Direct regeneration method of waste lithium battery positive electrode material

Abstract

The invention belongs to the field of waste lithium battery recovery and utilization, and particularly relates to a direct regeneration method of a waste lithium battery positive electrode material. The method comprises the following steps: 1) putting a lithium source on one side of a crucible, putting a circular truncated cone on the other side of the crucible, and arranging a waste lithium battery positive electrode material on the circular truncated cone; 2) sealing the crucible in which the lithium source and the waste lithium battery positive electrode material are placed in the step 1); and 3) putting the crucible sealed in the step 2) into a muffle furnace, heating to 850-900 DEG C, cooling to room temperature after reaction, and grinding the powder obtained in the crucible to obtain the repaired positive electrode powder. The regeneration method disclosed by the invention has the characteristics of simple process, low energy consumption, rapidness and the like, does not need to mix a lithium source with a waste lithium battery positive electrode material, does not need a secondary annealing step, can be applied to direct regeneration of a lithium cobalt oxide positive electrode, and also can be applied to direct regeneration of a waste ternary nickel-cobalt-manganese material and a waste lithium iron phosphate positive electrode.

Description

Technical Field

[0001] The invention belongs to the field of recycling and utilizing waste lithium batteries, and in particular relates to a method for directly regenerating waste lithium battery positive electrode materials. Background Art

[0002] With the rapid development of the global electric vehicle industry and the widespread popularity of portable electronic devices, the market demand for lithium-ion batteries as a core power source has shown explosive growth. However, this has also led to a sharp increase in the number of discarded lithium-ion batteries. The cycle life of lithium-ion batteries is generally only 8-10 years. It is estimated that the number of discarded lithium-ion batteries in the world will exceed 11 million tons by 2030, but currently less than 5% of discarded lithium batteries have been processed. If discarded lithium-ion batteries are not properly disposed of, it will not only cause serious waste of rare metal resources such as lithium, cobalt, and nickel, but may also cause significant pollution to the environment. Therefore, the efficient, environmentally friendly and economical recycling of discarded lithium battery positive electrode materials has become a key issue that needs to be urgently addressed in the current battery industry.

[0003] Traditional methods for regenerating waste lithium battery cathodes have many drawbacks. For example, some methods require a complex mixing operation of the lithium source and waste cathode powder, a process that not only consumes a lot of manpower and time, but also makes it difficult to ensure the uniformity of the mixing, which directly affects the performance of the recycled material. In addition, many traditional processes often require a secondary annealing step, which undoubtedly increases the energy consumption and time cost of the entire regeneration process and reduces production efficiency.

[0004] In the existing lithium cobalt oxide positive electrode regeneration technology, there are common problems of complex processes and cumbersome operations. Some methods require the use of a large amount of chemical reagents for pretreatment and post-treatment, which not only increases costs, but also may introduce impurities and affect the quality of the regenerated materials. Moreover, these methods are not ideal for lattice repair, and it is difficult to restore the lithium-cobalt ratio to the ideal 1:1 state, thus limiting the electrochemical performance of the regenerated lithium cobalt oxide.

[0005] The regeneration of waste ternary nickel-cobalt-manganese materials, waste lithium iron phosphate positive electrodes and waste lithium manganese oxide positive electrodes also faces similar difficulties. Existing regeneration technologies are difficult to achieve effective repair and improvement of material structure and performance while ensuring efficient regeneration. At the same time, traditional methods also have great limitations in achieving functional modifications of positive electrode materials and cannot meet the market's diverse needs for high-performance battery materials.

[0006] In summary, it is of great practical significance to develop a method that is simple in process, low in energy consumption, fast and efficient, and can directly regenerate a variety of waste lithium battery positive electrode materials and is expected to achieve functional modification during the regeneration process. Summary of the invention

[0007] In view of the above-mentioned disadvantages of the prior art, the object of the present invention is to provide a direct regeneration method for waste lithium-ion battery cathode materials, an innovative method for directly regenerating waste lithium-ion battery cathodes by sublimating the lithium source through one-step heating, aiming to overcome the deficiencies of the prior art and open up a new energy-saving and efficient way for the recycling of waste lithium-ion battery cathode materials.

[0008] The technical solution of the present invention is as follows:

[0009] On the one hand, the present invention provides a direct regeneration method for waste lithium-ion battery cathode materials, and the method includes the following steps:

[0010] 1) Place the lithium source on one side of the crucible, and place a frustum on the other side of the crucible, and the waste lithium-ion battery cathode material is provided on the frustum;

[0011] 2) Seal the crucible in which the lithium source and the waste lithium-ion battery cathode material are placed in step 1);

[0012] 3) Place the sealed crucible in a muffle furnace, heat it to 850 - 900 °C, cool it to room temperature after the reaction, and grind the powder obtained in the crucible to obtain the repaired cathode powder.

[0013] On the other hand, the present invention also provides a repaired cathode powder, which is prepared by using the direct regeneration method for waste lithium-ion battery cathode materials as described above in the present invention.

[0014] By adopting the foregoing technical solution, the beneficial effects of the present invention are as follows:

[0015] The present invention provides a method for directly regenerating waste lithium-ion battery cathode materials by sublimating the lithium source through one-step high temperature. In the present invention, the lithium source and the waste lithium-ion battery cathode material are separately placed in a sealed crucible, and by heating to 850 - 900 °C, the replenishment of active lithium and the lattice repair in the waste lithium-ion battery cathode material are realized. This regeneration method has the characteristics of simple process, low energy consumption, and rapidity. There is no need to mix the lithium source and the waste lithium-ion battery cathode material, and there is no step of secondary annealing. It can not only be applied to the direct regeneration of lithium cobalt oxide cathodes, but also be used for the direct regeneration of waste ternary nickel cobalt manganese materials, waste lithium iron phosphate cathodes, and waste lithium manganese oxide cathodes. At the same time, it is also expected to use this method to realize the functional modification of the cathode material during regeneration. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a photo of the device for repairing the cathode of the present invention.

[0017] Figure 2 It is a morphology diagram of the regenerated lithium cobalt oxide cathode material in Example 1 of the present invention. Figure 2 a and Figure 2 b respectively show the focused ion beam cross-section SEM images of the waste LCO and the repaired LCO,Figure 2 c is the repaired LiCoO 2 Overall morphology (10 μm), Figure 2 d is the repaired LiCoO 2 Overall morphology (2 μm).

[0018] Figure 3 This is the XRD comparison chart of the discarded LCO and the repaired LCO in Example 1 of the present invention.

[0019] Figure 4 This is the CV curve chart of LCO before and after repair in Example 1 of the present invention.

[0020] Figure 5 This is the comparison chart of the discharge specific capacity of the discarded LCO and the repaired LCO in Example 1 of the present invention.

[0021] Figure 6 c is the repaired LiCoO in Example 2 of the present invention 2 SEM image.

[0022] Figure 7 This is the XRD comparison chart of the discarded LCO and the repaired LCO in Example 2 of the present invention.

[0023] Figure 8 c is the repaired LiCoO in Example 3 of the present invention 2 SEM image.

[0024] Figure 9 This is the XRD comparison chart of the discarded LCO and the repaired LCO in Example 3 of the present invention.

[0025] Figure 10 c is the repaired LiCoO in Example 4 of the present invention 2 SEM image.

[0026] Figure 11 This is the XRD comparison chart of the discarded LCO and the repaired LCO in Example 4 of the present invention.

[0027] Figure 12 This is the SEM image of the repaired NCM523 obtained in Example 5 of the present invention.

[0028] Figure 13 This is the XRD comparison chart of the discarded NCM523 and the repaired NCM523 in Example 5 of the present invention.

[0029] Figure 14 This is the SEM image of the repaired NCM523 obtained in Example 6 of the present invention.

[0030] Figure 15XRD comparison diagram of the discarded NCM523 and the repaired NCM523 in Example 6 of the present invention.

[0031] Figure 16 SEM diagram of the repaired NCM523 obtained in Example 7 of the present invention.

[0032] Figure 17 XRD comparison diagram of the discarded NCM523 and the repaired NCM523 in Example 7 of the present invention.

[0033] Figure 18 SEM diagram of the repaired LMO in Example 8 of the present invention.

[0034] Figure 19 XRD comparison diagram of the discarded LMO and the repaired LMO in Example 8 of the present invention.

[0035] Figure 20 XRD diagram of the repaired LCO in Comparative Example 1 of the present invention, including an inset which is the XRD comparison diagram of the discarded LCO and the repaired LCO.

[0036] Figure 21 XRD diagram of the repaired LCO in Comparative Example 2 of the present invention, including an inset which is the XRD comparison diagram of the discarded LCO and the repaired LCO.

[0037] Figure 22 XRD diagram of the repaired LCO in Comparative Example 3 of the present invention, including an inset which is the XRD comparison diagram of the discarded LCO and the repaired LCO. Detailed implementation manners

[0038] Hereinafter, the implementation manners of the direct regeneration method for waste lithium-ion battery cathode materials provided by the present invention will be described in detail.

[0039] The "range" disclosed in this application is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a specific range. The ranges defined in this way can include or exclude the end values, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, ranges of 60-110 and 80-120 are understood to be anticipated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all anticipated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise specified, the numerical range "a~b" represents an abbreviated representation of any real number combination between a and b, where both a and b are real numbers. For example, the numerical range "0~5" means that all real numbers between "0~5" have been fully listed herein, and "0~5" is only an abbreviated representation of these numerical combinations. Additionally, when stating that a certain parameter is an integer ≥2, it is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0040] Through a large amount of exploration and research, the inventors of the present invention have provided a method for directly regenerating waste lithium-ion battery cathode materials by sublimating a lithium source at high temperature in one step. In the present invention, the lithium source and the waste lithium-ion battery cathode materials are separately placed in a sealed crucible, and by heating to 850-900°C, the replenishment of active lithium and the lattice repair in the waste lithium-ion battery cathode materials are achieved. This regeneration method has the characteristics of simple process, low energy consumption, and rapidity. There is no need to mix the lithium source and the waste lithium-ion battery cathode materials, and there is no step of secondary annealing. It can not only be applied to the direct regeneration of lithium cobalt oxide cathodes, but also be used for the direct regeneration of waste ternary nickel cobalt manganese materials, waste lithium iron phosphate cathodes, and waste lithium manganate cathodes. At the same time, it is also expected to use this method to achieve functional modification of the cathode materials during regeneration. On this basis, this application has been completed.

[0041]

Method for Direct Regeneration of Waste Lithium-Ion Battery Cathode Materials

[0042] On the one hand, the present invention provides a method for directly regenerating waste lithium-ion battery cathode materials, and the method includes the following steps:

[0043] 1) Place the lithium source on one side of the crucible, and place a frustum on the other side of the crucible, and the waste lithium-ion battery cathode materials are provided on the frustum;

[0044] 2) Seal the crucible in which the lithium source and the waste lithium-ion battery cathode materials are placed in step 1);

[0045] 3) Put the crucible sealed in step 2) into a muffle furnace, heat it up to 850 - 900 °C, cool it to room temperature after the reaction, and grind the powder obtained in the crucible to obtain the repaired positive electrode powder.

[0046] In the direct regeneration method of waste lithium - ion battery positive electrode materials provided by the present invention, in step 1), a lithium source is placed on one side of the crucible, and a frustum is placed on the other side of the crucible, and the waste lithium - ion battery positive electrode material is provided on the frustum.

[0047] In step 1) of the present invention, the mass ratio of the lithium source to the waste lithium - ion battery positive electrode material is (1 - 2):1. Optionally, it can be (1 - 1.5):1 or (1.5 - 2):1.

[0048] In step 1) of the present invention, the lithium source is selected from Li 2 CO 3 、LiOH、CH 3 COOLi、C 4 H 5 O 6 Li, or one or more of them. It provides lithium for the subsequent repair of waste lithium cobalt oxide powder. The present invention can use different lithium sources (LiOH, Li 2 CO 3 、CH 3 COOLi) for repair. The lithium source is mainly selected according to the melting point. The melting point of LiOH is 680 °C, the melting point of Li 2 CO 3 is 618 °C, the melting point of CH3COOLi is 283 °C, and the melting point of C 4 H 5 O 6 Li is 61 °C.

[0049] In step 1) of the present invention, the waste lithium - ion battery positive electrode material is selected from one or more of waste lithium cobalt oxide powder, waste ternary material powder, waste lithium iron phosphate positive electrode, and waste lithium manganate positive electrode. Optionally, the waste ternary material is selected from waste LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 powder, waste LiNi 0.5 Co 0.2 Mn 0.3 O 2 powder, waste LiNi 0.6 Co 0.2 Mn 0.2 O 2 powder, or one or more of them.

[0050] In step 1) of the present invention, the crucible is a magnesium oxide crucible. Optionally, the size of the magnesium oxide crucible is (40 - 80 mm) * (40 - 80 mm) * (30 - 80 mm). In a specific embodiment, a magnesium oxide crucible of appropriate size (40×60×30 cm 3 ) is selected to ensure its cleanliness and no damage, so as to ensure the sealing and stability of the experimental process.

[0051] In step 1) of the present invention, on the one hand, the frustum can prevent the Li 2 CO 3 powder from contacting with lithium cobaltate after melting during heating, avoiding unnecessary mixing of the two and affecting the repair effect; on the other hand, it can prevent lithium cobaltate from contaminating the crucible, ensuring the purity of the experimental environment and the reuse of the subsequent crucible. In a specific embodiment, the frustum is a magnesium oxide frustum.

[0052] In step 1) of the present invention, the waste lithium-ion battery cathode material is ground thoroughly. The purpose of grinding is to reduce agglomeration and increase the specific surface area of the powder, so that the lithium-ion battery cathode material can contact with the sublimated lithium source more fully during the subsequent repair process, improving the repair efficiency and effect. The ground lithium cobaltate waste powder is spread out on the magnesium oxide frustum.

[0053] In the direct regeneration method of the waste lithium-ion battery cathode material provided by the present invention, step 2) is to seal the crucible in which the lithium source and the waste lithium-ion battery cathode material are placed in step 1). Ensure that the whole experimental process is in a relatively closed environment to prevent foreign impurities from entering, and it is also conducive to the full reaction of the sublimated lithium source with the waste lithium-ion battery cathode material in the crucible.

[0054] In the direct regeneration method of the waste lithium-ion battery cathode material provided by the present invention, step 3) is to put the sealed crucible into a muffle furnace, heat it to 850 - 900 °C, cool it to room temperature after the reaction, and grind the powder obtained in the crucible to obtain the repaired cathode powder.

[0055] In step 3) of the present invention, it is heated to 850 - 900 °C in air at a heating rate of 3 - 8 °C / min. Optionally, the heating rate can be, for example, 3 - 5 °C / min or 5 - 8 °C / min. Within the above heating rate range, a relatively slow and stable heating rate can make the lithium source (such as Li 2 CO 3 etc.) and the waste lithium-ion battery cathode material (such as lithium cobaltate waste powder, etc.) be heated evenly, avoiding abnormal changes in the internal structure of the material caused by too fast heating and affecting the repair effect. Within the above temperature range, the lithium source can sublimate sufficiently and react effectively with the waste lithium-ion battery cathode material to achieve the replenishment of active lithium and lattice repair. In a specific embodiment, when the lithium source is Li 2 CO 3, when the waste lithium-ion battery cathode material is waste lithium cobalt oxide powder, 900 °C is the optimal reaction temperature verified by a large number of experiments. At this temperature, Li 2 CO 3 can be fully sublimated, react effectively with the waste lithium cobalt oxide, and achieve the replenishment of active lithium and lattice repair.

[0056] In step 3) of the present invention, after heating, heat preservation is carried out, and the heat preservation time is 2 to 5 h, and can be selected as 2 to 3 h, 2 to 4 h, 3 to 4 h or 3 to 5 h. The sublimated lithium source within the above range can continuously provide lithium elements for the waste lithium-ion battery cathode material, react with the defective parts in the lattice of the waste lithium-ion battery cathode material, gradually repair the lattice structure, and restore the lithium-cobalt ratio to the ideal state of 1:1.

[0057] In step 3) of the present invention, after the heat preservation is completed, wait for the crucible to cool to room temperature, and grind the powder obtained in the crucible again. The purpose of this grinding step is to disperse the powder particles, make the repaired lithium cobalt oxide powder have better uniformity and dispersibility, and is more conducive to subsequent characterization. Through this series of operations, the repaired cathode powder is obtained.

[0058] In step 3) of the present invention, in the repaired cathode powder, the lithium-cobalt molar ratio is 0.98 to 1.05:1. It can be selected as 0.98 to 1:1, 1 to 1.05:1. Preferably 1:1.

[0059]

Repaired Cathode Powder

[0060] The present invention also provides a repaired cathode powder, which is prepared by using the direct regeneration method of the waste lithium-ion battery cathode material as described above in the present invention.

[0061] The beneficial effects of the present invention are further described below in conjunction with embodiments.

[0062] In order to make the invention purpose, technical solution and beneficial technical effects of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. However, it should be understood that the embodiments of the present invention are only for explaining the present invention, not for limiting the present invention, and the embodiments of the present invention are not limited to the embodiments given in the specification. The specific experimental conditions or operating conditions not specified in the embodiments are made according to the conventional conditions, or according to the conditions recommended by the material suppliers.

[0063] In addition, it should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combined steps or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated; it should also be understood that the combined connection relationship between one or more devices / apparatuses mentioned in the present invention does not exclude the existence of other devices / apparatuses before and after the combined devices / apparatuses or the insertion of other devices / apparatuses between these two explicitly mentioned devices / apparatuses, unless otherwise stated. Moreover, unless otherwise stated, the numbers of the method steps are only convenient tools for identifying the method steps, rather than limiting the arrangement order of the method steps or the scope in which the present invention can be implemented. The change or adjustment of their relative relationship, without substantially changing the technical content, should also be regarded as the scope in which the present invention can be implemented.

[0064] In the following embodiments, unless otherwise specified, various raw materials of the present invention can be commercially purchased or prepared according to conventional methods in the art.

[0065] Example 1: (Li 2 CO 3 lithium source)

[0066] Prepare 0.3 g of Li 2 CO 3 powder and 0.3 g of ground waste LiCoO 2 powder (LiCoO 2 , abbreviated as LCO). At the same time, prepare a magnesia crucible with a lid and a magnesia frustum. Place the Li 2 CO 3 powder on one side of the crucible, and disperse the waste LCO powder on the frustum and then place it on the other side in the magnesia crucible. During this process, ensure that Li 2 CO 3 and LCO are not in contact. The specific device diagram is shown in Figure 1 . Place the crucible in a muffle furnace, set the heating program to heat up to 900 °C at a rate of 5 °C / min, keep it at this temperature for 5 h, and then cool it naturally. Take out the crucible. The Li 2 CO 3 has sublimated completely, and there is no residual Li 2 CO 3 . Take out the LCO on the frustum and simply grind it to make the powder disperse evenly. Figure 2 a and Figure 2 b respectively show the focused ion beam cross-section SEM images of the waste LCO and the repaired LCO. It can be clearly observed that there is a serious layer slip phenomenon on the surface of the waste LCO, the structure collapses severely, and there are large cracks inside. After repair, the surface of the LCO becomes smooth and the internal cracks disappear. The overall morphology of the repaired LiCoO 2 is shown in Figure 2 c andFigure 2 d. The repaired particles have a smooth and regular appearance. In addition, Figure 3 The XRD patterns of the discarded LCO and the repaired LCO were compared. The repaired LCO obviously has no impurity phase Co 3 O 4 , has a more obvious layered structure, and the lithium-cobalt ratio is restored to 1:1, proving the replenishment of lithium and the repair of the structure. Figure 4 The CV curves of LCO before and after repair were shown. It was obviously observed that the repaired LCO has smaller polarization and higher peak current, indicating a significant kinetic improvement of LCO. And Figure 5 The repaired LCO was shown to have a higher specific capacity and high-rate stability.

[0067] Example 2: (LiOH lithium source)

[0068] 0.3 g of LiOH·H 2 O powder and 0.3 g of ground discarded LiCoO 2 powder were prepared. At the same time, a magnesia crucible with a lid and a magnesia frustum were prepared. The LiOH·H 2 O powder was placed on one side of the crucible, and the waste LCO powder was dispersed on the frustum and then placed on the other side in the magnesia crucible. During this process, it was ensured that LiOH·H 2 O and LCO were not in contact. See the specific device diagram in Figure 1 . The crucible was placed in a muffle furnace, and the heating program was set to heat up to 900 °C at a rate of 5 °C / min, hold for 5 h, and then cool naturally. After the crucible was taken out, the LiOH·H 2 O had sublimated completely, and there was no residual LiOH·H 2 O. The LCO on the frustum was taken out and simply ground to make the powder disperse evenly. The SEM image of the obtained repaired LiCoO 2 can be seen in Figure 6 . The repaired LCO has a smooth and regular morphology. Figure 7 The XRD patterns of the discarded LCO and the repaired LCO were compared. The repaired LCO obviously has no impurity phase Co 3 O 4 , has a more obvious layered structure, and the lithium-cobalt ratio is restored to 1:1, proving the replenishment of lithium and the repair of the structure.

[0069] Example 3: (CH 3 COOLi lithium source)

[0070] 0.5 g of CH 3 COOLi powder and 0.3 g of ground discarded LiCoO 2 powder were prepared. At the same time, a magnesia crucible with a lid and a magnesia frustum were prepared. The CH 3The COOLi powder is placed on one side of the crucible, and the waste LCO powder is dispersed on the turntable and then placed on the other side in the magnesia crucible. During this process, ensure that CH 3 COOLi and LCO have no contact. See the specific device diagram in Figure 1 . Place the crucible in the muffle furnace, set the heating program to heat up to 850 °C at a rate of 5 °C / min, keep it warm for 5 h and then cool it naturally. Take out the crucible, CH 3 COOLi has completely sublimated, and there is no residual CH 3 COOLi. Take out the LCO on the turntable and simply grind it to make the powder evenly dispersed. The SEM image of the repaired LiCoO 2 can be seen in Figure 8 . The repaired LCO has a smooth and regular morphology. Figure 9 The XRD patterns of the discarded LCO and the repaired LCO were compared. The repaired LCO obviously has no impurity phase Co 3 O 4 , has a more obvious layered structure, and the lithium-cobalt ratio is restored to 1:1, proving the replenishment of lithium and the repair of the structure.

[0071] Example 4: (C 4 H 5 O 6 Li lithium source)

[0072] Prepare 0.6 g of C 4 H 5 O 6 Li powder and 0.3 g of ground waste LiCoO 2 powder. At the same time, prepare a magnesia crucible with a lid and a magnesia turntable. Place the C 4 H 5 O 6 Li powder on one side of the crucible, and disperse the waste LCO powder on the turntable and then place it on the other side in the magnesia crucible. During this process, ensure that C 4 H 5 O 6 Li and LCO have no contact. See the specific device diagram in Figure 1 . Place the crucible in the muffle furnace, set the heating program to heat up to 850 °C at a rate of 3 °C / min, keep it warm for 3 h and then cool it naturally. Take out the crucible, C 4 H 5 O 6 Li has completely sublimated, and there is no residual C 4 H 5 O 6 Li. Take out the LCO on the turntable and simply grind it to make the powder evenly dispersed. The SEM image of the repaired LiCoO 2 can be seen in Figure 10 . The repaired LCO has a smooth and regular morphology.Figure 11 The XRD patterns of the discarded LCO and the repaired LCO were compared. The repaired LCO obviously had no impurity phase of Co 3 O 4 , had a more obvious layered structure, and the lithium-cobalt ratio was restored to 1:1, proving the replenishment of lithium and the repair of the structure.

[0073] Example 5: (Repairing waste LiNi 0.5 Co 0.2 Mn 0.3 O 2 positive electrode)

[0074] Prepare 0.3 g of LiOH·H 2 O powder and 0.3 g of ground waste LiNi 0.5 Co 0.2 Mn 0.3 O 2 powder (LiNi 0.5 Co 0.2 Mn 0.3 O 2 , abbreviated as NCM523). At the same time, prepare a magnesia crucible with a lid and a magnesia frustum. Place the LiOH·H 2 O powder on one side of the crucible, and disperse the waste NCM523 powder on the frustum and then place it on the other side in the magnesia crucible. During this process, ensure that LiOH·H 2 O and NCM523 are not in contact. The specific device diagram is shown in Figure 1 . Place the crucible in a muffle furnace, set the heating program to heat up to 850 °C at a rate of 5 °C / min, keep it at this temperature for 5 h, and then cool it naturally. Take out the crucible. The LiOH·H 2 O has sublimated completely, and there is no residual LiOH·H 2 O. Take out the NCM523 on the frustum and simply grind it to make the powder disperse evenly. The SEM image of the repaired NCM523 obtained is shown in Figure 12 , and the repaired NCM523 has a smooth and regular morphology. Figure 13 The XRD patterns of the discarded NCM523 and the repaired NCM523 were compared. The repaired NCM523 had a lower degree of Li / Ni mixing (I 003 / I 104 was larger).

[0075] Example 6:

[0076] When using Li 2 CO 3 as the lithium source in this example, it is necessary to prepare 0.3 g of Li 2 CO 3 powder and 0.3 g of ground waste NCM523 powder, and place the Li2 CO 3 The powder is placed on one side of the crucible, and the waste NCM523 powder is dispersed on the round table and then placed on the other side in the magnesia crucible. During this process, ensure that Li 2 CO 3 and NCM523 are not in contact. Place the crucible in the muffle furnace, set the heating program to rise to 850 °C at a rate of 5 °C / min, keep it warm for 5 h and then cool naturally. Take out the crucible, Li 2 CO 3 has sublimated completely and there is no residual Li 2 CO 3 . Take out the NCM523 on the round table and simply grind it to make the powder evenly dispersed. The SEM image of the repaired NCM523 is shown in Figure 14 . The repaired NCM523 has a smooth and regular morphology. Figure 15 The XRD patterns of the waste NCM523 and the repaired NCM523 were compared. The repaired NCM523 has a lower degree of Li / Ni mixing (I 003 / I 104 is larger).

[0077] Example 7:

[0078] When using CH 3 COOLi as the lithium source, prepare 0.5 g of CH 3 COOLi powder and 0.3 g of ground waste NCM523 powder. At the same time, prepare a magnesia crucible with a lid and a magnesia round table. Place the CH 3 COOLi powder on one side of the crucible, and disperse the waste NCM523 powder on the round table and then place it on the other side in the magnesia crucible. During this process, ensure that CH 3 COOLi and NCM523 are not in contact. Place the crucible in the muffle furnace, set the heating program to rise to 800 °C at a rate of 5 °C / min, keep it warm for 5 h and then cool naturally. Take out the crucible, CH 3 COOLi has sublimated completely and there is no residual CH 3 COOLi. Take out the NCM523 on the round table and simply grind it to make the powder evenly dispersed. The SEM image of the repaired NCM523 is shown in Figure 16 . The repaired NCM523 has a smooth and regular morphology. Figure 17 The XRD patterns of the waste NCM523 and the repaired NCM523 were compared. The repaired NCM523 has a lower degree of Li / Ni mixing (I 003 / I 104 is larger).

[0079] Example 8: (Repairing waste LiMn 2 O4 Positive electrode)

[0080] In this example, when using Li 2 CO 3 as the lithium source, 0.3 g of Li 2 CO 3 powder and 0.3 g of ground waste LiMn 2 O 4 powder (LiMn 2 O 4 , abbreviated as LMO) were prepared. At the same time, a magnesia crucible with a lid and a magnesia frustum were prepared. The Li 2 CO 3 powder was placed on one side of the crucible, and the waste LMO powder was dispersed on the frustum and then placed on the other side in the magnesia crucible. During this process, it was ensured that Li 2 CO 3 and LMO were not in contact. The crucible was placed in a muffle furnace, and the heating program was set to heat up to 800 °C at a rate of 5 °C / min, hold for 5 h, and then cool naturally. After the crucible was taken out, Li 2 CO 3 had sublimated completely, and there was no residual Li 2 CO 3 . The LMO on the frustum was taken out and simply ground to make the powder disperse evenly. The SEM image of the repaired LMO obtained is shown in Figure 18 . The repaired LMO has a smooth and regular morphology. Figure 19 The XRD patterns of the waste LMO and the repaired LMO were compared. The XRD peaks of the repaired LMO have more significant spinel characteristics.

[0081] Comparative Example 1:

[0082] In this example, when using Li 2 O as the lithium source, 0.3 g of Li 2 O powder and 0.3 g of ground waste LCO powder were prepared. At the same time, a magnesia crucible with a lid and a magnesia frustum were prepared. The Li 2 O powder was placed on one side of the crucible, and the waste LCO powder was dispersed on the frustum and then placed on the other side in the magnesia crucible. During this process, it was ensured that Li 2 O and LCO were not in contact. The crucible was placed in a muffle furnace, and the heating program was set to heat up to 1100 °C at a rate of 5 °C / min, hold for 2 h, and then cool naturally. After the crucible was taken out, Li 2 O had sublimated completely, and there was no residual Li 2 O. The LCO on the frustum was taken out and simply ground to make the powder disperse evenly. It can be seen from the SEM image ( Figure 20 ) that the repaired LCO has many impurities, and the particle shape is irregular, and there is an obvious tendency to agglomerate. Figure 20The embedded diagram compares the XRD patterns of the discarded LCO and the repaired LCO. The XRD peaks of the repaired LCO are less crystalline and there is still Co 3 O 4 impurity present.

[0083] Comparative Example 2:

[0084] In this example, Li 2 CO 3 is used as the lithium source. 0.3 g of Li 2 CO 3 powder and 0.3 g of ground discarded LiCoO 2 powder are prepared. At the same time, a magnesia crucible with a lid and a magnesia frustum are prepared. The Li 2 CO 3 powder is placed on one side of the crucible, and the waste LCO powder is dispersed on the frustum and then placed on the other side in the magnesia crucible. During this process, it is ensured that Li 2 CO 3 and LCO are not in contact. The specific device diagram is shown in Figure 1 . The crucible is placed in a muffle furnace, and the heating program is set to heat up to 800 °C at a rate of 5 °C / min, hold for 5 h, and then cool naturally. After the crucible is taken out, the Li 2 CO 3 has sublimated completely and there is no residual Li 2 CO 3 . The LCO on the frustum is taken out and simply ground to make the powder disperse evenly. The SEM image of the repaired LiCoO 2 is shown in Figure 21 . The repaired LCO still has more unfavorable spinel and rock salt phases, and there are more surface impurities. This may be because the repair temperature is relatively low and the lithium salt does not have enough kinetics to enter the lattice, and the structure repair is not achieved. Figure 21 The embedded diagram compares the XRD patterns of the discarded LCO and the repaired LCO. The repaired LCO still has the impurity phase Co 3 O 4 , indicating that the LCO structure has not been fully restored.

[0085] Comparative Example 3:

[0086] In this example, Li 2 CO 3 is used as the lithium source. 0.1 g of Li 2 CO 3 powder and 0.5 g of ground discarded LiCoO 2 powder are prepared. At the same time, a magnesia crucible with a lid and a magnesia frustum are prepared. The Li 2 CO 3The powder is placed on one side of the crucible, and the waste LCO powder is spread on the round table and placed on the other side of the magnesium oxide crucible. 2 CO 3 No contact with LCO, see the specific device diagram Figure 1 Place the crucible in a muffle furnace, set the temperature program to 5℃ / min and heat to 900℃, keep it for 5h and then cool it naturally. 2 CO 3 Sublimation is complete, no residual Li 2 CO 3 , take out the LCO on the round table, grind it simply to make the powder dispersed evenly, and get the repaired LiCoO 2 See SEM images of Figure 22 The repaired LCO still shows significant spinel and rock salt phase morphology, and there are many impurities on the surface, indicating that the structure has not been repaired. Analysis may be due to insufficient lithium source, so that complete lithium replenishment has not been achieved, and long-term lithium-deficient environment at high temperature may lead to further deterioration of the structure. Figure 22 The inset image compares the XRD patterns of the abandoned LCO and the repaired LCO. The repaired LCO still has the impurity phase Co 3 O 4 , indicating that the LCO structure has not been fully restored.

[0087] In summary, the present invention effectively overcomes various shortcomings of the prior art and has high industrial utilization value.

[0088] The above is only a preferred embodiment of the present invention, and is not any formal or substantial limitation of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention, and these improvements and supplements should also be regarded as the protection scope of the present invention. Any technician familiar with this profession, without departing from the spirit and scope of the present invention, can make some changes, modifications and evolutions of the technical content disclosed above, which are equivalent embodiments of the present invention; at the same time, any changes, modifications and evolutions of any equivalent changes made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A direct regeneration method for waste lithium battery positive electrode materials, characterized in that: The method comprises the following steps: 1) placing a lithium source on one side of the crucible and placing a truncated table on the other side of the crucible, wherein the truncated table is provided with waste lithium battery positive electrode materials; 2) sealing the crucible in which the lithium source and the waste lithium battery positive electrode material are placed in step 1); 3) placing the sealed crucible in step 2) into a muffle furnace, heating it to 850-900° C., cooling it to room temperature after the reaction, and grinding the powder obtained in the crucible to obtain a repaired positive electrode powder.

2. The direct regeneration method of waste lithium battery positive electrode materials according to claim 1, characterized in that: In step 1), the mass ratio of the lithium source to the waste lithium battery positive electrode material is (1-2):

1.

3. The direct regeneration method of waste lithium battery positive electrode materials according to claim 1, characterized in that: In step 1), the lithium source is selected from one or more of Li2CO3, LiOH, CH3COOLi, and C4H5O6Li.

4. The direct regeneration method of waste lithium battery positive electrode materials according to claim 1, characterized in that: In step 1), the waste lithium battery positive electrode material is selected from one or more of waste lithium cobalt oxide powder, waste ternary material powder, waste lithium iron phosphate positive electrode, and waste lithium manganese oxide positive electrode.

5. The direct regeneration method of waste lithium battery positive electrode materials according to claim 4, characterized in that: In step 1), the waste ternary material is selected from waste LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 powder, waste LiNi 0.5 Co 0.2 Mn 0.3 O2 powder, waste LiNi 0.6 Co 0.2 Mn 0.2 One or more of O2 powder.

6. The direct regeneration method of waste lithium battery positive electrode materials according to claim 1, characterized in that: Also includes any one or more of the following features: A1) In step 1), the waste lithium battery positive electrode material is ground; A2) In step 1), the crucible is a magnesium oxide crucible; A3) In step 1), the truncated cone is a magnesium oxide truncated cone.

7. The direct regeneration method of waste lithium battery positive electrode materials according to claim 6, characterized in that: In feature A2), the size of the magnesium oxide crucible is (40-80 mm)*(40-80 mm)*(30-80 mm).

8. The direct regeneration method of waste lithium battery positive electrode materials according to claim 1, characterized in that: Also includes any one or more of the following features: B1) In step 3), the temperature is raised to 850-900°C in air at a heating rate of 3-8°C / min; B2) In step 3), the temperature is raised and then kept warm for 2 to 5 hours.

9. The direct regeneration method of waste lithium battery positive electrode materials according to claim 1, characterized in that: In step 3), the molar ratio of lithium to cobalt in the repaired positive electrode powder is 0.98 to 1.05:

1.

10. A repaired positive electrode powder, characterized in that: The waste lithium battery positive electrode material is prepared by the direct regeneration method according to any one of claims 1 to 9.

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