Positive electrode active material and processing method thereof, positive electrode plate, battery and electric device

Abstract

The invention discloses a positive active material and a processing method thereof, a positive pole piece, a battery and an electric device, and belongs to the technical field of batteries. The treatment method comprises the following steps: adding an original positive electrode active material into an acid solution to obtain slurry; and carrying out stirring treatment and ultrasonic treatment on the slurry to obtain the acidic modified positive electrode active material. The technical scheme provided by the embodiment of the invention is beneficial to improving the rate capability of the battery monomer.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a positive electrode active material and a processing method thereof, a positive electrode sheet, a battery, and an electrical device. Background Art

[0002] As environmental pollution becomes increasingly serious, the new energy industry has attracted more and more attention. In the new energy industry, battery technology is an important factor related to its development.

[0003] The development of battery technology needs to consider many design factors, such as energy density, cycle life, reliability, etc. The positive electrode active material in the battery cell is crucial to the rate performance of the battery cell, and the performance of the positive electrode active material is related to the processing method of the positive electrode active material. Therefore, how to provide a processing method for the positive electrode active material to improve the rate performance of the battery cell is a technical problem that needs to be solved urgently. Summary of the invention

[0004] The present application is made in view of the above-mentioned problems, and its purpose is to provide a method for treating a positive electrode active material to improve the rate performance of a battery cell.

[0005] In order to achieve the above-mentioned objectives, the present application provides a positive electrode active material and a processing method thereof, a positive electrode sheet, a battery, and an electrical device.

[0006] In a first aspect, a method for treating a positive electrode active material is provided, comprising: adding an original positive electrode active material to an acidic solution to obtain a slurry; and stirring and ultrasonically treating the slurry to obtain an acid-modified positive electrode active material.

[0007] In the embodiment of the present application, the acid can react with the alkaline impurities on the surface of the original positive electrode active material, thereby removing the alkaline impurities on the surface of the original positive electrode active material to a certain extent. Stirring the slurry is conducive to the contact between the original positive electrode active material and the acid, thereby facilitating the acid to etch the alkaline impurities on the surface of the original positive electrode active material. In addition, ultrasonic treatment of the slurry can utilize the effect of ultrasound to peel off the alkaline impurities from the surface of the original positive electrode active material, which is conducive to further reducing the alkaline impurities on the surface of the original positive electrode active material, and the treated positive electrode active material has a larger surface area, which is conducive to improving the rate performance of the battery cell.

[0008] In a possible implementation, the stirring and ultrasonically treating the slurry to obtain the acid-modified positive electrode active material includes: stirring and ultrasonically treating the slurry; separating and washing the slurry to obtain a washed material; and drying the washed material to obtain the acid-modified positive electrode active material.

[0009] In the above technical scheme, after the slurry is stirred and ultrasonically treated, the impurities and residual lithium on the surface of the original positive electrode active material are reacted and peeled off from the surface of the original positive electrode active material; by separating and washing the slurry, the peeled material can be separated from the acid-modified positive electrode active material to obtain the washed material; the washed material is dried to obtain the acid-modified positive electrode active material.

[0010] In a possible implementation, the method further includes: etching the acid-modified positive electrode active material using a laser to obtain a treated positive electrode active material.

[0011] In the above technical solution, laser etching of the acid-modified positive electrode active material can further increase the specific surface area of ​​the positive electrode active material, so that the surface of the positive electrode active material can have more active sites, which is beneficial to further improve the rate performance of the battery cell.

[0012] In a possible implementation, the power P of the laser satisfies: 800 W≤P≤1200 W, and the pulse time t1 of the laser satisfies 0.2 s≤t1≤0.5 s; optionally, 900 W≤P≤1000 W, 0.4 s≤t1≤0.5 s.

[0013] In the above technical solution, by setting the laser power and pulse time to meet the above range, it is possible to reduce the risk of difficulty in etching the surface of the positive electrode active material due to insufficient laser power and short pulse time, and to reduce the risk of adverse effects on the positive electrode active material due to excessive laser power and long pulse time.

[0014] In a possible implementation, the acidic solution includes a solvent, and the solvent includes an organic alcohol; optionally, the organic alcohol includes at least one of methanol, ethanol or ethylene glycol.

[0015] In the above technical solution, the acid in the acidic solution can be dissolved in the organic alcohol, so that the acid can fully contact and react with the residual lithium, alkaline impurities, etc. In addition, compared with the use of aqueous solvents, the use of organic alcohols as solvents can better remove the solvent in the subsequent process and can also reduce the risk of introducing water into the battery cells.

[0016] In a possible implementation, based on the total mass of the acidic solution, the mass content A of the acid in the acidic solution satisfies: 1000ppm≤A≤8000ppm; alternatively, A satisfies: 1000ppm≤A≤4000ppm. By setting the mass content of the acid to meet the above range, the acid can react fully with the residual lithium and alkaline impurities, and other risks caused by excessively high mass content of the acid can be reduced.

[0017] In a possible implementation, the frequency F of the ultrasonic treatment satisfies: 100kHz≤F≤250kHz; optionally, 100kHz≤F≤200kHz. By setting the frequency of the ultrasonic treatment to meet the above range, both the alkaline impurities and residual lithium on the surface of the positive electrode active material can be stripped from the surface of the positive electrode active material, and the adverse effects of excessively high frequency on the positive electrode active material can be reduced.

[0018] In a possible implementation, the rotation speed V of the stirring treatment satisfies: 200r / min≤V≤500r / min, and the time t2 of the stirring treatment satisfies: 10min≤t2≤60min; optionally, 200r / min≤V≤300r / min, 10min≤t2≤30min. By setting the rotation speed and time of the stirring treatment to meet the above range, it is beneficial for the acid to fully contact with the positive electrode active material, thereby facilitating the reaction of the acid with the alkaline impurities and residual lithium, thereby facilitating the reduction of the content of alkaline impurities and residual lithium on the surface of the positive electrode active material.

[0019] In a possible implementation, based on the total mass of the slurry, a ratio B of the mass content of the original positive electrode active material to the mass content of the solution satisfies: 0.3≤B≤0.5.

[0020] In the above technical scheme, when B is not less than 0.3, the mass content of the acid in the solution is relatively appropriate, which can reduce the adverse effects caused by excessive acid compared to the original positive electrode active material; when B is not greater than 0.5, it is easy to mix the original positive electrode active material and the solution evenly, which is beneficial to the reaction of the acid with alkaline impurities and residual lithium.

[0021] In a possible implementation, the stirring and ultrasonic treatment of the slurry to obtain the acid-modified positive electrode active material includes: stirring and ultrasonic treatment of the slurry at the same time to obtain the acid-modified positive electrode active material. In this way, while the acid reacts with the alkaline impurities and residual lithium, the alkaline impurities and residual lithium can be stripped from the surface of the positive electrode active material by ultrasound, so that the content of alkaline impurities and residual lithium on the surface of the positive electrode active material can be reduced in a shorter time.

[0022] In a possible implementation, the acid in the acidic solution includes at least one of boric acid, formic acid, acetic acid, or hydrochloric acid. The above acids can react well with alkaline impurities, thus having a good effect on removing alkaline impurities.

[0023] In a possible implementation, the positive electrode active material includes at least one of a positive electrode active material with a layered structure or a positive electrode active material with a spinel structure. Due to the influence of the preparation process, substances such as alkaline impurities and residual lithium are likely to exist on the surface of the materials with the above structures. By using the above method to treat the positive electrode active material, it is convenient to obtain a positive electrode active material with less residual lithium and alkaline impurities and a higher specific surface area, which is conducive to improving the rate performance of the battery cell.

[0024] In a second aspect, a positive electrode active material is provided, and the positive electrode active material is obtained by the treatment method in the first aspect and any one of its possible implementation manners.

[0025] In a possible implementation, the pH value of the positive electrode active material satisfies: 11 < pH ≤ 12. The pH value of the positive electrode active material can reflect the content of residual lithium and alkaline impurities on the surface of the positive electrode active material. Compared with the positive electrode active material without removing residual lithium and alkaline impurities, the pH value of the positive electrode active material in this implementation is lower, so the content of alkaline impurities and residual lithium on the surface of the positive electrode active material is less.

[0026] In a possible implementation, based on the total mass of the positive electrode active material, the mass content C of LiOH on the surface of the positive electrode active material satisfies: 30 ppm < C ≤ 80 ppm; the mass content D of Li2CO3 on the surface of the positive electrode active material satisfies: 1400 ppm < D ≤ 1700 ppm. In this way, the content of residual lithium on the surface of the positive electrode active material is less, which is conducive to improving the rate performance of the battery cell.

[0027] In a possible implementation, the specific surface area S1 of the positive electrode active material satisfies: 1.0 cm 2 / g < S1 < 1.3 cm 2 / g. In this way, it is more conducive to the extraction or insertion of active ions from the positive electrode active material, which is conducive to improving the transport rate of active ions and the rate performance of the battery cell.

[0028] In a third aspect, a positive electrode plate is provided, including the positive electrode active material obtained by the preparation method in the first aspect and any one of its possible implementation manners, and / or the positive electrode active material in the second aspect and any one of its possible implementation manners.

[0029] In a possible implementation, the active specific surface area S2 of the positive electrode plate satisfies: 3.6 cm2 / g <S2<3.8cm 2 / g. This is beneficial to improving the rate performance of the battery cell.

[0030] In a fourth aspect, a battery is provided, comprising the battery cell in the third aspect and any possible implementation thereof.

[0031] In a fifth aspect, an electrical device is provided, comprising the battery described in the fourth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without paying creative work.

[0033] Figure 1 A schematic diagram of a method for treating a positive electrode active material according to an embodiment of the present application;

[0034] Figure 2 A schematic diagram of a processing method according to an embodiment of the present application;

[0035] Figure 3 A schematic diagram of a battery cell according to an embodiment of the present application;

[0036] Figure 4 A schematic diagram of a battery according to an embodiment of the present application;

[0037] Figure 5 A schematic diagram of an electrical device according to an embodiment of the present application;

[0038] Figure 6 This is a SEM image of the positive electrode active material of one embodiment of the present application;

[0039] Figure 7 This is a SEM image of a pair of positive electrode active materials of this application;

[0040] Figure 8 The figure is a schematic diagram of the rate performance curve of some embodiments and comparative examples of the present application. DETAILED DESCRIPTION

[0041] The embodiments of the positive electrode active material and preparation method thereof, positive electrode sheet, battery cell, battery, and electrical device of the present application are specifically disclosed with appropriate reference to the drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of actually the same structure may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following descriptions are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0042] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0043] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0044] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0045] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0046] Typically, a battery cell includes a positive electrode sheet, a negative electrode sheet, an electrolyte, and a separator. During the charge and discharge process of the battery cell, active ions are embedded and removed back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting active ions between the positive electrode sheet and the negative electrode sheet. The separator is arranged between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, and at the same time to allow active ions to pass through. In some embodiments, the above-mentioned battery cell is also called a secondary battery, and the battery cell can be the smallest battery unit.

[0047] During the charging process of a lithium-ion battery, lithium ions are released from the positive electrode active material, moved and embedded in the negative electrode material; while during the discharging process, lithium ions are released from the negative electrode material, moved and embedded in the positive electrode active material.

[0048] It should be understood that the "embedding" process described in this application refers to the process of lithium ions being embedded in the positive electrode active material and the negative electrode material due to electrochemical reactions, and the "extraction" and "de-embedding" processes described in this application refer to the process of lithium ions being extracted from the positive electrode active material and the negative electrode material due to electrochemical reactions.

[0049] The development of battery technology must consider many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate, reliability, etc. The battery cell includes a positive electrode plate. The performance of the positive electrode active material in the positive electrode plate is crucial to the capacity, cycle performance, and charge and discharge rate performance of the battery cell. Affected by the preparation process and preparation technology, the surface of the prepared positive electrode active material usually has alkaline impurities such as residual lithium. The presence of these substances affects the performance of the positive electrode active material, thereby affecting the rate performance of the battery cell.

[0050] In order to reduce the impact of alkaline impurities such as residual lithium on the performance of battery cells, in some treatment methods, a fast ion conductor coating is provided on the surface of the positive electrode active material, but the process of preparing the coating is relatively complicated and not conducive to application. In other treatment methods, a water washing process is used to remove alkaline impurities such as residual lithium, but the effect of this treatment method is not strong.

[0051] In view of this, the present application provides a method for treating positive electrode active materials, which removes alkaline impurities such as residual lithium on the surface of the positive electrode active materials by combining acid solution etching and ultrasonic treatment. After the positive electrode active materials are treated by this method, the content of alkaline impurities such as residual lithium is greatly reduced, and the specific surface area of ​​the positive electrode active materials is increased, which is conducive to improving the rate performance of the battery cell.

[0052] [Processing method of positive electrode active material]

[0053] Figure 1 Schematic diagram of a method for processing a positive electrode active material according to an embodiment of the present application. In an embodiment of the present application, for example Figure 1 As shown, the processing method 200 includes the following steps.

[0054] Step 210, adding the original positive electrode active material into the acidic solution to obtain a slurry.

[0055] The original positive electrode active material refers to the positive electrode active material that has not been processed by the processing method 200 .

[0056] The original positive electrode active material may be a sintered material such as a positive electrode active material precursor and a lithium salt. Due to the influence of the preparation process and the preparation technology, there are alkaline impurities on the surface of the original positive electrode active material. The alkaline impurities may include residual lithium, inert rock salt type NiO phase and other substances. The presence of alkaline impurities will affect the transmission of active ions in the positive electrode active material, which is not conducive to the improvement of the rate performance of the battery cell.

[0057] The residual lithium may refer to lithium carbonate, lithium hydroxide, etc. The inert rock salt type NiO phase may refer to substances such as NiCO2·2Ni(OH)2·xH2O.

[0058] The acid in the acidic solution can react with the alkaline impurities, thereby consuming at least a portion of the alkaline impurities on the surface of the positive electrode active material. The acid can include an inorganic acid or an organic acid.

[0059] Step 220 , stirring and ultrasonically treating the slurry to obtain an acid-modified positive electrode active material.

[0060] After adding the original positive electrode active material to the acidic solution, the slurry is stirred to make the original positive electrode active material and the solution mixed more evenly, which is beneficial to the contact between the acidic solution and the original positive electrode active material, thereby facilitating the reaction between the acid and the residual lithium on the surface of the original positive electrode active material, the inert rock salt type NiO phase and other substances.

[0061] During the ultrasonic treatment of the slurry, the shock wave generated by ultrasonic cavitation can be used to peel off the residual lithium, inert rock salt type NiO phase and other impurities on the surface of the original positive electrode active material, thereby further reducing the alkaline impurities on the surface of the original positive electrode active material.

[0062] In step 220, the original positive electrode active material is acidically etched with acid, and the alkaline impurities on the surface of the original positive electrode active material are further removed by ultrasonic treatment, which can have a better effect of removing the alkaline impurities on the surface of the original positive electrode active material, thereby obtaining an acid-modified positive electrode active material.

[0063] In the acid-modified positive electrode active material, since the alkaline impurities are removed, the particle surface of the positive electrode active material has more active sites and the positive electrode active material has a larger specific surface area, the diffusion channels of active ions (such as lithium ions) and electrons are expanded, the charge transfer impedance of the positive electrode active material during the charging and discharging process is reduced, and the surface of the positive electrode active material has better electron transfer rate and ion transfer rate. Therefore, the acid-modified positive electrode active material has better kinetic properties, which is beneficial to improving the rate performance of the battery cell.

[0064] In the embodiment of the present application, the acid can react with the alkaline impurities on the surface of the original positive electrode active material, thereby removing the alkaline impurities on the surface of the original positive electrode active material to a certain extent. Stirring the slurry is conducive to the contact between the original positive electrode active material and the acid, thereby facilitating the acid to etch the alkaline impurities on the surface of the original positive electrode active material. In addition, ultrasonic treatment of the slurry can utilize the effect of ultrasound to peel off the alkaline impurities from the surface of the original positive electrode active material, which is conducive to further reducing the alkaline impurities on the surface of the original positive electrode active material, and the treated positive electrode active material has a larger surface area, which is conducive to improving the rate performance of the battery cell.

[0065] In some embodiments, the slurry is stirred and ultrasonically treated to obtain an acid-modified positive electrode active material, including: stirring and ultrasonically treating the slurry; separating and washing the slurry to obtain a washed material; and drying the washed material to obtain an acid-modified positive electrode active material.

[0066] After the slurry is stirred and ultrasonically treated, the slurry may include the product of the reaction between the acid and the alkaline impurities, the alkaline impurities stripped from the surface of the original positive electrode active material, and the acid-modified positive electrode active material (in this case, the slurry is a suspension). To this end, the slurry needs to be separated and washed to obtain a washed material, which includes the acid-modified positive electrode material.

[0067] The washed material needs to be dried, and optionally, sieved to select the acid-modified positive electrode active material with a suitable particle size.

[0068] As an example, the slurry is placed in a centrifuge for centrifugal separation, and then washed with ethanol. Optionally, the washing is performed 2 to 10 times.

[0069] As an example, the drying process is performed at 30 to 80° C. for 10 to 60 minutes. Optionally, the drying process is performed at 50° C.

[0070] In this embodiment, after the slurry is stirred and ultrasonically treated, the alkaline impurities on the surface of the original positive electrode active material are reacted and peeled off from the surface of the original positive electrode active material; by separating and washing the slurry, the peeled material can be separated from the acid-modified positive electrode active material to obtain the washed material; the washed material is dried to obtain the acid-modified positive electrode active material.

[0071] Figure 2 Schematic diagram of a processing method according to an embodiment of the present application. In some embodiments, for example, Figure 2 As shown, the method 200 further includes step 230 .

[0072] Step 230 , etching the acid-modified positive electrode active material with laser to obtain a treated positive electrode active material.

[0073] In one example, the acid-modified positive electrode active material is placed in a laser emitting device, and laser pulses are operated to perform laser etching on the acid-modified positive electrode active material.

[0074] Laser etching is a physical etching method. It can further increase the specific surface area of ​​the acid-modified positive electrode active material without destroying the composition and bulk structure of the acid-modified positive electrode active material. Thus, the surface of the acid-modified positive electrode active material has more active sites, the ion transmission rate and charge transfer rate are further improved, and the rate performance of the battery cell is further improved.

[0075] In some embodiments, the power P of the laser satisfies: 800 W≤P≤1200 W, and the pulse time t1 of the laser satisfies: 0.2 s≤t1≤0.5 s.

[0076] The power P of the laser can be 800 W, 9000 W, 1000 W, 1100 W, 1200 W or any value within the above range, and the pulse time t1 of the laser can be 0.2 s, 0.3 s, 0.4 s, 0.5 s or any value within the above range.

[0077] In this embodiment, by setting the laser power and pulse time to meet the above range, the risk of difficulty in etching the surface of the positive electrode active material due to insufficient laser power and short pulse time can be reduced, and the risk of adverse effects on the positive electrode active material due to excessive laser power and long pulse time can be reduced.

[0078] Optionally, the power P of the laser satisfies: 900W≤P≤1000W, and the pulse time t1 of the laser satisfies 0.4s≤t1≤0.5s. In this way, the positive electrode active material can be etched with a smaller power and a shorter pulse time. As an example, P is 1000W and t1 is 0.5s.

[0079] In some embodiments, the acidic solution further comprises a solvent, and the solvent comprises an organic alcohol; optionally, the organic alcohol comprises at least one of methanol, ethanol or ethylene glycol.

[0080] In this embodiment, the acid in the acid solution can be dissolved in the organic alcohol, thereby facilitating sufficient contact and reaction between the acid and the alkaline impurities, etc. In addition, compared with using a water-containing solvent, using an organic alcohol as a solvent can better remove the solvent in the subsequent process and can also reduce the risk of introducing water into the battery cell.

[0081] In some embodiments, based on the total mass of the solution, the mass content A of the acid in the acidic solution satisfies: 1000 ppm≤A≤8000 ppm; alternatively, A satisfies: 1000 ppm≤A≤4000 ppm.

[0082] A may be 1000 ppm, 2000 ppm, 3000 ppm, 4000 ppm, 5000 ppm, 7000 ppm, 8000 ppm or any value within the above range.

[0083] By setting the mass content of the acid to meet the above range, the acid can fully react with the residual lithium and alkaline impurities, and other risks caused by excessively high mass content of the acid can be reduced.

[0084] In some embodiments, the frequency F of the ultrasonic treatment satisfies: 100 kHz≤F≤250 kHz; optionally, 100 kHz≤F≤200 kHz.

[0085] F can be 100 kHz, 150 kHz, 200 kHz, 250 kHz or any value within the above range.

[0086] By setting the frequency of ultrasonic treatment to meet the above range, alkaline impurities and residual lithium on the surface of the positive electrode active material can be stripped from the surface of the positive electrode active material, and the adverse effects of excessively high frequency on the positive electrode active material can be reduced.

[0087] In some embodiments, the rotation speed V of the stirring treatment satisfies: 200r / min≤V≤500r / min, and the time t2 of the stirring treatment satisfies: 10min≤t2≤60min.

[0088] V can be 200r / min, 300r / min, 500r / min or any value within the above range, and t2 can be 10min, 30min, 50min, 60min or any value within the above range.

[0089] Optionally, the rotation speed V of the stirring process satisfies: 200 r / min≤V≤300 r / min, and the time t2 of the stirring process satisfies: 10 min≤t2≤30 min. In this way, sufficient contact between the acid and the positive electrode active material can be achieved through a smaller stirring speed and a shorter half-time.

[0090] By setting the rotation speed and time of the stirring treatment to meet the above range, it is beneficial to fully contact the acid with the positive electrode active material, thereby facilitating the reaction of the acid with alkaline impurities and residual lithium, thereby facilitating the reduction of the content of alkaline impurities and residual lithium on the surface of the positive electrode active material.

[0091] In some embodiments, based on the total mass of the slurry, a ratio B of the mass content of the original positive electrode active material to the mass content of the solution satisfies: 0.3≤B≤0.5.

[0092] The ratio of the mass content of the original positive electrode active material to the mass content of the solution can also be called the solid-liquid ratio.

[0093] B can be 0.3, 0.4, 0.5 or any value within the above range.

[0094] In this embodiment, when B is not less than 0.3, the mass content of the acid in the solution is relatively appropriate, which can reduce the adverse effects caused by excessive acid compared to the original positive electrode active material; when B is not greater than 0.5, it is easy to mix the original positive electrode active material and the solution evenly, which is beneficial to the reaction of the acid with alkaline impurities and residual lithium.

[0095] In some embodiments, the slurry is stirred and ultrasonically treated to obtain an acid-modified positive electrode active material, including: the slurry is stirred and ultrasonically treated at the same time to obtain an acid-modified positive electrode active material. In this way, while the acid reacts with the alkaline impurities and residual lithium, the alkaline impurities and residual lithium can be stripped from the surface of the positive electrode active material by ultrasonic waves, thereby reducing the content of alkaline impurities and residual lithium on the surface of the positive electrode active material in a shorter time.

[0096] As an example, the slurry is placed in a stirring device for stirring, and an ultrasonic device is used to perform ultrasonic treatment on the slurry during the stirring process.

[0097] In some embodiments, the positive electrode active material includes at least one of a layered positive electrode active material or a spinel positive electrode active material. Due to the influence of the preparation process, the surface of the material of the above structure is prone to alkaline impurities, residual lithium and other substances. By using the above method to treat the positive electrode active material, it is easy to obtain a positive electrode active material with less residual lithium and alkaline impurities and a higher specific surface area, which is conducive to improving the rate performance of the battery cell.

[0098] The layered positive electrode active material may include layered lithium cobalt oxide, lithium nickel oxide, and derivatives thereof.

[0099] The layered positive electrode active material may also include a layered ternary material, a lithium-rich manganese-based material and derivatives thereof.

[0100] The positive active material of the spinel structure may include lithium nickel manganese oxide, lithium manganese oxide and derivatives thereof.

[0101] As an example, a derivative of lithium cobalt oxide may be a substance obtained by doping or other modification of lithium cobalt oxide. The derivative of lithium cobalt oxide has a structure similar to or the same as that of lithium cobalt oxide, and alkaline impurities are generated on the surface of the material during the preparation process.

[0102] In some embodiments, the acid in the acidic solution includes at least one of boric acid, formic acid, acetic acid or hydrochloric acid. The above acids can react well with alkaline impurities, thereby having a good effect of removing alkaline impurities.

[0103] The acid may also include other acids, and the embodiments of the present application include but are not limited to these.

[0104] [Positive electrode active material]

[0105] An embodiment of the present application provides a positive electrode active material, which is obtained by the processing method in any of the above embodiments.

[0106] In some embodiments, the pH value of the positive electrode active material satisfies: 11 <pH≤12。

[0107] The pH value of the positive electrode active material may be 11.1, 11.5, 12 or any value within the above range.

[0108] The pH value of the positive electrode active material can reflect the content of residual lithium and alkaline impurities on the surface of the positive electrode active material. Compared with the positive electrode active material from which the residual lithium and alkaline impurities have not been removed, the pH value of the positive electrode active material in this implementation is lower, so that the content of alkaline impurities and residual lithium on the surface of the positive electrode active material is less.

[0109] In some embodiments, based on the total mass of the positive electrode active material, the mass content C of LiOH on the surface of the positive electrode active material satisfies: 30 ppm < C ≤ 80 ppm; the mass content D of Li2CO3 on the surface of the positive electrode active material satisfies: 1400 ppm < D ≤ 1700 ppm. In this way, the content of residual lithium on the surface of the positive electrode active material is less, which is beneficial to improving the rate performance of the battery cell.

[0110] C can be 30 ppm, 50 ppm, 60 ppm, 80 ppm or any value within the above range; D can be 1400 ppm, 1600 ppm, 1700 ppm or any value within the above range.

[0111] In some embodiments, the specific surface area S1 of the positive electrode active material satisfies: 1.0 cm 2 / g < S1 < 1.3 cm 2 / g.

[0112] S1 can be 1.15 cm 2 / g, 1.2 cm 2 / g, 1.29 cm 2 / g or any value within the above range.

[0113] The positive electrode active material has a relatively large specific surface area, which is more conducive to the extraction or insertion of active ions from the positive electrode active material, is beneficial to improving the transport rate of active ions, and is beneficial to improving the rate performance of the battery cell.

[0114] [Positive electrode tab]

[0115] The embodiments of the present application provide a positive electrode tab, including the positive electrode active material in any of the above embodiments, and / or the positive electrode active material prepared by the preparation method in any of the above embodiments.

[0116] In some embodiments, the active specific surface area S2 of the positive electrode tab satisfies: 3.6 cm 2 / g < S2 < 3.8 cm 2 / g.

[0117] S2 can be 3.65 cm 2 / g, 3.7 cm 2 / g, 3.79 cm 2 / g or any value within the above range.

[0118] The positive electrode tab has a relatively high active specific surface area, which is thus beneficial to improving the rate performance of the battery cell.

[0119] The positive electrode tab includes a positive electrode current collector and a positive electrode film layer provided on the positive electrode current collector, and the positive electrode film layer includes the positive electrode active material.

[0120] The positive electrode current collector may be a metal foil or a composite current collector. For example, the positive electrode current collector may be an aluminum foil.

[0121] The composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0122] The positive electrode film layer may also optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0123] The positive electrode film layer may also optionally include a conductive agent, which may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.

[0124] [Negative electrode]

[0125] The negative electrode plate includes a negative electrode current collector and a negative electrode film layer arranged on the negative electrode current collector.

[0126] The negative electrode current collector may be a metal foil or a composite current collector. The negative electrode current collector may be a copper foil. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0127] The negative electrode film layer includes a negative electrode active material. The negative electrode active material can be a negative electrode active material for a battery known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may include at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0128] The negative electrode film layer may also optionally include a conductive agent, which may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.

[0129] [Electrolytes]

[0130] The electrolyte plays a role in conducting ions between the positive electrode and the negative electrode. The present application embodiment has no specific restrictions on the type of electrolyte, which can be selected according to needs. For example, the electrolyte can be liquid, gel or all-solid.

[0131] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent.

[0132] The electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium bisoxalatoborate, lithium difluorobisoxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0133] The solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.

[0134] The electrolyte may also optionally include negative electrode film-forming additives, positive electrode film-forming additives, and may also include performance additives that can improve certain battery properties, such as improving battery overcharge performance, improving battery high temperature or low temperature performance, etc.

[0135] [Isolator]

[0136] The separator is used to separate the positive electrode sheet from the negative electrode sheet. The embodiment of the present application has no particular limitation on the type of separator, and any known porous structure separator with good chemical stability and mechanical stability can be selected.

[0137] The material of the separator may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0138] The positive electrode sheet, the negative electrode sheet and the separator can be made into an electrode assembly through a winding process or a lamination process.

[0139] [Battery Cell]

[0140] An embodiment of the present application provides a battery cell, comprising the positive electrode plate in the above embodiment.

[0141] The embodiment of the present application has no particular limitation on the shape of the battery cell, which may be cylindrical, square or any other shape. The battery cell may be a lithium-ion battery, a lithium-sulfur battery, a sodium-ion battery, a magnesium-ion battery, etc.

[0142] Figure 3 FIG. 1 is a schematic diagram of a battery cell according to an embodiment of the present application. Figure 3 As shown, the battery cell 3 includes a shell 31 , an end cover assembly 32 and an electrode assembly 33 . The electrode assembly 33 is disposed in the shell 31 , and the end cover assembly 32 is used to cover the shell 31 .

[0143] The end cap assembly 32 includes an electrode terminal 322, such as Figure 3 As shown, the end cap assembly 32 includes two electrode terminals 322, one of which is a positive electrode terminal and the other is a negative electrode terminal.

[0144] The electrode assembly 33 includes an electrode assembly body 331 and a tab 332 extending from the electrode assembly body 331 . The electrode assembly 33 can be made of a positive electrode sheet, a negative electrode sheet and a separator by a winding process or a lamination process.

[0145] The battery cell 3 further includes a current collecting member 34, which is used to connect the electrode tab 332 of the electrode assembly 33 and the electrode terminal 322. Figure 3 As shown, the battery cell 3 includes two current collecting members 34 , one current collecting member 34 is used to connect the positive electrode tab and the positive electrode terminal, and the other current collecting member 34 is used to connect the negative electrode tab and the negative electrode terminal.

[0146] In some embodiments, battery cells may be assembled into a battery module. The number of battery cells contained in the battery module may be one or more. The specific number may be selected by those skilled in the art according to the application and capacity of the battery module.

[0147] [Battery]

[0148] An embodiment of the present application provides a battery, comprising the battery cell in the above embodiment. Figure 4 Schematic diagram of a battery according to an embodiment of the present application. Figure 4 As shown, the battery 5 may include a plurality of battery cells (not shown in the figure).

[0149] The battery cells 3 can directly form the battery 5 , or can first form a battery module, and then multiple battery modules form the battery 5 .

[0150] [Electrical devices]

[0151] An embodiment of the present application provides an electrical device, comprising the battery described in the above embodiment.

[0152] Figure 5 FIG. 1 is a schematic diagram of an electrical device according to an embodiment of the present application. Figure 5 As shown, the present application provides an electrical device 6, including the battery in the above embodiment.

[0153] Optionally, the electrical device may also be an energy storage device, a lighting device, a spacecraft, etc. The embodiments of the present application include but are not limited to these.

[0154] Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific techniques or conditions are indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0155] [Example]

[0156] Example 1

[0157] 1) Prepare a solution: 2 g of boric acid and 998 g of ethanol are placed in the same container and stirred for 30 minutes at a stirring speed of 300 rpm. The mass content A of the acid (boric acid in Example 1) is 2000 ppm based on the total mass of the solution.

[0158] 2) Slowly add the original positive electrode active material to the above solution to obtain a slurry, and stir the slurry, control the stirring speed V to 300 rpm, and simultaneously perform ultrasonic treatment on the slurry with an ultrasonic power of a wave frequency F of 200 kHz. 0.8 Co 0.1 Mn 0.1 O2 (NCM811), the time t2 of ultrasonic treatment and stirring treatment was set to 30 min.

[0159] 3) The slurry was placed in a centrifuge, centrifuged, and washed with ethanol for 5 times. The washed material was transferred to a vacuum oven, dried at 50° C., and sieved and classified to obtain an acid-modified positive electrode active material.

[0160] 4) The acid-modified positive electrode active material is transferred to the experimental chamber of the laser pulse device, and the laser emitter is controlled to have an emission power P of 1000 W and a pulse time t1 of 0.5 s.

[0161] 5) After the laser-etched material cools down, the processed positive electrode active material is collected.

[0162] Embodiment 2-4

[0163] The difference between Example 2-4 and Example 1 is that the types of acids in the solution are different. In Example 2-4, boric acid is replaced by formic acid, acetic acid, and hydrochloric acid, respectively.

[0164] Embodiment 5-6

[0165] The difference between Example 5-6 and Example 1 is that the type of alcohol in the solution is different. In Example 5-6, ethanol is replaced by methanol and ethylene glycol respectively.

[0166] Embodiment 7-9

[0167] The difference between Examples 7-9 and Example 1 is that the mass content A of the acid in the acidic solution is different.

[0168] In Example 7, the boric acid is 1 g, the ethanol is 999 g, and A is 1000 ppm; in Example 8, the boric acid is 4 g, the ethanol is 996 g, and A is 4000 ppm; in Example 9, the boric acid is 8 g, the ethanol is 992 g, and A is 8000 ppm.

[0169] Embodiment 10-11

[0170] The difference between Example 10-11 and Example 1 is that the stirring speed V is different. In Examples 10-11, the stirring speed V is 200 rpm and 500 rpm, respectively.

[0171] Examples 12-13

[0172] The difference between Example 12-13 and Example 1 is that the frequency F of the ultrasonic treatment is different. In Examples 12-13, F is 250 kHz and 150 kHz, respectively.

[0173] Examples 14-15

[0174] The difference between Example 14-15 and Example 1 is that the time t2 of ultrasonic treatment and stirring treatment is different. In Examples 14-15, the time t2 is 10 min and 60 min respectively.

[0175] Examples 16-17

[0176] The difference between Example 16-17 and Example 1 is that the laser power P is different. In Examples 16-17, P is 800W and 1200W respectively.

[0177] Embodiment 18

[0178] The difference between Example 18 and Example 1 is that the pulse time t1 of the laser is 0.2 s.

[0179] Embodiment 19

[0180] The difference between Example 19 and Example 1 is that steps 4) and 5) are not included. That is, in Example 19, laser is not used to physically etch the acid-modified positive electrode active material.

[0181] Examples 20-22

[0182] The difference between Examples 20-22 and Example 1 is that the solid-liquid ratio B is different. The solid-liquid ratio is the ratio of the mass of the original positive electrode active material to the mass of the solution.

[0183] Comparative Example 1

[0184] The difference between Comparative Example 1 and Example 1 is that in step 1), deionized water is used as the solution instead of a solution of a mixture of acid and alcohol.

[0185] Comparative Example 2

[0186] The difference between Comparative Example 2 and Example 1 is that in step 1), no mixed solution of acid and alcohol is used, but only ethanol is used as the solution.

[0187] Comparative Example 3

[0188] The difference between Comparative Example 3 and Example 1 is that in step 2), the slurry is not subjected to ultrasonic treatment.

[0189] Table 1 shows the processing methods of the positive electrode active materials in different embodiments, Table 2 shows the positive electrode active materials obtained by the processing methods in different embodiments, and Table 3 shows the performance of battery cells prepared from the positive electrode active materials obtained by different processing methods.

[0190] Table 1 Parameters of the treatment methods of the positive electrode active materials of the embodiments and comparative examples

[0191]

[0192]

[0193] Table 2 Parameters of positive electrode active materials of Examples and Comparative Examples

[0194]

[0195]

[0196] Table 3 Test results of embodiments and comparative examples

[0197]

[0198] [Preparation of battery cells]

[0199] (1) Preparation of positive electrode sheets: A slurry is prepared with a mass ratio of positive electrode active material, conductive agent super-P and carbon nanotubes CNT, and binder PVDF of 95:1.5:0.5:3, and coated on a 13 μm aluminum foil. The positive electrode sheets are obtained after vacuum drying at 120°C, cold pressing, and cutting into strips.

[0200] (2) Preparation of negative electrode sheets: artificial graphite and hard carbon, conductive agent acetylene black, binder styrene butadiene rubber (SBR), and thickener sodium carboxymethyl cellulose (CMC) are dissolved in deionized water at a mass ratio of 90:5:2:2:1, and the mixture is stirred thoroughly to prepare a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector copper foil, and then dried, cold pressed, and cut to obtain a negative electrode sheet.

[0201] (3) Isolation film: polyethylene film is used.

[0202] (4) Preparation of lithium-ion battery cells: stack and wind the above-mentioned positive electrode sheets, separators, and negative electrode sheets in order to obtain an electrode assembly; place the electrode assembly in an outer package, add an electrolyte solution whose electrolyte salt is lithium hexafluorophosphate, and obtain a lithium-ion battery cell after packaging, standing, forming, aging, and other processes.

[0203] [Test of shape]

[0204] Scanning electron microscopy was used to characterize the surface morphology of the positive electrode active material.

[0205] [Residual lithium test]

[0206] The titration method is used to detect the residual alkali content on the surface of the positive electrode active material after acid etching and ultrasonic treatment, as well as the residual alkali content on the surface of the material after laser etching.

[0207] [Specific surface area test]

[0208] Based on the principle of gas adsorption, the change in the specific surface area of ​​the material before and after acid chemical etching and laser material etching is tested. The following is an example to introduce the test method of specific surface area.

[0209] (1) Place an appropriate amount of sample in a dedicated sample tube, heat and vacuum degas for 2 h, and weigh the total weight after cooling to room temperature. Subtract the mass of the sample tube from the total weight to obtain the sample mass. (2) Place the sample tube in a workstation and measure the amount of gas adsorbed on the solid surface at different adsorption pressures at a constant low temperature. Based on the BET multilayer adsorption theory and its formula, the monolayer adsorption amount of the sample is calculated, thereby calculating the specific surface area per unit mass of the solid sample. The adsorbed gas is nitrogen.

[0210] [pH value test]

[0211] (1) Prepare a solution with a fixed ratio of 1:9 between the sample and deionized water, seal it and place it on a magnetic stirrer for 30 minutes. After stirring, place the conical flask in a 25°C water bath and let it stand for 1.5 hours. (2) Insert a pH composite electrode into the solution to form an electrochemical primary cell and measure the electromotive force of the primary cell. Since the electromotive force of the primary cell is related to the pH value of the solution, the pH value can be measured.

[0212] [Test of active specific surface area]

[0213] The prepared battery cell was subjected to charge and discharge tests under the following test conditions: constant rate scanning CV test at 0.1 mV / s, voltage less than 5 V, current less than 400 mA. The active specific surface area of ​​the positive electrode was calculated according to the Randles-Sevcik formula.

[0214] [Rate performance test]

[0215] At 25°C, the battery cells were charged and discharged at current densities of 0.2C, 0.33C, 1C, and 4C, and each current rate was cycled 5 times. The voltage range was set to 2.8 to 4.35V.

[0216] Figure 6 This is a SEM image of the positive electrode active material of one embodiment of the present application. Figure 7 This is a SEM image of a pair of positive electrode active materials in this application. Figure 6 and Figure 7 As shown, the surface of the untreated positive electrode active material is relatively rough, and the surface of the treated positive electrode active material becomes smooth, indicating that impurities such as residual alkali on the surface of the positive electrode active material have been removed to a certain extent after the treatment.

[0217] Figure 8 Schematic diagram of the rate performance curve of the comparative example of the present application. Figure 8 As shown, Figure 8 The discharge specific capacities of Example 1, Example 2 and Comparative Example 1 at different current densities are shown. Figure 8 It can be seen that with the increase of current density, at a large rate, Example 1 and Example 2 have higher discharge specific capacity and also have a higher capacity retention rate; while the discharge specific capacity of the comparative example decreases more.

[0218] As shown in Examples 1-22 and Comparative Examples 1-3, the positive electrode active material obtained by the treatment method of the embodiment of the present application has greatly reduced residual lithium on its surface, greatly reduced mass content of lithium hydroxide and lithium carbonate, and increased specific surface area of ​​the positive electrode active material. In addition, since the content of residual lithium on the surface of the positive electrode active material is greatly reduced, the pH value of the positive electrode active material is lower than the pH value of the comparative example. The positive electrode sheet prepared from the positive electrode active material of the embodiment of the present application has a higher active specific surface area, and the battery cell prepared from the positive electrode active material of the embodiment of the present application still has a high discharge specific capacity at a current rate of 4C, and has a high capacity retention rate at a current rate of 4C.

[0219] As shown in Examples 1-4, the method of the present invention is applicable to a variety of different acids; as shown in Examples 5-6, the method of the present invention is applicable to a variety of different alcohols.

[0220] In combination with Examples 7-9, based on the total mass of the acidic solution, the mass content of the acid is set in the range of 1000ppm-8000ppm, which is convenient for the acid to react with the alkaline impurities on the surface of the positive electrode active material, thereby consuming the alkaline impurities; in addition, the mass content of the acid is in the range of 1000ppm-4000ppm, preferably at 2000ppm, and the mass content can be applied to a variety of different acids. In addition, different acids have different concentrations, and the mass content of the acid in the acidic solution can also be set according to the specific type of the acid.

[0221] In combination with Examples 10-11, by setting the stirring speed at 200 rpm-500 rpm, the slurry can be mixed evenly; in combination with Examples 12-13, the frequency of ultrasonic treatment is set at 100 kHz-250 kHz, so that the alkaline impurities on the surface of the positive electrode active material can be further removed by the action of ultrasonic waves; in combination with Examples 14-15, by setting the stirring and ultrasonic treatment times at 10 min-30 min, the alkaline impurities on the surface of the positive electrode active material can be better removed.

[0222] In combination with Examples 16-18, the laser power is set at 800W-1200W, and the laser pulse time is set at 0.2s-0.5s, so as to obtain the positive electrode active material after laser etching, and the positive electrode active material has a larger specific surface area; preferably, the laser power can be set at 900W-1000W, specifically 1000W, and the laser pulse time can be set at 0.4s-0.5s, specifically 0.5s, so that the positive electrode active material can have a more suitable specific surface area and is also convenient for laser etching operation.

[0223] As shown in Example 19 and Example 1, laser treatment is beneficial for obtaining a positive electrode active material with a larger specific surface area.

[0224] As shown in Examples 20-22, the solid-liquid ratio of the slurry is set to 0.3-0.5, preferably 0.4, to facilitate the removal of alkaline impurities on the surface of the positive electrode active material.

[0225] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for treating a positive electrode active material, characterized in that: Comprising: Adding the raw cathode active material into an acidic solution to obtain a slurry; Performing stirring treatment and ultrasonic treatment on the slurry to obtain an acid-modified cathode active material.

2. The processing method according to claim 1, characterized in that: The performing stirring treatment and ultrasonic treatment on the slurry to obtain an acid-modified cathode active material includes: Performing stirring treatment and ultrasonic treatment on the slurry; Performing separation treatment and washing treatment on the slurry to obtain a washed material; Performing drying treatment on the washed material to obtain the acid-modified cathode active material.

3. The processing method according to claim 1 or 2, characterized in that: The method further includes: Using laser etching on the acid-modified cathode active material to obtain a treated cathode active material.

4. The processing method according to claim 3, characterized in that: The power P of the laser satisfies: 800W ≤ P ≤ 1200W, and the pulse time t1 of the laser satisfies 0.2s ≤ t1 ≤ 0.5s; optionally, 900W ≤ P ≤ 1000W, 0.4s ≤ t1 ≤ 0.5s.

5. The processing method according to any one of claims 1 to 4, characterized in that: The acidic solution includes a solvent, and the solvent includes organic alcohol; optionally, the organic alcohol includes at least one of methanol, ethanol, or ethylene glycol.

6. The processing method according to any one of claims 1 to 5, characterized in that: Based on the total mass of the acidic solution, the mass content A of the acid in the acidic solution satisfies: 1000ppm ≤ A ≤ 8000ppm; optionally, A satisfies: 1000ppm ≤ A ≤ 4000ppm.

7. The processing method according to any one of claims 1 to 6, characterized in that: The frequency F of the ultrasonic treatment satisfies: 100kHz ≤ F ≤ 250kHz; optionally, 100kHz ≤ F ≤ 200kHz.

8. The processing method according to any one of claims 1 to 7, characterized in that: The rotation speed V of the stirring treatment satisfies: 200r / min ≤ V ≤ 500r / min, and the time t2 of the stirring treatment satisfies: 10min ≤ t2 ≤ 60min; optionally, 200r / min ≤ V ≤ 300r / min, 10min ≤ t2 ≤ 30min.

9. The processing method according to any one of claims 1 to 8, characterized in that: Based on the total mass of the slurry, the ratio B of the mass content of the raw cathode active material to the mass content of the solution satisfies: 0.3 ≤ B ≤ 0.

5.

10. The processing method according to any one of claims 1 to 9, characterized in that: The performing stirring treatment and ultrasonic treatment on the slurry to obtain an acid-modified cathode active material includes: Performing stirring treatment and ultrasonic treatment on the slurry simultaneously to obtain an acid-modified cathode active material.

11. The processing method according to any one of claims 1 to 10, characterized in that: The acid in the acidic solution includes at least one of boric acid, formic acid, acetic acid, or hydrochloric acid.

12. The processing method according to any one of claims 1 to 11, characterized in that: The cathode active material includes at least one of a layered structure cathode active material or a spinel structure cathode active material.

13. A positive electrode active material, characterized in that: The cathode active material is obtained according to the treatment method described in any one of claims 1 - 12.

14. The positive electrode active material according to claim 13, characterized in that The pH value of the cathode active material satisfies: 11 < pH ≤ 12.

15. The positive electrode active material according to claim 13 or 14, characterized in that: Based on the total mass of the cathode active material, the mass content C of LiOH on the surface of the cathode active material satisfies: 30ppm < C ≤ 80ppm; the mass content D of Li2CO3 on the surface of the cathode active material satisfies: 1400ppm < D ≤ 1700ppm.

16. The positive electrode active material according to any one of claims 13 to 15, characterized in that The specific surface area S1 of the positive electrode active material satisfies: 1.0 m 2 / g <S1<1.3m 2 / g.

17. A positive electrode plate, characterized in that: Comprising: The cathode active material prepared according to the treatment method described in any one of claims 1 - 12, and / or, the cathode active material described in any one of claims 13 - 16.

18. The positive electrode sheet according to claim 17, characterized in that: The active specific surface area S2 of the positive electrode sheet satisfies: 3.6 cm 2 / g <S2<3.8cm 2 / g.

19. A battery, characterized in that: Including the cathode electrode sheet described in claim 17 or 18.

20. An electrical device, characterized in that: Comprising the battery of claim 19.

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