CN112751006B - Cobalt-free lithium-ion battery layered positive electrode material, preparation method and application thereof - Google Patents

Abstract

The present application discloses a layered positive electrode material for a cobalt-free lithium ion battery and a preparation method and application thereof. The layered positive electrode material for a cobalt-free lithium-ion battery of the present application is a layered positive electrode material formed by alternately stacking lithium layers and cobalt-free transition metal oxide layers. It is formed by the transition metal in the transition metal oxide layer entering the lithium layer to occupy the position of lithium ions. The layered cathode material for cobalt-free lithium ion battery of the present application still has excellent electrochemical performance without using cobalt ions; and, because it does not need to use high-priced metal cobalt ions, the cost caused by cobalt dependence is solved question. The preparation method of the layered positive electrode material for the cobalt-free lithium ion battery of the present application is simple, and it is easy for large-scale industrial production.

Description

Cobalt-free lithium-ion battery layered positive electrode material, preparation method and application thereof

technical field

The present application relates to the field of battery materials, in particular to a layered positive electrode material for a cobalt-free lithium ion battery and a preparation method and application thereof.

Background technique

As the automotive industry transitions to electrification, rechargeable batteries must also meet future demands. While efforts to improve battery performance have had some success, they are currently hampered by prohibitive costs. These battery cost-related challenges are mainly related to rapidly rising prices and increasing demand for transition metals (TMs), cobalt as a component of widely used commercial cathode core materials, such as LiCoO ₂ , LiNi _x M _y Co ₁ , in particular in short supply. _-xy O ₂ , LiNi _0.8 Co _0.15 Al _0.05 O ₂ and other positive electrode materials. Co has become economically unattractive in recent years due to rising mining royalties, as well as political and ethical concerns in Africa. In response to these cost pressures, researchers have made great efforts to develop low-cobalt or even cobalt-free cathodes that do not have to trade off battery performance as much. Although some cathodes including lithium- and manganese-rich cathodes, high-voltage spinel LiNi _0.5 Mn _1.5 O ₄ and disordered rock-salt phase materials have been highlighted as possible alternatives to cobalt-containing cathodes, these alternative cathode materials have impractical Capacity and stability, difficult to use for large-scale commercial use. Therefore, current research on low Co dependence is mainly focused on layered oxide cathodes. Nickel-rich layered oxide cathode materials have high capacity and energy density. However, direct replacement of cobalt with nickel, such as LiNiO ₂ , is practically infeasible due to significantly reduced battery performance and thermal stability. Therefore, designing cobalt-free high-performance Li-ion layered cathode materials has become an important challenge.

It is generally believed that Co suppresses structural defects by reducing the Li/Ni mixing in the Ni-rich component and obtains a well-crystallized layered structure. This helps to ensure the rate capability of Ni-rich cathodes, but the effect on structural stability during cycling is unclear.

SUMMARY OF THE INVENTION

The purpose of this application is to provide a new layered positive electrode material for cobalt-free lithium ion battery and its preparation method and application.

This application adopts the following technical solutions:

One aspect of the present application discloses a layered positive electrode material for a cobalt-free lithium ion battery. The layered positive electrode material for a cobalt-free lithium ion battery is a layered positive electrode material formed by alternately stacking lithium layers and transition metal oxide layers that do not contain cobalt. , the lithium layer has 3-7% cation inversion, and the cation inversion is formed by the transition metal in the transition metal oxide layer entering the lithium layer to occupy the position of lithium ions. Therefore, 3-7% of cation inversion in the lithium layer means that in the lithium layer, 3-7% of the lithium ions are replaced by transition metal ions to form an inversion structure.

It should be noted that the key point of this application is that, without adding Co, by adjusting the amount and proportion of transition metals in the layered positive electrode material, and adjusting the preparation parameters, the inverse ratio of cations in the lithium layer is obtained to be 3-7 % Cobalt-free lithium-ion battery layered cathode material. The layered cathode material of the cobalt-free lithium ion battery of the present application also has excellent electrochemical performance without using Co, especially the cycle stability and thermal stability will be improved; and the cobalt-free lithium of the present application The preparation method of the layered positive electrode material for the ion battery is simple, and it is easy for large-scale industrial production.

In an implementation manner of the present application, the main transition metals of the transition metal oxide layer are nickel and manganese.

Preferably, the molar ratio of nickel and manganese is 6:4 to 99:1.

Preferably, in the layered positive electrode material of the cobalt-free lithium ion battery of the present application, the molar ratio of lithium element to other metal elements is 1-1.1:1. Among them, other metal elements refer to metal elements other than lithium, such as nickel and manganese, and if there are other doped metal elements, it also includes doped metal elements.

It should be noted that the lithium-rich and manganese-rich positive electrode materials or the nickel-rich layered oxide positive electrode materials are all positive electrode materials that already exist in the prior art; In the cathode material, by adding manganese, controlling the ratio of nickel and manganese, and adjusting the preparation process parameters, the ratio of cation inversion in the lithium layer is 3-7%; the Li(Ni _α Mn _β )O ₂ thus obtained has no The layered cathode material for cobalt lithium ion batteries not only has high cycle stability, but also has a rate performance that can meet the needs of lithium ion batteries and has excellent electrochemical performance.

In an implementation manner of the present application, the transition metal oxide layer is further doped with at least one of metal ions Al, Ti and Mg.

It should be noted that the transition metal oxide layer of the present application can be selected to add or not add doping metal ions such as Al, Ti and Mg according to the needs. , which is not specifically limited here.

In an implementation manner of the present application, the layered positive electrode material of the cobalt-free lithium ion battery is secondary micro-particles composed of primary nanoparticles.

Preferably, the size of the primary nanoparticles is 10-300 nanometers, and the size of the secondary microparticles is 1-20 microns.

In an implementation manner of the present application, the layered positive electrode material of the cobalt-free lithium ion battery is a single crystal particle with a micrometer size.

Preferably, the size of the single crystal particles is 0.5-10 microns.

It should be noted that the key point of this application lies in the creative discovery that the cobalt-free lithium-ion battery layered cathode material with a cation inversion ratio of 3-7% in the lithium layer has excellent electrochemical performance; as for the cobalt-free lithium-ion battery of this application The specific physical structure, particle size, single crystal structure and size, etc. of the layered cathode material can be regulated by the existing technology according to the application requirements. For example, the layered positive electrode material of the cobalt-free lithium ion battery of the present application can be made into a positive electrode material with a core-shell structure or an element gradient structure to meet various usage requirements.

Therefore, another aspect of the present application discloses a layered positive electrode material for a lithium ion battery. The layered positive electrode material for a lithium ion battery has a core-shell structure, and the coating material of the core-shell structure is the cobalt-free lithium ion battery layer of the present application. The core cathode material of the core-shell structure is at least one of lithium cobalt oxide, ternary layered material, spinel lithium manganate material and lithium iron phosphate material.

It can be understood that the key of this application is to apply the cobalt-free lithium ion battery layered positive electrode material of the present application to the lithium ion battery layered positive electrode material of the core-shell structure. As for the specific preparation methods of the core positive electrode material and the core-shell structure, All can refer to the prior art, which is not specifically limited here.

Another aspect of the present application discloses a layered positive electrode material for a lithium ion battery. The layered positive electrode material for the lithium ion battery has an element gradient structure, and the outermost layer material of the element gradient structure is the layered positive electrode for a cobalt-free lithium ion battery of the present application. Material, the interior of the element gradient structure is a material with a gradient of nickel and manganese elements, the nickel content increases from the outside to the inside, and the manganese content decreases from the outside to the inside.

It can be understood that the key of this application is to apply the cobalt-free lithium ion battery layered positive electrode material of the present application to the lithium ion battery layered positive electrode material of the element gradient structure. As for the internal elements of the element gradient structure, the ratio of internal elements The control and the specific preparation method of the layered positive electrode material for the lithium ion battery with the element gradient structure can all refer to the prior art, which is not specifically limited here.

Another aspect of the present application discloses the layered positive electrode material for cobalt-free lithium ion battery of the present application, or the layered positive electrode material for lithium ion battery using the layered positive electrode material for cobalt-free lithium ion battery of the present application in power lithium batteries and 3C consumer electronics. applications in lithium-ion batteries.

It should be noted that the cobalt-free lithium ion battery layered positive electrode material of the present application and the lithium ion battery layered positive electrode material using the cobalt-free lithium ion battery layered positive electrode material of the present application have excellent electrochemical performance, and can better Meet the needs of power lithium batteries and 3C consumer electronics lithium-ion batteries.

Another aspect of the present application discloses a battery in which the layered positive electrode material for a cobalt-free lithium ion battery of the present application or the layered positive electrode material for a lithium ion battery of the present application is used.

It should be noted that the battery of the present application has excellent electrochemical performance due to the use of the cobalt-free lithium ion battery layered positive electrode material of the present application or the lithium ion battery layered positive electrode material of the present application, and can better meet various requirements. Usage requirements.

Another aspect of the application discloses a method for preparing a layered positive electrode material for a cobalt-free lithium ion battery of the present application, wherein the layered positive electrode material for a cobalt-free lithium ion battery is synthesized by a high-temperature sintering method; the high-temperature sintering method includes mixing the raw materials uniformly, Sintering at 700-1100℃ for 3-24 hours in air or oxygen atmosphere.

Preferably, after the sintering is completed, the temperature is rapidly lowered to room temperature at a rate greater than 100° C./min, to obtain the layered positive electrode material for the cobalt-free lithium ion battery of the present application.

It should be noted that, in the high-temperature sintering method of the present application, if the sintering temperature is too high or too low, the amount of cation inversion will increase; therefore, in an implementation manner of the present application, sintering at 700-1100°C for 3-24 2 hours, adjust the amount of cationic translocation to make it meet the requirement of 3-7% cationic translocation in this application. As for quenching with rapid cooling at a rate greater than 100°C/min, this method will increase the amount of cation inversion compared to normal cooling; therefore, in an implementation manner of the present application, the cooling rate of quenching is also controlled by Control the amount of cation transposition.

Another aspect of the application discloses a method for preparing a layered positive electrode material for a cobalt-free lithium ion battery of the present application, wherein the layered positive electrode material for a cobalt-free lithium ion battery is synthesized by a microwave sintering method; the microwave sintering method includes mixing the raw materials uniformly, Treat for 3 minutes to 3 hours at a microwave power of 300-2000 watts.

In an implementation manner of the present application, before the high-temperature sintering or microwave sintering, a co-precipitation method is also included to synthesize the hydroxide precursor; wherein, the co-precipitation method includes placing the transition metal salt aqueous solution in a nitrogen atmosphere, adding NaOH The aqueous solution and NH ₄ OH aqueous solution are used as precipitating agent and complexing agent to react for 6-15 hours under the conditions of pH value 10-11, temperature 50-80 ℃, stirring speed 500-1000rpm/s, and then drying to obtain transition metal Hydroxide precursor. Among them, the transition metal is the transition metal in the transition metal oxide layer, such as nickel and manganese. After the transition metal hydroxide precursor is obtained, it is uniformly mixed with the lithium source, and then high-temperature sintering or microwave sintering is performed to obtain the layered positive electrode material for the cobalt-free lithium ion battery of the present application. If it also has doped metal ions such as Al, Ti or Mg, when preparing the hydroxide precursor, the metal salt aqueous solution doped with metal ions and the transition metal salt aqueous solution can be used to prepare the hydroxide precursor; After the transition metal hydroxide precursor is obtained, the transition metal hydroxide precursor, the lithium source and the metal oxide doped with metal ions are mixed together, and high temperature sintering or microwave sintering is performed.

The beneficial effects of this application are:

The layered cathode material for cobalt-free lithium ion battery of the present application still has excellent electrochemical performance without using cobalt ions; and, because it does not need to use high-priced metal cobalt ions, the cost caused by cobalt dependence is solved question. The preparation method of the layered positive electrode material for the cobalt-free lithium ion battery of the present application is simple, and it is easy for large-scale industrial production.

Description of drawings

1 is a schematic structural diagram of a layered positive electrode material with cation inversion in an embodiment of the present application;

2 is a scanning electron microscope image of a layered positive electrode material for a cobalt-free lithium-ion battery prepared in Example 1 of the present application;

3 is the cycle performance test result of the layered positive electrode material of the cobalt-free lithium ion battery prepared in Example 1 of the present application under C/3 and 1C rate current in the voltage range of 2.8-4.5V;

4 is a scanning electron microscope image of a layered positive electrode material for a cobalt-free lithium-ion battery prepared in Example 2 of the present application;

Fig. 5 is the powder diffraction pattern of the layered positive electrode material of the cobalt-free lithium ion battery prepared in Example 2 of the present application and the result of the refinement;

6 is the cycle performance test result of the layered positive electrode material of the cobalt-free lithium ion battery prepared in Example 2 of the present application under the C/2 rate current in the voltage range of 2.8-4.45V in the full battery;

Fig. 7 is the cycle performance test result of four kinds of positive electrode materials in the second to fifth embodiment of the present application under the C/3 rate current in the voltage range of 2.8-4.5V;

8 is a scanning electron microscope image of a single crystal of a layered positive electrode material for a cobalt-free lithium ion battery prepared in Example 8 of the present application.

Detailed ways

The research of this application shows that in the existing layered cathode materials of lithium ion batteries, the main reason for the interlayer mixing (cation disorder) of Li and transition metal ions during the preparation process of the lithium layer and the transition metal oxide layer Yes, it is affected by superexchange and magnetoresistive dislocations; the reason why cobalt ions need to be added is because cobalt ions can release magnetoresistive dislocations in the layer, reduce the interlayer superexchange effect, and thus suppress the structural defect of cation inversion. . Furthermore, further studies have shown that manganese ions can enhance the exchange between superlayers and exacerbate magnetoresistive dislocations, resulting in more structural defects.

Therefore, the addition of cobalt ions has the effect of regulating the transposition of cations. However, the previous research of this application found that although the cation inversion is affected by superexchange and magnetoresistive dislocation; however, in the specific production process, these two factors can be adjusted by adjusting the proportion of transition metal elements and production process parameters. . That is to say, the ratio of cation inversion in the lithium layer can be controlled by adjusting the ratio of transition metal elements, especially the ratio of nickel and manganese, and the production process parameters.

In addition, more importantly, the study of this application found that although the cation translocation is a structural defect, it will reduce the deintercalation barrier and kinetics of lithium ions, and will affect the crystallization of the layered structure; however, an appropriate proportion of cation translocation The cycle stability of the material can be improved; the layered cathode material has excellent electrochemical performance.

Based on the above research and understanding, the present application creatively proposes a new layered cathode material for cobalt-free lithium-ion batteries. The layered cathode material for cobalt-free lithium-ion batteries is alternating between lithium layers and transition metal oxide layers without cobalt. Stacked layered cathode material with 3-7% cation inversion in the lithium layer. A schematic structural diagram of the layered positive electrode material for a cobalt-free lithium-ion battery of the present application is shown in FIG. 1 , which shows a layered positive electrode material with cation inversion.

Among them, the ratio of cation inversion can be achieved by adjusting the proportion of transition metals and adjusting the preparation parameters, for example, adjusting the ratio of nickel and manganese, controlling the temperature, time, atmosphere, quenching, etc. of high-temperature sintering, and controlling the power and power of microwave sintering. time etc.

This application controls the cation inversion of the layered positive electrode material for cobalt-free lithium-ion batteries to 3-7%. Within this range, although there are structural defects, the performance of the battery positive electrode material is less affected, so the layered positive electrode material still have excellent electrochemical performance. Moreover, the layered positive electrode material of the cobalt-free lithium ion battery of the present application not only has high cycle stability, but also has the characteristics of low cost because it does not need to use cobalt ions. In addition, the layered positive electrode material of the cobalt-free lithium-ion battery of the present application only needs to use high temperature sintering or microwave sintering, and the previous hydroxide precursor only needs to use conventional co-precipitation method equipment, and there is no need to update the generation equipment. , the preparation method is simple, and it is easy to realize industrialization.

The present application will be further described in detail below through specific embodiments. The following examples are only to further illustrate the application, and should not be construed as a limitation to the application.

Example 1

The layered positive electrode material of the cobalt-free lithium-ion battery in this example is a layered positive electrode material composed of alternately stacking lithium layers and transition metal oxide layers without cobalt, wherein the transition metal oxide layer without cobalt is nickel cobalt oxide layer with 5% cation inversion in the lithium layer. In this example, a high-temperature sintering method is used to synthesize a layered cathode material for a cobalt-free lithium-ion battery, which includes:

(1) Synthesis of hydroxide precursor Ni _0.7 Mn _0.3 (OH) ₂ by co-precipitation method: A mixed aqueous solution of NiSO ₄ ·6H ₂ O and MnSO ₄ ·5H ₂ O with a concentration of 2.0 mol L ^-1 was placed in a nitrogen atmosphere It was pumped into a self-made continuous stirred tank reactor (4 L). At the same time, 4.0 mol L ^-1 of NaOH aqueous solution and 5.0 mol L ^-1 of NH ₄ OH aqueous solution were pumped into the reactor as precipitating agent and complexing agent, respectively. The pH value of the precursor solution was kept at 10.5-11, the temperature was kept at 60°C, and the stirring speed was kept at 1000 rpm/s. The reaction was carried out for 10 hours, filtered with suction, washed three times with deionized water, and dried in a vacuum oven at 80°C overnight.

(2) Using high temperature solid phase sintering to obtain the product: Mix and grind LiOH·H ₂ O and the Ni _0.7 Mn _0.3 (OH) ₂ precursor obtained above according to the molar ratio of Li:TM=1.03:1, and in an oxygen atmosphere After calcination at 825°C for 12 hours, the temperature was rapidly cooled at a rate of 110°C/min to obtain a product LiNi _0.7 Mn _0.3 O ₂ (NM73) polycrystalline material with an average particle size of 13 microns. Through the refinement of the structure of X-ray diffraction pattern, it is determined that the Li/Ni inversion amount in the material is 5.0%. Wherein, TM refers to other metal ions except lithium ions, and the following examples are the same.

(3) Electrochemical test: NM73 was mixed with carbon black and PVDF in a mass ratio of 80:10:10 and ground in a mortar to prepare a positive electrode with an active material loading of about 5.2 mg cm ^-2 . Lithium half-cells were prepared using 2032 type coin cells, using Celgard 2325 separators and 1.2 mol L ^-1 of GEN II electrolyte (LiPF ₆ dissolved in EC/EMC mixed solvent with a volume ratio of 3:7), and the half cells were placed at 2.8 Cycle between -4.5V (vs Li ⁺ /Li). For the full cell, a 2032 coin cell was assembled with a graphite negative electrode, cycled in the voltage range of 2.8-4.45V, and the N/P ratio of the full cell was about 1.2. Commercial graphite Fujian was provided by Shenzhen BTR New Energy Materials Company.

The layered positive electrode material for cobalt-free lithium ion battery prepared in this example was observed by scanning electron microscopy. The results are shown in Figure 2. The results show that dense secondary particles were prepared in this example, with an average particle size of 13 μm; in Figure 2 The scale bar is 2 μm.

The cycle performance of the layered cathode material for the cobalt-free lithium-ion battery in this example at C/3 and 1C rate current in the voltage range of 2.8-4.5V is shown in Figure 3. In Figure 3, the upper curve is the test result of C/3, and the lower curve is the test result of 1C. Figure 3 shows that the capacity retention rate at C/3 rate is 87.5%, and the capacity retention rate at 1C rate is 87.7%.

The results show that the layered cathode material of the cobalt-free lithium-ion battery in this example has a high capacity, and good cycle stability and thermal stability.

Embodiment 2

The layered positive electrode material of the cobalt-free lithium-ion battery in this example is a layered positive electrode material composed of alternately stacking lithium layers and transition metal oxide layers without cobalt, wherein the transition metal oxide layer without cobalt is nickel cobalt oxide layer with 5.5% cation inversion in the lithium layer. In this example, a high-temperature sintering method is used to synthesize a layered cathode material for a cobalt-free lithium-ion battery, which includes:

(1) Synthesis of hydroxide precursor Ni _0.8 Mn _0.2 (OH) ₂ by co-precipitation method: A mixed aqueous solution of NiSO ₄ ·6H ₂ O and MnSO ₄ ·5H ₂ O with a concentration of 2.0 mol L ^-1 was placed in a nitrogen atmosphere It was pumped into a self-made continuous stirred tank reactor (4 L). At the same time, 4.0 mol L ^-1 of NaOH aqueous solution and 5.0 mol L ^-1 of NH ₄ OH aqueous solution were pumped into the reactor as precipitating agent and complexing agent, respectively. The pH value of the precursor solution was kept at 10.5-11, the temperature was kept at 60°C, and the stirring speed was kept at 1000 rpm/s. The reaction was carried out for 10 hours, filtered with suction, washed three times with deionized water, and dried in a vacuum oven at 80°C overnight.

(2) High-temperature solid-phase sintering is used to obtain the product: LiOH·H ₂ O and the Ni _0.8 Mn _0.2 (OH) ₂ precursor obtained above are mixed and ground uniformly according to the molar ratio of Li:TM=1.03:1. After calcination at 800°C for 12 hours, the temperature was rapidly lowered at a rate of 110°C/min to obtain a product LiNi _0.8 Mn _0.2 O ₂ (NM82) polycrystalline material with an average particle size of 10 microns. Through the structure refinement of X-ray diffraction pattern, it is determined that the Li/Ni inversion amount in the material is 5.5%. Figure 5 shows the powder diffraction pattern of the layered positive electrode material for the cobalt-free lithium-ion battery in this example and the results of its refinement.

(3) Electrochemical test: NM82 was mixed with carbon black and PVDF in a mass ratio of 80:10:10 and ground in a mortar to prepare a positive electrode with an active material loading of about 5.2 mg cm ^-2 . Lithium half-cells were prepared using 2032 type coin cells, using Celgard 2325 separators and 1.2 mol L ^-1 of GEN II electrolyte (LiPF ₆ dissolved in EC/EMC mixed solvent with a volume ratio of 3:7), and the half cells were placed at 2.8 Cycle between -4.5V (vs Li ⁺ /Li). For the full cell, a 2032 coin cell was assembled with a graphite negative electrode, cycled in the voltage range of 2.8-4.45V, and the N/P ratio of the full cell was about 1.2. Commercial graphite Fujian was provided by Shenzhen BTR New Energy Materials Company.

The layered positive electrode material for cobalt-free lithium-ion battery prepared in this example was observed by scanning electron microscopy. The results are shown in Figure 4. The results show that dense secondary particles were prepared in this example, and the average particle size was equivalent to that of Example 1. The scale bar in the figure is 2 μm.

The cycle performance test results of the layered cathode material for the cobalt-free lithium-ion battery in this example under the C/2 rate current in the voltage range of 2.8-4.45V in the full battery are shown in Figure 6. The cycle performance test results in the voltage range of 2.8-4.5V under C/3 rate current are shown in Fig. 7. Figure 7 shows that the capacity retention rate of the cathode material NM82 in this example is 86.2%.

The results show that the layered cathode material of the cobalt-free lithium-ion battery in this example has a high capacity, and good cycle stability and thermal stability.

Embodiment 3

The layered positive electrode material of the cobalt-free lithium-ion battery in this example is a layered positive electrode material composed of alternately stacking lithium layers and transition metal oxide layers without cobalt, wherein the transition metal oxide layer without cobalt is nickel cobalt oxide layer, and doped with Al; the lithium layer has 4.5% cation inversion. In this example, a high-temperature sintering method is used to synthesize a layered cathode material for a cobalt-free lithium-ion battery, which includes:

( ¹ ) Synthesis of hydroxide precursor Ni _0.8 Mn _0.15 Al _0.05 (OH) ₂ by coprecipitation method: NiSO ₄ ·6H ₂ O, MnSO ₄ ·5H ₂ O, Al ₂ ( A mixed aqueous solution of SO ₄ ) ₃ ·18H ₂ O was pumped into a homemade continuous stirred tank reactor (4 L) under nitrogen atmosphere. At the same time, 4.0 mol L ^-1 of NaOH aqueous solution and 5.0 mol L ^-1 of NH ₄ OH aqueous solution were pumped into the reactor as precipitating agent and complexing agent, respectively. The pH value of the precursor solution was kept at 10.5-11, the temperature was kept at 60°C, and the stirring speed was kept at 1000 rpm/s. The reaction was carried out for 10 hours, filtered with suction, washed three times with deionized water, and dried in a vacuum oven at 80°C overnight.

(2) High-temperature solid-phase sintering is used to obtain a product: Mix and grind LiOH·H ₂ O and the Ni _0.8 Mn _0.15 Al _0.05 (OH) ₂ precursor obtained above according to the molar ratio of Li:TM=1.03:1, and in oxygen The product was calcined at 800°C for 12 hours in an atmosphere, and rapidly cooled at a rate of 110°C/min to obtain a product LiNi _0.8 Mn _0.15 Al _0.05 O ₂ (NMA) polycrystalline material with an average particle size of 10 microns. Through the refinement of the structure of X-ray diffraction pattern, it is determined that the Li/Ni inversion amount in the material is 4.5%.

(3) Electrochemical test: NMA was mixed with carbon black and PVDF in a mass ratio of 80:10:10 and ground in a mortar to prepare a positive electrode sheet with an active material loading of about 5.2 mg cm ^-2 . Lithium half-cells were prepared using 2032 type coin cells, using Celgard 2325 separators and 1.2 mol L ^-1 of GEN II electrolyte (LiPF ₆ dissolved in EC/EMC mixed solvent with a volume ratio of 3:7), and the half cells were placed at 2.8 Cycle between -4.5V (vs Li ⁺ /Li). For the full cell, a 2032 coin cell was assembled with a graphite negative electrode, cycled in the voltage range of 2.8-4.45V, and the N/P ratio of the full cell was about 1.2. Commercial graphite Fujian was provided by Shenzhen BTR New Energy Materials Company.

Figure 7 shows the cycle performance test results of the layered cathode material for the cobalt-free lithium-ion battery in this example at a C/3 rate current in the voltage range of 2.8-4.5V. Figure 7 shows that the capacity retention rate of the cathode material NMA in this example is 92.1%.

The results show that the layered cathode material of the cobalt-free lithium-ion battery in this example has a high capacity, and good cycle stability and thermal stability.

Embodiment 4

The layered positive electrode material of the cobalt-free lithium-ion battery in this example is a layered positive electrode material composed of alternately stacking lithium layers and transition metal oxide layers without cobalt, wherein the transition metal oxide layer without cobalt is nickel cobalt oxide layer, and doped with Ti; the lithium layer has 5.8% cation inversion. In this example, a high-temperature sintering method is used to synthesize a layered cathode material for a cobalt-free lithium-ion battery, which includes:

(1) Synthesis of hydroxide precursor Ni _0.8 Mn _0.2 (OH) ₂ by co-precipitation method: A mixed aqueous solution of NiSO ₄ ·6H ₂ O and MnSO ₄ ·5H ₂ O with a concentration of 2.0 mol L ^-1 was placed in a nitrogen atmosphere It was pumped into a self-made continuous stirred tank reactor (4 L). At the same time, 4.0 mol L ^-1 of NaOH aqueous solution and 5.0 mol L ^-1 of NH ₄ OH aqueous solution were pumped into the reactor as precipitating agent and complexing agent, respectively. The pH value of the precursor solution was kept at 10.5-11, the temperature was kept at 60°C, and the stirring speed was kept at 1000 rpm/s. The reaction was carried out for 10 hours, filtered with suction, washed three times with deionized water, and dried in a vacuum oven at 80°C overnight.

(2) High-temperature solid-phase sintering is used to obtain the product: firstly, the Ni _0.8 Mn _0.2 (OH) ₂ precursor obtained above is mixed with nano-scale TiO ₂ , and then mixed with LiOH·H ₂ O according to the molar ratio of Li:TM=1.03: 1 Mix and grind evenly, calcined at 800°C for 12 hours in an oxygen atmosphere, and rapidly cooled at a rate of 110°C/min to obtain the product LiNi _0.79 Mn _0.2 Ti _0.01 O ₂ (NMT) polycrystalline material with an average particle size of 10 microns. Through the structure refinement of X-ray diffraction pattern, it is determined that the Li/Ni inversion amount in the material is 5.8%.

(3) Electrochemical test: NMT was mixed with carbon black and PVDF in a mass ratio of 80:10:10 and ground in a mortar to prepare a positive electrode sheet with an active material loading of about 5.2 mg cm ^-2 . Lithium half-cells were prepared using 2032 type coin cells, using Celgard 2325 separators and 1.2 mol L ^-1 of GEN II electrolyte (LiPF ₆ dissolved in EC/EMC mixed solvent with a volume ratio of 3:7), and the half cells were placed at 2.8 Cycle between -4.5V (vs Li ⁺ /Li). For the full cell, a 2032 coin cell was assembled with a graphite negative electrode, cycled in the voltage range of 2.8-4.45V, and the N/P ratio of the full cell was about 1.2. Commercial graphite Fujian was provided by Shenzhen BTR New Energy Materials Company.

Figure 7 shows the cycle performance test results of the layered cathode material for the cobalt-free lithium-ion battery in this example at a C/3 rate current in the voltage range of 2.8-4.5V. Figure 7 shows that the capacity retention rate of the cathode material NMT in this example is 87.3%.

The results show that the layered cathode material of the cobalt-free lithium-ion battery in this example has a high capacity, and good cycle stability and thermal stability.

Embodiment 5

The layered positive electrode material of the cobalt-free lithium-ion battery in this example is a layered positive electrode material formed by alternately stacking lithium layers and transition metal oxide layers without cobalt, wherein the transition metal oxide layer without cobalt is nickel cobalt oxide layer, and doped with Mg; the lithium layer has 3.5% cation inversion. In this example, a high-temperature sintering method is used to synthesize a layered cathode material for a cobalt-free lithium-ion battery, which includes:

(1) Synthesis of hydroxide precursor Ni _0.8 Mn _0.2 (OH) ₂ by co-precipitation method: A mixed aqueous solution of NiSO ₄ ·6H ₂ O and MnSO ₄ ·5H ₂ O with a concentration of 2.0 mol L ^-1 was placed in a nitrogen atmosphere It was pumped into a self-made continuous stirred tank reactor (4 L). At the same time, 4.0 mol L ^-1 of NaOH aqueous solution and 5.0 mol L ^-1 of NH ₄ OH aqueous solution were pumped into the reactor as precipitating agent and complexing agent, respectively. The pH value of the precursor solution was kept at 10.5-11, the temperature was kept at 60°C, and the stirring speed was kept at 1000 rpm/s. The reaction was carried out for 10 hours, filtered with suction, washed three times with deionized water, and dried in a vacuum oven at 80°C overnight.

(2) High-temperature solid-phase sintering is used to obtain the product: firstly, the Ni _0.8 Mn _0.2 (OH) ₂ precursor obtained above is mixed with nano-scale MgO, and then mixed with LiOH·H ₂ O according to the molar ratio of Li:TM=1.03:1 Mix and grind uniformly, calcined at 800°C for 12 hours in an oxygen atmosphere, and rapidly cooled at a rate of 110°C/min to obtain a product LiNi _0.79 Mn _0.2 Mg _0.01 O ₂ (NMM) polycrystalline material with an average particle size of 10 microns. Through the structure refinement of X-ray diffraction pattern, it is determined that the Li/Ni inversion amount in the material is 3.5%.

(3) Electrochemical test: NMM was mixed with carbon black and PVDF in a mass ratio of 80:10:10 and ground in a mortar to prepare a positive electrode sheet with an active material loading of about 5.2 mg cm ^-2 . Lithium half-cells were prepared using 2032 type coin cells, using Celgard 2325 separators and 1.2 mol L ^-1 of GEN II electrolyte (LiPF ₆ dissolved in EC/EMC mixed solvent with a volume ratio of 3:7), and the half cells were placed at 2.8 Cycle between -4.5V (vs Li ⁺ /Li). For the full cell, a 2032 coin cell was assembled with a graphite negative electrode, cycled in the voltage range of 2.8-4.45V, and the N/P ratio of the full cell was about 1.2. Commercial graphite Fujian was provided by Shenzhen BTR New Energy Materials Company.

Figure 7 shows the cycle performance test results of the layered cathode material for the cobalt-free lithium-ion battery in this example at a C/3 rate current in the voltage range of 2.8-4.5V. Figure 7 shows that the capacity retention rate of the cathode material NMM in this example is 88.2%.

The results show that the layered cathode material of the cobalt-free lithium-ion battery in this example has a high capacity, and good cycle stability and thermal stability.

Embodiment 6

The layered positive electrode material of the cobalt-free lithium-ion battery in this example is a layered positive electrode material composed of alternately stacking lithium layers and transition metal oxide layers without cobalt, wherein the transition metal oxide layer without cobalt is nickel cobalt oxide layer; 7.0% cation inversion in the lithium layer. In this example, a high-temperature sintering method is used to synthesize a layered cathode material for a cobalt-free lithium-ion battery, which includes:

(1) Synthesis of hydroxide precursor Ni _0.8 Mn _0.2 (OH) ₂ by co-precipitation method: A mixed aqueous solution of NiSO ₄ ·6H ₂ O and MnSO ₄ ·5H ₂ O with a concentration of 2.0 mol L ^-1 was placed in a nitrogen atmosphere It was pumped into a self-made continuous stirred tank reactor (4 L). At the same time, 4.0 mol L ^-1 of NaOH aqueous solution and 5.0 mol L ^-1 of NH ₄ OH aqueous solution were pumped into the reactor as precipitating agent and complexing agent, respectively. The pH value of the precursor solution was kept at 10.5-11, the temperature was kept at 60°C, and the stirring speed was kept at 1000 rpm/s. The reaction was carried out for 10 hours, filtered with suction, washed three times with deionized water, and dried in a vacuum oven at 80°C overnight.

(2) High-temperature solid-phase sintering is used to obtain the product: LiOH·H ₂ O and the Ni _0.8 Mn _0.2 (OH) ₂ precursor obtained above are mixed and ground uniformly according to the molar ratio of Li:TM=1.03:1. After calcination at 800°C for 12 hours, the temperature was rapidly lowered at a rate of 130°C/min to obtain the product LiNi _0.8 Mn _0.2 O ₂ (NM82) polycrystalline material. Through the structure refinement of X-ray diffraction pattern, it is determined that the Li/Ni inversion amount in the material is 7.0%.

(3) Electrochemical test: NM82 was mixed with carbon black and PVDF in a mass ratio of 80:10:10 and ground in a mortar to prepare a positive electrode with an active material loading of about 5.2 mg cm ^-2 . Lithium half-cells were prepared using 2032 type coin cells, using Celgard 2325 separators and 1.2 mol L ^-1 of GEN II electrolyte (LiPF ₆ dissolved in EC/EMC mixed solvent with a volume ratio of 3:7), and the half cells were placed at 2.8 Cycle between -4.5V (vs Li ⁺ /Li). For the full cell, a 2032 coin cell was assembled with a graphite negative electrode, cycled in the voltage range of 2.8-4.45V, and the N/P ratio of the full cell was about 1.2. Commercial graphite Fujian was provided by Shenzhen BTR New Energy Materials Company.

The cycle performance of the layered cathode material for the cobalt-free lithium-ion battery in this example is tested at C/3 and 1C rate current in the voltage range of 2.8-4.5V. The results show that the layered cathode material of the cobalt-free lithium-ion battery in this example has a high capacity, and good cycle stability and thermal stability.

Embodiment 7

The layered positive electrode material of the cobalt-free lithium-ion battery in this example is a layered positive electrode material composed of alternately stacking lithium layers and transition metal oxide layers without cobalt, wherein the transition metal oxide layer without cobalt is nickel cobalt oxide layer; 4.0% cation inversion in the lithium layer. In this example, a high-temperature sintering method is used to synthesize a layered cathode material for a cobalt-free lithium-ion battery, which includes:

(1) Synthesis of hydroxide precursor Ni _0.8 Mn _0.2 (OH) ₂ by co-precipitation method: A mixed aqueous solution of NiSO ₄ ·6H ₂ O and MnSO ₄ ·5H ₂ O with a concentration of 2.0 mol L ^-1 was placed in a nitrogen atmosphere It was pumped into a self-made continuous stirred tank reactor (4 L). At the same time, 4.0 mol L ^-1 of NaOH aqueous solution and 5.0 mol L ^-1 of NH ₄ OH aqueous solution were pumped into the reactor as precipitating agent and complexing agent, respectively. The pH value of the precursor solution was kept at 10.5-11, the temperature was kept at 60°C, and the stirring speed was kept at 1000 rpm/s. The reaction was carried out for 10 hours, filtered with suction, washed three times with deionized water, and dried in a vacuum oven at 80°C overnight.

(2) High-temperature solid-phase sintering is used to obtain the product: LiOH·H ₂ O and the Ni _0.8 Mn _0.2 (OH) ₂ precursor obtained above are mixed and ground uniformly according to the molar ratio of Li:TM=1.03:1. After calcining at 850°C for 12 hours, the temperature was naturally lowered to obtain the product LiNi _0.8 Mn _0.2 O ₂ (NM82) polycrystalline material. Through the structure refinement of X-ray diffraction pattern, it is determined that the Li/Ni inversion amount in the material is 4.0%.

(3) Electrochemical test: NM82 was mixed with carbon black and PVDF in a mass ratio of 80:10:10 and ground in a mortar to prepare a positive electrode with an active material loading of about 5.2 mg cm ^-2 . Lithium half-cells were prepared using 2032 type coin cells, using Celgard 2325 separators and 1.2 mol L ^-1 of GEN II electrolyte (LiPF ₆ dissolved in EC/EMC mixed solvent with a volume ratio of 3:7), and the half cells were placed at 2.8 Cycle between -4.5V (vs Li ⁺ /Li). For the full cell, a 2032 coin cell was assembled with a graphite negative electrode, cycled in the voltage range of 2.8-4.45V, and the N/P ratio of the full cell was about 1.2. Commercial graphite Fujian was provided by Shenzhen BTR New Energy Materials Company.

The cycle performance of the layered cathode material for the cobalt-free lithium-ion battery in this example is tested at C/3 and 1C rate current in the voltage range of 2.8-4.5V. The results show that the layered cathode material of the cobalt-free lithium-ion battery in this example has a high capacity, and good cycle stability and thermal stability.

Embodiment 8

The layered positive electrode material of the cobalt-free lithium-ion battery in this example is a layered positive electrode material composed of alternately stacking lithium layers and transition metal oxide layers without cobalt, wherein the transition metal oxide layer without cobalt is nickel cobalt oxide layer; 4.8% cation inversion in the lithium layer. In this example, a high-temperature sintering method is used to synthesize a layered cathode material for a cobalt-free lithium-ion battery, which includes:

(1) Synthesis of hydroxide precursor Ni _0.8 Mn _0.2 (OH) ₂ by co-precipitation method: A mixed aqueous solution of NiSO ₄ ·6H ₂ O and MnSO ₄ ·5H ₂ O with a concentration of 2.0 mol L ^-1 was placed in a nitrogen atmosphere It was pumped into a self-made continuous stirred tank reactor (4 L). At the same time, 4.0 mol L ^-1 of NaOH aqueous solution and 5.0 mol L ^-1 of NH ₄ OH aqueous solution were pumped into the reactor as precipitating agent and complexing agent, respectively. The pH value of the precursor solution was kept at 10.5-11, the temperature was kept at 60°C, and the stirring speed was kept at 1000 rpm/s. The reaction was carried out for 10 hours, filtered with suction, washed three times with deionized water, and dried in a vacuum oven at 80°C overnight.

(2) High-temperature solid-phase sintering is used to obtain the product: LiOH·H ₂ O and the Ni _0.8 Mn _0.2 (OH) ₂ precursor obtained above are mixed and ground uniformly according to the molar ratio of Li:TM=1.03:1. calcined at 850°C for 12 hours, and quenched at 110°C per minute to obtain a product LiNi _0.8 Mn _0.2 O ₂ (NM82) polycrystalline material. Through the structure refinement of X-ray diffraction pattern, it is determined that the Li/Ni inversion amount in the material is 4.8%.

(3) Electrochemical test: NM82 was mixed with carbon black and PVDF in a mass ratio of 80:10:10 and ground in a mortar to prepare a positive electrode with an active material loading of about 5.2 mg cm ^-2 . Lithium half-cells were prepared using 2032 type coin cells, using Celgard 2325 separators and 1.2 mol L ^-1 of GEN II electrolyte (LiPF ₆ dissolved in EC/EMC mixed solvent with a volume ratio of 3:7), and the half cells were placed at 2.8 Cycle between -4.5V (vs Li ⁺ /Li). For the full cell, a 2032 coin cell was assembled with a graphite negative electrode, cycled in the voltage range of 2.8-4.45V, and the N/P ratio of the full cell was about 1.2. Commercial graphite Fujian was provided by Shenzhen BTR New Energy Materials Company.

Scanning electron microscope observation was carried out on the layered positive electrode material of cobalt-free lithium ion battery prepared in this example, and the results are shown in Fig. 8 .

The cycle performance of the layered cathode material for the cobalt-free lithium-ion battery in this example is tested at C/3 and 1C rate current in the voltage range of 2.8-4.5V. The results show that the layered cathode material of the cobalt-free lithium-ion battery in this example has a high capacity, and good cycle stability and thermal stability.

Embodiment 9

The layered positive electrode material of the cobalt-free lithium-ion battery in this example is a layered positive electrode material composed of alternately stacking lithium layers and transition metal oxide layers without cobalt, wherein the transition metal oxide layer without cobalt is nickel cobalt oxide layer; 4.3% cation inversion in the lithium layer. In this example, a high-temperature sintering method is used to synthesize a layered cathode material for a cobalt-free lithium-ion battery, which includes:

(1) Synthesis of hydroxide precursor Ni _0.8 Mn _0.2 (OH) ₂ by co-precipitation method: A mixed aqueous solution of NiSO ₄ ·6H ₂ O and MnSO ₄ ·5H ₂ O with a concentration of 2.0 mol L ^-1 was placed in a nitrogen atmosphere It was pumped into a self-made continuous stirred tank reactor (4 L). At the same time, 4.0 mol L ^-1 of NaOH aqueous solution and 5.0 mol L ^-1 of NH ₄ OH aqueous solution were pumped into the reactor as precipitating agent and complexing agent, respectively. The pH value of the precursor solution was kept at 10.5-11, the temperature was kept at 60°C, and the stirring speed was kept at 1000 rpm/s. The reaction was carried out for 10 hours, filtered with suction, washed three times with deionized water, and dried in a vacuum oven at 80°C overnight.

(2) High-temperature solid-phase sintering is used to obtain the product: LiOH·H ₂ O and the Ni _0.8 Mn _0.2 (OH) ₂ precursor obtained above are mixed and ground uniformly according to the molar ratio of Li:TM=1.2:1, and in an oxygen atmosphere The product was LiNi _0.8 Mn _0.2 O ₂ (NM82) single crystal material obtained by calcining at 950° C. for 20 hours, and rapidly cooling at a rate of 110° C./min, with an average particle size of about 2 microns. The Li/Ni antisite amount in the material was determined to be 4.3%.

(3) Electrochemical test: NM82 was mixed with carbon black and PVDF in a mass ratio of 80:10:10 and ground in a mortar to prepare a positive electrode with an active material loading of about 5.2 mg cm ^-2 . Lithium half-cells were prepared using 2032 type coin cells, using Celgard 2325 separators and 1.2 mol L ^-1 of GEN II electrolyte (LiPF ₆ dissolved in EC/EMC mixed solvent with a volume ratio of 3:7), and the half cells were placed at 2.8 Cycle between -4.5V (vs Li ⁺ /Li). For the full cell, a 2032 coin cell was assembled using a graphite negative electrode, cycled in the voltage range of 2.8-4.45V, and the N/P ratio of the full cell was about 1.2. Commercial graphite Fujian was provided by Shenzhen BTR New Energy Materials Company.

The cycle performance of the layered cathode material for the cobalt-free lithium-ion battery in this example is tested at C/3 and 1C rate current in the voltage range of 2.8-4.5V. The results show that the layered cathode material of the cobalt-free lithium-ion battery in this example has a higher capacity, and better cycle stability and thermal stability.

Embodiment ten

The layered positive electrode material of the cobalt-free lithium-ion battery in this example is a layered positive electrode material composed of alternately stacking lithium layers and transition metal oxide layers without cobalt, wherein the transition metal oxide layer without cobalt is nickel cobalt oxide layer; 6.0% cation inversion in the lithium layer. In this example, the microwave sintering method is used to synthesize the layered cathode material of cobalt-free lithium-ion battery, which includes:

(1) Synthesis of hydroxide precursor Ni _0.8 Mn _0.2 (OH) ₂ by co-precipitation method: A mixed aqueous solution of NiSO ₄ ·6H ₂ O and MnSO ₄ ·5H ₂ O with a concentration of 2.0 mol L ^-1 was placed in a nitrogen atmosphere It was pumped into a self-made continuous stirred tank reactor (4 L). At the same time, 4.0 mol L ^-1 of NaOH aqueous solution and 5.0 mol L ^-1 of NH ₄ OH aqueous solution were pumped into the reactor as precipitating agent and complexing agent, respectively. The pH value of the precursor solution was kept at 10.5-11, the temperature was kept at 60°C, and the stirring speed was kept at 1000 rpm/s. The reaction was carried out for 10 hours, filtered with suction, washed three times with deionized water, and dried in a vacuum oven at 80°C overnight.

(2) The product obtained by microwave sintering: the LiOH·H ₂ O and the Ni _0.8 Mn _0.2 (OH) ₂ precursor obtained above were mixed and ground uniformly according to the molar ratio of Li:TM=1.2:1, and the microwave was heated at a constant power of 500W. The reaction was continued for 1 hour to obtain the product LiNi _0.8 Mn _0.2 O ₂ (NM82) polycrystalline material. The Li/Ni antisite amount in the material was determined to be 6.0%.

(3) Electrochemical test: NM82 was mixed with carbon black and PVDF in a mass ratio of 80:10:10 and ground in a mortar to prepare a positive electrode with an active material loading of about 5.2 mg cm ^-2 . Lithium half-cells were prepared using 2032 type coin cells, using Celgard 2325 separators and 1.2 mol L ^-1 of GEN II electrolyte (LiPF ₆ dissolved in EC/EMC mixed solvent with a volume ratio of 3:7), and the half cells were placed at 2.8 Cycle between -4.5V (vs Li ⁺ /Li). For the full cell, a 2032 coin cell was assembled with a graphite negative electrode, cycled in the voltage range of 2.8-4.45V, and the N/P ratio of the full cell was about 1.2. Commercial graphite Fujian was provided by Shenzhen BTR New Energy Materials Company.

The cycle performance of the layered cathode material for the cobalt-free lithium-ion battery in this example is tested at C/3 and 1C rate current in the voltage range of 2.8-4.5V. The results show that the layered cathode material of the cobalt-free lithium-ion battery in this example has a high capacity, and good cycle stability and thermal stability.

Embodiment 11

The layered positive electrode material of the cobalt-free lithium-ion battery in this example is a layered positive electrode material formed by alternately stacking lithium layers and transition metal oxide layers without cobalt, wherein the transition metal oxide layer without cobalt is nickel cobalt oxide layer; 6.9% cation inversion in the lithium layer. In this example, the microwave sintering method is used to synthesize the layered cathode material of cobalt-free lithium-ion battery, which includes:

(1) Synthesis of hydroxide precursor Ni _0.8 Mn _0.2 (OH) ₂ by co-precipitation method: A mixed aqueous solution of NiSO ₄ ·6H ₂ O and MnSO ₄ ·5H ₂ O with a concentration of 2.0 mol L ^-1 was placed in a nitrogen atmosphere It was pumped into a self-made continuous stirred tank reactor (4 L). At the same time, 4.0 mol L ^-1 of NaOH aqueous solution and 5.0 mol L ^-1 of NH ₄ OH aqueous solution were pumped into the reactor as precipitating agent and complexing agent, respectively. The pH value of the precursor solution was kept at 10.5-11, the temperature was kept at 60°C, and the stirring speed was kept at 1000 rpm/s. The reaction was carried out for 10 hours, filtered with suction, washed three times with deionized water, and dried in a vacuum oven at 80°C overnight.

(2) Using microwave sintering to obtain the product: Mix and grind LiOH·H ₂ O and the Ni _0.8 Mn _0.2 (OH) ₂ precursor obtained above according to the molar ratio of Li:TM=1.2:1, and use a constant power microwave of 1500W. The reaction was continued for 10 minutes to obtain the product LiNi _0.8 Mn _0.2 O ₂ (NM82) polycrystalline material. The Li/Ni antisite amount in the material was determined to be 6.9%.

(3) Electrochemical test: NM82 was mixed with carbon black and PVDF in a mass ratio of 80:10:10 and ground in a mortar to prepare a positive electrode with an active material loading of about 5.2 mg cm ^-2 . Lithium half-cells were prepared using 2032 type coin cells, using Celgard 2325 separators and 1.2 mol L ^-1 of GEN II electrolyte (LiPF ₆ dissolved in EC/EMC mixed solvent with a volume ratio of 3:7), and the half cells were placed at 2.8 Cycle between -4.5V (vs Li ⁺ /Li). For the full cell, a 2032 coin cell was assembled with a graphite negative electrode, cycled in the voltage range of 2.8-4.45V, and the N/P ratio of the full cell was about 1.2. Commercial graphite Fujian was provided by Shenzhen BTR New Energy Materials Company.

The cycle performance of the layered cathode material for the cobalt-free lithium-ion battery in this example is tested at C/3 and 1C rate current in the voltage range of 2.8-4.5V. The results show that the layered cathode material of the cobalt-free lithium-ion battery in this example has a higher capacity, and better cycle stability and thermal stability.

The above content is a further detailed description of the present application in combination with specific embodiments, and it cannot be considered that the specific implementation of the present application is limited to these descriptions. For those of ordinary skill in the technical field to which the present application pertains, without departing from the concept of the present application, some simple deductions or substitutions can also be made.

Claims (13)

1. A layered positive electrode material for a cobalt-free lithium ion battery, characterized in that: the layered positive electrode material for a cobalt-free lithium ion battery is a layered positive electrode material formed by alternately stacking a lithium layer and a transition metal oxide layer that does not contain cobalt , the lithium layer has 3-7% cation inversion, and the cation inversion is formed when the transition metal in the transition metal oxide layer enters the lithium layer to occupy the position of lithium ions; The transition metal of the transition metal oxide layer includes nickel and manganese, and the molar ratio of nickel and manganese is 7:3 to 99:1. 2. The layered positive electrode material for a cobalt-free lithium ion battery according to claim 1, wherein: in the layered positive electrode material for a cobalt-free lithium ion battery, the mol ratio of lithium element and other metal elements is 1-1.1: 1. 3 . The layered positive electrode material for a cobalt-free lithium ion battery according to claim 2 , wherein the transition metal oxide layer is further doped with at least one of metal ions Al, Ti and Mg. 4 . 4 . The layered positive electrode material for a cobalt-free lithium ion battery according to claim 1 , wherein the layered positive electrode material for a cobalt-free lithium ion battery is a secondary microparticle composed of primary nanoparticles. 5 . 5. The layered positive electrode material for a cobalt-free lithium ion battery according to claim 4, wherein the size of the primary nanoparticles is 10-300 nanometers, and the size of the secondary microparticles is 1-20 microns. 6 . The layered positive electrode material for a cobalt-free lithium ion battery according to claim 4 , wherein the layered positive electrode material for a cobalt-free lithium ion battery is a single crystal particle of micron size. 7 . 7 . The layered positive electrode material for a cobalt-free lithium ion battery according to claim 6 , wherein the size of the single crystal particles is 0.5-10 μm. 8 . 8. A layered positive electrode material for lithium ion batteries, characterized in that: the layered positive electrode material for lithium ion batteries is a core-shell structure, and the coating material of the core-shell structure is any one of claims 1-7. In the layered positive electrode material of the cobalt-free lithium ion battery, the core positive electrode material of the core-shell structure is at least one of lithium cobalt oxide, ternary layered material, spinel lithium manganate material and lithium iron phosphate material. 9. A layered positive electrode material for lithium ion batteries, characterized in that: the layered positive electrode material for lithium ion batteries is an element gradient structure, and the outermost layer material of the element gradient structure is any one of claims 1-7. In the layered cathode material of the cobalt-free lithium ion battery, the interior of the element gradient structure is a material with a gradient of nickel and manganese elements, the nickel content increases from the outside to the inside, and the manganese content decreases from the outside to the inside. 10. The layered positive electrode material of cobalt-free lithium ion battery according to any one of claims 1-7 or the layered positive electrode material of lithium ion battery according to claim 8 or 9 is used in lithium ion power lithium batteries, 3C consumer electronics battery applications. 11. A battery, characterized in that: the battery adopts the layered positive electrode material for a cobalt-free lithium ion battery according to any one of claims 1 to 7 or the layered positive electrode material for a lithium ion battery according to claim 8 or 9. positive electrode material. 12. The method for preparing a layered positive electrode material for a cobalt-free lithium ion battery according to any one of claims 1 to 7, wherein the layered positive electrode material for a cobalt-free lithium ion battery is synthesized by a high temperature sintering method; The high-temperature sintering method includes mixing the raw materials uniformly, and sintering at 700-1100° C. for 3-24 hours in an air or oxygen atmosphere; After the sintering is completed, the temperature is rapidly lowered to room temperature at a rate of more than 100° C./min, and the layered positive electrode material for the cobalt-free lithium ion battery is obtained. 13. The method for preparing a layered positive electrode material for a cobalt-free lithium ion battery according to any one of claims 1 to 7, wherein the layered positive electrode material for a cobalt-free lithium ion battery is synthesized by a microwave sintering method; The microwave sintering method includes mixing the raw materials uniformly, and treating the raw materials for 3 minutes to 3 hours under the microwave power of 300-2000 watts.

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