Method for extracting lithium by means of electrochemical deintercalation and use thereof

Abstract

The present disclosure relates to a method for extracting lithium by means of electrochemical deintercalation and the use thereof. The method comprises the following steps: (1) constructing an electrolytic tank for lithium extraction; and (2) energizing the electrolytic tank to extract lithium, and in a lithium extraction process, periodically increasing the voltage and applying ultrasound to the electrolytic tank, so as to complete lithium extraction by means of electrochemical deintercalation. The voltage is periodically increased, and during lithium extraction, a slight water electrolysis reaction occurs on an electrode sheet by means of the changes of the voltage, such that micro- and nano-scale bubbles are generated in an electrode; and by means of the synergistic action of same and the ultrasonic effect, brine in the electrode can undergo ultrasonic cavitation and can be disturbed, such that the flowing of the brine is promoted, and an internal mass transfer channel blocked by an impurity phase is dredged.

Description

A method and application of electrochemical deintercalation and lithium extraction Technical Field

[0001] The present disclosure belongs to the technical field of lithium extraction from salt lakes, for example, a method and application of electrochemical deintercalation and extraction of lithium. Background Art

[0002] With economic development, lithium-ion batteries are attracting attention as a key component of clean energy initiatives. Lithium, a crucial strategic and economic resource, has been hailed as the "energy metal of the 21st century." With the rapid development of lithium-ion batteries, global demand for lithium continues to rise, making its development a global priority. Salt lake brines hold approximately 80% of the world's lithium resources, but the low lithium concentration in these brines makes extracting the material a challenging task.

[0003] Currently, commonly used methods for extracting lithium from salt lakes include evaporation and precipitation, electrodialysis, nanofiltration, ion exchange, and electrochemical adsorption. Adsorption is a relatively effective method given the characteristics of salt lake brine. However, the preparation of ion adsorbents is difficult, desorption requires acidic conditions, the production process is difficult to continue, and the lithium extraction efficiency is relatively low.

[0004] The electrochemical method of extracting lithium from salt lakes has attracted widespread attention from researchers due to its energy-saving, environmental protection and simple operation.

[0005] CN 105600807A discloses a method for electrochemically extracting lithium salts from brine with a high magnesium-to-lithium ratio. In a LiCl solution, a LiMn2O4 working electrode and a titanium mesh counter electrode are respectively connected to the positive and negative electrodes of a power supply for charging, thereby releasing lithium ions from the LiMn2O4 to form a lithium ion sieve. Discharging the above electrode system in brine with a high magnesium-to-lithium ratio can selectively embed lithium ions into the lithium ion sieve. The charge-discharge cycle operation realizes the electrochemical extraction of lithium salts.

[0006] CN 112645362A provides a method for electrochemically extracting lithium from chloride-type lithium-containing brine to directly prepare lithium carbonate. Using chloride-type lithium-containing brine as the electrolyte, a lithium ion sieve electrode and a chloride ion capture electrode serve as the positive and negative electrodes, respectively, to form a primary cell. Discharging the primary cell embeds lithium ions from the brine into the lithium ion sieve. Using a lithium salt recovery solution as the electrolyte, the lithium ion sieve electrode embedding lithium ions and an inert electrode serve as the anode and cathode, respectively, to form an electrolytic cell. Recharging the electrolytic cell releases lithium ions into the lithium salt recovery solution. However, brine has a complex composition, and impurities and miscellaneous ions in the brine can enter the electrodes, blocking mass transfer channels and affecting lithium extraction efficiency.

[0007] Therefore, it is urgent to solve the problem of impurities in brine entering the interior of the electrode and blocking the mass transfer channel in related technologies.

[0008] Summary of the Invention

[0009] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0010] In view of the problems existing in the related art, the present disclosure provides a method and application of electrochemical deintercalation and lithium extraction, which adopts the method of periodically increasing the voltage. While extracting lithium, the voltage change causes a slight electrolysis reaction of water to occur on the electrode, so that micro-nano-level bubbles are generated inside the electrode. The synergistic effect of ultrasound can cause ultrasonic cavitation of the brine inside the electrode, disturb the brine, promote the flow of the brine, and dredge the internal mass transfer channel blocked by impurity phases.

[0011] To achieve this goal, the present disclosure adopts the following technical solutions:

[0012] In a first aspect, the present disclosure provides a method for electrochemical deintercalation and extraction of lithium, the method comprising the following steps:

[0013] (1) Constructing an electrolytic cell for lithium extraction;

[0014] (2) Power is supplied to the electrolytic cell to extract lithium. During the process of lithium extraction, the voltage is periodically increased and ultrasound is applied to the electrolytic cell to complete the electrochemical deintercalation and lithium extraction.

[0015] The present invention adopts a method of periodically increasing the voltage. While extracting lithium, a slight electrolysis reaction of water occurs on the electrode through the change of voltage, so that micro-nano-level bubbles are generated inside the electrode. The synergistic effect can cause ultrasonic cavitation of the brine inside the electrode, disturb the brine, promote the flow of the brine, and dredge the internal mass transfer channel blocked by impurities.

[0016] In one embodiment, the electrolytic cell for lithium extraction in step (1) comprises a cathode, an anode, an extraction solution and a recovery solution.

[0017] In one embodiment, a monovalent cation membrane is used in the electrolytic cell of step (1) to separate the anode extract and the cathode recovery solution.

[0018] In one embodiment, the extract is salt lake brine.

[0019] In one embodiment, the recovery liquid includes a KCl aqueous solution and / or a NaCl aqueous solution.

[0020] In one embodiment, the concentration of the recovery liquid is 0.05 to 0.1 mol / L, for example, it can be 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L or 0.1 mol / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] In one embodiment, the cathode comprises a lithium-rich electrode comprising a lithium-extracting active material.

[0022] In one embodiment, the preparation method of the lithium-rich electrode includes: mixing a lithium-extracting active material, a conductive agent and a binder to obtain a slurry, coating the obtained slurry on the surface of a current collector, and drying to obtain the lithium-rich electrode.

[0023] In one embodiment, the lithium-extracting active material includes any one of lithium manganate, lithium iron phosphate, lithium iron manganese phosphate or lithium titanate, or a combination of at least two of them. Typical but non-limiting combinations include a combination of lithium manganate and lithium iron phosphate, a combination of lithium iron phosphate and lithium iron manganese phosphate, a combination of lithium iron manganese phosphate and lithium titanate, a combination of lithium manganate and lithium iron manganese phosphate, and a combination of lithium iron phosphate and lithium titanate.

[0024] In one embodiment, the mass ratio of the lithium-extracting active material, the conductive agent, and the binder is 90:5:5 to 70:15:15, for example, it can be 90:5:5, 85:7:8, 80:10:10, 75:12:13, or 70:15:15, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0025] The conductive agent is a conventional conductive agent, and illustratively, may be conductive acetylene black and / or conductive carbon black.

[0026] The binder is a conventional binder, and illustratively, may be PTFE and / or PVDF.

[0027] The current collector is a conventional current collector, and illustratively, may be aluminum foil, carbon cloth, titanium mesh or carbon paper.

[0028] In one embodiment, the coating surface density is 5 to 25 mg / cm 2 , for example, it can be 5mg / cm 2 、10mg / cm 2 、15mg / cm 2 , 20mg / cm 2 or 25 mg / cm 2 , but not limited to the listed values, other unlisted values ​​within the numerical range are also applicable.

[0029] In one embodiment, the drying temperature is 50-70°C, for example, 50°C, 55°C, 60°C, 65°C or 70°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] In one embodiment, the drying time is 8 to 12 hours, for example, 8 hours, 9 hours, 10 hours, 11 hours or 12 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] In one embodiment, the anode is a lithium-deficient electrode.

[0032] In the present disclosure, a lithium-poor electrode refers to an electrode from which some lithium ions have been deintercalated relative to a lithium-rich electrode, and the lithium content in the lithium-poor electrode is lower than that in the lithium-rich electrode.

[0033] In one embodiment, the preparation method of the lithium-poor electrode includes: using the lithium-rich electrode as a cathode and a silver chloride electrode as an anode to construct an electrolytic cell, applying constant voltage to the electrolytic cell for delithiation, and the lithium-rich electrode after delithiation is the lithium-poor electrode.

[0034] In one embodiment, the electrolyte in the electrolytic cell includes a KCl aqueous solution and / or a NaCl aqueous solution.

[0035] In one embodiment, the concentration of the electrolyte is 0.05 to 0.1 mol / L, for example, it can be 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L or 0.1 mol / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] In one embodiment, the constant voltage power supply voltage is 0.3-1.3V, for example, 0.3V, 0.5V, 0.7V, 1V or 1.3V, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0037] In one embodiment, the constant voltage is applied to a current of less than 0.3 mA, such as 0.3 mA, 0.2 mA, 0.1 mA, 0.05 mA or 0.01 mA, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0038] In one embodiment, the power-on in step (2) is a constant voltage power-on with a voltage of 0.3 to 1.3 V, for example, 0.3 V, 0.5 V, 0.7 V, 1 V or 1.3 V, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] In one embodiment, the premise for periodically increasing the voltage in step (2) is that during the process of power-on lithium extraction, the current drops below 0.3 mA, for example, it can be 0.3 mA, 0.2 mA, 0.1 mA, 0.05 mA or 0.01 mA, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] In one embodiment, the voltage in step (2) is increased to 1.3-1.8V, for example, 1.3V, 1.4V, 1.5V, 1.6V, 1.7V or 1.8V, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0041] If the voltage is raised too high, impurities are easily introduced; if the voltage is raised too low, the efficiency of microbubble generation is too low.

[0042] In one embodiment, the time for increasing the voltage in step (2) is 1 to 5 minutes, for example, 1 minute, 2 minutes, 3 minutes, 4 minutes or 5 minutes, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0043] In one embodiment, the frequency of applying ultrasound in step (2) is 20 to 40 Hz, for example, 20 Hz, 25 Hz, 30 Hz, 35 Hz or 40 Hz, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0044] When the frequency of applied ultrasound is too high, the electrodes will be damaged, and when the frequency is too low, the effect of ultrasonic cavitation cannot be achieved.

[0045] In one embodiment, the number of periodicities is ≥ 1, for example, it can be 1, 3, 5, 10 or 20, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0046] In one embodiment, after the voltage is increased and ultrasound is applied to the electrolytic cell, the current no longer changes, ie, the power is stopped.

[0047] In one embodiment, after the step (2) of powering on to extract lithium is completed, the position of the cathode and the anode are exchanged, and the operation steps of step (2) are repeated.

[0048] In one embodiment, the repeated steps include: applying power to the electrolytic cell to extract lithium, and during the lithium extraction process, periodically increasing the voltage and applying ultrasound to the electrolytic cell.

[0049] In one embodiment, the number of repetitions is ≥ 1, for example, it can be 1, 3, 5, 10 or 20, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] In one embodiment, after completing step (2), the method further includes collecting the recovered liquid and measuring the concentration of lithium ions in the recovered liquid.

[0051] As an optional technical solution of the method described in the first aspect of the present disclosure, the method includes:

[0052] (1) Mixing a lithium-extracting active material, a conductive agent, and a binder in a mass ratio of 90:5:5 to 70:15:15 to obtain a slurry, and coating the obtained slurry on the surface of the current collector with a coating surface density of 5 to 25 mg / cm 2 After drying at 50-70° C. for 8-12 hours, the lithium-rich electrode is obtained;

[0053] (2) using the lithium-rich electrode of step (1) as a cathode, a silver chloride electrode as an anode, and an electrolyte comprising a KCl aqueous solution and / or a NaCl aqueous solution with a concentration of 0.05 to 0.1 mol / L, to construct an electrolytic cell, applying a constant voltage of 0.3 to 1.3 V to the electrolytic cell for delithiation, and stopping the delithiation process after the current is less than 0.3 mA. The lithium-rich electrode after the delithiation process is the obtained lithium-poor electrode;

[0054] (3) using the lithium-rich electrode obtained in step (1) as a cathode and the lithium-poor electrode obtained in step (2) as an anode, separating the anode extract and the cathode recovery liquid by a monovalent cation membrane, wherein the extract is salt lake brine and the recovery liquid is a 0.05-0.1 mol / L KCl aqueous solution and / or a NaCl aqueous solution, to construct a lithium extraction electrolytic cell;

[0055] (4) applying a constant voltage of 0.3 to 1.3 V to the electrolytic cell used for lithium extraction in step (3) to extract lithium. During the lithium extraction process, after the current drops below 0.3 mA, the voltage is increased to 1.3 to 1.8 V and ultrasound of 20 to 40 Hz is applied to the electrolytic cell for 1 to 5 minutes. After the treatment, lithium extraction is continued at a constant voltage of 0.3 to 1.3 V. When the current drops to 0.3 mA, the above treatment is repeated until the current does not change, and the power is stopped.

[0056] (5) exchanging the positions of the anode and the cathode, repeating the operation of step (4) for a number of times ≥ 1, and then collecting the recovered liquid to complete the electrochemical deintercalation and lithium extraction.

[0057] In a second aspect, the present disclosure provides an application of the method according to the first aspect, wherein the method is used for extracting lithium from brine.

[0058] According to the above technical solutions, the beneficial effects of the present disclosure are as follows:

[0059] The present invention adopts a method of periodically increasing the voltage. While extracting lithium, a slight electrolysis reaction of water occurs on the electrode through the change of voltage, so that micro-nano-level bubbles are generated inside the electrode. The synergistic effect can cause ultrasonic cavitation of the brine inside the electrode, disturb the brine, promote the flow of the brine, and dredge the internal mass transfer channel blocked by impurities.

[0060] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The accompanying drawings are used to provide a further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of this application, they are used to explain the technical solution of this article and do not constitute a limitation on the technical solution of this article.

[0062] FIG1 is a mechanism diagram of the electrochemical deintercalation and lithium extraction method. DETAILED DESCRIPTION

[0063] The following further illustrates the technical solution of the present disclosure with reference to the accompanying drawings and specific implementation methods. However, the following examples are merely simplified examples of the present disclosure and do not represent or limit the scope of protection of the present disclosure. The scope of protection of the present disclosure shall be subject to the claims.

[0064] Example 1

[0065] This embodiment provides a method for electrochemical deintercalation and extraction of lithium, the method comprising:

[0066] (1) Lithium manganate, conductive acetylene black, and PVDF were mixed in a mass ratio of 80:10:10 to obtain a slurry, which was coated on the surface of the current collector with a coating density of 15 mg / cm 2 After drying at 60° C. for 10 h, the lithium-rich electrode is obtained;

[0067] (2) using the lithium-rich electrode of step (1) as a cathode, the silver chloride electrode as an anode, and the electrolyte comprising a KCl aqueous solution with a concentration of 0.08 mol / L, to construct an electrolytic cell, applying a constant voltage of 0.8 V to the electrolytic cell for delithiation, and stopping the process when the current is less than 0.3 mA. The lithium-rich electrode after the process is completed is the obtained lithium-poor electrode;

[0068] (3) using the lithium-rich electrode obtained in step (1) as a cathode and the lithium-poor electrode obtained in step (2) as an anode, separating the anode extract from the cathode recovery liquid by a monovalent cation membrane, wherein the extract is salt lake brine and the recovery liquid is a 0.08 mol / L KCl aqueous solution, to construct a lithium extraction electrolytic cell;

[0069] (4) applying a constant voltage of 0.8 V to the electrolytic cell used for lithium extraction in step (3) to extract lithium. During the lithium extraction process, after the current drops below 0.3 mA, the voltage is increased to 1.5 V and 30 Hz ultrasound is applied to the electrolytic cell for 2 minutes. After the treatment, lithium extraction is continued at a constant voltage of 0.8 V. When the current drops to 0.3 mA, the above treatment is repeated until the current does not change, and the power is stopped.

[0070] (5) exchanging the positions of the anode and cathode, repeating the operation of step (4) three times, and then collecting the recovered liquid to complete the electrochemical deintercalation and lithium extraction.

[0071] Example 2

[0072] This embodiment provides a method for electrochemical deintercalation and extraction of lithium, the method comprising:

[0073] (1) Lithium titanate, conductive carbon black, and PVDF were mixed in a mass ratio of 90:5:5 to obtain a slurry, which was coated on the surface of the current collector with a coating density of 5 mg / cm 2 After drying at 70° C. for 8 h, the lithium-rich electrode is obtained;

[0074] (2) using the lithium-rich electrode of step (1) as a cathode, the silver chloride electrode as an anode, and the electrolyte comprising a 0.05 mol / L NaCl aqueous solution to construct an electrolytic cell, applying a constant voltage of 0.3 V to the electrolytic cell for delithiation, and stopping the delithiation after the current is less than 0.3 mA. The lithium-rich electrode after the delithiation is the obtained lithium-poor electrode;

[0075] (3) using the lithium-rich electrode obtained in step (1) as a cathode and the lithium-poor electrode obtained in step (2) as an anode, separating the anode extract and the cathode recovery liquid by a monovalent cation membrane, wherein the extract is salt lake brine and the recovery liquid is a 0.05 mol / L NaCl aqueous solution, to construct a lithium extraction electrolytic cell;

[0076] (4) applying a constant voltage of 0.3 V to the electrolytic cell used for lithium extraction in step (3) to extract lithium. During the lithium extraction process, after the current drops below 0.3 mA, the voltage is increased to 1.3 V and 20 Hz ultrasound is applied to the electrolytic cell for 15 minutes. After the treatment, lithium extraction is continued at a constant voltage of 0.3 V. When the current drops to 0.3 mA, the above treatment is repeated until the current does not change, and the power is stopped.

[0077] (5) exchanging the positions of the anode and the cathode, repeating the operation of step (4) once, and then collecting the recovered liquid to complete the electrochemical deintercalation and lithium extraction.

[0078] Example 3

[0079] This embodiment provides a method for electrochemical deintercalation and extraction of lithium, the method comprising:

[0080] (1) Mix lithium manganese iron phosphate, conductive acetylene black and PVDF in a mass ratio of 70:15:15 to obtain a slurry, which is coated on the surface of the current collector with a coating surface density of 25 mg / cm 2 After drying at 70° C. for 8 h, the lithium-rich electrode is obtained;

[0081] (2) using the lithium-rich electrode of step (1) as a cathode, the silver chloride electrode as an anode, and the electrolyte comprising a KCl aqueous solution with a concentration of 0.1 mol / L, to construct an electrolytic cell, applying a constant voltage of 1.5 V to the electrolytic cell for delithiation, and stopping the delithiation after the current is less than 0.3 mA. The lithium-rich electrode after the delithiation is the obtained lithium-poor electrode;

[0082] (3) using the lithium-rich electrode obtained in step (1) as a cathode and the lithium-poor electrode obtained in step (2) as an anode, separating the anode extract and the cathode recovery liquid by a monovalent cation membrane, wherein the extract is salt lake brine and the recovery liquid is a 0.1 mol / L KCl aqueous solution, to construct a lithium extraction electrolytic cell;

[0083] (4) applying a constant voltage of 1.3 V to the electrolytic cell used for lithium extraction in step (3) to extract lithium. During the lithium extraction process, after the current drops below 0.3 mA, the voltage is increased to 1.8 V and 40 Hz ultrasound is applied to the electrolytic cell for 1 min. After the treatment, lithium extraction is continued at a constant voltage of 1.3 V. When the current drops to 0.3 mA, the above treatment is repeated until the current does not change, and the power is stopped.

[0084] (5) exchanging the positions of the anode and the cathode, repeating the operation of step (4) twice, and then collecting the recovered liquid to complete the electrochemical deintercalation and lithium extraction.

[0085] Example 4

[0086] This embodiment provides a method for electrochemical deintercalation and extraction of lithium, which differs from embodiment 1 in that the voltage is increased to 2V in step (4).

[0087] Example 5

[0088] This embodiment provides a method for electrochemical deintercalation and extraction of lithium, which differs from embodiment 1 in that the voltage is increased to 1.25V in step (4).

[0089] Example 6

[0090] This embodiment provides a method for electrochemical deintercalation and lithium extraction, which differs from embodiment 1 in that the frequency of applying ultrasound in step (4) is 50 Hz.

[0091] Example 7

[0092] This embodiment provides a method for electrochemical deintercalation and extraction of lithium, which differs from embodiment 1 in that the frequency of applying ultrasound in step (4) is 10 Hz.

[0093] Example 8

[0094] This embodiment provides a method for electrochemical deintercalation and lithium extraction, which differs from embodiment 1 in that the lithium-poor electrode in step (3) is replaced by a silver chloride electrode.

[0095] Comparative Example 1

[0096] This comparative example provides a method for electrochemical deintercalation and lithium extraction, which differs from Example 1 in that in step (4), when the current is lower than 0.3 mA, the voltage is not changed and only ultrasonic treatment is applied.

[0097] Comparative Example 2

[0098] This comparative example provides a method for electrochemical deintercalation and lithium extraction, which differs from Example 1 in that in step (4), when the current is lower than 0.3 mA, only the voltage is changed, and no ultrasonic treatment is applied.

[0099] Comparative Example 3

[0100] This comparative example provides a method for electrochemical deintercalation and lithium extraction, which differs from Example 1 in that in step (4), when the current is lower than 0.3 mA, the voltage is not changed and ultrasonic treatment is not applied.

[0101] The concentration of lithium ions in the recovered liquid obtained by the above method was tested by ICP, and the test results are shown in Table 1.

[0102] Table 1

[0103] Combined with the mechanism shown in Figure 1, the present disclosure adopts a periodic increase in voltage. While extracting lithium, a slight electrolysis reaction of water occurs on the electrode through the change of voltage, so that micro-nano-level bubbles are generated inside the electrode. In conjunction with the ultrasonic effect, ultrasonic cavitation can be caused in the brine inside the electrode, disturbing the brine, promoting the flow of the brine, and unblocking the internal mass transfer channel blocked by impurities.

Claims

1. A method for electrochemical lithium extraction, comprising the following steps: (1) constructing an electrolytic cell for lithium extraction; (2) Power is supplied to the electrolytic cell to extract lithium. During the process of extracting lithium, the voltage is periodically increased and ultrasound is applied to the electrolytic cell to complete the electrochemical deintercalation and lithium extraction.

2. The method for electrochemical deintercalation and extraction of lithium according to claim 1, wherein: The lithium extraction electrolytic cell in step (1) comprises a cathode, an anode, an extraction solution and a recovery solution; Optionally, in the electrolytic cell of step (1), a monovalent cation membrane is used to separate the extract and the recovery liquid; Optionally, the anode is placed in the extraction solution, and the cathode is placed in the recovery solution; Optionally, the extract is salt lake brine; Optionally, the recovery liquid includes a KCl aqueous solution and / or a NaCl aqueous solution.

3. The method for electrochemical deintercalation and extraction of lithium according to claim 2, wherein: The concentration of the recovery liquid is 0.05-0.1 mol / L.

4. The method for electrochemical deintercalation and extraction of lithium according to claim 2 or 3, wherein: The cathode comprises a lithium-rich electrode; Optionally, the lithium-rich electrode includes a lithium-extracting active substance; Optionally, the lithium-extracting active material includes any one of lithium manganese oxide, lithium iron phosphate, lithium iron manganese phosphate or lithium titanate, or a combination of at least two thereof.

5. The method for electrochemical deintercalation and extraction of lithium according to claim 4, wherein: The preparation method of the lithium-rich electrode comprises: mixing a lithium-extracting active material, a conductive agent and a binder to obtain a slurry, coating the obtained slurry on the surface of a current collector, and drying to obtain the lithium-rich electrode; Optionally, the mass ratio of the lithium-extracting active material, the conductive agent and the binder is 90:5:5 to 70:15:15; Optionally, the surface density of the coating is 5 to 25 mg / cm 2 ; Optionally, the drying temperature is 50-70°C; Optionally, the drying time is 8 to 12 hours.

6. The method for electrochemical deintercalation and extraction of lithium according to any one of claims 2 to 5, wherein: The anode is a lithium-deficient electrode.

7. The method for electrochemical deintercalation and extraction of lithium according to claim 6, wherein: The preparation method of the lithium-poor electrode comprises: using the lithium-rich electrode as a cathode and a silver chloride electrode as an anode to construct an electrolytic cell, applying electricity to the electrolytic cell at a constant voltage to remove lithium, and the lithium-rich electrode after the lithium removal is the lithium-poor electrode; Optionally, the electrolyte in the electrolytic cell includes a KCl aqueous solution and / or a NaCl aqueous solution; Optionally, the concentration of the electrolyte is 0.05-0.1 mol / L; Optionally, the constant voltage power supply voltage is 0.3 to 1.3V; Optionally, the constant voltage is energized to a current of less than 0.3 mA.

8. The method for electrochemical lithium extraction according to any one of claims 1 to 7, wherein: The power-on in step (2) is a constant voltage power-on with a voltage of 0.3 to 1.3 V; Optionally, the premise of periodically increasing the voltage in step (2) is that during the lithium extraction process, the current drops below 0.3 mA; Optionally, in step (2), the voltage is increased to 1.3-1.8V; Optionally, the time for increasing the voltage in step (2) is 1 to 5 minutes.

9. The method for electrochemical lithium extraction according to any one of claims 1 to 8, wherein: The frequency of applying ultrasound in step (2) is 20 to 40 Hz; Optionally, the number of periodicity is ≥ 1; Optionally, after the voltage is increased and ultrasound is applied to the electrolytic cell, the current no longer changes, that is, the power supply is stopped.

10. The method for electrochemical lithium extraction according to any one of claims 1 to 9, wherein: After the step (2) of powering on to extract lithium is completed, the position of the cathode and the anode are exchanged, and the operation steps of step (2) are repeated.

11. The method for electrochemical lithium extraction according to claim 10, wherein: The repeated steps are: applying power to the electrolytic cell to extract lithium, and during the process of extracting lithium, periodically increasing the voltage and applying ultrasound to the electrolytic cell; Optionally, the number of repetitions is ≥1.

12. The method for electrochemical lithium extraction according to any one of claims 1 to 11, wherein: After completing step (2), the method further includes collecting the recovery liquid and determining the concentration of lithium ions in the recovery liquid.

13. The method for electrochemical lithium extraction according to any one of claims 1 to 12, wherein: The method comprises: (1) Mixing a lithium-extracting active material, a conductive agent, and a binder in a mass ratio of 90:5:5 to 70:15:15 to obtain a slurry, and coating the obtained slurry on the surface of the current collector with a coating surface density of 5 to 25 mg / cm 2 After drying at 50-70°C for 8-12h, a lithium-rich electrode is obtained; (2) using the lithium-rich electrode of step (1) as a cathode, the silver chloride electrode as an anode, and the electrolyte comprising a KCl aqueous solution and / or a NaCl aqueous solution with a concentration of 0.05 to 0.1 mol / L, to construct an electrolytic cell, applying a constant voltage of 0.3 to 1.3 V to the electrolytic cell for lithium removal, and stopping the process when the current is less than 0.3 mA, and the lithium-rich electrode after the process is completed is used as the lithium-poor electrode; (3) using the lithium-rich electrode of step (1) as a cathode and the lithium-poor electrode of step (2) as an anode, separating the anode extract and the cathode recovery liquid by a monovalent cation membrane, wherein the extract is salt lake brine and the recovery liquid is a 0.05-0.1 mol / L KCl aqueous solution and / or a NaCl aqueous solution, to construct a lithium extraction electrolytic cell; (4) The electrolytic cell for lithium extraction in step (3) is energized at a constant voltage of 0.3 to 1.3 V to extract lithium. During the process of lithium extraction, after the current drops below 0.3 mA, the voltage is increased to 1.3 to 1.8 V and ultrasound of 20 to 40 Hz is applied to the electrolytic cell for 1 to 5 min. Lithium is extracted at a constant voltage of 0.3 to 1.3 V. When the current drops to Repeat the above process at 0.3mA until the current does not change, then stop energizing; (5) exchanging the positions of the anode and the cathode, repeating the operation of step (4) for a number of times ≥ 1, and then collecting the recovered liquid to complete the electrochemical deintercalation and lithium extraction.

14. An application of the method according to any one of claims 1 to 13, wherein: The method is used for extracting lithium from brine.

Images