CN103078107A - Polybasic layered oxide lithium ion battery material and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of lithium-ion battery materials, in particular to a multi-layered oxide lithium-ion battery material and a preparation method thereof. The battery material is Li(Ni _1-xyz Co _x Mn _y M _z )O ₂ , wherein M is Zn, Mg, Al, Cu, As, Cd or Pb; each metal element in a single particle of the material is at a distance from the particle center There is a gradient distribution at different thicknesses. The present invention uses a simple and easy method to successfully prepare a multi-layered oxide lithium-ion battery material whose composition is easy to control. The electrochemical test results show that the charge-discharge reversibility of the multi-layered oxide lithium-ion battery material provided by the invention Good, good cycle performance.

Description

A kind of multi-layered oxide lithium-ion battery material and preparation method thereof

technical field

The invention belongs to the technical field of lithium-ion battery materials, in particular to a multi-layered oxide lithium-ion battery material and a preparation method thereof.

Background technique

At present, lithium-ion batteries have become the main batteries used in various mobile communication devices and electric tools due to their high specific energy and long life. At the same time, their applications in electric bicycles, electric vehicles and other fields are gradually expanding. The application makes the annual production and consumption of lithium-ion batteries huge. However, in the market of mobile devices such as mobile phones and notebooks that use lithium-ion batteries in large quantities, most of the currently dominant lithium-ion batteries are still made of LiCoO ₂ , which was the first to enter the commercial market.

As we all know, _LiCoO2 material as a lithium-ion battery material has a relatively high specific capacity and good cycle stability, but the Co element is relatively expensive, which makes the cost of the entire battery remain high. Multi-component oxides can combine the advantages of LiCoO ₂ , LiNiO ₂ , and LiMnO ₂ , such as LiNi _1-x MnO ₂ , LiNi _1-xy Co _x Mn _y O ₂ . Among them, the Ni-rich ternary material LiNi _1-xy Co _x Mn _y O ₂ with a relatively low price has obvious advantages in high capacity, while the Ni-poor layered multi-component material LiNi _1-xy Co _x Mn _y O ₂ and Al And Mg-substituted Li[Ni _0.8 Co _0.1 Mn _0.1-xy Al _x Mg _y ]O ₂ showed better electrochemical cycle stability. Then, how to adjust the structure and central metal composition of layered multi-component materials will become a key scientific issue to improve the comprehensive electrochemical performance of such materials.

Contents of the invention

The object of the present invention is to provide a multi-layered oxide lithium-ion battery material and a preparation method thereof, the battery material composition can be adjusted, and has good electrochemical performance.

The technical scheme that the present invention adopts is as follows:

A multi-layered oxide lithium-ion battery material, the battery material is Li(Ni _1-xyz Co _x Mn _y M _z )O ₂ , wherein M is Zn, Mg, Al, Cu, As, Cd or Pb; Each metal element in a single particle of the material presents a gradient distribution at different thicknesses from the center of the particle.

The battery material has a diameter of 0.1-30 microns.

The present invention further provides a method for preparing the multi-layered oxide lithium-ion battery material, dispersing the (Ni _1-xy Co _x Mn _y )(OH) ₂ material in a solvent, and mixing it with the metal ion M ⁿ⁺ The aqueous solution of the soluble salt is fully mixed and reacted to obtain the precursor of the battery material; the precursor is mixed with the lithium-containing compound and then calcined to obtain the multi-layered oxide lithium ion battery material.

Wherein, when the precursor of the battery material is obtained by the reaction, the soluble salt solution of (Ni _1-xy Co _{x Mny} )(OH) ₂ and M ⁿ⁺ is reacted at 40-200°C for 2-48h, and then the solid-liquid separation is performed, and Dry at 40-100° C. for 1-48 hours to obtain the precursor material.

The molar ratio of the metal in the aqueous solution of the soluble metal salt to the metal element contained in (Ni _1-xy Co _x Mn _y )(OH) ₂ is 0.05-5:1.

The concentration of the aqueous solution of the soluble metal salt is 0.01-5 mol/L.

The precursor is mixed with the lithium-containing compound and calcined at 450-550° C. for 4-12 hours, and then calcined at 650-850° C. for 8-24 hours to obtain the multi-layered oxide lithium ion battery material.

Wherein said (Ni _1-xy Co _x Mn _y ) (OH) The preparation method of ₂ can adopt the method in the prior art, but preferably proceeds as follows: dissolving soluble nickel salt, cobalt salt, manganese salt and alkali respectively according to proportion Prepare a solution in a solvent, mix and react at 40-200°C for 4-48h, separate and dry to obtain (Ni _1-xy Co _x Mn _y )(OH) ₂ .

Described soluble nickel salt, cobalt salt, manganese salt are one or more in its chloride, sulfate, nitrate, acetate; Described alkali is sodium hydroxide, potassium hydroxide, lithium hydroxide or One or more of urea; the solvent is one or more of water, ethanol, isopropanol; the soluble salt of M is its nitrate, chloride, sulfate or acetate .

The present invention provides a simple, efficient, and easy-to-operate new method for preparing a composition-adjustable multi-layered oxide lithium-ion battery material and its precursor. The multi-layered oxide lithium-ion battery material prepared by this method The metal elements are distributed in a gradient at different thicknesses from the particle center, and the specific capacity and cycle performance of the material can be significantly improved. This preparation method is more suitable for large-scale operation.

Compared with the prior art, the present invention has the following advantages:

The present invention uses a simple and easy method to successfully prepare a multi-layered oxide lithium-ion battery material whose composition is easy to control. The electrochemical test results show that the charge-discharge reversibility of the multi-layered oxide lithium-ion battery material provided by the invention Good, good cycle performance.

Description of drawings

Figure 1 is a scanning electron microscope image of the precursor prepared in step 2) of Example 1;

Fig. 2 is the scanning electron micrograph of the lithium ion battery material that embodiment 1 makes;

Fig. 3 is the electron micrograph after the lithium-ion battery material particle prepared in embodiment 1 is partially broken;

Figure 4 is the energy spectrum surface scanning curve of the particles in Figure 3, the abscissa is 0, and the metal elements corresponding to the four curves from top to bottom are Ni, Mn, Co, Al;

Fig. 5 is the charge-discharge curve diagram of the electrode that the lithium ion battery material that embodiment 1 prepares makes;

FIG. 6 is a discharge specific capacity cycle performance graph of electrodes made of lithium ion battery materials prepared in Example 1. FIG.

Detailed ways

The technical scheme of the present invention is described below with specific examples, but protection scope of the present invention is not limited to this:

The composition of the materials involved in the following examples is determined by ICP testing.

Example 1

1) Preparation of (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ : Weigh 0.00512mol Ni(NO ₃ ) ₂ 6H ₂ O, 0.00064mol Co(NO ₃ ) ₂ 6H ₂ O, 0.00064mol Mn(NO ₃ ) ₂ and 0.0064 mol of urea were respectively dissolved in 64 mL of solvent (ethanol: water = 4:1), and the corresponding concentrations of nickel, cobalt, and manganese in the solutions obtained after thorough mixing were 0.08, 0.01, and 0.01 mol/L, respectively. Then the mixture was transferred to a 100mL reactor, reacted at 180°C for 7.5 hours, naturally cooled to room temperature, centrifuged, and dried at 60°C for 12 hours to obtain the precursor (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ .

2) Mix 20mL of 0.00673mol/L aluminum nitrate solution and 30m aqueous solution dispersed with 0.25g (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ into a 90 mL reactor and react at 150°C for 4 hours , naturally cooled to room temperature, centrifuged, and dried at 60°C, the precursor with optimized composition can be obtained. It can be determined by ICP test that its molecular formula is Ni _0.783 Co _0.096 Mn _0.065 Al _0.056 (OH) ₂ (see Figure 1 for its electron microscope picture ), the material is in the form of spherical particles with a particle size of about 6 microns.

3) Preparation of lithium-ion battery material: The obtained lithium-ion battery material precursor Ni _0.783 Co _0.096 Mn _0.065 Al _0.056 (OH) ₂ was fully mixed with stoichiometric lithium hydroxide and calcined at 500°C for 5 hours and 650°C respectively. ℃ calcination for 12 hours to obtain a multilayer layered oxide lithium-ion battery material composed of Li(Ni _0.780 Co _0.100 Mn _0.068 Al _0.052 )O ₂ (see Figure 2 for its electron micrograph). As can be seen in the figure, the material basically inherits the The spherical shape and particle size of its precursor remain basically unchanged, about 6 microns, but obvious secondary crystal small particles can be observed on the spherical particles, indicating that these spherical materials are composed of smaller crystals .

In addition, the distribution of each metal element (Ni _, Co _, Mn _, Al) in the prepared multi-layered oxide lithium-ion battery material was characterized by using the line scan function of the energy spectrum attached to the scanning electron microscope. In order to characterize the content of different metal elements in the obtained spherical particles at different depths, the obtained complete spherical particles were crushed by ultrasonic waves, and the partially excavated spherical particles were selected for characterization. The results are shown in Figures 3 and 4. shown in . Figure 3 shows partially excavated spherical multi-layered oxide lithium-ion battery material particles. The content of different metal elements was line-scanned along the direction of the arrow in the figure, and the results are shown in Figure 4. It can be seen from the figure that when the scan reaches the edge of the spherical particle, the elements of Ni _, Co _, Mn _{, and} Al begin to appear, and as the scan moves toward the center of the particle (the thickness of the particle gradually increases), the elements of Ni _, Co _, Mn The content of each element of , _Al increased rapidly; when scanning into the excavated area until its center, the content of Ni element gradually increased, while the content of Al element gradually decreased, while the content of Co _and Mn elements remained basically unchanged; when Scanning from the center of the excavated area to before leaving the excavated area, the content of Ni elements gradually decreases, while the content of Al elements gradually increases, while the contents of Co _and Mn elements remain basically unchanged; when scanning away from the excavated area The content of Ni _, Co _, Mn _{, and} Al elements decreases rapidly from the region to the edge of spherical particles (the particle thickness gradually decreases). The energy spectrum results of the above line scan show that the metal elements (Ni _, Co _, Mn _, Al) in the prepared multi-layered oxide lithium-ion battery material are distributed in a gradient at different thicknesses from the particle center.

The lithium-ion battery material prepared in the above steps is made into a bonded electrode for charge and discharge tests. The counter electrode is a lithium sheet, and the electrolyte is 1 mol/L LiPF6/EC (ethylene carbonate) + DMC (dimethyl carbonate) (volume ratio 1:1) solution.

The test results show that the discharge specific capacity of the prepared multi-layered oxide lithium-ion battery material is about 200 mAh/g, and the discharge curve has a high discharge potential, which is mainly distributed between 4.3-3.5V. In addition, the charge-discharge cycle test of the material shows that the material shows a significant loss of discharge capacity at the initial stage of charge-discharge, and after about 15 weeks, its discharge specific capacity is basically maintained at 150 mAh/g.

Example 2

The preparation of (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ is the same as in Example 1.

20mL of 0.00673mol/L aluminum acetate solution and 30mL of aqueous solution dispersed with 0.25g (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ were fully mixed, then transferred to a 90mL reactor and reacted at 120°C for 4 hours, and cooled naturally to After centrifugation at room temperature and drying at 60°C, the precursor with optimized composition can be obtained. Then it is fully mixed with lithium hydroxide in a stoichiometric ratio, and then calcined at 480° C. for 5 hours and 650° C. for 12 hours respectively to obtain a multi-layered oxide lithium ion battery material.

The lithium-ion battery material with optimized composition prepared in the above steps was made into a bonded electrode for charge and discharge tests. The results showed that the discharge specific capacity of the prepared multi-layered oxide lithium-ion battery material was about 160 mAh/g.

Example 3

The preparation of (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ is the same as in Example 1.

20mL 0.00673mol/L aluminum nitrate solution and 30mL aqueous solution dispersed with 0.25g precursor (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ were fully mixed and then transferred to a 90mL reactor and reacted at 160°C for 4 hours. Naturally cooled to room temperature, centrifuged and dried at 60°C, the precursor with optimized composition can be obtained. Then, it is fully mixed with lithium hydroxide in a stoichiometric ratio, and then calcined at 500° C. for 5 hours and 650° C. for 12 hours respectively to obtain a multi-layered oxide lithium ion battery material.

The lithium-ion battery material with optimized composition prepared in the above steps was made into a bonded electrode for charge and discharge tests. The results showed that the discharge specific capacity of the prepared multi-layered oxide lithium-ion battery material was about 160 mAh/g.

Example 4

The preparation of (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ is the same as in Example 1.

20mL 0.00673mol/L aluminum nitrate solution and 30mL aqueous solution dispersed with 0.25g precursor (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ were fully mixed and then transferred to a 100mL three-necked flask and reacted at 70°C for 4 hours. Naturally cooled to room temperature, centrifuged and dried at 60°C, the precursor with optimized composition can be obtained. Then, it is fully mixed with lithium hydroxide in a stoichiometric ratio, and then calcined at 500° C. for 5 hours and 650° C. for 12 hours respectively to obtain a multi-layered oxide lithium ion battery material.

The lithium-ion battery material with optimized composition prepared by the above steps was made into a bonded electrode for charge and discharge tests. The results showed that the discharge specific capacity of the prepared multi-layered oxide lithium-ion battery material was about 185 mAh/g.

Example 5

The preparation of (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ is the same as in Example 1.

20mL of 0.00673mol/L aluminum nitrate solution and 30mL of aqueous solution dispersed with 0.25g of precursor (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ were fully mixed, then transferred to a 100mL three-necked flask and reacted at 50°C for 6 hours. Naturally cooled to room temperature, centrifuged and dried at 60°C, the precursor with optimized composition can be obtained. Then, it is fully mixed with lithium hydroxide in a stoichiometric ratio, and then calcined at 500° C. for 5 hours and 650° C. for 12 hours respectively to obtain a multi-layered oxide lithium ion battery material.

The lithium-ion battery material with optimized composition prepared by the above steps was made into a bonded electrode for charge and discharge tests. The results showed that the discharge specific capacity of the prepared multi-layered oxide lithium-ion battery material was about 162 mAh/g.

Example 6

The preparation method of (Ni _0.5 Co _0.3 Mn _0.2 ) (OH) ₂ is compared with Example 1, and the ratio of raw materials can be adjusted.

20mL 0.00673mol/L aluminum nitrate solution and 30mL aqueous solution dispersed with 0.25g precursor (Ni _0.5 Co _0.3 Mn _0.2 )(OH) ₂ were fully mixed and then transferred to a 90mL reactor and reacted at 150°C for 4 hours. Naturally cooled to room temperature, centrifuged and dried at 60°C, the precursor with optimized composition can be obtained. Then, it is fully mixed with lithium hydroxide in a stoichiometric ratio, and then calcined at 500° C. for 5 hours and 650° C. for 12 hours respectively to obtain a multi-layered oxide lithium ion battery material.

The lithium-ion battery material with optimized composition prepared in the above steps was made into a bonded electrode for charge and discharge tests. The results showed that the discharge specific capacity of the prepared multi-layered oxide lithium-ion battery material was about 150mAh/g.

Example 7

The preparation method of (Ni _1/3 Co _1/3 Mn _1/3 ) (OH) ₂ is compared with Example 1, and the proportion of raw materials can be adjusted.

The aluminum nitrate solution of 20mL 0.00673mol/L and the 30mL aqueous solution of the precursor (Ni _1/3 Co _1/3 Mn _1/3 )(OH) dispersed with 0.25g were fully mixed and _then transferred to a 90mL reaction kettle. React at 150°C for 4 hours, naturally cool to room temperature, centrifuge, and dry at 60°C to obtain a precursor with optimized composition. Then, it is fully mixed with lithium hydroxide in a stoichiometric ratio, and then calcined at 500° C. for 5 hours and 650° C. for 12 hours respectively to obtain a multi-layered oxide lithium ion battery material.

The lithium-ion battery material with optimized composition prepared by the above steps was made into a bonded electrode for charge and discharge tests. The results showed that the discharge specific capacity of the prepared multi-layered oxide lithium-ion battery material was about 150 mAh/g.

Example 8

The preparation of (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ is the same as in Example 1.

20mL of 0.00673mol/L chromium acetate solution and 30mL of aqueous solution dispersed with 0.25g of precursor (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ were fully mixed and then transferred to a 90mL reactor and reacted at 150°C for 4 hours. Naturally cooled to room temperature, centrifuged and dried at 60°C, the precursor with optimized composition can be obtained. Then, it is fully mixed with lithium hydroxide in a stoichiometric ratio, and then calcined at 500° C. for 5 hours and 650° C. for 12 hours respectively to obtain a multi-layered oxide lithium ion battery material.

The lithium-ion battery material with optimized composition prepared by the above steps was made into a bonded electrode for charge and discharge tests. The results showed that the discharge specific capacity of the prepared multi-layered oxide lithium-ion battery material was about 178 mAh/g.

Example 9

The preparation of (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ is the same as in Example 1.

20mL of 0.00673mol/L lead chloride solution and 30mL of aqueous solution dispersed with 0.25g of precursor (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ were fully mixed and then transferred to a 90mL reactor and reacted at 150°C for 4 hours , naturally cooled to room temperature, centrifuged and dried at 60°C, the precursor with optimized composition can be obtained. Then it is fully mixed with lithium hydroxide in a stoichiometric ratio, and then calcined at 500° C. for 5 hours and 650° C. for 12 hours respectively to obtain the multi-layered oxide lithium ion battery material.

The lithium-ion battery material with optimized composition prepared in the above steps was made into a bonded electrode for charge and discharge tests. The results showed that the discharge specific capacity of the prepared multi-layered oxide lithium-ion battery material was about 140mAh/g.

Example 10

The preparation of (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ is the same as in Example 1.

20mL of 0.00673mol/L arsenic chloride solution and 30mL of aqueous solution dispersed with 0.25g of precursor (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ were fully mixed, then transferred to a 90mL reactor and reacted at 150°C for 4 hours , naturally cooled to room temperature, centrifuged and dried at 60°C, the precursor with optimized composition can be obtained. Then, it is fully mixed with lithium hydroxide in a stoichiometric ratio, and then calcined at 500° C. for 5 hours and 650° C. for 12 hours respectively to obtain a multi-layered oxide lithium ion battery material.

The lithium-ion battery material with optimized composition prepared in the above steps was made into a bonded electrode for charge and discharge tests. The results showed that the discharge specific capacity of the prepared multi-layered oxide lithium-ion battery material was about 125mAh/g.

Example 11

The preparation of (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ is the same as in Example 1.

20mL 0.00673mol/L zinc nitrate solution and 30mL aqueous solution dispersed with 0.25g precursor (Ni _0.8 Co _0.1 Mn _0.1 )(OH) ₂ were fully mixed, then transferred to a 90mL reactor and reacted at 150°C for 4 hours. Naturally cooled to room temperature, centrifuged and dried at 60°C, the precursor with optimized composition can be obtained. Then, it is fully mixed with lithium hydroxide in a stoichiometric ratio, and then calcined at 500° C. for 5 hours and 650° C. for 12 hours respectively to obtain a multi-layered oxide lithium ion battery material.

The lithium-ion battery material with optimized composition prepared in the above steps was made into a bonded electrode for charge and discharge tests. The results showed that the discharge specific capacity of the prepared multi-layered oxide lithium-ion battery material was about 130mAh/g.

The trend of the gradient distribution of each metal element (Ni _, Co _, Mn _, Al) in the battery material particles obtained in the above Examples 2-11 at different thicknesses from the particle center is the same as that in Example 1.

The above-mentioned embodiment is the preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes that do not deviate from the present invention should be equivalent replacement methods, and are all included in the present invention. within the scope of protection.

Claims (9)

1. a polynary layered oxide lithium ion battery material is characterized in that, described battery material is Li (Ni _1-x-y-zCo _xMn _yM _z) O ₂, wherein M is Zn, Mg, Al, Cu, As, Cd or Pb; Each metallic element is in different-thickness place, distance particle center distribution gradient in the individual particle of material.

2. polynary layered oxide lithium ion battery material as claimed in claim 1 is characterized in that, described battery material diameter is the 0.1-30 micron.

3. the preparation method of the described polynary layered oxide lithium ion battery material of claim 1 is characterized in that, with (Ni _1-x-yCo _xMn _y) (OH) ₂Dispersion of materials is in solvent, with metal ions M ^N+The aqueous solution of soluble-salt fully mix, reaction obtains the presoma of battery material; To calcine behind presoma and the lithium-containing compound mixing, obtain described polynary layered oxide lithium ion battery material.

4. the preparation method of polynary layered oxide lithium ion battery material as claimed in claim 3 is characterized in that, when reaction obtains the presoma of battery material, (Ni _1-x-yCo _xMn _y) (OH) ₂And M ^N+Soluble-salt solution at 40-200 ℃ of lower reaction 2-48h, Separation of Solid and Liquid afterwards, and in 40-100 ℃ of dry 1-48 hour, namely obtain persursor material.

5. the preparation method of polynary layered oxide lithium ion battery material as claimed in claim 3, it is characterized in that, prior to 450-550 ℃ of calcining 4-12 hour, then namely got polynary layered oxide lithium ion battery material in 8-24 hour in 650-850 ℃ of calcining behind presoma and the lithium-containing compound mixing.

6. the preparation method of polynary layered oxide lithium ion battery material as claimed in claim 3 is characterized in that, the metal ion in the aqueous solution of described soluble metallic salt and (Ni _1-x-yCo _xMn _y) (OH) ₂The mol ratio of the middle metallic element that comprises is 0.05-5:1.

7. the preparation method of polynary layered oxide lithium ion battery material as claimed in claim 6 is characterized in that, the concentration of the aqueous solution of soluble metallic salt is 0.01-5mol/L.

8. such as the preparation method of the arbitrary described polynary layered oxide lithium ion battery material of claim 3-7, it is characterized in that described (Ni _1-x-yCo _xMn _y) (OH) ₂The preparation method be: soluble nickel salt, cobalt salt, manganese salt and alkali proportionally be dissolved in respectively be mixed with solution in the solvent, after mixing in 40-200 ℃ of reaction 4-48h, separates dry must (Ni _1-x-yCo _xMn _y) (OH) ₂

9. the preparation method of polynary layered oxide lithium ion battery material as claimed in claim 8 is characterized in that, described soluble nickel salt, cobalt salt, manganese salt are one or more in its chloride, sulfate, nitrate, the acetate; Described alkali is one or more in NaOH, potassium hydroxide, lithium hydroxide or the urea; Described solvent is one or more in water, ethanol, the isopropyl alcohol; The soluble-salt of described M is its nitrate, chloride, sulfate or acetate.

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