 mA was generated. Moreover, other ions in the seawater did not permeate the LISM. With both ends of the LISM bound with a negative and positive electrode, hydrated Li ion was transformed to Li ion only because Li ion can permeate through the LISM [1]. Furthermore, tritium needed as a fuel for fusion reactors is produced via neutron capture by lithium-6 (6Li). However, natural Li contains only about 7.8% 6Li, and enrichment of 6Li up to 90% is required for adequate tritium breeding in fusion reactors. Therefore, new Li isotope separation technique using a Li ionic rconductor functioning as a LISM have been developed. Because the mobility of 6Li ions is higher than that of 7Li ions, 6Li can be enriched on the cathode side of a cell. Using Li0.29La0.57TiO3 (LLTO) as the Li ionic superconductor was prepared, and the relationship between the 6Li separation coefficient and the electrodialysis time was investigated. After electrodialysis, we obtained a maximum of 1.05 for the 6Li isotope separation coefficient. This result showed that the 6Li isotope separation coefficient of this method is the same as that of the amalgamation process using mercury (1.06). Thus, this method has the potential to be a superior 6Li enrichment method to produce 90% enriched tritium breeder for fusion reactors. [1] T. Hoshino, Desalination, 359, 59-63 (2015). Figure 1

Tritium needed as a fuel for fusion reactors is produced via neutron capture by lithium-6 (6Li). However, natural Li contains only about 7.8% 6Li, and enrichment of 6Li up to 90% is required for adequate tritium breeding in fusion reactors. The mercury amalgam method is superior to some of the lithium isotope enrichment methods. In Japan, lithium isotope enrichment methods have been developed to avoid the environmental hazards of using mercury. However, the isotope separation coefficient and efficiency is too low to meet the practical need of large mass production of 6Li. Therefore, new Li isotope separation technique using a Li ionic superconductor functioning as a Li isotope separation membrane (LISM) have been developed [1]. Li ions move by electrodialysis through LISM between the cathode and the anode in lithium solutions. Because the mobility of 6Li ions is higher than that of 7Li ions, 6Li can be enriched on the cathode side of a cell. It has been reported that the difference in the mobility between 6Li and 7Li become large in ionic superconductor. The isotope effect in ionic superconductor is expected to be applicable to isotope separation membrane. In this research, we numerically investigated the ionic mobility of Li isotopes in ionic superconductor. Combing the first principle and the kinetics Monte Calro simulation, we calculate the diffusion constant of 6Li and 7Li. I show the two important effects for the difference in the mobility between isotope of Li. The first is the quantum effect, which decrease the diffusion barrier for Li ion and increase the ratio of the diffusion constant of Li isotopes. The second is the correlation effect between 6Li, 7Li and vacancy. Using Li0.29La0.57TiO3 (LLTO) as the Li ionic superconductor was prepared, and the relationship between the 6Li separation coefficient and the electrodialysis time was investigated. After electrodialysis, we obtained a maximum of 1.04 for the 6Li isotope separation coefficient. This result showed that the 6Li isotope separation coefficient of this method is the same as that of the amalgamation process using mercury (1.06). Thus, this method has the potential to be a superior 6Li enrichment method to produce 90% enriched tritium breeder for fusion reactors. Figure 1

In recent years, the industrial importance of lithium (Li) has increased due to its use in Li-ion batteries. For example, large-sized Li-ion batteries are used as power supplies for electric vehicles and for storage of electricity in smart grids and smart houses. Therefore, a large amount of Li is required worldwide. The extraction of Li from used Li-ion batteries would allow a large amount of Li to be inexpensively acquired. The technology for recycling cobalt (Co) and nickel (Ni) from used Li-ion batteries has already been established. On the contrary, the technology for recycling Li from used Li-ion batteries is not yet established. I have developed a method for the recovery of Li from seawater using a Li ionic superconductor functioning as a Li-ion separation membrane (LISM) [1]. Only Li ions were successfully recovered from seawater through the LISM; other ions in the seawater did not permeate the membrane. Therefore, I have developed an innovative new method for recycling Li from used Li-ion batteries using the LISM. Figure shows the proposed Li recovery method. This innovative method involves the use of an LISM whereby only Li ions in a solution of used Li-ion batteries permeate from the positive electrode side to the negative electrode side during electrodialysis; the other ions, including Co, Al, and F, do not permeate the membrane. Li0.29La0.57TiO3 was selected as the LISM because it exhibits high durability against water. The positive side of the dialysis cell was filled with used Li-ion battery solution, supplied by DOWA ECO-SYSTEM Co., Ltd., Japan; the Li concentration of the solution was 2543.5 mg/L. Then the negative side was filled with distilled water. The applied dialysis voltage was 5 V, and electrode area was 16 cm2. The calculation of the Li recovery ratios for this first of a kind electrodialysis technique with an LISM sheet was performed. The Li recovery ratio increased with electrodialysis time, reaching approximately 10% at 72 h of dialysis. The recovery ratios of Co, Al, and F were not calculated because the concentrations of Co, Al, and F were below the detection limit of inductively coupled plasma atomic emission spectrometry (ICP-AES). After electrodialysis, CO2 gas was bubbled in the Li recovery water to produce lithium carbonate (Li2CO3) as a raw material for Li-ion batteries. The Li2CO3 deposition was easily generated by the reaction of CO2gas and the Li recovery solution as a lithium hydroxide (LiOH) solution. This new method for recycling Li-ion batteries shows good energy efficiency and is easily scalable. Thus, this electrodialysis method is suitable for the recovery of Li from used Li-ion batteries. [1] T. Hoshino, Desalination, 359, 59-63 (2015). Figure 1

Lithium (Li) is rapidly becoming a valuable commodity. In recent years, the industrial importance of Li has increased due to its use in Li-ion batteries. For example, large-sized Li-ion batteries are used as power supplies for electric vehicles and for storage of electricity in smart grids and smart houses. Therefore, a large amount of Li is required worldwide. Li reserves in the South American countries of Chile, Bolivia, and Argentina account for more than half of the world’s Li reserves; these countries have outstanding Li resources (brine water). Although Li extraction from chloride brine water is easy, the quantity of natural resources in these waters is limited. In contrast, the quantity of natural resources in sulfate brine water is large; however, the Li recovery technology from sulfate brine water has yet to be established. Thus, the extraction of Li from used Li-ion batteries would allow a large amount of Li to be inexpensively acquired. The technology for recycling cobalt (Co) and nickel (Ni) from used Li-ion batteries has already been established. On the contrary, the technology for recycling Li from used Li-ion batteries is not yet established, because the cost of Li recycling is higher than the import price of Li from South America. I have developed a method for the recovery of Li from seawater using a Li ionic superconductor functioning as a Li-ion separation membrane (LISM) [1]. Only Li ions were successfully recovered from seawater through the LISM; other ions in the seawater did not permeate the membrane. Therefore, I have developed an innovative new method for recycling Li from used Li-ion batteries using the LISM. Figure 1 shows the proposed Li recovery method. This innovative method involves the use of an LISM whereby only Li ions in a solution of used Li-ion batteries permeate from the positive electrode side to the negative electrode side during electrodialysis; the other ions, including Co, Al, and F, do not permeate the membrane. In this study, Li0.29La0.57TiO3 was selected as the LISM because it exhibits high durability against water. The area and thickness of the LISM are 25 cm2 (5.0 cm × 5.0 cm) and 0.5 mm, respectively. The positive side of the dialysis cell was filled with used Li-ion battery solution, supplied by DOWA ECO-SYSTEM Co., Ltd., Japan; the Li concentration of the solution was 2543.5 mg/L. Then the negative side was filled with distilled water. The applied dialysis voltage was 5 V, and the duration of dialysis was 72 h. The electrodes were Ti–Ir alloy on the positive electrode side and SUS316 on the negative electrode side, and electrode area was 16 cm2. The calculation of the Li recovery ratios for this first of a kind electrodialysis technique with an LISM sheet was performed. The Li recovery ratio increased with electrodialysis time, reaching approximately 10% at 72 h of dialysis. The recovery ratios of Co, Al, and F were not calculated because the concentrations of Co, Al, and F were below the detection limit of inductively coupled plasma atomic emission spectrometry (ICP-AES). Moreover, the Li concentration dependency of the Li recovery amount was measured. These measurements showed that the amount of Li in the recovery solution increased with the Li concentration of the used Li-ion battery solution. This indicates that a used Li-ion battery solution with high Li concentration enables good Li recovery efficiency by this method. After electrodialysis, CO2 gas was bubbled in the Li recovery water to produce lithium carbonate (Li2CO3) as a raw material for Li-ion batteries. The Li2CO3 deposition was easily generated by the reaction of CO2 gas and the Li recovery solution as a lithium hydroxide (LiOH) solution. This new method for recycling Li-ion batteries shows good energy efficiency and is easily scalable. Furthermore, the estimated cost of 1 kg Li2CO3 produced by this method is approximately $3. This value is lower than the import price of Li ($5 to $8) from South America. Thus, this electrodialysis method is suitable for the recovery of Li from used Li-ion batteries. Reference [1] T. Hoshino, Innovative lithium recovery technique from seawater by using world-first dialysis with a lithium ionic superconductor, Desalination, 359 (2015) 59-63. Figure 1

not Available.