Positive electrode lithium supplement material, its preparation and application in lithium supplementation of positive electrode of lithium ion battery

Abstract

The present invention belongs to the technical field of lithium supplementation for lithium-ion cathodes, and specifically relates to a lithium supplementation material for a Li x Mn 0.54 Ni 0.26 O2 cathode, which has a radial morphology and 1.24 ≤ x ≤ 1.6. The present invention also provides the preparation of the lithium supplementation material and its application in lithium supplementation for cathodes. The material described in the present invention has excellent lithium supplementation performance and air resistance stability.

Description

Technical Field:

[0001] The present invention belongs to the field of energy storage devices, and particularly relates to a cathode material for lithium-ion batteries. Background Art:

[0002] Cathode materials for lithium-ion batteries, such as layered LiCoO 2 materials, spinel-structured LiMn 2 O 4 materials, olivine-structured LiFePO 4 materials and high-nickel ternary cathode materials have been widely used in the fields of portable electronic devices and automotive power batteries, and have advantages such as high energy density, long cycle life, and no memory effect. Considering that the Coulombic efficiency (CE), defined as the ratio of discharge capacity to charge capacity, is a key indicator of a lithium-ion battery (LIBs) because it quantifies the capacity loss per cycle and can further predict the life of a lithium-ion battery. In a closed system, active lithium ions come from a limited lithium source in the lithium-containing cathode and cannot be replenished. It should be noted that during the initial charging process, the formation of the solid electrolyte interface (SEI) film will cause the lithium-containing cathode to consume 5-10% of the lithium ions, resulting in a problem of low initial Coulombic efficiency (ICE) of lithium ions. For Si-based anodes (15-35%) and other anodes with large volume changes and large specific surface areas, the loss of active Li + is even higher. To address this problem, it is urgent to develop a simple and novel lithium supplementation technology.

[0003] Currently, lithium supplementation technologies are mainly divided into cathode lithium supplementation and anode lithium supplementation. However, anode lithium supplementation inevitably uses highly active lithium metal sheets, which have high safety hazards and it is difficult to precisely control the degree of lithium supplementation, and there are high requirements for the atmosphere environment and equipment during the production process. While the cathode lithium supplementation technology mainly adds the lithium supplementation material in the mixing process without changing the battery process and equipment. In recent years, due to considerations such as safety, production cost, and compatibility with the current lithium-ion battery production process, cathode lithium supplementation has gradually attracted the attention of enterprises and researchers in related fields.

[0004] Currently, Li 5 FeO 4 、Li 2 NiO 2 、Li 3Positive electrode lithium supplement materials such as N, although they have a relatively high irreversible capacity in the first cycle, have extremely poor air stability, complex synthesis processes, are not conducive to mass production, and are difficult to achieve industrial applications. Based on the above problems, the positive electrode lithium supplement technology urgently needs to find a more suitable positive electrode lithium supplement material to achieve a safer and more stable lithium supplement process. Summary of the Invention:

[0005] In view of the existing problems, the first object of the present invention is to provide a lithium supplement material for the positive electrode of a lithium-ion battery, Li x Mn 0.54 Ni 0.26 O 2 , where: 1.24 ≤ x ≤ 1.6; aiming to improve the lithium supplement effect of the positive electrode.

[0006] The second object of the present invention is to provide a preparation method for the lithium supplement material of Li x Mn 0.54 Ni 0.26 O 2 positive electrode, aiming to prepare a new material with the special radial structure and excellent positive electrode lithium supplement activity.

[0007] The third object of the present invention is to provide the application of the lithium supplement material of Li x Mn 0.54 Ni 0.26 O 2 positive electrode in the preparation of lithium-supplemented positive electrode active materials, lithium-supplemented positive electrode materials, lithium-supplemented positive electrodes, and lithium-supplemented lithium-ion batteries.

[0008] The fourth object of the present invention is to provide a lithium-supplemented positive electrode active material, a lithium-supplemented positive electrode material, a lithium-supplemented positive electrode, and a lithium-supplemented lithium-ion battery containing the lithium supplement material.

[0009] A lithium supplement material for the positive electrode of Li x Mn 0.54 Ni 0.26 O 2 positive electrode, having a radial morphology, and 1.24 ≤ x ≤ 1.6.

[0010] The present invention provides a new material with a radial Li x Mn 0.54 Ni 0.26 O 2 phase. Innovatively using it as a lithium supplement material, based on the synergy of its phase and structure, it can exhibit excellent lithium supplement activity.

[0011] In the present invention, the special chemical formula phase and the radial morphology of the new material are the key to synergistically endowing the material with excellent lithium compensation performance. In the present invention, the radial morphology can be understood as a morphology that includes a core and diverges from the core into three-dimensional space. The material of the present invention can reduce lithium vacancies, improve the initial cycle lithium compensation capacity of the material, and at the same time improve the lithium ion migration path and passage. Combining the combination of the chemical formula phase and the radial structure helps to significantly improve the lithium compensation performance.

[0012] The present invention also provides a method for preparing the positive electrode lithium compensation material of Li x Mn 0.54 Ni 0.26 O 2 , and the steps include:

[0013] (1): Preparation of carbonate-type precursor material

[0014] Add carbonate solution A to the bottom liquid dissolved with nickel source and manganese source, carry out the first-stage reaction, then supplement carbonate solution B, carry out the second-stage reaction, and then obtain the carbonate-type precursor through solid-liquid separation;

[0015] In the total metal of Ni and Mn in the bottom liquid, the molar ratio of Ni / Mn elements is 1:2 to 2.2;

[0016] The molar ratio of the carbonate in carbonate solution A to the total metal in the bottom liquid (in the present invention, the total metal is calculated as Mn and Ni) is 1.3 to 1.2:1;

[0017] The molar ratio of the carbonate in carbonate solution B to the total metal in the bottom liquid is 1.1 to 1.0:1;

[0018] The temperature in the first-stage reaction and the second-stage reaction is 60 - 70 °C;

[0019] (2): Lithium doping roasting

[0020] Compound the prepared carbonate-type precursor and lithium carbonate and carry out roasting in an oxygen-containing atmosphere to obtain the positive electrode lithium compensation material of Li x Mn 0.54 Ni 0.26 O 2 ;

[0021] Among them, the molar ratio of Li in lithium carbonate to the total metal is 1.55 - 2:1.

[0022] In the present invention, how to successfully construct Li x Mn 0.54 Ni 0.26 O 2The problem faced in the preparation of the material of the present invention is the phase of the substance, solving the preparation of mixed phases in the described chemical formula, and how to successfully construct a radial morphology, and further how to improve the lithium compensation activity of the obtained material. In response to this problem of new material preparation, the present invention has found through research that, innovatively, a carbonate precursor is constructed based on the described two-stage reaction, and further combined with the joint control of parameters such as the dosage, temperature, and element ratio of the carbonate in the second-stage reaction, the Li x Mn 0.54 Ni 0.26 O 2 phase can be prepared, reducing the preparation of mixed phases. Moreover, it is also beneficial for the preparation of materials with a radial morphology. More importantly, based on the combination of the described preparation process and parameters, the lithium compensation activity of the obtained material can be significantly improved.

[0023] In the present invention, the idea of preparing the two-stage carbonate precursor and the joint control of the dosage and temperature of each stage of carbonate in the preparation process are the keys to synergistically improving the phase, radial morphology, and lithium compensation performance of the prepared lithium compensation material.

[0024] In the present invention, the nickel source is a water-soluble salt; preferably one or more of nickel acetate, nickel nitrate, and nickel sulfate;

[0025] Preferably, the manganese source is a water-soluble salt, preferably one or more of manganese acetate, manganese nitrate, and manganese sulfate;

[0026] Preferably, the solvent in the bottom liquid is water or a mixed solvent of water - organic solvent; the organic solvent is a solvent miscible with water;

[0027] The molar concentration of the total metal in the bottom liquid can be adjusted according to the preparation needs, for example, it can be 2 - 2.2 M;

[0028] Preferably, in the bottom liquid, the molar ratio of Ni to Mn is 1:2.

[0029] In the present invention, the carbonate solution A and the carbonate solution B are each an aqueous solution of at least one of sodium carbonate, potassium carbonate, and ammonium carbonate;

[0030] In the carbonate solution A and the carbonate solution B, the concentration of the solute can be adjusted according to the preparation needs, etc., for example, it can be 2 - 2.2 M alone;

[0031] Preferably, ammonia water is added to the carbonate solution A and the carbonate solution B. In the present invention, under the idea of preparing the two-stage carbonate precursor and parameter control, further combined with the application of ammonia water, it helps to further synergistically improve the phase, radial morphology, and lithium compensation performance of the obtained lithium compensation material.

[0032] In carbonate solution A and carbonate solution B, the addition amount of ammonia water can be adjusted as needed. For example, its molar amount relative to carbonate can be 0.1 to 2 times.

[0033] Preferably, the first-stage reaction and the second-stage reaction are carried out under a protective atmosphere. The protective atmosphere is, for example, at least one of nitrogen and inert gas.

[0034] In the present invention, the stirring speed in the first-stage reaction and the second-stage reaction is 500 - 700 r / min;

[0035] Preferably, in the first-stage reaction, carbonate solution A is uniformly dropped into the bottom liquid. Preferably, the pH of the system in the first-stage reaction is controlled to be maintained at 10.6 - 10.0;

[0036] Preferably, during the second-stage reaction, carbonate solution B is uniformly dropped into the first-stage reaction system. Preferably, the pH of the system in the second-stage reaction is controlled to be maintained at 10.0 - 9.4.

[0037] Preferably, the temperature of the first-stage reaction and the second-stage reaction is 60 - 65 °C.

[0038] In the present invention, after the second-stage reaction, solid-liquid separation is carried out, and then it is washed, dried, and optionally ground to obtain the carbonate-type precursor. For example, washing, drying, and grinding can all be achieved based on existing means. For example, the drying temperature is 100 - 130 °C, preferably 100 - 110 °C, and the time is 20 - 30 h, preferably 24 - 30 h.

[0039] In the present invention, under the innovative precursor preparation process, further cooperating with the control of the lithium source and dosage in the lithium-doping roasting stage is beneficial to preparing the material with the desired phase, morphology, and excellent lithium-doping performance. On this basis, further controlling the temperature in the roasting stage helps to further improve the phase, morphology, and lithium-doping performance of the prepared material.

[0040] In the present invention, the roasting stage is carried out under an oxygen-containing atmosphere. The oxygen-containing atmosphere is, for example, air, oxygen, a mixed gas of oxygen and inert gas, etc. Considering the treatment cost, the oxygen-containing gas is air. In the present invention, a lithium-doping material is prepared under an oxygen-containing atmosphere, and the prepared material has unexpected oxygen-containing atmosphere stability in the field of lithium doping and has a better application prospect.

[0041] In the present invention, the roasting process includes two heat preservation sections. Among them, the temperature of the first heat preservation section is 400 - 500 °C, preferably 450 - 500 °C; the heat preservation time of the first heat preservation section is 3 - 6 h, preferably 5 - 6 h;

[0042] The temperature of the second heat preservation section is 750 - 900 °C, preferably 800 - 850 °C; the time of the second heat preservation section is 10 - 24 h, preferably 12 - 15 h.

[0043] The heating rate in the sintering stage is, for example, 2 - 5 °C / min; preferably 3 - 5 °C / min.

[0044] The present invention also provides an application of the above-mentioned Li x Mn 0.54 Ni 0.26 O 2 positive electrode lithium supplement material. It is used as a positive electrode lithium supplement material and is compounded with a positive electrode active material to prepare a lithium-supplemented positive electrode active material for a lithium-ion battery;

[0045] Preferably, the lithium-supplemented positive electrode active material is compounded with a conductive agent and a binder to be used as a lithium-supplemented positive electrode material;

[0046] Preferably, the lithium-supplemented positive electrode material is compounded on a current collector to prepare a lithium-supplemented positive electrode;

[0047] Preferably, the lithium-supplemented positive electrode is assembled to form a lithium-ion battery.

[0048] For the application of the present invention, based on existing means, the lithium supplement material can be prepared into a lithium-supplemented positive electrode active material, a lithium-supplemented positive electrode material, a lithium-supplemented positive electrode, and a lithium-ion battery.

[0049] The present invention also provides a lithium-supplemented positive electrode active material for a lithium-ion battery, which includes a positive electrode active material and also includes the above-mentioned Li x Mn 0.54 Ni 0.26 O 2 positive electrode lithium supplement material.

[0050] In the present invention, the positive electrode active material can be a positive electrode active material well-known in the field of lithium-ion batteries, such as at least one of LiFePO 4 、LiCoO 2 、NCM ternary positive electrode material, NCA ternary positive electrode material, lithium-rich manganese-based layered oxide, lithium nickel manganate, lithium manganate;

[0051] In the present invention, for the positive electrode active material, the weight ratio of Li x Mn 0.54 Ni 0.26 O 2 positive electrode lithium supplement material can be adjusted as needed, for example, it can be 80 - 99:20 - 1; preferably 90 - 95:10 - 5.

[0052] The present invention also provides a lithium-ion battery lithium-supplementing cathode material, which includes the above-mentioned lithium-supplementing cathode active material, and also includes a conductive agent and a binder.

[0053] In the present invention, the conductive agent and the binder can be materials well-known in the field of lithium-ion batteries and having conductive and binding properties. For example, the conductive agent is at least one of conductive carbon black, acetylene black, Ketjen black, graphene oxide and graphene. The binder is at least one of PVDF and PTFE.

[0054] In the present invention, the contents of the conductive agent and the binder in the lithium-supplementing cathode material can be adjusted as needed. For example, in the lithium-ion battery lithium-supplementing cathode material, the content of the conductive agent is 5-15 wt.%; the content of the binder is 5-15 wt.%.

[0055] The present invention also provides a lithium-ion battery lithium-supplementing cathode, which includes a current collector and the above-mentioned lithium-supplementing cathode material compounded on its surface.

[0056] In the present invention, the current collector can be a positive electrode current collector material well-known in the field of lithium-ion batteries.

[0057] The present invention also provides a lithium-ion battery, the positive electrode of which is the positive electrode described in the present invention.

[0058] Compared with the prior art, the present invention has the following remarkable advantages:

[0059] (1) The present invention provides a radial Li x Mn 0.54 Ni 0.26 O 2 material, which is innovatively used as a lithium-supplementing material. Based on the combined synergy of its chemical formula phase and radial morphology, it exhibits excellent lithium-supplementing activity. The new material described in the present invention has a relatively high first-cycle irreversible capacity, and can effectively supplement the loss of Li + during the first charge and discharge process of the lithium-ion battery, thereby improving the first charge and discharge efficiency of the lithium-ion battery. At the same time, this material has extremely high cycle stability at low voltages and can still provide a considerable discharge specific capacity during subsequent cycles.

[0060] (2) The present invention innovatively constructs a carbonate precursor based on the above-mentioned two-stage reaction, and further cooperates with the combined control of parameters such as the dosage, temperature, and element ratio of the carbonate in the second-stage reaction, and can successfully prepare the Li x Mn 0.54 Ni 0.26 O 2 phase, reduce the preparation of impurity phases. Moreover, it is also beneficial to prepare materials with a radial morphology. More importantly, based on the combination of the above-mentioned preparation process and parameters, the lithium-supplementing activity of the prepared material can be significantly improved.

[0061] In addition, the lithium supplement material described in the present invention is prepared in an oxygen-containing atmosphere and has extremely strong air stability. This greatly reduces the production cost, simplifies the production process, has excellent industrial application prospects, and is conducive to large-scale commercial production. BRIEF DESCRIPTION OF THE DRAWINGS:

[0062] Figure 1 X-ray diffraction pattern of Example 1;

[0063] Figure 2 SEM image of Example 1; DETAILED DESCRIPTION OF THE EMBODIMENTS:

[0064] Example 1

[0065] (1) Using nickel sulfate and manganese sulfate as raw materials, the reaction raw materials are weighed according to the molar ratio of Ni and Mn elements of 1:2, and deionized water is added to prepare a 2 mol / L metal salt solution;

[0066] First-stage reaction: In an N 2 atmosphere, a 2 mol / L sodium carbonate solution A is added dropwise to the metal salt solution for the first-stage reaction to obtain a suspension. Among them, the reaction temperature is 65 °C, the molar ratio of sodium carbonate in the sodium carbonate solution A to the metal salt is 1.2:1 (controlling the pH during the reaction to be 10.3 - 10.0), and the rotation speed is 650 r / min; after the addition of the sodium carbonate solution A is completed (1.5 - 2.5 h), the second-stage reaction is carried out;

[0067] Second-stage reaction: In an N 2 atmosphere, continue to add a 2 M carbonate solution B to the suspension for the second-stage reaction. Among them, the molar ratio of sodium carbonate in the sodium carbonate solution B to the metal salt is 1.05:1 (controlling the pH during the reaction to be 10.0 - 9.6, and the dropping time of the sodium carbonate solution B is 1 - 2.5 h), and the rotation speed is 550 r / min; the reaction temperature is 65 °C to obtain a precursor suspension;

[0068] (2) Filter the precursor suspension, wash the filter residue with a 2 mol / L sodium carbonate solution and hot water, and then dry it at 100 °C for 24 h. After grinding, a carbonate-type precursor material is obtained;

[0069] (3) The above precursor material and lithium carbonate are uniformly mixed according to the molar ratio of transition metal to lithium of 1:2. In an air atmosphere, first perform a low-temperature pretreatment at 500 °C (TI), and then raise the temperature to 800 °C (T2) for sintering. The heating rate is 3 °C / min. After cooling, the lithium supplement material Li 1.6 Mn 0.54 Ni 0.26O 2 The XRD and SEM images of the materials are shown in Figure 1 and Figure 2 .

[0070] (4) The newly prepared (referring to the time exposed to air after synthesis being less than or equal to 1 h) cathode lithium supplement material Li 1.6 Mn 0.54 Ni 0.26 O 2 , carbon black conductive agent (SP), binder polyvinylidene fluoride (PVDF) and LiFePO 4 are mixed in a weight ratio of 6:10:10:74. Then, 120% of N-methylpyrrolidone (NMP) based on the weight of the mixture is added as a solvent. After mixing evenly, through slurry adjustment, coating, drying, and rolling, a cathode electrode sheet is obtained. Combined with lithium metal, a 2025 coin-type half-cell is made. Among them, the first charge is carried out at a constant current or constant voltage of 0.1C, with a cut-off voltage of 4.6V. The first discharge is carried out at a constant current of 0.1C, with a cut-off voltage of 2.5V. Subsequently, it is cycled 100 times at 0.5C within a voltage window of 2.5 - 4.2V.

[0071] Example 2

[0072] Compared with Example 1, the difference is only that in the first-stage reaction of step (1), the molar ratio of sodium carbonate solution A to the metal salt solution changes from 1.2:1 to 1.3:1, and other steps remain unchanged.

[0073] Example 3

[0074] Compared with Example 1, the difference is only that in the second-stage reaction of step (1), the molar ratio of sodium carbonate solution B to the metal salt solution changes from 1.05:1 to 1.0:1, and other steps remain unchanged.

[0075] Example 4

[0076] Compared with Example 1, the difference is only that in step (1), the sodium carbonate solution A and B are replaced with a mixed solution of sodium carbonate - ammonia water, and the total solute molar concentration of the mixed solution is 2M. Among them, the molar ratio of sodium carbonate to ammonia water (calculated as NH 3 ) is 4:1, and other steps remain unchanged.

[0077] Example 5

[0078] Compared with Example 1, the difference is only that in step (1), the reaction temperature of the first-stage reaction and the second-stage reaction changes from 65°C to 70°C, and other steps remain unchanged.

[0079] Example 6

[0080] Compared with Example 1, the only difference is that in step (1), the reaction temperatures of the first-stage reaction and the second-stage reaction are changed from 65 °C to 60 °C, and other steps remain unchanged.

[0081] Example 7

[0082] Compared with Example 1, the only difference is that in step (3), the elemental molar ratio of the transition metal to lithium is changed from 1:2 to 1:1.55, and other steps remain unchanged. The chemical formula of the prepared material is Li 1.24 Mn 0.54 Ni 0.26 O 2 .

[0083] Example 8

[0084] Compared with Example 1, the only difference is that in step (3), the elemental molar ratio of the transition metal to lithium is changed from 1:2 to 1:1.65, and other steps remain unchanged. The chemical formula of the prepared material is Li 1.32 Mn 0.54 Ni 0.26 O 2 .

[0085] Example 9

[0086] Compared with Example 1, the only difference is that in step (3), the high-temperature sintering temperature T2 is changed from 800 °C to 900 °C, and other steps remain unchanged.

[0087] Comparative Example 1

[0088] Compared with Example 1, the only difference is that a hydroxide precursor is prepared. For example, in step (1), sodium carbonate is replaced with sodium hydroxide (the pH control in each stage is the same as in Example 1), and other steps remain unchanged.

[0089] Comparative Example 2

[0090] Compared with Example 1, the only difference is that in step (1), the elemental molar ratio of Ni and Mn in the reaction raw materials is changed from 1:2 to 1:3, and other steps remain unchanged.

[0091] Comparative Example 3

[0092] Compared with Example 1, the only difference is that in step (1), the reaction raw materials contain sulfates of Ni, Co, and Mn, and the molar ratio of Ni:Co:Mn = 1:1:4, and other steps remain unchanged. The prepared Li 1.6 Mn 0.54 Ni 0.13 Co 0.13 O 2 .

[0093] Comparative Example 4

[0094] Compared with Example 1, the only difference is that in step (1), the reaction raw materials include sulfates of Ni, Co, and Mn, and the molar ratio of Ni:Co:Mn = 2:2:6, and the other steps remain unchanged.

[0095] Comparative Example 5

[0096] Compared with Example 1, the only difference is that in the nucleation stage of step (1), the molar ratio of sodium carbonate solution A to metal salt solution changes from 1.2:1 to 1.5:1, and the other steps remain unchanged.

[0097] Comparative Example 6

[0098] Compared with Example 1, the only difference is that in the crystal nucleus growth stage of step (1), the molar ratio of sodium carbonate solution B to metal salt solution changes from 1.05:1 to 1.3:1, and the other steps remain unchanged.

[0099] Comparative Example 7

[0100] Compared with Example 1, the only difference is that the temperature of the first-stage reaction and the second-stage reaction in step (1) changes from 65°C to 85°C, and the other steps remain unchanged.

[0101] Comparative Example 8

[0102] Compared with Example 1, the only difference is that the temperature of the first-stage reaction and the second-stage reaction in step (1) changes from 65°C to 55°C, and the other steps remain unchanged.

[0103] Comparative Example 9

[0104] Compared with Example 1, the only difference is that lithium carbonate in step (3) is replaced with lithium hydroxide, and the other steps remain unchanged.

[0105] Comparative Example 10

[0106] Compared with Example 1, the only difference is that the element molar ratio of transition metal to lithium in step (3) changes from 1:2 to 1:1.25, and the other steps remain unchanged.

[0107] The newly prepared materials in each case were measured by a method similar to that of Example 1. In addition, the materials prepared in each case were placed for 30 days under the conditions of an air atmosphere, a temperature of 20 - 25°C, and a humidity of 10% - 30%, and then assembled into a battery and subjected to electrochemical performance measurement according to the method of Example 1. The results are shown in Table 1:

[0108] The test results are shown in Table 1:

[0109]

[0110]

[0111] It can be seen from the above-described embodiments and comparative examples that the synthesis method of the technical solution of the present invention is simple and easy to realize industrial production. The cathode lithium supplement material obtained by the present invention has stable properties, excellent air stability, cycle stability and good lithium supplement effect, can effectively solve the problem that the low Coulomb efficiency of the first cycle of the battery affects the energy density, and can also provide a considerable discharge capacity during the battery cycle, thereby improving the cycle stability performance of the battery and having great commercial potential.

Claims

1. A Li x Mn 0.54 Ni 0.26 O 2 cathode lithium supplement material, It is characterized in that it has a radial morphology and 1.24 ≤ x ≤ 1.6; The described Li x Mn 0.54 Ni 0.26 O 2 The cathode lithium supplement material is prepared through the following steps: (1): Preparation of carbonate-type precursor material Add carbonate solution A to the bottom liquid dissolved with nickel source and manganese source, carry out the first-stage reaction, then supplement carbonate solution B and carry out the second-stage reaction, and then obtain the carbonate-type precursor through solid-liquid separation; In the total metal of Ni and Mn in the bottom liquid, the molar ratio of Ni / Mn elements is 1:2 to 2.2; The molar ratio of the carbonate in carbonate solution A to the total metal in the bottom liquid is 1.3 to 1.2:1; The molar ratio of the carbonate in carbonate solution B to the total metal in the bottom liquid is 1.1 to 1.0:1; The temperature in the first-stage reaction and the second-stage reaction is 60 - 70 °C; (2): Lithium-doping roasting The prepared carbonate-type precursor and lithium carbonate are combined and calcined in an oxygen-containing atmosphere to obtain the Li x Mn 0.54 Ni 0.26 O 2 positive electrode lithium supplement material; Among them, the molar ratio of Li in lithium carbonate to the total metal is 1.55 to 2:

1.

2. The preparation method of the lithium supplement cathode material of Li x Mn 0.54 Ni 0.26 O 2 as claimed in claim 1 It is characterized in that the steps include: (1): Preparation of carbonate-type precursor material Add carbonate solution A to the bottom liquid dissolved with nickel source and manganese source, carry out the first-stage reaction, then supplement carbonate solution B and carry out the second-stage reaction, and then obtain the carbonate-type precursor through solid-liquid separation; In the total metal of Ni and Mn in the bottom liquid, the molar ratio of Ni / Mn elements is 1:2 to 2.2; The molar ratio of the carbonate in carbonate solution A to the total metal in the bottom liquid is 1.3 to 1.2:1; The molar ratio of the carbonate in carbonate solution B to the total metal in the bottom liquid is 1.1 to 1.0:1; The temperature in the first-stage reaction and the second-stage reaction is 60 - 70 °C; (2): Lithium-doping roasting The obtained carbonate-type precursor and lithium carbonate are combined and calcined in an oxygen-containing atmosphere to obtain the Li x Mn 0.54 Ni 0.26 O 2 positive electrode lithium supplement material; Among them, the molar ratio of Li in lithium carbonate to the total metal is 1.55 to 2:

1.

3. According to claim 2, the Li x Mn 0.54 Ni 0.26 O 2 Preparation method of cathode lithium supplement material, It is characterized in that the nickel source is a water-soluble salt; the manganese source is a water-soluble salt.

4. According to claim 3, the Li x Mn 0.54 Ni 0.26 O 2 Preparation method of cathode lithium supplement material It is characterized in that the nickel source is one or more of nickel acetate, nickel nitrate, and nickel sulfate; the manganese source is one or more of manganese acetate, manganese nitrate, and manganese sulfate.

5. According to claim 2, the Li x Mn 0.54 Ni 0.26 O 2 Preparation method of cathode lithium supplement material It is characterized in that the solvent in the bottom liquid is water or a mixed solvent of water - organic solvent; the organic solvent is a solvent miscible with water.

6. The Li according to claim 2 x Mn 0.54 Ni 0.26 O 2 Method for preparing cathode lithium supplement material It is characterized in that in the bottom liquid, the molar concentration of the total metal is 2 - 2.2 M.

7. The Li according to claim 2 x Mn 0.54 Ni 0.26 O 2 Method for preparing cathode lithium supplement material It is characterized in that in the bottom liquid, the molar ratio of Ni and Mn is 1:

2.

8. The Li according to claim 2 x Mn 0.54 Ni 0.26 O 2 Preparation method of cathode lithium supplement material It is characterized in that the carbonate solution A and the carbonate solution B are each an aqueous solution of at least one of sodium carbonate, potassium carbonate, and ammonium carbonate.

9. The Li according to claim 8 x Mn 0.54 Ni 0.26 O 2 Preparation method of cathode lithium supplement material It is characterized in that in the carbonate solution A and the carbonate solution B, the concentration of the solute is each 2 - 2.2 M.

10. The Li according to claim 2 x Mn 0.54 Ni 0.26 O 2 Method for preparing cathode lithium supplement material It is characterized in that ammonia water is added to the carbonate solution A and the carbonate solution B.

11. According to claim 2, the Li x Mn 0.54 Ni 0.26 O 2 Preparation method of cathode lithium supplement material, It is characterized in that the first-stage reaction and the second-stage reaction are carried out under a protective atmosphere.

12. According to claim 2, the Li x Mn 0.54 Ni 0.26 O 2 Preparation method of cathode lithium supplement material It is characterized in that the roasting process includes two heat preservation sections. Among them, the temperature of the first heat preservation section is 400 - 500 °C, and the heat preservation time of the first heat preservation section is 3 - 6 h; the temperature of the second heat preservation section is 750 - 900 °C; the time of the second heat preservation section is 10 - 24 h.

13. According to claim 12, the Li x Mn 0.54 Ni 0.26 O 2 Preparation method of cathode lithium supplement material It is characterized in that the temperature of the first heat preservation section is 450 - 500 °C; the heat preservation time of the first heat preservation section is 5 - 6 h; the temperature of the second heat preservation section is 800 - 850 °C; the time of the second heat preservation section is 12 - 15 h.

14. A Li as described in claim 1 x Mn 0.54 Ni 0.26 O 2 The application of the lithium - supplementing cathode material or the Li x Mn 0.54 Ni 0.26 O 2 prepared by the preparation method according to any one of claims 2 to 13, It is characterized in that it is used as a cathode lithium supplement material and is compounded with a cathode active material to prepare a cathode lithium supplement active material for a lithium-ion battery.

15. The application according to claim 14, it is characterized in that the cathode lithium supplement active material is compounded with a conductive agent and a binder to be used as a cathode lithium supplement material.

16. The application according to claim 15, it is characterized in that the cathode lithium supplement material is compounded on a current collector to prepare a cathode lithium supplement.

17. The application according to claim 16, it is characterized in that the cathode lithium supplement is assembled to form a lithium-ion battery.

18. A cathode lithium supplement active material for a lithium-ion battery, it is characterized in that It includes a positive electrode active material and also includes Li as described in claim 1 x Mn 0.54 Ni 0.26 O 2 A positive electrode lithium supplement material or Li prepared by the preparation method according to any one of claims 2 to 13 x Mn 0.54 Ni 0.26 O 2 A positive electrode lithium supplement material.

19. The cathode lithium supplement active material for a lithium-ion battery according to claim 18, it is characterized in that The positive electrode active material includes LiFePO 4 , LiCoO 2 , at least one of NCM ternary positive electrode materials, NCA ternary positive electrode materials, lithium-rich manganese-based layered oxides, lithium nickel manganate, and lithium manganate.

20. The cathode lithium supplement active material for a lithium-ion battery according to claim 19, it is characterized in that Ultra-active material, Li x Mn 0.54 Ni 0.26 O 2 The weight ratio of the cathode lithium supplement material is 80~99:20~1.

21. A cathode lithium supplement material for a lithium-ion battery, it is characterized in that it includes the cathode lithium supplement active material according to any one of claims 18 to 20, and also includes a conductive agent and a binder.

22. The cathode lithium supplement material for a lithium-ion battery according to claim 21, it is characterized in that in the cathode lithium supplement material for a lithium-ion battery, the content of the conductive agent is 5 to 15 wt.%; the content of the binder is 5 to 15 wt.%.

23. A cathode lithium supplement for a lithium-ion battery, it is characterized in that it includes a current collector and the cathode lithium supplement material according to claim 21 or 22 compounded on its surface.

24. A lithium-ion battery, it is characterized in that its cathode is the cathode according to claim 23.

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