KR20170102293A - Multicomponent materials having a classification structure for lithium ion batteries, a method for manufacturing the same, an anode of a lithium ion battery and a lithium ion battery - Google Patents

Abstract

The present invention provides a multicomponent material having a gradient structure for a lithium ion battery, a method for manufacturing the same, an anode of a lithium ion battery, and a lithium ion battery. The multicomponent material having a gradient structure for a lithium ion battery provided by the present invention has an average composition of the following formula (I)
LiNi _x Co _y Mn _z G _d O ₂ (I)
Mg, Ca, Sr, Ba, and Z are selected from the group consisting of Li, Cr, Fe, The content of Ni element in the multi-component material including at least one of B, Al, Y, Sm, Ti, Zn, Zr, V, Nb, Ta, Mo and W, Continuously decreasing from the center to the surface of the particle). A lithium ion battery using the multi-component material having a gradient structure for a lithium ion battery provided by the present invention has not only improved cycle performance and safety performance, but also is relatively inexpensive.

Description

Multicomponent materials with a classification structure of lithium-ion batteries, a method for manufacturing the same, lithium-ion batteries and lithium-ion batteries,

The present invention relates to a multicomponent material having a gradient structure for a lithium ion battery, a method of manufacturing the same, an anode of a lithium ion battery, and a lithium ion battery, and belongs to the technical field of a lithium ion battery.

Lithium-ion batteries have a dominant use in mobile phones, notebook computers, power tools and electric vehicles, and are becoming more widely used in modern society. As demand for large capacity lithium ion batteries grows, there is an urgent need to develop high safety, high energy density, high power, long life, environmentally friendly and low cost lithium ion batteries.

The anode material is a key factor in the performance and cost of lithium ion batteries. Current cathode material _{LiCoO 2, LiNiO 2, LiNi x} Co 1 - has as its main component, and the _{x O 2, LiNi x Co y} Mn 1 -x- y O 2, LiMn 2 O 4 and LiFePO _4, LiCoO ₂ has a performance It is the first material to be commercialized because it is stable and easy to synthesize, and it is a widely used cathode active material. Limited Co resources result in high cost of materials and limit its application in some emerging markets. LiNiO ₂ is high capacity but difficult to produce, its performance is low, consistency and reproducibility, and has serious safety issues. LiNiCo _{1 - x} O ₂ is LiNiO can be considered to be ₂ and a solid solution (solid solution) of the LiCoO _2, LiNiO ₂ and LiCoO was once thought of as a new cathode material for the most likely replacement for LiCoO ₂ as the advantages of the _two sides, There is still room for improvement in its comprehensive nature because it has drawbacks such as difficult synthesis and low safety. LiMn ₂ O ₄ having a cubic spinel structure has disadvantages such as low capacity and deterioration tendency at a low cost. And the olivine structure of LiFePO ₄ has disadvantages such as low voltage and low density.

Since the layered structure is preferable for the reversible intercalation / deintercalation of Li ⁺ , it is desired that a cathode material of a layered structure having low cost, environmentally friendly and superior performance is developed. In recent years, studies on nickel-rich cathode materials (stacked LiNi _x Co _y Mn _1-xy O ₂ ) have demonstrated the advantages of LiNiO ₂ , LiCoO ₂ , LiMn ₂ O ₄ and other materials such as high capacity, It is increasingly popular in that it combines excellent rate (speed) performance and thermal stability, and has a high value for use in a wide range of commercial applications.

In stacked LiNi _x Co _y Mn _{1 -x- y} O ₂ , an increase in the Ni content can improve the specific capacity, for example, LiNi _{0 . 8} Co _{0 . 1} Mn _{0 .} The reversible capacity of ₁ O ₂ can reach up to about 190 mAh / g. This is much higher than LiCoO ₂ (about 145 mAh / g). However, the cycle performance and safety performance are somewhat reduced, and practical application is limited.

First, the nickel-based cathode material undergoes a dramatic phase transition of the crystal structure accompanied by volume change during repeated charging and discharging, and the space of the crystal layer is partially collapsed to interfere with the intercalation / deintercalation of lithium ions , Resulting in an increase in polarization resistance as well as a decrease in cycle performance. In the prior art, attempts have been made to solve the above problems by optimizing the synthesis conditions of the nickel-rich cathode material, but the results have proved unsatisfactory. The reason for this is that the produced cathode material can not fundamentally prevent the phase transition of the crystal structure as well as the phase transition and decomposition of the lithium deficiency phase during heating and thus can not solve the problem of severe deterioration due to repeated charge and discharge cycles Because.

Secondly, in the process of manufacturing the nickel-rich cathode material, the probability that nickel and lithium are arranged in a mixed state increases, and the amount of Li remaining on the surface of the particles and the particles after the reaction increases. Residual Li present in the form of Li ₂ CO ₃ and LiOH may be decomposed during storage or recycling (recycle) to generate a gas such as CO ₂ , which may worsen the safety of battery expansion and high temperature.

Chinese Patent Application CN1778003 discloses a general formula _{Li y (Ni x Co 1-2x Mn} x) O 2 discloses a positive electrode material having a composition represented by (wherein, 0.025≤x≤0.5), and is good cycle performance and safety performance, nickel Since the content is low, the specific capacity is low. The Chinese patent application CN101300696 discloses a composition comprising Li _x (Ni _1-ab (Ni _1/2 Mn _1/2 ) _a Co _b A _k ) _y O ₂ wherein 0.4? Ni? 0.7, 0.1? Co? 0.4, Mn? 0.6). Both the nickel content and the non-capacity are somewhat improved, but the cycle performance and safety performance are poor.

The present invention provides a multicomponent material having a gradient structure for a lithium ion battery. Lithium ion batteries made of multicomponent materials have high capacity, improved cycle performance and safety performance and relatively low cost.

The present invention also provides a method for producing the multi-component material having a gradient structure for a lithium ion battery, which is simple in process, low in cost, and continuous and suitable for industrial production.

The present invention also provides a positive electrode of a lithium ion battery made of a multi-component material having a gradient structure for the lithium ion battery.

The present invention also provides a lithium ion battery including a positive electrode of the lithium ion battery and having a high capacity and excellent cycle performance and safety performance.

The multicomponent material having a gradient structure for a lithium ion battery provided by the present invention has the average composition shown in formula (I)

LiNi _x Co _y Mn _z G _d O _{2 The} formula (I)

Wherein G is at least one element selected from the group consisting of Li, Cr, Fe, Mg, Ca, Sr, Ba, B In the multi-component material having a gradient structure for a lithium ion battery, the content of the Ni element is at least one selected from the group consisting of Al, Y, Sm, Ti, Zn, Zr, V, Nb, Ta, Mo, From surface to surface.

The multicomponent material having a gradient structure for a lithium ion battery provided by the present invention is spherical particles; The content of Ni element decreases continuously (monotonically) from the center of the particle to the surface. Since the granular cathode material having this gradient Ni content has a high Ni content at its center, a high specific capacity of the cathode material can be achieved. On the other hand, since the Ni content of the particle surface is relatively small, It is possible to simultaneously satisfy the demand for the performance of cycle performance and safety of the cathode material. In addition, since the content of the Ni element in the granular material continuously changes from the center to the surface, the content of the Ni element is abruptly lowered during the electrode reaction and the granular material does not cause stratification, Safety can be further assured.

In addition, the median diameter of the multicomponent material having a gradient structure for a lithium ion battery is 3 to 25 占 퐉, and the median diameter for the particle size is a particle size corresponding to a distribution percentage of 50%, which must be specifically adjusted as required do. The tap density of a multi-component material having a gradient structure for a lithium ion battery is 1.5-3.0 g / cm < ^{3 &} gt ;. In addition, the battery made from the cathode material provided by the present invention has a larger capacity at the same battery capacity as compared with the conventional cathode material, which is useful for the lightweight production of the lithium ion battery.

The multicomponent material having a gradient structure for a lithium ion battery provided by the present invention can be obtained by gradually adding a metal salt containing at least one of Ni, Co, Mn and G elements to a Ni-containing metal salt solution to precipitate and precipitate with a complex Next, the precipitated product and the lithium source are sintered in an oxygen gas-containing atmosphere.

The present invention also provides a method of manufacturing a multi-component material having a gradient structure for a lithium-ion battery, comprising the steps of:

(1) dissolving a Ni-containing metal salt in water to prepare an initial salt solution, and dissolving a metal salt containing at least one of Ni, Co, Mn and G elements in water to prepare a second salt solution;

(2) While stirring, gradually adding the second salt solution to the initial salt solution to obtain a mixed salt solution. Then, the mixed salt solution, the complex and the precipitant are simultaneously injected into the reactor, and the pH value is 8 to 13 and the reaction temperature is 40 to 80 And the reaction time is adjusted to 5 to 50 hours to obtain a precursor precipitate, followed by filtration, washing and heat treatment to obtain a multi-component precursor having a gradient structure;

(3) mixing the multi-component material precursor having the gradient structure with the lithium source uniformly and heating the mixture at 500 to 1100 ° C for 4 to 30 hours, preferably at 700 to 1000 ° C, Sintering and pulverizing the mixture for 20 hours to obtain a multi-component material having a gradient structure for a lithium ion battery.

In this process, the concentration of the Ni element in the mixed salt solution gradually decreases with the addition of the second salt solution, and granular (granular) precipitation is formed under the action of the complexing agent and the precipitating agent, While the reacting metal elements then grow slowly along the periphery of the particles to form the multicomponent material with a gradient structure for the lithium ion battery. The gradual addition of the secondary salt solution leads to a gradual reduction of the Ni concentration, so that the content of Ni element in the produced material continuously decreases from the center of the particle to the surface.

Further, the initial salt solution R1 may contain at least one element other than Ni, for example, Co, Mn and G elements.

Also, the secondary salt solution R2 is added and stirred into the initial salt solution at a flow rate (flow rate) of 0.1-0.6 times the flow rate (flow rate) at which the mixed salt solution is added to the reactor. That is, when the flow rate of the mixed salt solution injected into the reactor is v, the flow rate of the second salt solution injected into the initial salt solution is 0.1 to 0.6 v.

In this method, the metal salt is at least one of soluble metal salts such as sulfate, chloride, nitrate and acetate.

The complex (complex compound) is at least one of EDTA, ammonia water, ammonium chloride, ammonium sulfate, ammonium nitrate, ammonium citrate and ethylenediamine. The ratio of the complex to the total metal salt (complex: mole ratio of the total metal salt) can be determined according to complexation equilibrium or the principle of the actual requirement, for example the molar ratio of the complex to the total metal salt (complex: ) Is usually 0.1: 1-3: 1, where the total metal salt means the total number of moles of metal salts contained in R1 and R2.

The precipitant is a compound containing OH-, CO ₃ ^2-, etc., such as one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium bicarbonate, ammonium carbonate, sodium bicarbonate and sodium carbonate, and can form precipitates with the metal. The ratio of the precipitant to the total metal salt can be determined according to the reaction equilibrium or the principle of the actual requirement, for example, the molar ratio of the precipitant to the total metal salt can generally be 1: 1-2.5: 1 and the total metal salt is contained in R1 and R2 Means the total number of moles of metal salt.

In the above production process, the heat treatment in step (2) may be dry at 70 to 150 ° C or may be sintered at 300 to 700 ° C in an oxygen gas-containing atmosphere.

The lithium source is a lithium source conventionally used for producing a cathode material for a lithium ion battery. For example, the lithium source is at least one of lithium carbonate, lithium hydroxide, and lithium nitrate.

The present invention also provides a positive electrode of a lithium ion battery made of a multi-component material having a gradient structure for the lithium ion battery. The manufacturing method can be referred to the method of the prior art. For example, the multi-component material having a gradient structure for a lithium ion battery is mixed with carbon black and polyvinylidene fluoride (PVDF) in a weight ratio of 94%: 3%: 3% and coated to form an electrode plate, A positive electrode of a lithium ion battery is manufactured.

The present invention also comprises rolling a separator between a positive electrode of a lithium ion battery, a negative electrode using artificial graphite, and a positive electrode and a negative electrode, and then injecting an electrolyte to form a lithium ion battery. The electrochemical performance and safety of the manufactured lithium ion batteries can be tested according to relevant standards.

The present invention has the following advantages.

1. Multicomponent materials having a gradient structure for a lithium ion battery provided by the present invention fully exploit the properties of nickel, cobalt, manganese and other elements wherein the content of Ni element is continuously reduced from the center to the surface of the particle and; The prepared electrode has high non-capacity and excellent high temperature cycle performance and safety performance.

2. In a multi-component material having a gradient structure for a lithium ion battery provided by the present invention, the Ni element content of the granular multi-component material is continuously decreased from the inside to the outside, Avoid efficiently.

3. The multi-component material having a gradient structure for a lithium ion battery provided by the present invention is suitable for industrialization since it has a simple manufacturing process, a low requirement for equipment, and a relatively low cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a reaction process of a multi-component material having a gradient structure for a lithium ion battery provided by the present invention. FIG.
Fig. 2 is a scanning electron microscope image of the multi-component material produced by Embodiment 2. Fig.
3 is an electron microscope image of a cross section of the multicomponent material particle of FIG.
4 is an energy spectrum line scanning image of the Ni, Co, and Mn elements from the center to the periphery of the multicomponent material particles shown in the electron microscope image of the cross section of Fig.

In order to more clearly describe the objects, technical solutions and advantages of the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be explained clearly and completely as follows with reference to the drawings accompanying the embodiments. It is to be understood that the embodiments of the invention and obviously, are not all embodiments of the invention, but only some of them. All other embodiments acquired by those skilled in the art based on the embodiments of the present invention without any creative effort are within the scope of protection claimed by the present invention.

Embodiment 1

Nickel sulfate was dissolved to obtain 300 L of a 1.5 mol / L initial salt solution R1; Dissolving cobalt sulfate and manganese sulfate in a metal molar ratio of 0.5: 0.5 to obtain a second salt solution R2 of 1.5 mol / L; 5.0 mol / L ammonia solution as complexant C and 8 mol / L sodium hydroxide solution as precipitant D; Place the initial salt solution R1 in a container with a stirrer.

Secondary salt solution R2 is added to initial salt solution R1 at a flow rate of 6.67 L / h with stirring to obtain a mixed salt solution; The mixed salt solution, the precipitant D and the complex C are then simultaneously added to the reactor A for the reaction, wherein the flow rate of the mixed salt solution to the reactor A is 16.66 L / h, the reaction process is shown in Figure 1, Is reacted under a nitrogen atmosphere while controlling the reaction temperature to 50 ° C, the molar ratio of ammonia water to the total metal salt to 1: 1, and the reaction time to 30 hours to obtain a precursor precipitate.

The precursor precipitate is filtered, washed and dried at 120 캜 to obtain a precursor of a multi-component material. The precursor is thoroughly mixed with lithium hydroxide in a molar ratio of 1: 1.05 and held at 890 占 폚 for 10 hours in an air atmosphere. Natural cooling, crushing and screening are performed to obtain spherical multicomponent materials having a distribution structure.

The material produced by this embodiment is LiNi _{0 . 6} Co _{0 . 2} Mn _{0 . 2} O ₂ , the content of Ni element in the center of the granular material is 100 mol%, the content of Ni element continuously decreases from the inside to the outside, and the granular material is spherical; The median diameter (median glasses) was 15.3 탆 and the tap density was 2.55 g / cm ³ .

The electrode plate was formed by mixing and blending carbon black and polyvinylidene fluoride (PVDF) in a weight ratio of 94%: 3%: 3% to the multi-component material having a gradient structure for a lithium ion battery, An electrode using artificial graphite as an anode and a cathode, and a separator between an anode and a cathode are prepared, rolled, and then an electrolyte is injected to form a 053048 square aluminum shell battery. .

The manufactured lithium ion battery is tested according to GB / T18287-2000, an electrochemical performance and safety performance test according to the national standard for lithium ions. Specifically, the test is as follows.

Non-discharge capacity

0.2C ₅ A During charge-discharge, the unit of capacity released by 1 g of anode material in the discharged state is mAh / g. In the test, the multi-component material having the gradient structure for the lithium ion battery manufactured by this embodiment has a non-discharge capacity of 171 mAh / g.

1C ₅ A Charge-Discharge Cycle

At 20 ± 5 ℃ and charged to 4.2V at 1C ₅ A, after switching to the constant voltage charging until the charging current ≤0.01C ₅ A, and to 2.75V and discharged at 1C to form a first cycle at ₅ A, 1C ₅ A Charging / discharging is repeated. At the time of testing, the multi-component material having a gradient structure for a lithium ion battery manufactured by this embodiment has a charge-discharge cycle of 100 hours at 1C ₅ A, a capacity retention rate of 95% at room temperature, and excellent cycle performance.

High-temperature charge-discharge cycle at 1C ₅ A

45 ± filled in 2 ℃ from C ₅ A at 4.2V, and the switching to the constant voltage charging until the charging current ≤0.01C ₅ A, and discharged at 1C to 2.75V ₅ A after forming the first cycle, 1C ₅ A Charging / discharging is repeated. During the test, the multi-component material that has a lithium ion battery 1C ₅ A gradient structure for manufactured by the present embodiment has a capacity maintenance rate of 92% at 45 ℃ after 100 cycles, and has a good cycle performance at high temperatures.

Rate of change in battery thickness after high temperature storage at 85 ° C

20 ± 5 ℃ charged in 0.2C at ₅ A at 4.2V, and, after switching to the constant voltage charging until the charging current ≤0.01C ₅ A, and discharged to 2.75V to form a first cycle at 1C ₅ A, 1C ₅ A < / RTI > charge / discharge cycles and when the battery is cycled from the third cycle to the charged state, the battery is removed to measure the initial thickness; The battery is then left at 85 ± 5 ° C for 4 hours and the thickness is measured; The rate of change of thickness of the battery is calculated. At the time of testing, the multi-component material having a gradient structure for a lithium ion battery produced by this embodiment had a growth rate of the battery thickness of 6.7% after storage at a high temperature of 85 캜 for 4 hours, and the battery expansion at a high temperature was small .

Heat shock in a 150 ° C hot air oven

At 20 ± 5 ℃ and charged to 4.2V at 0.2 C ₅ A, and then switch to constant voltage charging until the charging current ≤0.01C ₅ A, and discharged to 2.75V to form a first cycle at 1C ₅ A, 1C ₅ A charging / discharging cycle was carried out. When the battery was circulated in the charging state in the third cycle, the battery was removed and heated in an oven at a heating rate of 5 ° C / min to 150 ° C. do. At the time of testing, the multicomponent material having a gradient structure for a lithium ion battery produced by this embodiment had no explosion or cracking within 60 minutes, as evidenced by the results of a thermal shock test at 150 DEG C in a hot air oven, Respectively.

The multi-component material having a gradient structure for a lithium ion battery manufactured by the above embodiment has a high non-discharge capacity of 170 mAh / g, much higher than LiCoO ₂ (about 145 mAh) Performance and safety performance.

Embodiment 2

Nickel sulfate, cobalt sulfate and manganese sulfate were dissolved in a metal molar ratio of 0.87: 0.06: 0.07 to obtain 225 mg of an initial salt solution R1 of 1.5 mol / L, and cobalt sulfate and manganese sulfate were dissolved at a metal molar ratio of 1: 1.3 to obtain 1.5 mol / L Secondary salt solution R2 35 L is obtained, and a 5.0 mol / L ammonia aqueous solution as complexing agent C and an 8 mol / L sodium hydroxide solution as precipitant D are prepared, and the initial salt solution R1 is put in a container with a stirrer.

Adding a second salt solution R2 to the first salt solution R1 with stirring at a flow rate of 1.16 L / h to obtain a mixed salt solution; The mixed salt solution, precipitant D and complex C are simultaneously added to reactor A for the reaction, wherein the flow rate at which the mixed salt solution is added to reactor A is 8.67 L / h, the reaction process is shown in Figure 1, The reaction is carried out under nitrogen atmosphere protection while adjusting the reaction temperature to 50 占 폚, the molar ratio of amphoteric ammonia to total metal salt to 1: 1, and the reaction time to 30 hours to obtain a precursor precipitate.

The precursor precipitate is filtered, washed and dried at 110 캜 to obtain a precursor of a multi-component material. The precursor was thoroughly mixed with lithium hydroxide in a molar ratio of 1: 1.05 and maintained at 890 DEG C for 10 hours in an oxygen gas atmosphere. Followed by natural cooling, pulverization and screening to obtain spherical multicomponent materials having a gradient structure.

Using the method of Embodiment 1, a positive electrode is prepared from a multi-component material having a gradient structure for a lithium ion battery manufactured in this embodiment, and the positive electrode is processed into a 053048 square aluminum-cell battery.

The multi-component material having a gradient structure for the lithium ion battery manufactured by this embodiment is LiNi _{0 . 77} Co _{0 . 10} Mn _{0 . 13} O _2. The content of Ni element in the center of the granular material is 87 mol%, and continuously decreases from the inside of Ni element to the outside, and the granular material is spherical. When tested, the central 10.6㎛ diameter, tap density was 2.43g / cm ^3, the non-discharge capacity is 183 mAh / g, 100 cycle charge at 1C5A - capacity retention ratio at room temperature and after-discharge cycle is 90%, and 100 cycles at 45 ℃ And the growth rate of the battery thickness after storage for 4 hours at a high temperature of 85 占 占 폚 was 7.9%. The thermal shock test result showed no explosion or cracking in the hot air oven at 150 占 폚 within 60 minutes.

2 is a scanning electron microscope image of a multicomponent material manufactured according to Embodiment 2. FIG. 3 is an electron microscope image of a cross section of the multicomponent material particle of FIG. 4 is an energy spectrum line scanning image of Ni, Co, and Mn elements from the center to the periphery of the multicomponent material particles shown in the electron microscope image for the section of Fig. As can be seen from Figs. 2, 3 and 4, the multi-component material produced according to the present embodiment shows that the content of Ni decreases from the center portion to the peripheral portion continuously and without increase, and the content of Mn and Co decreases from the center portion to the peripheral portion .

Embodiment 3

Nickel chloride, cobalt chloride and manganese chloride were dissolved in a metal molar ratio of 0.85: 0.1: 0.05 to obtain 500 ml of a 2 mol / L initial salt solution; Cobalt nitrate, manganese sulfate and aluminum nitrate were dissolved in a metal molar ratio of 0.52: 0.05: 0.43 to obtain 66.5 L of 2 mol / L of a second salt solution R2 66.5 L; A 2 mol / L ammonium sulphate solution as complex C was prepared, wherein the molar ratio of complex C to total metal salt was 0.7: 1; A 5 mol / L potassium hydroxide solution was prepared as precipitant D, wherein the molar ratio of precipitant D to total metal salt was adjusted to 2: 1; Place the initial salt solution R1 in a container with a stirrer.

The mixed salt solution, the precipitant D and the complex C are simultaneously added to the reactor A for reaction after adding the secondary salt solution R2 to the primary salt solution R1 with stirring at a flow rate of 3.33 L / h to obtain a mixed salt solution. In this case, the flow rate of the mixed salt solution to be added to the reactor A is 28.32 L / h. The reaction process is shown in FIG. 1, and the reaction temperature is adjusted to 11.5, the reaction temperature is 60 ° C., The reaction is carried out under protection to obtain a precursor precipitate.

The precursor precipitate is filtered, washed and dried at 80 캜 to obtain a precursor of a multi-component material. The precursor is thoroughly mixed with lithium carbonate in a molar ratio of 1: 0.52, and then maintained in an oxygen gas atmosphere at 800 DEG C for 15 hours. Followed by natural cooling, pulverization and screening to obtain spherical multicomponent materials having a gradient structure.

Using the method of Embodiment 1, a positive electrode is manufactured from a multi-component material having a gradient structure for a lithium ion battery manufactured in this embodiment, and the positive electrode is processed into a 053048 square aluminum-cell battery.

The multi-component material having a gradient structure for the lithium ion battery manufactured by this embodiment is LiNi _{0 . 75} Co _{0 . 15} Mn _{0 . 05} A1 _{0 . 05} O ₂ , the Ni element content is 85 mol% at the center of the granular material, the Ni element continuously decreases from the inside to the outside, and the granular material is spherical. At the time of the test, the capacity retention ratio at room temperature after 100 charge-discharge cycles at a center diameter of 10.1 탆, a tap density of 2.45 g / cm ³ , a non-discharge capacity of 180 mAh / g and 1 C ₅ A was 92% The capacity retention rate after 100 cycles was 90%. The growth rate of the battery thickness after storage for 4 hours at a high temperature of 85 占 占 폚 was 7.7%. The thermal shock test result showed explosion or cracking in a hot air oven at 150 占 폚 within 60 minutes Do not.

Embodiment 4

Manganese sulfate, aluminum nitrate, and magnesium chloride were mixed at a molar ratio of metal of 0.5: 0.366: 0.1: 0.1 to obtain 11.11 L of 1.8 mol / L initial salt solution R1, 0.107: 0.027 to obtain 667 L of a second salt solution R2 of 1.8 mol / L, and a 10 mol / L aqueous ammonia solution was prepared as Complex C, the molar ratio of complex C to total metal salt was 0.8: 1; An 8 mol / L sodium hydroxide solution is prepared as precipitant D, wherein the molar ratio of precipitant D to total metal salt is adjusted to 2.05: 1 and the initial salt solution R1 is placed in a vessel with a stirrer.

A second salt solution R2 was added to the first salt solution R1 with stirring at a flow rate of 26.7 L / h to obtain a mixed salt solution; The mixed salt solution, the precipitant D and the complex C are simultaneously added to the reactor A for the reaction, wherein the flow rate (flow rate) of the mixed salt solution added to the reactor A is 71.12 L / h, The reaction is carried out under a nitrogen atmosphere while adjusting the pH to 11.5, the reaction temperature to 55 ° C and the reaction time to 25 hours to obtain a precursor precipitate.

The precursor precipitate is filtered, washed and dried at 100 占 폚 to obtain a precursor of a multi-component material. The precursor is thoroughly mixed with lithium carbonate in a molar ratio of 1: 0.525 and held at 950 < 0 > C for 16 hours in an air atmosphere. Followed by natural cooling, pulverization and screening to obtain spherical multicomponent materials having a gradient structure.

Using the method of Embodiment 1, a positive electrode is prepared from a multi-component material having a gradient structure for a lithium ion battery manufactured in this embodiment, and the positive electrode is processed into a 053048 square aluminum-cell battery.

The multi-component material having a gradient structure for the lithium ion battery manufactured by this embodiment is LiNi _{0 . 50} Co _{0 . 25} Mn _{0 . 20} Al _{0 . 04} Mg _{0 . 01} O ₂ , the content of Ni element in the center of the granular material is 80 mol%, the content of Ni element continuously decreases from the inside to the outside, and the granular material is spherical. The capacity retention rate at room temperature after 100 charge-discharge cycles at a center diameter of 9.9 탆, a tap density of 2.46 g / cm ³ , a non-discharge capacity of 158 mAh / g and 1 C ₅ A was 96% The capacity retention rate after 100 cycles was 93%. The growth rate of the battery thickness after storage at a high temperature of 85 占 占 폚 for 4 hours was 5.9%. The thermal shock test result showed no explosion or cracking in the hot air oven at 150 占 폚 within 60 minutes .

Embodiment 5

Nickel sulfate, cobalt sulfate and manganese sulfate were dissolved in a metal molar ratio of 0.7: 0.15: 0.15 to make 250 mol of the initial salt solution R1, and aluminum sulfate and magnesium sulfate were dissolved at a metal molar ratio of 0.5: 0.5 to prepare a 2 mol / L of a second salt solution R2 was obtained, and ammonium chloride and EDTA were dissolved at a molar ratio of 0.8: 0.2 to obtain 2 moles / L of complex C, and the molar ratio of the complex C to the total metal salt (complex C: total metal salt) Is 0.2: 1; Prepare a 7 mol / L sodium hydroxide solution as precipitant D, adjust the molar ratio of precipitant D to total metal salt to 2.1: 1, and place the initial salt solution R1 in a vessel with a stirrer.

Adding a second salt solution R2 to the first salt solution R1 with stirring at a flow rate of 0.7 L / h to obtain a mixed salt solution; The mixed salt solution, the precipitant D and the complex C were simultaneously added to the reactor A, and the flow rate of the mixed salt solution added to the reactor A was 17.36 L / h. The reaction process is shown in FIG. 1, The reaction is carried out under the protection of nitrogen atmosphere while controlling the temperature to 60 DEG C and the reaction time to 15 hours to obtain a precursor precipitate.

The precursor precipitate is filtered, washed and dried at 140 캜 to obtain a precursor of a multi-component material. The precursor is thoroughly mixed with lithium nitrate in a molar ratio of 1: 1.03 and maintained at 820 占 폚 for 12 hours in an oxygen gas atmosphere. Followed by natural cooling, pulverization and screening to obtain spherical multicomponent materials having a gradient structure.

Using the method of Embodiment 1, a positive electrode is prepared from a multi-component material having a gradient structure for a lithium ion battery manufactured in this embodiment, and the positive electrode is processed into a 053048 square aluminum-cell battery.

The multi-component material having a gradient structure for the lithium ion battery manufactured by this embodiment is LiNi _{0 . 672} Co _{0 . 144} Mn _{0 . 144} Al _{0 . 02} Mg _{0 . 02} O ₂ , the content of Ni element in the center of the granular material is 70 mol%, the content of Ni element continuously decreases from the inside to the outside, and the granular material is spherical. During the test, the center of the diameter 6.5㎛ material, tap density was 2.21 g / cm ^3, the non-discharge capacity is 175 mAh / g, 1C 100 cycle charge at ₅ A - capacity retention ratio at room temperature and after-discharge cycle was 92%, 45 The capacity retention rate after 100 cycles at 100 ° C was 90%, the battery thickness increase rate after storage for 4 hours at 85 ± 2 ° C was 8.6%, and the thermal shock test results showed no explosion or cracking in the hot air oven at 150 ° C within 60 minutes .

Embodiment 6

667 L of a 1.5 mol / L nickel sulfate solution as an initial salt solution R1 was prepared, and cobalt sulfate, manganese sulfate, aluminum nitrate, magnesium sulfate and yttrium nitrate were dissolved in a metal molar ratio of 0.375: 0.3: 0.1: 0.1. 167 L of a second salt solution R2 of 0.05 mol / L is obtained, and 1 mol / L of an ethylenediamine solution is prepared as the complex C, the molar ratio of the complex C to the total metal salt is 0.2: 1; Prepare a 2 mol / L sodium carbonate solution as precipitant D, adjust the molar ratio of precipitant D to total metal salt to 1.1: 1, and place the initial salt solution R1 in a vessel with a stirrer.

Adding a second salt solution R2 to the first salt solution R1 with stirring at a flow rate of 4.18 L / h to obtain a mixed salt solution; Mixed salt solution, precipitant D and complex C were simultaneously added to reactor A, wherein the flow rate of the mixed salt solution added to reactor A was 20.85 L / h, and the reaction process is shown in FIG. The reaction is carried out under a nitrogen atmosphere while controlling the reaction temperature to 9.0, the reaction temperature to 45 ° C and the reaction time to 40 hours to obtain a precursor precipitate.

The precursor precipitate is filtered, washed and sintered at 500 < 0 > C to obtain a precursor of a multi-component material. The precursor and lithium hydroxide were thoroughly mixed in a molar ratio of 1: 1.04 and maintained at 750 DEG C for 15 hours in an oxygen gas atmosphere. Natural cooling, crushing and screening are performed to obtain spherical multicomponent materials having a gradient structure.

Using the method of Embodiment 1, a positive electrode is fabricated from a multi-component material having a gradient structure for a lithium-ion battery manufactured in this embodiment, and the positive electrode is processed into a 053048 square aluminum-shell battery.

The multi-component material having a gradient structure for the lithium ion battery manufactured by this embodiment is LiNi _{0 . 80} Co _{0 . 075} Mn _{0 . 075} Al _{0 . 02} Mg _{0 . 02} Y _{0 . 01} O ₂ , the content of Ni element in the center of the granular material is 100 mol%, the content of Ni element continuously decreases from the inside to the outside, and the granular material is spherical. When tested, the central 24.5㎛ diameter, tap density was 2.73 g / cm ^3, the non-discharge capacity is 100 times of charging at _{184 mAh / g, 1C 5 A} - capacity retention ratio at room temperature and after-discharge cycle is at 91%, 45 ℃ , The capacity retention after 100 cycles was 89%, the rate of increase of the battery thickness after storage for 4 hours at a high temperature of 85 占 占 폚 was 8.0%, and the result of thermal shock test showed that explosion or cracking occurred within 60 minutes in a hot air oven at 150 占 폚 I can not see.

Embodiment 7

Nickel chloride and cobalt sulfate were dissolved in a metal molar ratio of 0.9: 0.1 to obtain 1000 L of an initial salt solution R1 of 1 mol / L, and cobalt sulfate, manganese sulfate, magnesium sulfate and calcium chloride were mixed in a metal molar ratio of 0.2: 0.6: 0.1: 0.1 To prepare 250 ml of a second salt solution R2 of 1.0 mol / L and a 1 mol / L ammonium nitrate solution as the complexing agent C, the molar ratio of the complexing agent C to the total metal salt (complexing agent C: total metal salt) was 0.2: 1; A 3 mol / L ammonium bicarbonate solution is prepared as the precipitant D, the molar ratio of the precipitant D to the whole metal salt is adjusted to 1: 1, and the initial salt solution R1 is placed in a vessel equipped with a stirrer.

Adding a second salt solution R2 to the first salt solution R1 with stirring at a flow rate of 25 L / h to obtain a mixed salt solution; The mixed salt solution, the precipitant D and the complex C are simultaneously added to the reactor A, and the flow rate (flow rate) of the mixed salt solution added to the reactor A at this time is set to 125 L / h. The reaction is carried out under a nitrogen atmosphere while controlling the reaction pH to 8.7, the reaction temperature to 40 ° C and the reaction time to 10 hours to obtain a precursor precipitate.

The precursor precipitate is filtered, washed and sintered at 600 ° C to obtain a precursor of a multi-component material. The precursor is thoroughly mixed with lithium hydroxide in a molar ratio of 1: 1.04 and maintained at 800 占 폚 for 16 hours in an oxygen gas atmosphere. Followed by natural cooling, pulverization and screening to obtain spherical multicomponent materials having a gradient structure.

The multi-component material having a gradient structure for the lithium ion battery manufactured by this embodiment is LiNi _{0 . 72} Co _{0 . 12} Mn _{0 . 12} Mg _{0 . 02} Ca _{0 . 02} O ₂ , the content of Ni element in the center of the granular material is 90 mol%, the content of Ni element continuously decreases from the inside to the outside, and the granular material is spherical. During the test, the center of the diameter 7.3㎛ material, tap density was 2.33 g / cm ^3, the non-discharge capacity is 177 mAh / g, 1C 100 cycle charge at ₅ A - capacity retention ratio at room temperature and after-discharge cycle was 93%, 45 The battery capacity growth rate after storage for 4 hours at a high temperature of 85 ± 2 ° C was 7.4%. The thermal shock test result showed that explosion or cracking occurred within 150 minutes at 150 ° C in a hot air oven. I can not see.

Embodiment 8

667 L of a 1.5 mol / L nickel sulfate solution as an initial salt solution R1 was prepared, and cobalt sulfate, manganese sulfate, aluminum nitrate, magnesium sulfate and yttrium nitrate were dissolved in a metal molar ratio of 0.375: 0.3: 0.1: 0.1. 167 L of a second salt solution R2 of 0.05 mol / L is obtained and an ammonia solution of 5 mol / L is prepared as complexing agent C, the molar ratio of the complexing agent C to the total metal salt is 0.95: 1; An 8 mol / L sodium hydroxide solution was prepared as precipitant D, the molar ratio of precipitant D to total metal salt was adjusted to 2.07: 1, and the initial salt solution R1 was placed in a vessel with a stirrer.

Adding a second salt solution R2 to the first salt solution R1 with stirring at a flow rate of 4.18 L / h to obtain a mixed salt solution; The mixed salt solution, the precipitant D and the complex C were simultaneously added to the reactor A, and the flow rate (flow rate) of the mixed salt solution added to the reactor A at this time was 20.85 L / h and the reaction process was shown in FIG. The pH of the reaction was adjusted to 12.1, the reaction temperature to 50 ° C and the reaction time to 40 hours, and the reaction process was shown in FIG. The reaction is carried out to obtain a precursor precipitate.

The precursor precipitate is filtered, washed, and dried at 130 캜 to obtain a precursor of a multi-component material. The precursor is thoroughly mixed with lithium hydroxide in a molar ratio of 1: 1.04 and maintained at 760 占 폚 for 15 hours in an oxygen gas atmosphere. Followed by natural cooling, pulverization and screening to obtain spherical multicomponent materials having a gradient structure.

The multi-component material having a gradient structure for the lithium ion battery manufactured by this embodiment is LiNi _{0 . 8} Co _{0 . 075} Mn _{0 . 075} Al _{0 . 02} Mg _{0 . 02} Y _{0 . 01} O ₂ , and the content of Ni element in the center of the granular material is 100%. The content of Ni element continuously decreases from the inside to the outside, and the granular material is spherical. At the time of the test, the capacity maintenance ratio at room temperature after 90 cycles of 100 charge-discharge cycles at 1 C ₅ A, 90% at 45 C, and 45% at 45 C was 12.2 μm, tap density was 2.60 g / cm ³ , 187 mAh / g non- The capacity retention rate after 100 cycles at 100 ° C was 88%. The growth rate of the battery thickness after storage at a high temperature of 85 ± 2 ° C for 4 hours was 8.4%. The thermal shock test result showed that explosion or cracking I can not see.

Comparative Example

Nickel sulfate, cobalt sulfate and manganese sulfate were dissolved in a metal molar ratio of 0.6: 0.2: 0.2 to obtain 500 L of a 1.5 mol / L mixed salt solution. A 5.0 mol / L aqueous ammonia solution was used as complexing agent C and 8 mol / After the sodium salt solution was prepared, the mixed salt solution, the precipitant D and the complex C were simultaneously added to the reactor A, and the flow rate (flow rate) of the mixed salt solution added to the reactor A at this time was 16.67 L / h and the reaction pH was 11.3 , The reaction temperature is 50 ° C, the molar ratio of the aqueous ammonia solution to the total metal salt is 1: 1, and the reaction time is 30 hours. The reaction is carried out under a nitrogen atmosphere to obtain a precursor precipitate.

The precursor precipitate is filtered, washed and dried at 120 캜 to obtain a precursor of a multi-component material. The precursor is thoroughly mixed with lithium hydroxide in a molar ratio of 1: 1.05 and maintained at 890 占 폚 for 10 hours in an air atmosphere. Followed by natural cooling, pulverization and screening to obtain spherical multicomponent materials having a gradient structure.

Using the method of Embodiment 1, a positive electrode is manufactured from a multi-component material having a gradient structure for a lithium ion battery manufactured in this embodiment, and the positive electrode is processed into a 053048 square aluminum-shell battery.

The multi-component material having a gradient structure for the lithium ion battery manufactured by this embodiment is LiNi _{0 . 6} Co _{0 . 2} Mn _{0 . 2} O ₂ , and the particulate material is spherical. When tested, the central 15.6㎛ diameter, tap density was 2.56 g / cm ^3, the non-discharge capacity of 170m Ah / g, 1C 100 cycle charge at ₅ A - capacity retention ratio at room temperature and after-discharge cycle is at 85% 45 ℃ 100 The capacity retention rate after the cycle is 70%. The growth rate of the battery thickness after storage for 4 hours at a high temperature of 85 ± 2 ° C is 14.5%, and the thermal shock test results show no explosion or cracking in the hot air oven at 150 ° C within 60 minutes.

From the above test data, the multi-component material having a gradient structure for a lithium ion battery manufactured by the comparative example had apparently low non-discharge capacity, capacity retention ratio at normal temperature after 100 charge-discharge cycles at 1C5A reached only 85% Since the capacity retention after 100 cycles at 45 캜 is 70%, both the room temperature and high temperature cycle performances of the multi-component materials of the comparative examples are lower than those of the materials produced by the embodiments of the present invention, Safety performance is also bad.

Finally, it should be noted that the above embodiments are for illustrative purposes only, not for limiting the technical solution of the present invention; Although the present invention has been specifically described with reference to the above embodiments, it will be understood by those of ordinary skill in the art that modifications may be made to all or some of the technical solutions described in the foregoing embodiments, Will not deviate from the scope of the technical solution of the above-described embodiments of the present invention.

Claims (12)

As a multi-component material having a gradient structure for a lithium ion battery,
Wherein the multicomponent material has an average composition of formula (I)
LiNi _x Co _y Mn _z G _d O ₂ (I)
Mg, Ca, Sr, Ba, and Z are selected from the group consisting of Li, Cr, Fe, Wherein the content of the Ni element in the multi-component material having at least one of B, Al, Y, Sm, Ti, Zn, Zr, V, Nb, Ta, Mo and W, Lt; / RTI > to the surface of the particle). The method according to claim 1,
A multi-component material having a gradient structure for a lithium ion battery, wherein the multi-component material having a gradient structure for the lithium ion battery has a center diameter of 3 to 25 탆 and a tap density of 1.5 to 3.0 g / m ³ . The method according to claim 1,
The multi-component material is prepared by gradually adding a metal salt containing at least one of Ni, Co, Mn and G elements to a Ni-containing metal salt solution, precipitating the precipitant with the complex, Wherein the multi-component material has a gradient structure for a lithium ion battery. A method for producing a multi-component material having a gradient structure for a lithium ion battery according to any one of claims 1 to 3,
(1) dissolving a Ni-containing metal salt in water to prepare an initial salt solution, and dissolving a metal salt containing at least one of Ni, Co, Mn and G elements in water to prepare a second salt solution;
(2) The second salt solution is gradually added to the initial salt solution while stirring to obtain a mixed salt solution. Then, the mixed salt solution, the complex and the precipitant are simultaneously injected into the reactor, and the pH value is adjusted to 8-13 Obtaining a precursor precipitate by controlling the reaction time to 40 to 80 ° C and a reaction time of 5 to 50 hours to obtain a precursor of a multi-component material having a gradient structure by filtering, washing and heat-treating the precursor precipitate; And
(3) The precursor of the multi-component material having the above-mentioned gradient structure is uniformly mixed with the lithium source, sintered at 500 to 1100 DEG C for 4 to 30 hours in an air or oxygen gas atmosphere, pulverized, Lt; RTI ID = 0.0 > multi-component < / RTI > 5. The method of claim 4,
The second salt solution is added to the initial salt solution at a flow rate of 0.1-0.6 times the flow rate of the mixed salt solution added to the reactor and stirred. 5. The method of claim 4,
The precursor of the multi-component material having the above-mentioned gradient structure and the lithium source are uniformly mixed and heat-treated at 700 to 1000 ° C for 7 to 20 hours in a reaction atmosphere of air or oxygen gas and pulverized to obtain a multi- To obtain a material. 5. The method of claim 4,
Wherein the metal salt is at least one of a sulfate, a chloride, a nitrate, and an acetate. 5. The method of claim 4,
Wherein the complex is at least one of EDTA, ammonia water, ammonium chloride, ammonium sulfate, ammonium nitrate, ammonium citrate and ethylenediamine, and the molar ratio of the complex to the total metal salt is 0.1: 1-3.0: 1. 5. The method of claim 4,
Wherein the precipitant is at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium bicarbonate, ammonium carbonate, sodium bicarbonate and sodium carbonate and the molar ratio of the complexing agent to the total metal salt is 1.0: 1-2.5: 1. A positive electrode of a lithium ion battery, wherein the raw material of the positive electrode comprises a multi-component material having a gradient structure for the lithium ion battery according to any one of claims 1 to 3. 11. The method of claim 10,
Wherein the raw material further comprises carbon black and polyvinylidene fluoride. A lithium ion battery comprising the positive electrode of the lithium ion battery according to claim 10.

Images