Electrochemical deintercalation and extraction method for lithium without electrode coating and its application

Abstract

The present disclosure provides an electrode-free electrochemical deintercalation and lithium extraction method and its application, which relates to the technical field of lithium extraction from salt lakes. The electrode-free electrochemical deintercalation and lithium extraction method includes using lithium ion battery powder separated from waste lithium ion batteries as lithium intercalation powder, and using lithium ion battery powder after lithium removal as lithium removal powder; adding the lithium intercalation powder and lithium removal powder to the anode area and cathode area of ​​a lithium extraction electrolytic cell respectively, and at the same time, adding solid conductive particles to the anode area and cathode area respectively, the particle size of the solid conductive particles is larger than that of the lithium intercalation powder and the lithium removal powder; applying voltage to the anode electrode and the cathode electrode to extract lithium. The present disclosure uses the positive and negative electrode powders of waste lithium ion batteries as lithium ion adsorbents, which are directly added to brine, without the need for a carrier or coating on an electrode plate, and lithium can be extracted only by powering on. The method is easy to operate and makes resourceful use of waste lithium ion batteries.

Description

Technical Field

[0001] The present disclosure relates to the technical field of lithium extraction from salt lakes, and in particular to an electrochemical lithium extraction method without electrode coating and its application. Background Art

[0002] Lithium has many excellent physical and chemical properties, and its functions and uses are very extensive. It is considered to be "the energy metal that promotes the progress of the world". Lithium products were originally used mainly in the military. With the rapid development of new energy, metallurgy, aerospace, glass manufacturing and other industries, people's demand for lithium has increased year by year, and the development of lithium extraction technology has also received increasing attention. The content of lithium in the earth's crust is only about 0.0065%, of which a small part exists in rock deposits, while about 80% of lithium resources are contained in salt lake brine.

[0003] Adsorption is currently the most commonly used method for extracting lithium from salt lake brine. This method uses an adsorbent that is selective for lithium ions to bind lithium ions, and then elutes and extracts lithium ions under the action of an eluent, thereby separating lithium ions from other impurity ions. The key to this method lies in the selection of lithium ion adsorbents. Finding lithium ion adsorbents that are selective for lithium, recyclable, and have relatively low production costs is the key to the success of this method. According to the properties of the adsorbent, the adsorbent can be divided into two types: organic ion exchange adsorbents and inorganic ion exchange adsorbents. They mainly rely on the characteristics of the material itself to selectively adsorb lithium ions. Because of their high selectivity and memory effect, lithium can be better separated from other impurities.

[0004] Commonly used adsorbents include aluminum-based adsorbents, layered adsorbents, ion sieve adsorbents, etc. Aluminum-based adsorbents are mainly divided into amorphous aluminum hydroxide adsorbents and aluminum salt adsorbents. In the lithium adsorption production process of amorphous aluminum hydroxide adsorbents, the larger free acidic hydroxyl groups on the surface of the amorphous aluminum hydroxide adsorbent can promote the formation of hydroxyl complexes on the oxide surface to combine with lithium ions, so that lithium ions are separated from other impurities. However, this type of adsorbent mainly exists in the form of powder, which has the disadvantages of poor fluidity and permeability, and is easy to cause the loss of adsorbent during the production process. Layered adsorbents are generally 4-valent metal acid salts with a layered structure. Among the 4-valent metal acid salts, phosphates and arsenates show higher selectivity for lithium ions, and the closer the interlayer spacing of this type of adsorbent is to the diameter of lithium ions, the stronger the affinity of the adsorbent for lithium ions, and it shows superior selectivity for lithium ions. Ion sieve adsorbents are highly selective in extracting and separating lithium. Under certain conditions, a lithium salt precursor is synthesized, and then lithium ions are eluted to obtain a metal oxide with a porous structure, which is a lithium ion sieve adsorbent. This adsorbent has a memory effect on lithium ions and can separate lithium ions from other impurity ions. In the conventional lithium extraction process, these adsorbents require a carrier or are coated on an electrode plate before they can be used for lithium extraction, which is cumbersome and complicated.

[0005] In view of this, the present disclosure is proposed. Summary of the invention

[0006] The purpose of the present disclosure includes providing an electrochemical deintercalation and lithium extraction method without electrode coating and its application, which uses waste lithium-ion battery positive and negative electrode powders as lithium ion adsorbents, directly adds them into brine, does not require a carrier and does not need to be coated on the electrode plate, and can extract lithium only by powering on. The method is easy to operate and makes resourceful use of waste lithium-ion batteries.

[0007] In order to achieve at least one of the above-mentioned objectives of the present disclosure, the following technical solutions may be adopted:

[0008] In a first aspect, the present disclosure provides an electrochemical deintercalation and lithium extraction method without electrode coating, comprising:

[0009] Using part of the lithium ion battery powder separated from waste lithium ion batteries as lithium-intercalated powder, and removing lithium from another part of the lithium ion battery powder as lithium-depleted powder;

[0010] The lithium-insertion powder and the lithium-removal powder are added to the anode area and the cathode area of ​​a lithium-extraction electrolytic cell respectively, and solid conductive particles are added to the anode area and the cathode area respectively, wherein the particle size of the solid conductive particles is larger than that of the lithium-insertion powder and the lithium-removal powder;

[0011] A voltage is applied to the anode electrode in the anode region and the cathode electrode in the cathode region to extract lithium.

[0012] In some embodiments of the present disclosure, the added amounts of the lithium insertion powder and the lithium removal powder are both 1500 g / L-2500 g / L.

[0013] In some embodiments of the present disclosure, the mass of the solid conductive particles added to the anode region accounts for 5%-15% of the mass of the lithium-inserted powder, and the mass of the solid conductive particles added to the cathode region accounts for 5%-15% of the mass of the lithium-stripped powder.

[0014] In some embodiments of the present disclosure, the particle size of the solid conductive particles is 20-300 times the particle size of the lithium insertion powder and the lithium removal powder.

[0015] In some embodiments of the present disclosure, the particle sizes of the lithium-inserted powder and the lithium-removed powder are both 0.1 mm-0.25 mm.

[0016] In some embodiments of the present disclosure, the solid conductive particles are spherical, and the volume of the spherical solid conductive particles is 5 mm 3 -30mm 3 .

[0017] In some embodiments of the present disclosure, the solid conductive particles are prepared from one or more of carbon fibers, carbon nanotubes and graphene.

[0018] In some embodiments of the present disclosure, a brine inlet is opened at the lower portion of the cathode zone, a wastewater outlet is opened at the upper portion of the cathode zone, a pure water inlet is opened at the lower portion of the anode zone, and a lithium-rich solution outlet is opened at the upper portion of the anode zone. During the lithium extraction process, brine is continuously introduced from the brine inlet, and pure water is continuously introduced from the pure water inlet.

[0019] In some embodiments of the present disclosure, the introduction rate of the brine and the pure water is 2L / h-4L / h.

[0020] In some embodiments of the present disclosure, the diameters of the brine inlet, the wastewater outlet, the pure water inlet and the lithium-rich solution outlet are all 3 cm-5 cm.

[0021] In some embodiments of the present disclosure, filter membranes are provided at both the wastewater outlet and the lithium-rich solution outlet.

[0022] In some embodiments of the present disclosure, the air permeability of the filter membrane is 3m 2 / s-12m 2 / s.

[0023] In some embodiments of the present disclosure, under the action of an electric field, the lithium-intercalating powder releases lithium ions into pure water, while the lithium-de-lithium powder absorbs lithium ions in brine; the lithium-intercalating powder and the lithium-de-lithium powder are exchanged, and the lithium extraction process is repeated.

[0024] In some embodiments of the present disclosure, when the number of cycles of the lithium-inserted powder and the lithium-removed powder reaches an upper limit, the lithium-inserted powder and the lithium-removed powder are added with acid for acid leaching, and are recovered by a dry method or a wet method.

[0025] In some embodiments of the present disclosure, separating the lithium ion battery powder from waste lithium ion batteries includes: first separating positive and negative electrode sheets from the waste lithium ion batteries, and then separating copper and aluminum foil fragments from the positive and negative electrode sheets to obtain the lithium ion battery powder.

[0026] In some embodiments of the present disclosure, before separating the copper and aluminum foil fragments from the positive and negative electrode sheets, the positive and negative electrode sheets are also cleaned, impurities removed and crushed.

[0027] In some embodiments of the present disclosure, the cleaning includes cleaning the positive and negative electrode sheets with an organic solvent to remove residual electrolyte on the surface, followed by drying.

[0028] In some embodiments of the present disclosure, the impurity removal includes placing the dried positive and negative electrode sheets at 500° C.-550° C. and keeping the temperature for 4-5 hours.

[0029] In some embodiments of the present disclosure, separating the positive and negative electrodes from the waste lithium-ion battery includes: discharging the waste lithium-ion battery to 1.8V on a charge and discharge instrument for complete discharge, cutting the aluminum shell of the waste lithium-ion battery, separating the battery cell covered with a plastic film from the aluminum shell, then peeling off the plastic film covering the battery cell, removing the electrolyte, obtaining the battery cell, and removing the positive and negative electrodes of the lithium-ion battery from the battery cell.

[0030] In some embodiments of the present disclosure, the waste lithium-ion battery includes at least one of a lithium iron phosphate lithium-ion battery and a ternary lithium-ion battery.

[0031] In some embodiments of the present disclosure, the first lithium extraction capacity of the electrode-free electrochemical deintercalation and lithium extraction method is greater than 40 mg / g, and the current density is greater than 50.5 A / m 2 .

[0032] In a second aspect, the present disclosure provides an electrode-coating-free electrochemical deintercalation and lithium extraction method for use in lithium extraction from salt lake brine.

[0033] Compared with the prior art, the beneficial effects of the present invention include:

[0034] The present invention provides an electrode coating-free electrochemical deintercalation and lithium extraction method, which crushes and separates waste lithium-ion batteries to separate the positive and negative electrodes in the battery cells of the waste lithium-ion batteries, and uses the crushed positive and negative electrodes as lithium-intercalation powder, which is then used as lithium-deintercalation powder for lithium extraction after delithiation. The lithium-intercalation powder is directly in contact with pure water, and the lithium-deintercalation powder is directly in contact with brine. Since the present invention directly adds the powder, the specific surface area of ​​the lithium extraction material is increased. At the same time, solid conductive particles are directly added to the anode region and the cathode region. Since the particle size of the solid conductive particles is larger than that of the lithium-intercalation powder (or lithium-deintercalation powder), the accumulation or agglomeration of powdered lithium-intercalation powder (or lithium-deintercalation powder) with a small particle size can be avoided, thereby enhancing the dispersion effect of the lithium-intercalation powder (or lithium-deintercalation powder). Furthermore, the provision of solid conductive particles is conducive to increasing the porosity between the lithium-embedded powder in the anode region (or the lithium-depleted powder in the cathode region), enhancing the flow channel, and then enhancing the flow of pure water (or brine), so that the lithium-embedded powder is in full contact with the pure water, and the lithium-depleted powder is in full contact with the brine. The lithium-embedded powder and the lithium-depleted powder disclosed in the present invention contain a large amount of carbon material, which can effectively conduct electricity, and the provision of solid conductive particles can also enhance the conductivity and facilitate the effect of conducting electricity. Compared with the related art that requires the adsorbent to be coated on the electrode plate for lithium extraction, the lithium extraction method disclosed in the present invention directly adds the lithium-embedded powder and the lithium-depleted powder to the anode region and the cathode region respectively, and can extract lithium without electrode coating, avoiding the use of PVDF in the coating process, and the mass transfer efficiency is high in the lithium extraction process, which improves the lithium extraction rate and capacity of the electrode. In addition, the present disclosure has low performance requirements for materials. The use of positive and negative black powder materials of lithium-ion batteries can meet the material conductivity and ion mass transfer efficiency in the lithium extraction process, can efficiently extract lithium, is easy to operate, and has low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 A diagram showing the working principle of the electrode-coating-free electrochemical lithium extraction method provided in the present invention.

[0037] Icons: 100-lithium extraction electrolytic cell; 110-anode area; 111-pure water inlet; 112-lithium-rich solution outlet; 113-lithium-embedded powder; 120-cathode area; 121-brine inlet; 122-wastewater outlet; 123-lithium-depleted powder; 130-anion exchange membrane; 140-anode electrode; 150-cathode electrode; 160-filter membrane; 170-solid conductive particles. DETAILED DESCRIPTION

[0038] The embodiments of the present disclosure will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present disclosure and should not be considered to limit the scope of the present disclosure. Where specific conditions are not specified in the examples, they are carried out under conventional conditions or conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments used are not specified, they are all conventional products that can be purchased commercially.

[0039] The endpoints and any values ​​of the ranges disclosed in this disclosure are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0040] The present invention provides a method for electrochemical lithium extraction without electrode coating. Figure 1 , which comprises the following steps:

[0041] S1. Separating lithium-ion battery powder from waste lithium-ion batteries.

[0042] First, separate the positive and negative electrodes from the waste lithium-ion batteries, and then separate the copper and aluminum foil fragments from the positive and negative electrodes to obtain lithium-ion battery powder.

[0043] Specifically, the waste lithium-ion batteries include at least one of lithium iron phosphate lithium-ion batteries and ternary lithium-ion batteries. The waste lithium-ion batteries are discharged to 1.8V on a charge and discharge instrument for complete discharge, the aluminum shell of the waste lithium-ion batteries is cut, the battery core covered with a plastic film is separated from the aluminum shell, and then the plastic film covering the battery core is peeled off, the electrolyte is removed, the battery core is obtained, and the positive and negative electrodes of the lithium-ion battery are taken out from the battery core. The positive and negative electrodes are cleaned, impurities are removed and crushed, wherein the cleaning includes cleaning the positive and negative electrodes with an organic solvent to remove the electrolyte remaining on the surface, and then drying. Impurity removal includes placing the dried positive and negative electrodes at 500℃-550℃ and keeping warm for 4-5 hours. The copper and aluminum foil fragments in the crushed positive and negative electrodes are separated to obtain lithium-ion battery powder.

[0044] The impurity removal temperature can be, for example, any one of 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, or a range between any two of them, and the insulation time can be, for example, any one of 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5 hours, or a range between any two of them.

[0045] S2, using part of the lithium ion battery powder separated from the waste lithium ion batteries as lithium-intercalated powder 113, and using the other part of the lithium ion battery powder as lithium-depleted powder 123 after lithium removal.

[0046] S3. Add the lithium-inserted powder 113 and the lithium-removed powder 123 into the anode area 110 and the cathode area 120 of the lithium extraction electrolytic cell 100 respectively. At the same time, add solid conductive particles 170 into the anode area 110 and the cathode area 120 respectively. The particle size of the solid conductive particles 170 is larger than that of the lithium-inserted powder 113 and the lithium-removed powder 123.

[0047] The addition amount of the lithium intercalation powder 113 and the lithium removal powder 123 is 1500 g / L-2500 g / L. In some embodiments, the addition amount of the lithium intercalation powder 113 and the lithium removal powder 123 can be, for example, 1500 g / L, 1600 g / L, 1700 g / L, 1800 g / L, 1900 g / L, 2000 g / L, 2100 g / L, 2200 g / L, 2300 g / L, 2400 g / L, 2500 g / L, or any range value between any two thereof.

[0048] The amount of solid conductive particles 170 added to the anode region 110 accounts for 5%-15% of the lithium intercalation powder 113, and the amount of solid conductive particles 170 added to the cathode region 120 accounts for 5%-15% of the lithium removal powder 123. In certain embodiments, the amount of solid conductive particles 170 added to the anode region 110 accounts for any one of 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% of the lithium intercalation powder 113, or a range value between any two of them. The amount of solid conductive particles 170 added to the cathode region 120 accounts for any one of 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% of the lithium removal powder 123, or a range value between any two of them.

[0049] The solid conductive particles 170 are spherical, and the volume of the spherical solid conductive particles 170 is 5 mm 3 -30mm 3 In some embodiments, the volume of the spherical solid conductive particles 170 is 5 mm 3 , 8mm 3 , 10mm 3 , 12mm 3 , 15mm 3 、18mm 3 , 20mm 3 , 21mm 3 , 22mm 3 , 25mm 3 、28mm 3 、29mm3 , 30mm 3 Any one of them or the range between any two.

[0050] The solid conductive particles 170 include but are not limited to one or more of carbon fiber, carbon nanotubes and graphene. Although metal materials can also conduct electricity, they will also discharge during the lithium extraction process. The solid conductive particles 170 in the present disclosure need to be stable in nature and cannot discharge. Therefore, materials such as carbon fiber, carbon nanotubes and graphene are selected as solid conductive particles 170.

[0051] In the present disclosure, solid conductive particles 170 are added to the cathode region 120 and the anode region 110 respectively. Since the particle size of the solid conductive particles 170 is larger than the particle size of the lithium-inserted powder 113 and the lithium-removed powder 123, the solid conductive particles 170 can disperse the lithium-inserted powder 113 or the lithium-removed powder 123 when mixed with the lithium-inserted powder 113 and the lithium-removed powder 123 respectively, thereby avoiding the accumulation or agglomeration of the lithium-inserted powder 113 or the lithium-removed powder 123 with small particle size, thereby increasing the separation of the positive and negative electrode powders. Dispersion effect, further, the provision of solid conductive particles 170 is conducive to increasing the porosity between the lithium-embedded powder 113 in the anode region 110 (or the lithium-depleted powder 123 in the cathode region 120), enhancing the flow channel, and then enhancing the flow of pure water (or brine), so that the contact area between the lithium-embedded powder 113 and the pure water is increased. Similarly, the contact area between the lithium-depleted powder 123 and the brine is increased. The solid conductive particles 170 are directly added to the brine to make the lithium-depleted powder 123 fully contact with the brine, thereby enhancing the relative movement between the two. The lithium-embedded powder 113 and the lithium-depleted powder 123 disclosed in the present invention contain a large amount of carbon material, which can effectively conduct electricity, and the provision of solid conductive particles 170 can also enhance conductivity and facilitate conductivity. The method of this scheme has high mass transfer efficiency during lithium extraction, which improves the lithium extraction rate and capacity of the electrode.

[0052] S4. Insert the anode electrode 140 into the anode region 110 , insert the cathode electrode 150 into the cathode region 120 , and apply voltage to the anode electrode 140 and the cathode electrode 150 to extract lithium.

[0053] The cathode region 120 and the anode region 110 are separated by an anion exchange membrane 130, a brine inlet 121 is provided at the bottom of the cathode region 120, a wastewater outlet 122 is provided at the top of the cathode region 120, a pure water inlet 111 is provided at the bottom of the anode region 110, and a lithium-rich solution outlet 112 is provided at the top of the anode region 110. During the lithium extraction process, brine is continuously introduced from the brine inlet 121, and pure water is continuously introduced from the pure water inlet 111. The introduction rate of brine and pure water is 2L / h-4L / h. The present disclosure can well control the lithium extraction effect of brine by controlling the introduction rate of brine and pure water, and realize continuous lithium extraction.

[0054] The diameters of the brine inlet 121, the wastewater outlet 122, the pure water inlet 111 and the lithium-rich solution outlet 112 are all 3 cm to 5 cm (in some embodiments, the diameters are any one of 3 cm, 4 cm, 5 cm or a range between any two of them). A filter membrane 160 is provided at the wastewater outlet 122 and the lithium-rich solution outlet 112, and the air permeability of the filter membrane 160 is 3 cm. 2 / s-12m 2 / s. In the present disclosure, the waste lithium-ion batteries include lithium iron phosphate lithium-ion batteries and ternary lithium-ion batteries, and the corresponding powders obtained are ferrophosphorus material powders and ternary material powders. The particle size of ferrophosphorus material is relatively small, and the air permeability of the filter membrane 160 is selected to be smaller. The ternary material is relatively large, and a larger air permeability membrane is selected. In some embodiments, the air permeability of the filter membrane 160 is 3m 2 / s、4m 2 / s、5m 2 / s、6m 2 / s、7m 2 / s、8m 2 / s、9m 2 / s、10m 2 / s、11m 2 / s、12m 2 / s or any range between them.

[0055] S5. Under the action of the electric field (1.2V), the lithium-insertion powder 113 releases lithium ions into the pure water, while the lithium-removal powder 123 absorbs lithium ions in the brine; the lithium-insertion powder 113 and the lithium-removal powder 123 are exchanged, and the lithium extraction process is repeated. The first lithium extraction capacity is greater than 40mg / g, and the current density is greater than 50.5A / m 2 .

[0056] Since the lithium-intercalated powder 113 and the lithium-de-lithium powder 123 disclosed in the present invention contain a large amount of carbon material, when voltage is applied to the anode electrode 140 and the cathode electrode 150, the lithium-intercalated powder 113 and the lithium-de-lithium powder 123 can play a conductive role in the lithium extraction process, thereby realizing the deintercalation of lithium ions in the brine and increasing the lithium extraction efficiency. At the same time, the particles used for dispersion in the present invention are solid conductive particles 170, which also have conductive properties. When combined with the lithium-intercalated powder 113 and the lithium-de-lithium powder 123, the conductive properties are better, which is beneficial to improving the lithium extraction efficiency.

[0057] S6. When the number of cycles of the lithium-inserted powder 113 and the lithium-removed powder 123 reaches the upper limit, the lithium-inserted powder 113 and the lithium-removed powder 123 are added with acid (sulfuric acid or hydrochloric acid) for acid leaching, and are recovered by a dry method or a wet method.

[0058] In addition, the present disclosure also provides an application of an electrode-coating-free electrochemical deintercalation and lithium extraction method in lithium extraction from salt lake brine.

[0059] The solution of the present disclosure is further described below in conjunction with embodiments.

[0060] Example 1

[0061] A method for electrochemical deintercalation and lithium extraction without electrode coating, wherein the waste lithium-ion battery in this embodiment is a lithium iron phosphate battery (steel shell cylindrical lithium iron phosphate battery 18650 model), comprising:

[0062] (1) Treatment of waste lithium iron phosphate batteries

[0063] Discharge the used lithium iron phosphate battery to 1.8V on a charge and discharge instrument for complete discharge. Use a hacksaw or shear to cut the aluminum shell of the lithium iron phosphate battery, separate the battery cell covered with plastic film from the aluminum shell, then peel off the plastic film covering the battery cell, remove the electrolyte, obtain the battery cell, and take out the positive and negative electrodes of the lithium iron phosphate battery from the battery cell for later use.

[0064] (2) Pretreatment of positive and negative electrodes

[0065] The recovered lithium iron phosphate positive and negative electrodes were cleaned with dimethyl carbonate to remove residual electrolyte on the surface and dried. The dried positive and negative electrodes were placed in a tubular furnace, the temperature in the tubular furnace was raised from room temperature to 500°C, and the temperature was kept for 5 hours to remove impurities such as electrolyte and PVDF.

[0066] (3) Post-processing of positive and negative electrodes

[0067] After the positive and negative electrode sheets are crushed, the copper and aluminum foil fragments in the positive and negative electrode sheets are separated by sorting to obtain the positive and negative electrode powders of the lithium iron phosphate battery.

[0068] (4) Use of positive and negative electrode materials from waste batteries for lithium extraction

[0069] A portion of the sorted positive and negative electrode powders of the lithium iron phosphate battery is used as lithium-intercalated powder 113, and the lithium iron phosphate battery powder is electrically de-lithiated to form lithium-de-lithiated powder 123. The lithium-intercalated powder 113 is then added to the anode area 110 of the electrolytic cell, and the lithium-de-lithiated powder 123 is added to the cathode area 120 of the electrolytic cell. In this solution, brine is introduced into the cathode area 120, and pure water is introduced into the anode area 110. The volume ratio of the added mass of the lithium-intercalated powder 113 to the pure water is 1500g / L, and the volume ratio of the added mass of the lithium-de-lithiated powder 123 to the brine is 1500g / L. At the same time, 5mm in size are added to the anode area 110 and the cathode area 120, respectively. 3Solid conductive particles 170 made of carbon fiber material with a content of 15% are used. The anode electrode 140 is inserted into the anode area 110, and the cathode electrode 150 is inserted into the cathode area 120. A voltage of 1.2V is applied to the anode electrode 140 and the cathode electrode 150 to extract lithium.

[0070] (5) A brine inlet 121 with a diameter of 5 cm is provided at the lower part of the cathode region 120, a wastewater outlet 122 with a diameter of 5 cm is provided at the upper part of the cathode region 120, a pure water inlet 111 with a diameter of 5 cm is provided at the lower part of the anode region 110, a lithium-rich solution outlet 112 with a diameter of 5 cm is provided at the upper part of the anode region 110, and a layer of gas permeability of 3 m 2 / s filter membrane 160, during the lithium extraction process, brine is continuously introduced from the brine inlet 121, pure water is continuously introduced from the pure water inlet 111, and at the same time, the waste water of the cathode area 120 is discharged from the waste water outlet 122, and the lithium-rich solution of the anode area 110 flows out from the lithium-rich solution outlet 112, and the brine and pure water are continuously introduced during the lithium extraction process.

[0071] (6) Under the action of the electric field, the lithium-inserted powder 113 releases lithium ions into the pure water, while the lithium-removed powder 123 absorbs lithium ions in the brine; the lithium-inserted powder 113 and the lithium-removed powder 123 are exchanged, and the lithium extraction process is repeated. When the number of lithium-inserted powder 113 and the lithium-removed powder 123 lithium extraction cycles reaches the upper limit, the positive and negative electrode materials in the lithium-inserted or lithium-removed state are added with hydrochloric acid for acid leaching, and then recycled by dry or wet methods.

[0072] Example 2

[0073] A method for electrochemical deintercalation and lithium extraction without electrode coating, wherein the waste lithium ion battery in this embodiment is a ternary lithium ion battery (commercially available, model NCM523), comprising:

[0074] (1) Treatment of waste ternary lithium-ion batteries

[0075] Discharge the used ternary lithium-ion battery to 1.8V on a charge and discharge instrument for complete discharge, cut the aluminum shell of the ternary lithium-ion battery with a hacksaw or shearing machine, separate the battery cell covered with plastic film from the aluminum shell, then peel off the plastic film covering the battery cell, remove the electrolyte, obtain the battery cell, take out the positive and negative electrodes of the ternary lithium-ion battery from the battery cell and set them aside.

[0076] (2) Pretreatment of positive and negative electrodes

[0077] The recovered positive and negative electrodes of the ternary lithium-ion battery were cleaned with diethyl carbonate to remove residual electrolyte on the surface and dried. The dried positive and negative electrodes were placed in a tubular furnace, and the temperature in the tubular furnace was raised from room temperature to 550°C for 4 hours to remove impurities such as electrolyte and PVDF.

[0078] (3) Post-processing of positive and negative electrodes

[0079] After the positive and negative electrode sheets are crushed, the copper and aluminum foil fragments in the positive and negative electrode sheets are separated by sorting to obtain ternary lithium-ion battery powder.

[0080] (4) Use of positive and negative electrodes of used batteries for lithium extraction

[0081] A portion of the sorted ternary lithium-ion battery powder is used as lithium-intercalated powder 113, and the other portion of the ternary lithium-ion battery powder is electrically de-lithiated to form lithium-depleted powder 123. The lithium-intercalated powder 113 is then added to the anode area 110 of the electrolytic cell, and the lithium-depleted powder 123 is added to the cathode area 120 of the electrolytic cell. In this scheme, brine is introduced into the cathode area 120, and pure water is introduced into the anode area 110. The volume ratio of the added mass of the lithium-intercalated powder 113 to the pure water is 1500g / L, and the volume ratio of the added mass of the lithium-depleted powder 123 to the brine is 1500g / L. At the same time, a 5mm-sized particle is added to the anode area 110 and the cathode area 120, respectively. 3 The solid conductive particles 170 have a content of 15%, the anode electrode 140 is inserted into the anode region 110, the cathode electrode 150 is inserted into the cathode region 120, and a voltage of 1.2V is applied to the anode electrode 140 and the cathode electrode 150 to extract lithium.

[0082] (5) A brine inlet 121 with a diameter of 5 cm is provided at the lower portion of the cathode region 120, a wastewater outlet 122 with a diameter of 5 cm is provided at the upper portion of the cathode region 120, a pure water inlet 111 with a diameter of 5 cm is provided at the lower portion of the anode region 110, a lithium-rich solution outlet 112 with a diameter of 5 cm is provided at the upper portion of the anode region 110, and a layer of gas permeability of 12 m 2 / s filter membrane 160, during the lithium extraction process, brine is continuously introduced from the brine inlet 121, pure water is continuously introduced from the pure water inlet 111, and at the same time, the waste water of the cathode area 120 is discharged from the waste water outlet 122, and the lithium-rich solution of the anode area 110 flows out from the lithium-rich solution outlet 112, and the brine and pure water are continuously introduced during the lithium extraction process.

[0083] (6) Under the action of the electric field, the lithium-inserted powder 113 releases lithium ions into the pure water, while the lithium-removed powder 123 absorbs lithium ions in the brine; the lithium-inserted powder 113 and the lithium-removed powder 123 are exchanged, and the lithium extraction process is repeated. When the number of lithium-inserted powder 113 and the lithium-removed powder 123 lithium extraction cycles reaches the upper limit, the positive and negative electrode materials in the lithium-inserted or lithium-removed state are added with sulfuric acid for acid leaching, and then recycled by dry or wet methods.

[0084] Example 3

[0085] The difference from Example 1 is that the solid contents of the added lithium insertion powder 113 and the lithium removal powder 123 are 2000 g / L respectively.

[0086] Example 4

[0087] The difference from Example 1 is that the solid contents of the lithium-insertion powder 113 and the lithium-removal powder 123 are 2500 g / L respectively.

[0088] Example 5

[0089] The difference from Example 1 is that a 15 mm 3 The content of solid conductive particles 170 is 10%.

[0090] Example 6

[0091] The difference from Example 1 is that a 30 mm 3 The solid conductive particles 170 have a content of 5%.

[0092] Comparative Example 1

[0093] Compared with Example 1, this comparative example directly uses the coated ferrophosphorus positive electrode material as the adsorbent.

[0094] (1) A portion of the carbon-coated small-particle lithium iron phosphate material (purchased from Angxing New Carbon Material Changzhou Co., Ltd.) was added to the anode region as a lithium-intercalated powder, and the other portion of the carbon-coated small-particle lithium iron phosphate material was electrically de-lithiated. The de-lithiated material was then added to the cathode region of the electrolytic cell for lithium extraction. Brine was introduced into the cathode region, and pure water was introduced into the anode region. The solid content of the carbon-coated small-particle lithium iron phosphate material added to the cathode region and the anode region was 1500 g / L. At the same time, 5 mm-sized particles were added to the anode region and the cathode region, respectively. 3 The content of solid conductive particles 170 is 15%.

[0095] (2) A brine inlet 121 with a diameter of 1 cm is provided at the lower portion of the cathode region 120, a wastewater outlet 122 with a diameter of 1 cm is provided at the upper portion of the cathode region 120, a pure water inlet 111 with a diameter of 1 cm is provided at the lower portion of the anode region 110, a lithium-rich solution outlet 112 with a diameter of 1 cm is provided at the upper portion of the anode region 110, and a layer of gas permeability of 3 m 2 / s filter membrane 160, during the lithium extraction process, brine is continuously introduced from the brine inlet 121, pure water is continuously introduced from the pure water inlet 111, and at the same time, the waste water of the cathode area 120 is discharged from the waste water outlet 122, and the lithium-rich solution of the anode area 110 flows out from the lithium-rich solution outlet 112, and the brine and pure water are continuously introduced during the lithium extraction process.

[0096] (3) When the number of times the carbon-coated lithium iron phosphate material is recycled reaches the upper limit, the positive and negative electrode materials in the lithium-intercalated or lithium-extracted state are added with hydrochloric acid for acid leaching, and then recycled by dry or wet methods.

[0097] Comparative Example 2

[0098] Compared with Example 1, no additional solid conductive particles 170 are added in this comparative example.

[0099] Comparative Example 3

[0100] Compared with Example 1, in this comparative example, only solid conductive particles 170 are added, and lithium insertion powder 113 and lithium removal powder 123 are not added.

[0101] Comparative Example 4

[0102] The difference from Example 1 is that a 15 mm 3 The content of solid conductive particles 170 is 20%.

[0103] Comparative Example 5

[0104] The difference from Example 1 is that the solid contents of the lithium-intercalated powder 113 and the lithium-deintercalated powder 123 are 1000 g / L respectively.

[0105] Comparative Example 6

[0106] The difference from Example 1 is that the solid contents of the added lithium insertion powder 113 and the lithium removal powder 123 are 3000 g / L respectively.

[0107] Comparative Example 7

[0108] In this comparative example, the undelithiated lithium iron phosphate material and the delithiated lithium iron phosphate material are respectively coated on the surface of the positive electrode and the negative electrode to make positive and negative electrode plates, with a coating thickness of 200 μm. Subsequently, the positive electrode and the negative electrode are respectively inserted into the anode area and the cathode area, and a voltage of 1.2 V is applied to the anode electrode and the cathode electrode to extract lithium.

[0109] Experimental example

[0110] The lithium extraction processes of the above Examples 1-6 and Comparative Examples 1-7 were tested, and the test results are shown in the following table:

[0111] Among them, the detection method of the first lithium extraction capacity includes using a conductivity meter to test the lithium extraction capacity;

[0112] Current density is the ratio of the current to the cross-sectional area of ​​the conductor through which the current flows.

[0113]

[0114]

[0115] It can be seen from the data of Example 1 and Example 2 that the waste batteries provided by the present invention, which are waste lithium iron phosphate batteries and waste ternary lithium-ion batteries, can achieve better first lithium extraction capacity and current density. It can be seen from the data of Example 1, Examples 3 and 4 and Comparative Examples 5 and 6 that the first lithium extraction capacity and current density can be improved by increasing the solid content of the lithium-embedded powder 113 and the lithium-removed powder 123. However, after the solid content of the lithium-embedded powder 113 and the lithium-removed powder 123 exceeds 2000 g / L and continues to increase, the first lithium extraction capacity and current density are slightly reduced. When the solid content of the lithium-embedded powder 113 and the lithium-removed powder 123 exceeds the scope of the present invention, too low or too high a solid content will have a greater impact on the first lithium extraction capacity and current density. It can be seen from Examples 5 and 6 and Comparative Examples 2-4 that the larger the volume of the solid conductive particles 170, the better the dispersion effect of the lithium-embedded powder 113 (lithium-depleted powder 123), and the better the initial lithium extraction capacity and current density. Without the addition of the solid conductive particles 170, the (lithium-depleted powder 123) is easy to accumulate, resulting in a significant decrease in the initial lithium extraction capacity, while the addition of the solid conductive particles 170 alone cannot exert the lithium extraction effect. In addition, excessive addition of the solid conductive particles 170 will result in a significant decrease in the lithium extraction capacity. It can be seen from Example 1, Comparative Example 1 and Comparative Example 2 that the effect of using a carbon-coated iron phosphide positive electrode material as an adsorbent is significantly worse than that of Example 1, and significantly worse than that of Comparative Example 2. It can be seen from Example 1 and Comparative Example 7 that the method of coating lithium iron phosphate on the electrode and then extracting lithium in Comparative Example 7 has a lithium extraction capacity and current density that are significantly lower than those of Example 1.

[0116] In summary, the electrode coating-free electrochemical deintercalation and lithium extraction method provided by the present invention crushes and separates the waste lithium-ion batteries to separate the positive and negative electrodes in the battery cells of the waste lithium-ion batteries, and uses the crushed positive and negative electrodes as lithium intercalation powder and lithium deintercalation powder for lithium extraction. The lithium intercalation powder is directly in contact with pure water, and the lithium deintercalation powder is directly in contact with brine. Since the present invention directly adds the powder, the specific surface area of ​​the lithium extraction material is increased. At the same time, solid conductive particles are directly added to the anode region and the cathode region. Since the particle size of the solid conductive particles is larger than that of the lithium intercalation powder (or lithium deintercalation powder), the accumulation or agglomeration of powdered lithium intercalation powder (or lithium deintercalation powder) with a small particle size can be avoided, thereby enhancing the dispersion effect of the lithium intercalation powder (or lithium deintercalation powder). Furthermore, the provision of solid conductive particles is conducive to increasing the porosity between the lithium-embedded powder in the anode region (or the lithium-depleted powder in the cathode region), enhancing the flow channel, and then enhancing the flow of pure water (or brine), so that the lithium-embedded powder is in full contact with the pure water, and the lithium-depleted powder is in full contact with the brine. The lithium-embedded powder and the lithium-depleted powder disclosed in the present invention contain a large amount of carbon material, which can effectively conduct electricity, and the provision of solid conductive particles can also enhance the conductivity and facilitate the effect of conducting electricity. Compared with the related art that requires the adsorbent to be coated on the electrode plate for lithium extraction, the lithium extraction method disclosed in the present invention directly adds the lithium-embedded powder and the lithium-depleted powder to the anode region and the cathode region respectively, and can extract lithium without electrode coating, avoiding the use of PVDF in the coating process, and the mass transfer efficiency is high in the lithium extraction process, which improves the lithium extraction rate and capacity of the electrode. In addition, the present disclosure has low performance requirements for materials. The use of positive and negative black powder materials of lithium-ion batteries can meet the material conductivity and ion mass transfer efficiency in the lithium extraction process, can efficiently extract lithium, is easy to operate, and has low cost.

[0117] The optional implementation modes of the present disclosure are described in detail above, but the present disclosure is not limited thereto. Within the technical concept of the present disclosure, the technical solution of the present disclosure can be subjected to a variety of simple modifications, including combining various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present disclosure and belong to the protection scope of the present disclosure.

[0118] Industrial Applicability

[0119] The present invention provides an electrode coating-free electrochemical deintercalation and lithium extraction method, which crushes and separates waste lithium-ion batteries to separate the positive and negative electrodes in the battery cells of the waste lithium-ion batteries, and uses the crushed positive and negative electrodes as lithium intercalation powder and lithium deintercalation powder for lithium extraction. The lithium intercalation powder is directly in contact with pure water, and the lithium deintercalation powder is directly in contact with brine. Since the present invention directly adds the powder, the specific surface area of ​​the lithium extraction material is increased. At the same time, solid conductive particles are directly added to the anode region and the cathode region. Since the particle size of the solid conductive particles is larger than that of the lithium intercalation powder (or lithium deintercalation powder), the accumulation or agglomeration of powdered lithium intercalation powder (or lithium deintercalation powder) with a small particle size can be avoided, thereby enhancing the dispersion effect of the lithium intercalation powder (or lithium deintercalation powder). Furthermore, the provision of solid conductive particles is conducive to increasing the porosity between the lithium-embedded powder in the anode region (or the lithium-depleted powder in the cathode region), enhancing the flow channel, and then enhancing the flow of pure water (or brine), so that the lithium-embedded powder is in full contact with the pure water, and the lithium-depleted powder is in full contact with the brine. The lithium-embedded powder and the lithium-depleted powder disclosed in the present invention contain a large amount of carbon material, which can effectively conduct electricity, and the provision of solid conductive particles can also enhance the conductivity and facilitate the effect of conducting electricity. Compared with the related art that requires the adsorbent to be coated on the electrode plate for lithium extraction, the lithium extraction method disclosed in the present invention directly adds the lithium-embedded powder and the lithium-depleted powder to the anode region and the cathode region respectively, and can extract lithium without electrode coating, avoiding the use of PVDF in the coating process, and the mass transfer efficiency is high in the lithium extraction process, which improves the lithium extraction rate and capacity of the electrode. In addition, the present disclosure has low performance requirements for materials. The use of positive and negative black powder materials of lithium-ion batteries can meet the material conductivity and ion mass transfer efficiency in the lithium extraction process, can efficiently extract lithium, is easy to operate, and has low cost.

Claims

1. A method for electrochemical lithium extraction without electrode coating, characterized in that: It includes: Using part of the lithium ion battery powder separated from waste lithium ion batteries as lithium-intercalated powder, and removing lithium from another part of the lithium ion battery powder as lithium-depleted powder; The lithium-insertion powder and the lithium-removal powder are added to the anode area and the cathode area of ​​the lithium-extraction electrolytic cell respectively, and at the same time, solid conductive particles are added to the anode area and the cathode area respectively, and the particle size of the solid conductive particles is larger than that of the lithium-insertion powder and the lithium-removal powder; the added mass of the solid conductive particles in the anode area accounts for 5%-15% of the mass of the lithium-insertion powder, and the added mass of the solid conductive particles in the cathode area accounts for 5%-15% of the mass of the lithium-removal powder, and the particle size of the solid conductive particles is 20-300 times that of the particle size of the lithium-insertion powder and the lithium-removal powder, and the particle size of the lithium-insertion powder and the lithium-removal powder is 0.10-0.25 mm; Voltage is applied to the anode electrode in the anode area and the cathode electrode in the cathode area to extract lithium; a brine inlet is opened at the lower part of the cathode area, a wastewater outlet is opened at the upper part of the cathode area, a pure water inlet is opened at the lower part of the anode area, and a lithium-rich solution outlet is opened at the upper part of the anode area. During the lithium extraction process, brine is continuously introduced from the brine inlet, and pure water is continuously introduced from the pure water inlet.

2. The electrode-free electrochemical deintercalation and lithium extraction method according to claim 1, characterized in that: The addition amount of the lithium-insertion powder and the lithium-removal powder is 1500 g / L-2500 g / L.

3. The electrode-free electrochemical deintercalation and lithium extraction method according to claim 1, characterized in that: The solid conductive particles are spherical, and the volume of the spherical solid conductive particles is 5 mm 3 -30mm 3 .

4. The electrode-free electrochemical deintercalation and lithium extraction method according to claim 1, characterized in that: The solid conductive particles are prepared from one or more of carbon fibers, carbon nanotubes and graphene.

5. The electrode-free electrochemical deintercalation and lithium extraction method according to claim 1, characterized in that: The introduction rate of the brine and the pure water is 2L / h-4L / h.

6. The electrode-free electrochemical deintercalation and lithium extraction method according to claim 1, characterized in that: The diameters of the brine inlet, the wastewater outlet, the pure water inlet and the lithium-rich solution outlet are all 3 cm to 5 cm.

7. The method for electrochemical lithium extraction without electrode coating according to claim 1, characterized in that: Filter membranes are provided at the wastewater outlet and the lithium-rich solution outlet.

8. The electrode-free electrochemical deintercalation and lithium extraction method according to claim 7, characterized in that: The air permeability of the filter membrane is 3m 2 / s -12m 2 / s.

9. The electrode-free electrochemical deintercalation and lithium extraction method according to claim 1, characterized in that: Under the action of the electric field, the lithium-intercalating powder releases lithium ions into pure water, while the lithium-de-lithium powder absorbs lithium ions in brine; the lithium-intercalating powder and the lithium-de-lithium powder are exchanged, and the lithium extraction process is repeated.

10. The electrochemical deintercalation and lithium extraction method without electrode coating according to claim 1, characterized in that: When the number of cycles of the lithium-inserted powder and the lithium-removed powder reaches an upper limit, the lithium-inserted powder and the lithium-removed powder are acid-leached and then recycled by a dry method or a wet method.

11. The electrochemical deintercalation and lithium extraction method without electrode coating according to claim 1, characterized in that: Separating the lithium ion battery powder from the waste lithium ion batteries comprises: firstly separating the positive and negative electrode sheets from the waste lithium ion batteries, and then separating the copper and aluminum foil fragments from the positive and negative electrode sheets to obtain the lithium ion battery powder.

12. The method for electrochemical lithium extraction without electrode coating according to claim 11, characterized in that: Before separating the copper and aluminum foil fragments from the positive and negative electrode sheets, the positive and negative electrode sheets are also cleaned, impurities removed and crushed.

13. The electrochemical deintercalation and lithium extraction method without electrode coating according to claim 12, characterized in that: The cleaning includes cleaning the positive and negative electrode sheets with an organic solvent to remove residual electrolyte on the surface, followed by drying.

14. The electrochemical deintercalation and lithium extraction method without electrode coating according to claim 12, characterized in that: The impurity removal includes placing the dried positive and negative electrode sheets at 500° C.-550° C. and keeping the temperature for 4-5 hours.

15. The electrochemical deintercalation and lithium extraction method without electrode coating according to claim 11, characterized in that: Separating the positive and negative electrodes from the waste lithium-ion battery includes: discharging the waste lithium-ion battery to 1.8V on a charge and discharge instrument for complete discharge, cutting the aluminum shell of the waste lithium-ion battery, separating the battery core covered with a plastic film from the aluminum shell, then peeling off the plastic film covering the battery core, removing the electrolyte, obtaining the battery core, and taking out the positive and negative electrodes of the lithium-ion battery from the battery core.

16. The electrochemical deintercalation and lithium extraction method without electrode coating according to claim 1, characterized in that: The waste lithium-ion battery includes at least one of a lithium iron phosphate lithium-ion battery and a ternary lithium-ion battery.

17. The electrochemical deintercalation and lithium extraction method without electrode coating according to claim 1, characterized in that: The electrochemical deintercalation and lithium extraction method without electrode coating has an initial lithium extraction capacity of more than 40 mg / g and a current density of more than 50.5 A / m 2 .

18. Use of the electrode-free electrochemical deintercalation and lithium extraction method as claimed in claim 1 in lithium extraction from salt lake brine.

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