Doping type precursor for positive electrode lithium supplementing agent and preparation method and application thereof

Abstract

The invention discloses a doping type precursor for a positive electrode lithium supplement agent and a preparation method and application thereof, and the method comprises the following steps: introducing doping elements in a nickel hydroxide forming process by adopting an ammonia coordination parallel flow coprecipitation process, so that the doping elements are uniformly distributed in the precursor; then calcining at a low temperature and in a protective atmosphere, and strictly controlling the oxygen content and the tapping temperature to obtain a doped nickel oxide precursor with lower crystallinity, larger specific surface area and higher porosity; and mixing with a lithium salt, and sintering in a high-temperature protective atmosphere to prepare the high-purity positive electrode lithium supplementing agent. The material has the characteristics of low trivalent nickel content, uniform particle size distribution, high reaction activity and the like, residual lithium and side reactions can be remarkably reduced, and the charging capacity and the irreversible capacity are improved. Compared with the prior art, the process is simple, the doping uniformity is good, the precursor activity is high, and the obtained lithium supplementing agent is high in purity, stable in structure, excellent in conductivity and capable of effectively compensating initial lithium loss when applied to the lithium ion battery.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of battery material preparation, in particular to a doped precursor for a positive electrode lithium supplementing agent and a preparation method and application thereof. BACKGROUND

[0002] In a lithium ion battery, a series of complex physical and chemical changes occur inside the battery as the charging and discharging cycle progresses, resulting in gradual capacity attenuation of the battery. In order to compensate for the loss of lithium during the use of the battery, the application of a lithium supplementing agent becomes crucial. The lithium-rich lithium nickelate Li2NiO2 has a lithium supplementing capacity greater than 270 mAh / g, and the lithium supplementing capacity is high. When 2%-5% is added, the irreversible lithium loss caused by the formation of a solid electrolyte interface film (SEI film) can be compensated for, thereby improving the battery performance. NiO is one of the key raw materials for preparing the lithium supplementing agent Li2NiO2, and the synthesis method and index of the NiO have a significant influence on the effect of the lithium supplementing agent.

[0003] At present, the common nickel oxide synthesis method has some deficiencies. For example, the purity of the nickel oxide prepared by some traditional methods is not high, and a large amount of impurities are contained, which will affect the performance of the lithium supplementing agent, cause low lithium supplementing efficiency, and cannot effectively improve the cycle life and capacity retention rate of the battery. Patent document No. CN117813263B provides a positive electrode lithium supplementing agent precursor with a core-shell structure, the core is a porous spherical Ni(OH)2 composed of nanosheets; the shell material contains at least one of an oxide of an M element and a hydroxide of the M element, a solid solution can be formed between the core and the shell, and the shell material on the surface of the material can form a lithium-containing metal oxide with a lithium source at low temperature. The lithium-containing metal oxide formed can play a role of a catalyst, promote the reaction between the lithium source and the internal core material, reduce the energy barrier of the reaction, and the sintering reaction between the precursor and the lithium source can be carried out at a relatively low temperature (for example, not more than 650 DEG C). The synthesis process of the precursor of the application involves a two-step co-precipitation process, and heating and pressurization are involved in the second step process. The process is relatively complex.

[0004] Patent document No. CN113571781A / B limits the performance threshold (purity, residual alkali, capacity interval) of the product, and the internal causal relationship between the precursor structure, the measurable parameters and the process window is not described, which is difficult to directly guide the "reviewable process link" and the consistency control of the scale; patent document Nos. CN110218078A and CN118117093A disclose general solid-phase or direct mixing doping, and the combination of the following measurable thresholds is less limited: Ni 3 + content upper limit, BET lower limit, XRD (200) half peak width (FWHM) lower limit, porosity lower limit, etc. There is a lack of a precursor preparation and evaluation method targeting the same.

[0005] Patent documents CN110218078A and CN118117093A lack verification indicators related to process parameters in terms of doping uniformity, intragranular diffusion path, and agglomeration inhibition, which may lead to risks of insufficient reaction activity or excessively high residual lithium.

[0006] Patent document CN116102077B discloses a doped precursor and a preparation method thereof. The method introduces nickel, manganese, and elements such as iron and gallium together through a liquid-phase coprecipitation process to achieve uniform doping of multiple elements in the precursor stage. Although this technology shows certain advantages in the Ni-Mn-based LNMO positive electrode system, its research focus is on improving the interface stability of high-voltage positive electrodes, which is different from the NiO-based positive electrode lithium supplement system, and it fails to solve the key problems of the lithium supplement precursor in terms of crystallinity control, specific surface area improvement, trivalent nickel content suppression, and residual lithium control. Patent document CN120463256A mainly targets the nickel-cobalt-manganese ternary positive electrode system, and its core function is to enhance the structural stability and rate performance, but it does not solve the key problems of the lithium supplement precursor in terms of low crystallinity regulation, trivalent nickel content reduction, and residual lithium control.

[0007] In addition, the valence of Ni in Li2NiO2 is +2, so the presence of trivalent nickel (Ni 3 +) in the raw material nickel oxide will have many adverse effects on its performance. At the same time, the particle size distribution of the nickel oxide precursor prepared by the traditional method is not uniform, and the specific surface area is small, which affects the reaction activity between the lithium source and the nickel oxide, and further affects the quality of the lithium supplement. Therefore, it is of great significance to develop a synthesis method for high-efficiency, low-trivalent nickel content, and high-reactivity nickel oxide. SUMMARY

[0008] The technical problem to be solved by the present application is to overcome the existing defects and provide a doped precursor for positive electrode lithium supplement and a preparation method and application thereof. The present application solves the problems of uneven doping, high Ni 1-x M x O in the prior art, insufficient specific surface area and pore structure, difficulty in balancing phase purity and residual lithium, and complex process, etc., by using a set process of "ammonia coordination and flow coprecipitation → low-temperature controlled dehydration / calcination to obtain low-crystallinity doped Ni 3 + → strict atmosphere and low tapping temperature control → high-temperature lithiation", thereby obtaining a positive electrode lithium supplement with better electrochemical performance and production consistency, which can effectively solve the problems in the background art.

[0009] To achieve the above-mentioned purposes, the present application provides the following technical solutions: a doped precursor for positive electrode lithium supplement and a preparation method and application thereof, comprising the following steps:

[0010] S1. Prepare a mixed solution of nickel salt and M salt according to stoichiometric ratio, prepare a sodium hydroxide solution as a precipitant, and prepare an ammonia solution as a complexing agent;

[0011] S2. Add the mixed solution of nickel salt and M salt, the sodium hydroxide solution, and the ammonia solution into a reaction kettle in a certain proportion in parallel flow, control the pH of the reaction process to be 10-12, and react at 45-60℃ until the target particle size is reached, then stop the reaction, and obtain the doped nickel hydroxide Ni 1-x Mx(OH)2by centrifugation, washing, drying, and screening.

[0012] S3. Perform low-temperature calcination on the doped Ni 1-x Mx(OH)2obtained in step S2 in a protective atmosphere, with an oxygen volume fraction ≤0.02%, a calcination temperature of 250-350℃, a time of 2-4h, and a heating rate of 3-8℃ / min, cool after calcination, and discharge at an out-of-furnace temperature ≤60℃ to obtain a doped nickel oxide precursor Ni 1-x M x O with low crystallinity.

[0013] S4. Mix the prepared doped precursor Ni 1-x M x O with a lithium salt, and perform high-temperature calcination in a protective atmosphere, with a temperature controlled between 600-800℃, an oxygen content controlled at ≤0.005%, and a sintering time of 12-24h, and then crush and pulverize to obtain a high-purity positive electrode lithium supplement material.

[0014] Further, M is one or more of Al and Mg elements, and 0

[0015] Further, the nickel salt is one or more of nickel sulfate, nickel nitrate, nickel acetate, and nickel chloride, and the M salt is one or more of the corresponding sulfate or nitrate.

[0016] Further, the lithium salt in S4 is selected from one or more of lithium carbonate, lithium hydroxide, lithium oxide, and lithium oxalate, and the oxygen content in the protective atmosphere in S3 and S4 is monitored and controlled by an online oxygen analyzer.

[0017] Further, the out-of-furnace temperature in step S3 is preferably ≤30℃, and step S3 is performed in a dynamic sintering furnace, which is a rotary kiln or a dynamic device with equivalent material stirring and gas-solid contact capacity.

[0018] Further, a doped precursor for a positive electrode lithium supplement material is prepared by the method in any one of claims 1-5, and the chemical formula of the doped precursor is Ni 1-x M x O, Ni 3+content of < 0.5%.

[0019] Further, the doped precursor has a specific surface area of > 80 m 2 / g, and an average particle size of 3-10 microns.

[0020] Further, the doped precursor has no impurity phase in XRD diffraction peaks, and the diffraction peak half-width of the 200 crystal face is > 1.400°, and the porosity is > 20%.

[0021] Further, a positive electrode lithium supplementing agent, the chemical formula of the lithium supplementing agent is Li2Ni 1-x M x O2, residual lithium < 3.5%, specific capacity of charging > 420 mAh / g, and irreversible capacity > 290 mAh / g.

[0022] Further, the use of the positive electrode lithium supplementing agent in a lithium ion battery is used as a positive electrode lithium supplementing additive to compensate for the initial irreversible lithium loss of the battery and improve the cycle stability.

[0023] Compared with the prior art, the beneficial effects of the present application are:

[0024] 1. In the present application, a doping element is introduced in the co-precipitation stage of nickel hydroxide, so that it is uniformly distributed in the crystal growth process, avoiding the problems of agglomeration or uneven distribution in the later stage; by dynamic dehydration under low temperature and protective atmosphere, and strictly controlling the oxygen content and discharge temperature, a doped nickel oxide precursor with low crystallinity can be obtained; the low crystallinity structure is more prone to form defects in the crystal lattice, thereby providing more active sites for subsequent reactions.

[0025] 2. In the high-temperature reaction process with lithium salt, the precursor with low crystallinity and rich defects can promote the doping element to smoothly enter the NiO crystal lattice, and the doping effect is more sufficient under high-temperature sintering, thereby improving the structural stability of the Li2Ni 1-x M x O2 lithium supplementing agent; by this method, the generation of impurities is effectively inhibited, and the purity and phase stability of the product are significantly improved.

[0026] 3. The doped precursor has a large specific surface area and good particle size consistency, and the reaction with lithium salt is more sufficient; the lithium supplementing agent prepared therefrom not only has high conductivity and high purity, but also exhibits high irreversible capacity and low impurity content; in actual battery applications, the lithium supplementing agent can maintain structural stability, and the gas generation tendency is significantly reduced, thereby effectively improving the cycle performance and safety of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 XRD diffraction spectrum of the doped nickel oxide prepared for Example 1;

[0028] Figure 2 SEM image of the doped positive electrode lithium supplement prepared in Example 1;

[0029] Figure 3 SEM image of the doped lithium supplement prepared in Example 1;

[0030] Figure 4 Charge-discharge curve of the doped positive electrode lithium supplement prepared in the examples and comparative examples. DETAILED DESCRIPTION

[0031] The present application is further described in conjunction with the specific examples, it should be understood that the specific examples described herein are intended to explain, not to limit, the present application.

[0032] Please refer to Figures 1-4 The present application provides a technical solution: a doped precursor for a positive electrode lithium supplement and a preparation method and application thereof

[0033] Example 1

[0034] 1) Prepare a nickel sulfate solution with a concentration of 2 mol / L, an aluminum sulfate solution with a concentration of 0.8 mol / L, and mix the nickel salt and Al salt solutions according to the stoichiometric ratio of 98:2. The concentration of sodium hydroxide solution is 8 mol / L, and the concentration of ammonia water is 9 mol / L;

[0035] The mixed solution of nickel salt and Al salt is added to the reaction kettle in a certain proportion and flows with the sodium hydroxide solution and ammonia water. The pH of the reaction process is controlled at 11, and the reaction is carried out at 50±1℃. The growth is stopped when the particle size reaches 3.5 microns. After centrifugation, washing, drying and screening, the doped nickel hydroxide Ni 0.98 Al 0.02 (OH)2is obtained.

[0036] 2) The doped Ni 0.98 Al 0.02 (OH)2after drying is calcined at low temperature under nitrogen atmosphere, with oxygen content controlled at 0.01%, temperature at 310℃, heating rate at 5℃ / min, time for 3 hours, and cooled to room temperature to obtain the doped Ni 0.98 Al 0.02 O precursor.

[0037] 3) The prepared doped precursor Ni 0.98 Al 0.02 O is mixed with Li2O and calcined at high temperature under nitrogen atmosphere, with temperature controlled at 750℃, oxygen content at 0.005%, sintering time for 18h, and broken and crushed to obtain the synthesized high-purity positive electrode lithium supplement material.

[0038] Example 2

[0039] 1) The concentration of nickel sulfate solution is 2 mol / L, the concentration of aluminum sulfate is 0.8 mol / L, the nickel salt and Al salt solution is mixed according to the stoichiometric ratio of 98:2, the concentration of sodium hydroxide solution is 8 mol / L, and the concentration of ammonia is 9 mol / L;

[0040] 2) The mixed solution of nickel salt and Al salt is added into the reaction kettle with sodium hydroxide solution and ammonia in a certain proportion, the pH of the reaction process is controlled to be 10.8, and the reaction is carried out at 50±1℃, and the growth is stopped when the particle size reaches 3.5 microns. After centrifugation, washing, drying and screening, the doped nickel hydroxide Ni 0.98 Al 0.02 (OH)2 is obtained.

[0041] 3) The doped Ni 0.98 Al 0.02 (OH)2 after drying is calcined at low temperature under nitrogen atmosphere, the oxygen content is controlled to be 0.02%, the temperature is 320℃, the heating rate is 5℃ / min, the time is 2 hours, and the cooling is carried out. The discharge temperature is 50℃, and the doped Ni 0.98 Al 0.02 O precursor is obtained.

[0042] 4) The prepared doped precursor Ni 0.98 Al 0.02 O is mixed with Li2O and calcined at high temperature under nitrogen atmosphere, the temperature is controlled to be 750℃, the oxygen content is 0.005%, the sintering time is 18h, and the high-purity positive electrode lithium supplement material is obtained by crushing and crushing.

[0043] Example 3

[0044] In the example, the aluminum sulfate is replaced by magnesium sulfate, and the others are the same as in example 1.

[0045] Comparative Example 1

[0046] 1) The concentration of nickel sulfate solution is 2 mol / L, the concentration of sodium hydroxide solution is 8 mol / L, and the concentration of ammonia is 9 mol / L;

[0047] 2) The nickel salt is added into the reaction kettle with sodium hydroxide solution and ammonia in a certain proportion, the pH of the reaction process is controlled to be 11, and the reaction is carried out at 50±1℃, and the growth is stopped when the target particle size reaches 3.5 microns. After centrifugation, washing, drying and screening, the nickel hydroxide Ni(OH)2 is obtained.

[0048] 3) The dried Ni(OH)2 is calcined at low temperature under nitrogen atmosphere, the oxygen content is controlled to be 0.01%, the temperature is 320℃, the heating rate is 5℃ / min, the time is 2 hours, and the cooling is carried out. The discharge temperature is 50℃, and the NiO precursor is obtained.

[0049] 4) The prepared precursor NiO is mixed with Li2O, calcined at high temperature under nitrogen atmosphere, the temperature is controlled at 750℃, the oxygen content is 0.005%, the sintering time is 18h, and the high-purity positive electrode lithium supplement material is obtained by crushing and pulverizing.

[0050] Comparative Example 2

[0051] 1) The concentration of the prepared nickel sulfate solution is 2mol / L, the concentration of the aluminum sulfate is 0.8mol / L, the nickel salt and Al salt solution are mixed according to the stoichiometric ratio of 98:2, the concentration of the sodium hydroxide solution is 8mol / L, and the concentration of the ammonia water is 9mol / L;

[0052] 2) The mixed solution of nickel salt and Al salt is added to the reaction kettle in parallel with the sodium hydroxide solution and ammonia water in a certain proportion, the pH of the reaction process is controlled at 11, and the reaction is stopped when the particle size reaches 3.5 microns at 50±1℃, and the doped nickel hydroxide Ni 0.98 Al 0.02 (OH)2 is obtained by centrifugation, washing, drying and screening.

[0053] 3) The dried doped Ni 0.98 Al 0.02 (OH)2 is calcined at low temperature under nitrogen atmosphere, the oxygen content is controlled at 0.01%, the temperature is 500℃, the heating rate is 5℃ / min, the time is 2 hours, and the high-crystallinity doped Ni 0.98 Al 0.02 O precursor is obtained by cooling to room temperature.

[0054] 4) The prepared doped precursor Ni 0.98 Al 0.02 O is mixed with Li2O, calcined at high temperature under nitrogen atmosphere, the temperature is controlled at 750℃, the oxygen content is 0.005%, the sintering time is 18h, and the high-purity positive electrode lithium supplement material is obtained by crushing and pulverizing.

[0055] Evaluation method of the material:

[0056] Specific surface area test:

[0057] The specific surface area of the sample is obtained by determining the adsorption amount of the sample relative to the standard sample by dynamic chromatography method with nitrogen as the adsorption gas.

[0058] Trivalent nickel content test:

[0059] The content of trivalent nickel is tested by oxidation-reduction titration method with ferrous ammonium sulfate as the reducing agent.

[0060] XRD test:

[0061] The doped nickel oxide prepared in Example 1 and the positive electrode lithium supplementing agent were subjected to X-ray diffraction test, with a scanning range of 15-70° and a scanning speed of 0.03° / min.

[0062] Electrical performance test:

[0063] The lithium supplementing agent prepared in the example and the comparative example was used to prepare a button cell, was coated on an aluminum foil to prepare a positive electrode sheet, and a lithium sheet was used as a negative electrode to assemble a button cell.

[0064] Table 1 is a comparison of the indicators of the samples prepared in the example and the comparative example:

[0065]

[0066] The present application proposes a set process of "ammonia coordination and concurrent precipitation→low-temperature controlled dehydration / calcination to obtain low-crystallinity doped Ni 1-x MxO→strict atmosphere / outlet window→high-temperature lithiation" and a measurable structure threshold value coordination control strategy to solve the problems of "only result-based performance limitation", "difficulty in balancing doping uniformity and activity in solid-phase direct doping", and "complex core-shell precursor process", and the following verifiable technical effects are achieved:

[0067] (1) Doping uniformity and low crystallinity, improving lithiation reaction activity and phase purity

[0068] M (Al / Mg) is introduced in the co-precipitation stage to make the doping elements uniformly distributed in situ in the hydroxide precursor; low-crystallinity Ni 1-x MxO is obtained by calcination at a low temperature of 250-350°C, which increases the lattice defects and diffusion channels and reduces the activation energy of the solid-phase reaction with lithium salt.

[0069] The results show that the lithium salt can be fully lithiated at 600-800°C, and the final Li2Ni 1-x M x O2 XRD has no impurity phase, and the low-crystallinity characteristics of the precursor (200) face FWHM≥1.400° and the phase purity of the product form a causal correspondence.

[0070] (2) Atmosphere and outlet window linkage to inhibit Ni 3 + and side reactions

[0071] The O2 volume fraction in the atmosphere is controlled to be ≤0.02% in the precursor stage and ≤0.005% in the lithiation stage, and the outlet temperature is controlled to be ≤60°C (preferably ≤30°C), which effectively avoids uneven reduction / oxidation at the hot end and re-oxidation, moisture absorption and alkalization at the cold end.

[0072] The results show that the precursor Ni 3+≤0.5%, product surface residual alkali / residual lithium generation is controlled, residual lithium (Li2CO3% + LiOH%) ≤3.5%, subsequent side reactions and gas generation are significantly reduced in the use of the subsequent battery.

[0073] (Three) Specific surface area and pore structure optimization, promote solid phase contact and reaction completeness

[0074] Through dynamic kiln low-temperature dehydration, a porous precursor with BET≥80m 2 / g, porosity≥20% and reasonable particle size D50=3~10μm is obtained, which is beneficial to the dense mixing and short-range diffusion of lithium salt.

[0075] The results show that: the lithiation reaction is more complete, the agglomeration tendency is reduced, the final material phase purity is high, the residual lithium is low, the tabletting consistency and the electrode stability are better.

[0076] (Four) Dynamic rotary kiln ensures material state consistency and batch stability

[0077] Dynamic turning of materials, strengthening of gas-solid mass transfer and thermal uniformity, reducing the probability of local overburning / underburning, making the crystallinity, pore structure and oxygen-containing state of the precursor stable within / between batches.

[0078] The results show that: the fluctuations of key indicators (Ni 3 +, BET, FWHM, D50) converge, which provides process guarantee for mass production and quality control.

[0079] (Five) Electrochemical performance and application effect are quantitatively improved

[0080] Due to the fact that the dopant is more easily incorporated into the NiO lattice and stabilizes Li2Ni 1-x MxO2 structure, the material conductivity, structural stability and initial reaction kinetics are improved.

[0081] The results show that: under the conditions of 3.0~4.3V and 0.1C, the charge specific capacity is≥420mAh / g, and the irreversible capacity is≥290mAh / g; after assembling the battery, the cycle stability is significantly improved, and the risk of gas evolution is significantly reduced.

[0082] (Six) Comprehensive progress compared with the prior art

[0083] Compared with the route of "only performance threshold", the present application designs a closed loop of process window-structure threshold-performance result, which clearly defines the reviewable technical cause and effect chain from the precursor to the finished product.

[0084] Compared with "solid phase direct doping / ball milling - sintering", the present application simultaneously optimizes the uniformity of doping, the completeness of lithiation and the control of residual lithium through low crystallinity doping precursor and two-stage oxygen control + low discharge temperature.

[0085] Compared with the complicated process such as "core-shell / pressurized secondary co-precipitation", the process of the application is more concise, the parameters are quantifiable, easy to scale up, and the process complexity and manufacturing cost are reduced while the performance is ensured.

[0086] In summary, the application realizes high activity, low residual lithium, high phase purity, low gas evolution and batch stability of Li2Ni 3 O2 positive electrode lithium supplementing agent, which significantly overcomes the deficiencies of the prior art in terms of doping uniformity, reaction completeness and mass production consistency. 1-x M x O2 positive electrode lithium supplementing agent, which significantly overcomes the deficiencies of the prior art in terms of doping uniformity, reaction completeness and mass production consistency.

[0087] The basic principles, main features and advantages of the application are shown and described above, and various changes and improvements can be made to the application without departing from the spirit and scope of the application. These changes and improvements fall within the scope of the application.

Claims

1. A method for preparing a positive electrode lithium supplementing agent, characterized by, Comprising the following steps: S1. Preparing a mixed solution of nickel salt and M salt according to stoichiometric ratio, preparing a sodium hydroxide solution as a precipitant, and preparing an ammonia solution as a complexing agent; S2. The mixed solution of nickel salt and M salt is added into the reactor with sodium hydroxide solution and ammonia water in a certain proportion, the pH value of the reaction process is controlled at 10-12, and the reaction is stopped when the target particle size is reached at 45-60℃. After centrifugation, washing, drying and screening, the doped nickel hydroxide Ni 1-x Mx(OH)2; S3. drying the doped Ni obtained in step S2 at 300-350°C for 2-4h 1-x Mx(OH)2 is low-temperature calcined under a protective atmosphere, the oxygen volume fraction in the atmosphere is ≤0.02%, the calcination temperature is 250-350°C, the time is 2-4h, the temperature rising rate is 3-8°C / min, after the calcination is completed, the Mx(OH)2 is cooled and discharged at a discharge temperature ≤60°C, and a doped nickel oxide precursor Ni with low crystallinity is obtained 1- x M x O; S4. The prepared doped precursor Ni 1-x M x O is mixed with a lithium salt, calcined at high temperature under a protective atmosphere, the temperature is controlled between 600-800℃, the oxygen content is controlled at ≤0.005%, the sintering time is 12-24h, and the high-purity positive electrode lithium supplement material is obtained by crushing and pulverizing.

2. The method of claim 1, wherein, M is one or more of Al and Mg elements, and 0 < x < 0.

05.

3. The method according to claim 1 or 2, characterized in that, The nickel salt is one or more of nickel sulfate, nickel nitrate, nickel acetate, and nickel chloride, and the M salt is one or more of the corresponding sulfate or nitrate.

4. The method of claim 1, wherein, The lithium salt of S4 is selected from one or more of lithium carbonate, lithium hydroxide, lithium oxide, and lithium oxalate, and the oxygen content of the protective atmosphere of S3 and S4 is monitored and controlled by an online oxygen analyzer.

5. The method according to any one of claims 1 to 4, characterized in that, The discharge temperature of step S3 is preferably ≤ 30℃, and step S3 is performed in a dynamic sintering furnace, which is a rotary kiln or a dynamic device with equivalent material stirring and gas-solid contact capacity.

6. A doped precursor for an anode lithium supplementing agent, characterized in that, The doped precursor is prepared by the method according to any one of claims 1-5, and the chemical formula of the doped precursor is Ni 1-x M x O, Ni 3+ ≤0.5%.

7. The doped precursor for positive electrode lithium supplementing agent according to claim 6, characterized in that, The doped precursor has a specific surface area of ≥ 80 m 2 / g, with an average particle size of 3-10 microns.

8. The doped precursor for positive electrode lithium supplementing agent according to claim 6 or 7, characterized in that, The XRD diffraction peak of the doped precursor has no impurity phase, and the diffraction peak half-width of the 200 crystal face is ≥ 1.400°, and the porosity is ≥ 20%.

9. A positive electrode lithium replenishing agent, characterized in that, The positive lithium supplementing agent is obtained by sintering the doped precursor of any one of claims 6-8 with a lithium salt, and the chemical formula of the lithium supplementing agent is Li2Ni 1-x M x O2, residual lithium ≤3.5%, charge specific capacity ≥420 mAh / g, and irreversible capacity ≥290 mAh / g.

10. Use of the positive electrode lithium supplementing agent of claim 9 in a lithium ion battery as a positive electrode lithium supplementing additive to compensate for initial irreversible lithium loss of the battery and improve cycle stability.

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