Method for spontaneously recovering waste lithium battery through metal electric contact

Abstract

The invention belongs to the field of comprehensive utilization of resources, and particularly relates to a method for spontaneously recovering a waste lithium battery through metal electric contact, which comprises the following steps of: performing short-circuit discharge on the waste lithium battery and disassembling to obtain a positive electrode active material and a current collector, so that the positive electrode active material is in electric contact with metal; the metal is waste lithium battery current collector metal or standard electrode potential lt; immersing the metal and the positive electrode active material which are kept in electrical contact into an electrolyte solution to be subjected to oxidation-reduction reaction, and leaching lithium ions and transition metal ions to obtain a metal enrichment solution; and respectively precipitating lithium ions and transition metal ions by using a precipitator generated in situ in the leaching process or other precipitators added additionally. The method is simple in process, uses potential difference between metal and transition metal as driving force, does not depend on high temperature, strong acid and strong alkali, and is high in operability, low in cost and small in GHG emission, and the leaching efficiency of each metal is close to 100%.

Description

Technical Field

[0001] The invention belongs to the field of comprehensive resource utilization, and in particular relates to a method for spontaneously recycling waste lithium batteries through metal electrical contacts. Background Art

[0002] Lithium-ion batteries (LIBs) are widely used in a variety of modern devices, including mobile phones, portable electronic devices and computers. Improper disposal of waste batteries will lead to environmental pollution and the loss of a large amount of non-renewable resources. From an economic point of view, lithium, cobalt, nickel and manganese in waste batteries are all expensive metal resources. Therefore, recycling waste lithium batteries is of great significance.

[0003] Pyrometallurgy and hydrometallurgy are the most commonly used recycling methods in industry. Pyrometallurgy is widely used in industry because of its convenient operation, but the pyrometallurgical process requires extremely high temperatures. First, it needs to be pretreated at 550°C for 500 minutes, and then calcined with graphite at a temperature above 1000°C for 30 minutes. This method will result in high energy consumption and carbon emissions. Some researchers have found that the pyrometallurgical recovery temperature can be reduced by adding salt for co-roasting, but because the pyrometallurgical recovery product is an alloy and lithium cannot be recovered, the current recovery methods are mostly wet methods. Hydrometallurgy is to dissolve the waste battery powder with strong acids and alkalis, and then precipitate the transition metal ions with chemical precipitants. The wet method has a high recovery rate and can recover more than 90% of lithium and other metals. For hydrometallurgy, it has been reported that the use of organic acids (such as citric acid and acetic acid) instead of concentrated inorganic acids can reduce environmental damage. Ionic liquids and deep eutectic solvents have high leaching efficiency and recyclability, and are also studied for recycling lithium-ion batteries.

[0004] However, these methods cannot avoid their inherent limitations, including high energy consumption and greenhouse gas (GHG) emissions. These shortcomings not only lead to environmental pollution, but also increase the cost of the recycling process. Recycling one ton of spent lithium-ion batteries through pyrometallurgy requires an energy input of about 3.9×10 5 MJ and produces approximately 1,311 kg of carbon dioxide. Hydrometallurgy avoids the need for high temperatures, but requires mechanical separation of the aluminum foil from the cathode active material during the pretreatment process, which also requires some energy consumption. Various chemicals are used in the process of leaching valuable metal elements, including concentrated sulfuric acid, concentrated nitric acid and hydrogen peroxide. Subsequently, chemical precipitants, such as sodium carbonate, are required for the precipitation step, and the use of these chemicals leads to large amounts of greenhouse gas and toxic gas emissions. Therefore, there is an urgent need to develop an environmentally friendly method for recycling spent LIBs with low energy consumption, reduced GHG emissions and less chemical use. Summary of the invention

[0005] In order to solve the problems of high energy consumption, high carbon emissions and the formation of a large amount of waste acid and waste water caused by the current high-temperature smelting and acid leaching (alkaline leaching) recovery of lithium batteries, the present invention provides a method for spontaneously recovering waste lithium batteries through metal electrical contact, through the potential difference formed between the positive electrode active material of the waste battery and the metal, electrons are transferred to the positive electrode material in the electrolyte solution, and the transition metal in the positive electrode material in a high valence state is reduced after receiving the electrons, and hydrogen-lithium exchange occurs in the solution, and lithium and other transition metals are leached at the same time, and the transition metal ions and Li are respectively precipitated by a precipitant generated in situ during the reaction or other precipitants added separately. + After the precipitation is filtered, the electrolyte solution can be reused. This method uses the potential difference as the driving force for the leaching of the positive electrode active material. The process is simple, the operability is strong, the cost is low, the GHG emission is small, and the leaching efficiency of each metal is close to 100%.

[0006] The technical solution provided by the present invention is as follows:

[0007] A method for spontaneously recycling waste lithium batteries through metal electrical contact comprises the following steps: short-circuiting and disassembling the waste lithium batteries to obtain positive electrode active materials and current collectors, making the positive electrode active materials maintain electrical contact with metals, wherein the metals are metals of the current collectors of the waste lithium batteries or other metals with a standard electrode potential of less than 1.51 V, immersing the metals and positive electrode active materials that maintain electrical contact in an electrolyte solution to undergo redox reactions, and obtaining metal-enriched liquid after leaching lithium ions and transition metal ions; and using a precipitant generated in situ during the leaching process or adding other precipitants to precipitate lithium ions and transition metal ions respectively.

[0008] Furthermore, the method for short-circuiting the waste lithium battery includes: immersing the waste lithium battery in a salt solution and discharging to a termination voltage of 0.5-1.5V; the salt solution is a NaCl solution, and the solubility of the salt solution is 4-6wt%.

[0009] Furthermore, the metal is any one or more of aluminum, copper, iron, zinc, magnesium, titanium, chromium, vanadium, nickel, cobalt, and manganese.

[0010] Furthermore, the electrical contact method includes at least one of stirring, ultrasound, and ball milling.

[0011] Furthermore, the waste lithium batteries include at least one of lithium manganese oxide, lithium cobalt oxide, nickel aluminum cobalt oxide, and nickel manganese cobalt oxide batteries.

[0012] Furthermore, the electrolyte solution solute is at least one of a soluble gas, an acid, an alkali, and a salt, and the soluble gas is introduced at a pressure of 0.1 to 4 MPa. Preferably, the soluble gas introduced is CO2, NO2, or SO2.

[0013] Furthermore, the in-situ generated precipitant includes CO3 generated in-situ during the reaction after CO2 is introduced as the electrolyte solution. 2- , or OH generated in situ when using alkaline electrolyte solution - The in-situ generated precipitant reacts with the transition metal ions during the leaching process to precipitate the transition metal ions.

[0014] Furthermore, during the precipitation process, the pH is adjusted between 10 and 14 to precipitate transition metal ions, and after the transition metal precipitate is filtered, carbonate or phosphate is added to precipitate lithium ions.

[0015] Furthermore, the molar ratio of the positive electrode active material to the metal is 0.1~3:1.

[0016] Furthermore, the metal and the positive electrode active material that maintain electrical contact are immersed in an electrolyte solution to undergo a redox reaction at a reaction temperature of 25 to 200°C and a reaction time of 1 to 50 hours. Preferably, the reaction temperature is 50 to 80°C.

[0017] Beneficial Effects

[0018] This method utilizes the potential difference between the positive electrode current collector and the positive electrode material of the waste lithium battery to spontaneously reduce the positive electrode material of the waste lithium battery. Only an electrolyte solution is needed as an ion transmission medium to achieve metal leaching in the waste lithium battery, avoiding the use of a large amount of strong acid, strong alkali and reducing agent in the traditional wet method, and does not require high-temperature smelting like the pyrometallurgy. The operation is simple, and the complicated pretreatment process is avoided. The metal current collector that needs to be removed by various means in the general recovery method is fully utilized, and the electrolyte solution can be reused, so that the method of the present invention can generate a lot of profits while avoiding high carbon emissions. The method of the present invention is an effective electrochemical way to convert harmful corrosion of metals into recycling lithium-ion batteries. The method is applicable to almost all commercial positive electrode systems, such as layered LCO, spinel LMO and ternary materials, and the recovery rate of lithium and transition metals is close to 100%. Example 1 Using carbon dioxide and water as leaching agents and precipitants, lithium salts and transition metal salts can be successfully leached and precipitated without adding additional chemicals. Compared with the traditional pyrometallurgical recovery, 1311 kg of carbon dioxide is emitted for each ton of waste batteries recovered, and 1843 kg of carbon dioxide is emitted for each ton of waste batteries recovered by the wet method. The method of the present invention can absorb 236 kg of carbon dioxide for each ton of waste batteries recovered. Since the method of the present invention has simple steps, the consumption of chemicals can be avoided, and high temperature is not required, so the cost is very low. At present, due to the sharp drop in the prices of lithium salts and cobalt salts, the pyrometallurgical and wet methods can no longer achieve profitability, but the present method can still achieve a profit of 9,000 yuan / ton. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1This is the lithium and cobalt leaching efficiency curve of Example 1 in which lithium cobalt oxide is electrically contacted with aluminum in a carbonate solution for 32 hours;

[0020] Figure 2 is the X-ray diffraction peak intensity curve of lithium carbonate precipitate collected after the reaction in Example 1;

[0021] Figure 3 is the X-ray diffraction peak intensity curve of the cobalt carbonate precipitate collected after the reaction in Example 1;

[0022] Figure 4 This is the lithium-cobalt leaching efficiency curve of Example 2 in which lithium cobaltate is electrically contacted with aluminum in a sulfurous acid solution for 20 hours;

[0023] Figure 5 This is a scanning electron microscope image of the lithium cobalt oxide electrode of Example 2 before and after the reaction;

[0024] Figure 6 This is the lithium cobalt nickel manganese leaching efficiency curve of Example 3 in which lithium nickel manganese cobalt oxide (NMC111) is electrically contacted with aluminum in an ammonium acetate solution for 48 hours;

[0025] Figure 7 The scanning electron microscope images of lithium nickel manganese cobalt oxide (NMC111) before and after the reaction of Example 3 are shown;

[0026] Figure 8 The lithium and manganese leaching efficiency curve of Example 4 in which lithium manganate is in contact with iron in an ammonium chloride solution for 12 hours;

[0027] Fig. 9 The metal ion leaching efficiency is compared between Comparative Example 1 and Example 1 with or without the current collector;

[0028] Fig.10 The leaching efficiency of Comparative Example 3 and Example 4 is compared when there is metallic electrical contact with iron or not;

[0029] Fig.11 The conventional pyro-wet method and the implementation steps of Example 1 are compared;

[0030] Fig.12 The cost comparison between the traditional pyrometallurgical method and Example 1 is shown;

[0031] Fig.13 Comparison of carbon dioxide emissions caused by traditional pyrometallurgical and wet methods and Example 1. DETAILED DESCRIPTION

[0032] In order to more clearly illustrate the technical solution of the present invention, the present invention will be further described below; obviously, the following description is only a part of the embodiments, and for ordinary technicians in this field, without paying creative work, the technical solution of the present invention can also be applied to other similar scenarios based on these; in order to more clearly illustrate the technical solution of the present invention, the technical solution of the present invention is further described in detail below.

[0033] Example 1

[0034] Spontaneous recovery of lithium cobalt oxide is achieved by electrical contact between aluminum current collector and lithium cobalt oxide electrode material in carbonate solution:

[0035] (1) The used lithium manganese oxide battery was immersed in a 5wt% NaCl solution and discharged to a voltage of 1V. Since the current collector of the lithium battery is aluminum foil, the lithium cobalt oxide positive electrode sheet containing the current collector aluminum was obtained after disassembly, and 1-2 g of the electrode sheet was taken;

[0036] (2) placing the lithium cobalt oxide positive electrode sheet containing current collector aluminum obtained in step (1) in a reactor, and adding 50 mL of distilled water into the reactor;

[0037] (3) introducing 2 Mpa of carbon dioxide into the reactor in step (2);

[0038] (4) The temperature of the reactor in step (3) was set to 50° C. and the reaction was carried out for 32 hours;

[0039] (5) evaporating and concentrating the solution in step (4) at 60° C., and removing excess carbon dioxide from the solution to raise the pH to about 6.1;

[0040] (6) Filter the solid precipitate in step 5, wherein the precipitate contains Al 3+ Al(OH)3 formed due to pH;

[0041] (7) Continue evaporating the aqueous solution in step (6) until it is completely evaporated to dryness to obtain a mixture of lithium carbonate and cobalt carbonate, which are then separated using the magnetic properties of cobalt carbonate.

[0042] The leaching rate of lithium cobalt from lithium cobalt oxide was characterized by inductively coupled plasma optical emission spectrometry (ICP-OES), and the collected products were characterized by X-ray diffraction (XRD).

[0043] The lithium-cobalt leaching efficiency curve of lithium cobalt oxide in a carbonate solution after 32 hours of electrical contact reaction with aluminum is as follows: Figure 1 As shown, the lithium leaching efficiency reached 100% and the cobalt leaching efficiency reached 96%; the X-ray diffraction peak intensity curves of lithium carbonate and cobalt carbonate precipitates collected after the reaction are shown in Figure 2 and 3As shown, the characteristic peaks are completely consistent with those of lithium carbonate and cobalt carbonate, and the peaks are sharp, indicating that the precipitated cobalt carbonate and lithium carbonate are clean in composition, good in crystallinity, and free of obvious impurities; among them, Li2C03-PDF#22-1141 refers to the standard card of lithium carbonate, and CoCO3-PDF#11-0692 refers to the standard card of cobalt carbonate.

[0044] Example 2

[0045] Spontaneous recovery of lithium cobalt oxide is achieved by electrical contact between the aluminum current collector and the lithium cobalt oxide electrode material in a sulfurous acid solution:

[0046] (1) The used lithium cobalt oxide battery was immersed in a 5wt% NaCl solution and discharged to a voltage of 1V. Since the current collector of the lithium battery is aluminum foil, the lithium cobalt oxide positive electrode sheet containing the current collector aluminum was obtained after disassembly, and 1-2 g of the electrode sheet was taken;

[0047] (2) placing the lithium cobalt oxide positive electrode sheet containing current collector aluminum obtained in step (1) in a reactor, and adding 50 mL of distilled water into the reactor;

[0048] (3) introducing 0.5 Mpa of sulfur dioxide into the reactor in step (2);

[0049] (4) setting the temperature of the reactor in step (3) to 50°C and reacting for 20 hours;

[0050] (5) evaporating and concentrating the solution in step (4) at 60° C., removing excess sulfur dioxide from the solution, and raising the pH to about 6.5;

[0051] (6) filtering the solid precipitate in step (5), wherein the precipitate contains Al 3+ Al(OH)3 formed due to pH;

[0052] (7) In step (6), NaOH is first added to the metal enrichment solution to adjust the pH to 10-14, so that the transition metal forms a hydroxide precipitate and is filtered, and then carbonate is added to Li + Precipitated as Li2CO3.

[0053] Lithium cobalt oxide + 、Co 2+ The leaching rate of LCO was characterized by ICP. The surface of LCO positive electrode before and after the reaction was characterized by scanning electron microscopy (SEM). The lithium cobalt leaching efficiency curve of lithium cobalt oxide in sulfurous acid solution and aluminum electrical contact reaction for 20 hours is shown in the figure below. Figure 4 As shown, after 20 hours of leaching, Li + and Co 2+ The recovery rate reached 100%. SEM observation of the electrode before and after the reaction was performed. Figure 5 As shown, it was found that before the reaction, the LCO particles were evenly distributed on the surface of the electrode, and the carbon black tightly surrounded the LCO particles. After the reaction, the LCO particles of the electrode disappeared, and pits appeared where the original particles were located, proving that LCO has been completely leached.

[0054] Example 3

[0055] The aluminum current collector and the nickel manganese cobalt oxide (NMC111) electrode material are electrically contacted in an ammonium acetate solution to achieve spontaneous recovery of nickel manganese cobalt oxide:

[0056] (1) Used nickel manganese cobalt oxide (NMC111) batteries were immersed in 5wt% NaCl solution and discharged to a voltage of 1V. Since the current collector of the lithium battery is aluminum foil, the nickel manganese oxide positive electrode sheet containing current collector aluminum was obtained after disassembly, and 1-2 g of the electrode sheet was taken;

[0057] (2) placing the nickel manganese cobalt oxide lithium positive electrode sheet containing current collector aluminum obtained in step (1) in a reactor, and adding 50 mL of distilled water into the reactor;

[0058] (3) Add 0.5 g of ammonium acetate to the reactor in step (2) and stir to dissolve, pH = 6.0;

[0059] (4) The temperature of the reactor in step (3) was set to 50°C and the reaction was carried out for 48 hours;

[0060] (5) Add Al in step (4) 3+ Al(OH)3 precipitate is generated due to pH reasons, which is filtered to obtain metal-enriched solution;

[0061] (7) In step (6), NaOH is first added to the metal enrichment solution to adjust the pH to 10-14, so that the transition metal forms hydroxides and then precipitates together and is filtered, and then carbonate is added to Li + Precipitated as Li2CO3.

[0062] The leaching rate of lithium nickel manganese cobalt of lithium nickel manganese cobalt oxide was characterized by ICP. The leaching efficiency curve of lithium cobalt nickel manganese of lithium nickel manganese cobalt oxide after 48 hours of electrical contact reaction with aluminum in ammonium acetate solution is as follows: Figure 6 As shown, it shows that the lithium, nickel, manganese and cobalt metal elements have all reached 100% leaching. The surface of the NMC111 positive electrode before and after the reaction was characterized by scanning electron microscopy (SEM). Figure 7 As shown, it was found that NMC111 particles were evenly distributed on the surface of the electrode before the reaction, and the particles on the surface of the electrode disappeared after the reaction, and pits appeared where the particles were originally located, proving that NMC111 has been completely leached.

[0063] Example 4

[0064] Spontaneous recovery of lithium manganate is achieved by electrical contact between metallic iron and lithium manganate in ammonium chloride solution:

[0065] (1) Soak the waste lithium manganese oxide battery in a 5wt% NaCl solution and discharge it to a voltage of 1V. After disassembly, the lithium manganese oxide pole piece is obtained. After removing the current collector and crushing it, lithium manganese oxide black powder is obtained. The lithium manganese oxide black powder is mixed with iron powder in a ratio of 1:3, and 1-2 g of the mixed powder is taken;

[0066] (2) Place the mixed powder obtained in step (1) in a beaker and add 50 mL of distilled water into the reactor;

[0067] (3) Add 0.5 g of ammonium chloride solid to the reactor in step (2) and stir to dissolve;

[0068] (4) setting the temperature of step (3) to 50° C., stirring the reaction for 12 hours, and filtering the solid impurities to obtain a metal-enriched solution;

[0069] (5) In step (4), NaOH is first added to the metal enrichment solution to adjust the pH to 10-14, so that the transition metal forms hydroxides and then precipitates together and is filtered, and then carbonate is added to Li + Precipitated as Li2CO3.

[0070] The leaching rate of lithium manganese from lithium manganate was characterized by ICP. The leaching efficiency curve of lithium manganese from lithium manganate after 12 hours of contact reaction between lithium manganate and iron in ammonium chloride solution is shown in Figure 2. Figure 8 As shown, the lithium leaching efficiency is high, and it has been completely leached in 8 hours, while manganese has also reached 100% leaching after 12 hours.

[0071] Comparative Example 1

[0072] The waste lithium cobalt oxide is leached, and the other steps are the same as those in Example 1, the only difference being that the current collector aluminum of the waste battery is removed. Fig. 9 The comparison of lithium cobalt leaching efficiency under the condition of leaching for 32 hours with and without current collector is shown. In the case of leaching without current collector, after leaching for 32 hours, lithium is only leached 2.215% and cobalt is only leached 0.445. The difference between Example 1 and Comparative Example 1 is whether there is a current collector, which leads to the difference in the leaching rate of valuable metal elements. The role of the current collector is to provide electrons to the transition metal of the waste battery, prompting its reduction leaching. At the same time, the reduction of the high-valent transition metal promotes the hydrogen-lithium exchange process. Therefore, under the condition of the current collector, the lithium cobalt leaching efficiency is close to 100%, while in the case of no current collector, the leaching efficiency is very low.

[0073] Comparative Example 2

[0074] The waste lithium manganese oxide was leached, and the other steps were the same as those in Example 4, except that the waste lithium manganese oxide black powder was no longer mixed with iron powder, and the black powder was directly immersed in ammonium chloride solution for reaction for 12 hours. Fig.10 The leaching effect of the case with and without ferroelectric contact after 12 hours of leaching is compared. In the absence of iron, after 12 hours of leaching, only 1.07% of lithium is leached, and the leaching rate of manganese is 0.53%. The difference between Example 4 and Comparative Example 3 is whether or not there is electrical contact with iron, which leads to the difference in the leaching rate of valuable metal elements. The role of the presence of iron is to provide electrons to the transition metal manganese in the waste battery, promoting its reduction leaching.

[0075] Comparative Example 3

[0076] Fig.11 The conventional method is compared with the specific steps of Example 1. The conventional method is relatively complicated. The present method uses the potential difference between the aluminum foil of the waste battery and the lithium transition metal oxide as the driving force. No additional reducing agent is required, and the use of irritating chemicals is avoided. High-temperature smelting is not required. Water and carbon dioxide act as leaching agents and precipitants at the same time, and the target products of lithium carbonate and cobalt carbonate are obtained in one step.

[0077] Comparative Example 4

[0078] Fig.12 The cost of recycling waste batteries by traditional methods (fire and wet methods) is compared with that of recycling waste batteries by the method in Example 1. The traditional method requires high temperature or strong acid to drive the leaching of valuable metal elements, and then precipitate metal ions by salt. The operation process is cumbersome, and the cost includes waste batteries, chemicals, electricity, and some other costs (this part of the cost includes transportation, storage, management, etc., and this part of the cost of all methods is considered to be the same). Compared with the traditional wet method and fire method, this work does not require high-temperature smelting or chemicals to drive metal ion leaching. Relying on the current collector aluminum to provide electrons as a driving force, spontaneous recovery can be achieved in an environment of water and carbon dioxide. Carbon dioxide also acts as a precipitant, so no additional chemical reagents are required for precipitation, so the cost is low and the economic benefit is high.

[0079] Comparative Example 5

[0080] Fig.13The carbon emissions of waste batteries recovered by traditional methods (pyrometallurgy and hydrometallurgy) are compared with those of waste batteries recovered by the method in Example 1. The traditional method requires high temperature or strong acid to drive the leaching of valuable metal elements, and then salt to precipitate metal ions. The energy consumption and the use of chemicals are converted into corresponding carbon dioxide emissions. Compared with the traditional hydrometallurgy and pyrometallurgy, this work does not require high-temperature smelting or chemicals to drive the leaching of metal ions. Relying on the current collector aluminum to provide electrons as a driving force, spontaneous recovery can be achieved in a water and carbon dioxide environment. Using carbon dioxide as a precipitant not only does not emit carbon dioxide, but also achieves negative carbon recovery.

Claims

1. A method for spontaneously recycling waste lithium batteries through metal electrical contacts, characterized in that: The method comprises the following steps: short-circuiting and disassembling waste lithium batteries to obtain positive electrode active materials and current collectors, making the positive electrode active materials maintain electrical contact with metals, wherein the metals are current collector metals of waste lithium batteries or other metals with a standard electrode potential of less than 1.51 V, immersing the metals and positive electrode active materials that maintain electrical contact in an electrolyte solution to undergo redox reactions, and obtaining metal-enriched solution after leaching lithium ions and transition metal ions; and utilizing a precipitant generated in situ during the leaching process or other precipitants that are added separately to precipitate lithium ions and transition metal ions respectively.

2. The method for spontaneously recycling waste lithium batteries through metal electrical contacts according to claim 1, characterized in that: The method for short-circuiting the waste lithium battery comprises: immersing the waste lithium battery in a salt solution, and discharging until the termination voltage is 0.5-1.5V; the salt solution is a NaCl solution, and the solubility of the salt solution is 4-6wt%.

3. The method for spontaneously recycling waste lithium batteries through metal electrical contacts according to claim 1, characterized in that: The metal is any one or more of aluminum, copper, iron, zinc, magnesium, titanium, chromium, vanadium, nickel, cobalt and manganese.

4. The method for spontaneously recycling waste lithium batteries through metal electrical contacts according to claim 1, characterized in that: The electrical contact method includes at least one of stirring, ultrasound, and ball milling.

5. The method for spontaneously recycling waste lithium batteries through metal electrical contacts according to claim 1, characterized in that: The waste lithium battery includes at least one of lithium manganese oxide, lithium cobalt oxide, nickel aluminum cobalt oxide, and nickel manganese cobalt oxide lithium batteries.

6. The method for spontaneously recycling waste lithium batteries through metal electrical contacts according to claim 1, characterized in that: The electrolyte solution solute is at least one of a soluble gas, an acid, an alkali, and a salt, and the introduction pressure of the soluble gas is 0.1-4 Mpa.

7. The method for spontaneously recycling waste lithium batteries through metal electrical contacts according to claim 1, characterized in that: The in-situ generated precipitant includes CO3 generated in-situ during the reaction after CO2 is introduced as an electrolyte solution. 2- , or OH generated in situ when using alkaline electrolyte solution - The in-situ generated precipitant reacts with the transition metal ions during the leaching process to precipitate the transition metal ions.

8. The method for spontaneously recycling waste lithium batteries through metal electrical contacts according to claim 1, characterized in that: During the precipitation process of adding a precipitant, the pH is first adjusted between 10 and 14 to precipitate transition metal ions. After the transition metal precipitate is filtered, carbonate or phosphate is added to precipitate lithium ions.

9. The method for spontaneously recycling waste lithium batteries through metal electrical contacts according to claim 1, characterized in that: The molar ratio of the positive electrode active material to the metal is 0.1~3:

1.

10. The method for spontaneously recycling waste lithium batteries through metal electrical contacts according to claim 1, characterized in that: The metal and the positive electrode active material that maintain electrical contact are immersed in an electrolyte solution to undergo a redox reaction at a reaction temperature of 25 to 200°C and a reaction time of 1 to 50 hours.

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