WO2006136050A1

WO2006136050A1 - A multicomponent composite lithium oxide containing nickel and cobalt, a method for producing the same, the use thereof as a positive electrode active material for lithium ion secondary battery and lithium ion secondary battery

Info

Publication number: WO2006136050A1
Application number: PCT/CN2005/000884
Authority: WO
Inventors: Song Sheng Fang
Original assignee: Shenzhen Bak Battery Co., Ltd
Priority date: 2005-06-20
Filing date: 2005-06-20
Publication date: 2006-12-28

Abstract

A multicomponent composite lithium oxide of formula Lia(NibCoc)M1-b-cO2 is provided, wherein M is at least one metal atom selected from iron (Fe), aluminum (AL), manganese (Mn), titanium (Ti), copper (Cu), and calcium (Ca), and a=0.97~1.07, 0.3≤b<1, 0<c≤0.5, and 0.8≤b+c<1. A method for producing the same is also provided. The method comprises the steps of (a) producing a complesx solution of nickel, cobalt, metal M and ammonia water in a buffer solution; (b) adding the complex solution and an alkali solution and an alkali solution into a reactor, slowly, for coprecipitating Ni-Co-M composite hydroxide, then performing aging, separating, washing and drying, and then a precursor is obtained; (c) mixing and milling the precursor together with lithium hydroxide or lithium salt, then heat treating to obtain finished product. The use of the composite lithium oxide as a positive electrode active material for lithium ion secondary battery, and lithium ion secondary battery having this positive electrode active material are provided.

Description

Multi-component oxide containing cobalt and nickel, preparation method thereof and application thereof in lithium ion secondary battery

[Technical Field]

The invention relates to the field of high energy electrochemistry, and in particular to a multicomponent oxide containing cobalt and nickel, a preparation method thereof and the use thereof in a lithium ion secondary battery.

【Background technique】

In the past ten years, lithium cobalt oxide has been the first choice for commercial lithium ion battery cathode materials due to its excellent properties, such as high specific capacity, good cycle performance and excellent processing behavior. However, cobalt is a rare metal, and its resources are scarce. Continue to soar. However, with the rapid development of mobile communication electronic equipment and electric vehicles in the IT industry, new requirements for high cycle performance and high specific energy of lithium-ion batteries have been demanded, and new low-cost, high-cost alternatives to lithium-cobalt oxygen have been sought. A new cathode material that is more energy efficient, environmentally friendly, and long lasting.

At present, there are some domestic and foreign manufacturers that are researching and producing high-nickel-based materials, such as CITIC Guoan, Hunan Ruixiang, Shanshan Technology, etc., such as Japan's Benzhuang, Japan's Sanyo, South Korea's Samsung, etc., whose production methods are mainly solid. The phase reaction method, the solid phase reaction method is a process in which the material to be reacted is mixed by machine grinding, and then it is sintered. One of the outstanding advantages of this method is that the industrialization is simple and the production process cost is not high. The disadvantage is that the precursor material is difficult to mix uniformly, resulting in uneven product composition and performance, especially when the reaction components are large. The material is easy to freeze during pulping, and the slurry storage time is not frozen for a short time; the compactness of the pole piece is low, and the formed pole piece is hard, particularly brittle and easily broken, so that the volume specific energy of the material Lower, poor processing behavior.

[Summary of the Invention]

In view of the deficiencies of the above prior art, the object of the present invention is to provide a cobalt-nickel-containing multicomponent oxide Li _a (Ni _b Co _c ) M^ having a uniform particle size distribution and a high volume specific energy of the material. _c 0 ₂ .

Another object of the present invention is to provide a cobalt-nickel-containing multicomponent oxide having a simple preparation process and high handleability. Li _a (Ni _b Co _c ) M _1-bc 0 ₂ is prepared by using the multi-component oxide prepared above as a positive electrode material, and the prepared slurry has good fluidity and uniformity, and the slurry is stored. The freezing time is long, the processing behavior of the pole piece is good, and the cycle performance and capacity retention of the battery can be improved.

A technical solution for achieving the above object - a cobalt-nickel-containing multicomponent oxide Li _a (Ni _b Co.) M _lb- . 0 ₂ (wherein M is at least one metal atom selected from the group consisting of iron (Fe), aluminum (Al), manganese (Mn), titanium (Ti), copper (Cu), and calcium (Ca), a=0.97 -1. 07, 0. 3 b<l, 0<c 0. 5, 0. 8<b+c<l)

Multi-component oxide containing cobalt and nickel

The preparation method comprises the following steps:

(a) In a buffer solution, prepare a mixed ammonia complex solution of nickel, cobalt and other metals M with ammonia (Ni _b Co _c M ₁ . _b . _c )(NH ₃ )n _i where n is based on the price of each metal State, 0<n 6;

(b) and the alkali solution is slowly added to the reactor at the same time, coprecipitation

Forming a Ni-Co-M composite hydroxide, aging, separating, washing, and drying to obtain a precursor;

(c) mixing the precursor prepared in the step (b) with lithium hydroxide or a lithium salt;

(d) heat-treating the mixture obtained after the mixing to remove the adsorbed water and the structural water, the heat treatment temperature is 240-550 V, and the heat treatment time is 3-7 hours;

(e) Heat treatment step The product obtained in the step (d) is a lithium composite oxide having a heat treatment temperature of 650 to 850 ° C and a heat treatment time of 5 to 18 hours.

The metal M salt is at least one metal oxide selected from the group consisting of iron (Fe;), aluminum (Al), manganese (Mn), titanium (Ti), copper (Cu), and calcium (Ca) or a metal salt thereof.

The buffer solution consists of ammonia and an amine salt or ammonia and a weak acid.

The pH of the buffer solution in the step (a) is 8-11.

The temperature of the coprecipitation reaction in the step (b) is 40-80 ° C, and the stirring speed of the stirrer during the reaction is At 240-1 OOO rpm, the pH of the solution during the reaction is 10-12, and the time of the coprecipitation reaction is 4-10 hours. The above-mentioned cobalt-nickel-containing multi-component oxide is used as a positive electrode material of a lithium ion secondary battery.

A lithium ion battery comprising a positive electrode sheet, and a positive electrode active material on the positive electrode sheet contains the above-mentioned cobalt-nickel-containing multicomponent oxide.

With the above technical solution, in combination with the embodiments to be described in detail below, the effective technical effects of the present invention are as follows: 1. A multi-component oxide containing cobalt and nickel is provided.

(wherein M is at least one metal atom selected from the group consisting of iron (Fe), aluminum (Al), manganese (Mn), titanium (Ti), copper (Cu), and calcium (Ca), a = 0.97-1.07, 0 3^b<l, 0, c 0. 5, 0. 8<b+c, l), the multi-component oxide is used as a lithium positive active material, cycle performance, capacity retention and pole piece of the battery The processing behavior is greatly improved compared to the prior art. 2. Since the preparation method of the invention adopts the coprecipitation reaction, the element components of the material are mixed at the atomic level to form an ellipsoidal particle having a uniform particle size, and is easy to be separated, and can be obtained by coprecipitation after washing, precipitation and sintering. The resulting ellipsoidal particles are similar in particle uniformity. According to the examples in the specific embodiments and the comparative examples, the XRD test results show that the active material is a layered structure, the crystal form is well developed, and no other impurity peaks appear, that is, the doped ions are distributed in the layered crystal structure. The results of SEM test show that the particle size distribution of the material is uniform, and it is an ellipsoidal structure with an average particle size of 5-16 μ πι and a tap density of 2.15-2.35g/cm ³ . The multi-component oxide containing cobalt and nickel is used. The prepared slurry has good fluidity and uniformity, and the slurry storage time is long, and the processing behavior of the pole piece is good. The electrochemical performance test shows that the cycle performance, capacity retention and processing behavior of the pole piece are all There is a great improvement, and the specific capacity is also improved. 3. The preparation method is not only simple in process, but also has the characteristics of high process operability, good production repeatability, good product uniformity, easy to realize industrialization, and relatively low cost. low.

[Description of the Drawings]

Fig. 1 is an X-ray diffraction chart (XRD) of a positive electrode active material for a lithium ion secondary battery prepared in Example 1.

2 is a scanning electron micrograph (SEM:) of a positive electrode active material of a lithium ion secondary battery prepared in Example 1. 3 is a graph showing the first charge and discharge curves of the positive electrode active material of the lithium ion secondary battery prepared in Example 1. 4 is a graph showing charge and discharge cycle performance of a lithium ion secondary battery positive electrode active material prepared in Example 1. FIG.

【detailed description】

A method for preparing a multi-component oxide containing cobalt and nickel is to prepare a mixed solution of nickel-cobalt and metal M with ammonia in an ammonia-amine salt or an ammonia-weak acid buffer solution having a pH of 8-11, and then Simultaneously adding to the reaction kettle simultaneously with the lye to carry out a coprecipitation reaction, wherein the coprecipitation reaction time is 4-10 hours, the reaction temperature is 40-80 ° C, and the stirring speed is 240-1000 rpm to form a Ni-Co-M composite. Hydroxide, aging, separation and washing of Ni-Co-M composite hydroxide, to obtain ellipsoidal Ni-Co-M composite hydroxide particles with uniform particle size, high density and excellent electrochemical performance; Drying the Ni-Co-M composite hydroxide particles in an air atmosphere at a drying temperature of 60-120 Torr or under vacuum for 16-36 hours, mixing with lithium hydroxide or lithium salt, and heat-treating the mixture at 240-550 Torr. 3-7 hours; then heat-treating the mixture at 650-850 Torr for 5-18 hours to obtain a multi-component oxide containing cobalt nickel.

In the above test conditions, when the pH of the dosing solution is lower than 8, more salt solution needs to be added, and we need to use the ammonia ion in the ammonia water, the purpose of which is only used to balance the pH value, the other is On the other hand, more additions like amine salts require more lye to be consumed; when the pH is higher than 11, the precipitation tends to occur when the complex solution is complexed. The synthesis conditions (reaction time, temperature, pH, agitation speed) and the range of heat treatment conditions are used to control the particle size and density of the product particles, as well as the cost of the combination. If outside the range, physical and chemical properties of the synthetic material may be caused. deterioration. The reaction time is too short (<4h). The reaction is incomplete. The reaction is completed after a long time (>10h). Prolonging the reaction time reduces the production efficiency. The stirring speed is too slow (<240ipm), the mixing is uneven, and the reaction is not complete. If the stirring speed is too fast (>1000 rpm), the particles of the generated material will be too fine, which will affect the structure of the product. If the temperature during sintering is lower than 650'C, the material will be incompletely sintered and the crystallization will be incomplete. If it is higher than 85CTC, the structure will be destroyed.

Example 1: Positive active material

Preparation and performance structure testing

Nickel (Ni) was taken at a molar ratio of 0.75:0.1, and a total of 8.5 moles of cobalt (Co) sulfate was slowly stirred under constant stirring. Add 10L of nickel-cobalt-ammonium complex solution by adding ammonia and ammonium sulfate to a buffer solution of pH 10, and mix it with 10L, 2.2M NaOH and 0.1M A1 ₂ (S04) ₃ with constant stirring. The mixed aqueous solution was slowly dropped into a reaction vessel containing 7 L of an aqueous solution and adjusted to a pH of 11 with a 2.2 M pure NaOH solution at a reaction temperature of 40 V and a stirring speed of 400 rpm. After 6 hours, the Ni-Co-Al composite hydroxide was separated, aged for 2 hours, washed with distilled water several times, dried at 80 ° C for 16 hours, ground and sieved to obtain a precursor, and the water was accurately measured and carbonated. Manganese and lithium hydroxide monohydrate (LiOH*H ₂ 0) molar ratio 1: 0.053: 1.06 mixed and placed in an intelligent control muffle furnace, heated to 320 °C at 2 ° C / min in a dry air and kept at a constant temperature The first heat treatment was carried out for 6 hours, and then the temperature was raised to 750 ° C at C / min and the temperature was kept for 16 hours to carry out sintering, followed by natural cooling to room temperature, grinding, sieving and classification to obtain a positive electrode active material.

The structure and morphology test results of the product obtained in this example: The XRD pattern is shown in Figure la, similar to the XRD pattern of LiCo0 ₂ , the peak intensity ratio of 1003/1104 is as high as 1.9 or more, the structural peaks 006 and 102 and the peaks 008 and 110 Both tend to exist as independent peaks, so it can be considered that the synthesized product has a layered structure and the crystal form is well developed, the structure is complete, and the defects are few. The SEM spectrum showed that the particle shape of the synthesized product was ellipsoidal, the size was uniform, the average particle size was 5-16 μ ηι, and the tap density of the powder was 2.19 g/cm ³ . The electrochemical performance of the product has been tested on a button cell made with a Xinwei low current tester. The negative electrode of the button battery is metal lithium, the separator is glass fiber filter paper, and the positive electrode is made of synthetic product. The positive electrode sheet is prepared similarly to the large battery pole piece method, that is, 92 parts of the product of the invention, 4 parts of conductive agent, and sticky The mixture of 4 parts of polyvinylidene fluoride (PVdF) and a suitable amount of solvent N-methylpyrrolidone (NMP) was mixed and stirred to obtain a paddle, and then coated on aluminum foil with a single side of about 160 um thick, dried, compacted. It is about UOum thick, and a disc with a diameter of about 18 mm is punched by a puncher, and it is vacuum-dried for 8 to 12 hours and assembled into a 2430 type button battery in a glove box. The battery was charged to 4.3 volts at a constant current of 0.1 C, and discharged at a constant current of 0.1 C to 2.75 volts after constant voltage charging at 4.3 V. The first charge specific capacity of the positive electrode material of the present invention was measured to be 196.2258 mAh/g, and the first discharge specific capacity was 167.2495. mAh/g, coulombic efficiency is 85.23% (as shown in Figure 3); the reversible specific capacity after 100 cycles is 160.2937 mAh / g, the capacity retention rate is 97.00%, The electrochemical cycle performance is excellent (as shown in Figure 4). The pulping and coating process of the pole piece were good. No gelation occurred after the slurry was placed for 48 hours. The surface of the produced pole piece was smooth and there was no dropping phenomenon.

Example 2: Positive active material

Preparation and performance structure test molar ratio of 0.85:0.1:0.02:0.01 Take nickel (Ni), cobalt (Co), manganese (Mn), copper (Cu) sulfate total 9.8 moles slowly added under constant stirring conditions 10L of nickel, cobalt, manganese, copper and ammonia mixed complex solution was prepared from a buffer solution of pH 9 prepared by ammonia water and ammonium sulfate. There was a 7 L aqueous solution and the pH was adjusted to 10 in a 2.2 M pure NaOH solution, the reaction temperature was 50 ° C, and the stirring speed was 600 rpm. After 7 hours, the Ni-Co-Mn-Cu composite hydroxide was separated, aged for 1 hour, washed several times with distilled water, dried at 100 Torr for 10 hours, ground and sieved to obtain a precursor, and the water was accurately measured. After being mixed with titanium dioxide and lithium carbonate by molar ratio 1: 0.02: 0.53, it is placed in an intelligent control muffle furnace, heated to 200 Torr at 5 ° C / min in dry air and heated for 4 hours for the first heat treatment. The temperature was raised to 800 ° C at 2 ° C / min and the temperature was kept for 12 hours to carry out sintering, followed by natural cooling to room temperature, grinding, sieving and classification to obtain a positive electrode active material.

The structure and morphology test results of the product obtained in this example: The XRD pattern is similar to the XRD pattern of Example 1, the peak intensity ratio of 1003/1104 is as high as 1.6 or more, and the structural peaks 006 and 102 and peaks 008 and 110 tend to be independent peaks. Existence, it can be considered that the synthesized product has a layered structure and the crystal form is well developed, the structure is complete, and the defects are few. The SEM spectrum was similar to the SEM spectrum of Example 1, and it was shown that the particle shape of the synthesized product was ellipsoidal, the size was uniform, the average particle size was 6-12 μιη, and the tap density of the powder was 2.24 g/cm ³ . The electrochemical performance of the product has been tested with a Xinwei small current tester. The material has a first charge specific capacity of 192.4837 mAh/g, a first discharge specific capacity of 173.5134 mAh/g, and a coulombic efficiency of 90.14%. After 100 cycles, the capacity retention rate is 98.13%, and the reversible capacity is 170.26S7 mAh/g. The pulping and coating process of the pole piece are good. No gelation occurs after 48 hours of slurry placement. The surface of the sheet is smooth and there is no dropping. Example 3: Positive active material

Preparation and performance structure test molar ratio of 0.75:0.15:0.03:0.02:0.05 Take nickel (Ni), cobalt (Co), iron (Fe), titanium (Ti), manganese (Mn) sulfate total 10 mol Under the condition of constant stirring, slowly add a buffer solution of pH 8 prepared from ammonia water and boric acid to prepare 10L of mixed complex solution, and mix it with 10L, 2.2M NaOH while slowly stirring. A 7 L aqueous solution was placed and the pH was adjusted to 10.5 with a 2.2 M pure NaOH solution at a reaction temperature of 60 ° C and a stirring speed of 800 rpm. After 9 hours, the Ni-Co-Mn-Fe-Ti composite hydroxide was separated, aged for 3 hours, washed with distilled water several times, and then dried at 6 (TC for 24 hours, ground and sieved to obtain a precursor, accurately measured The water is mixed with anhydrous lithium nitrate at a ratio of 1:1.04 and placed in an intelligent control muffle furnace. The temperature is raised to 500 5 at 5 ° C/min in dry air and the temperature is maintained for 3 hours for the first heat treatment. Then, the temperature was raised to 780 Torr at 5 ° C / min and the temperature was kept for 16 hours to carry out sintering, followed by natural cooling to room temperature, grinding, sieving and classification to obtain a positive electrode active material.

The structure and morphology test results of the product obtained in this example: The XRD pattern is similar to the XRD pattern of Example 1, the peak intensity ratio of 1003/1104 is about 1.7, and the structural peaks 006 and 102 and peaks 008 and 110 tend to be independent peaks. Existence, it can be considered that the synthesized product has a layered structure and the crystal form is well developed, the structure is complete, and the defects are few. The SEM spectrum is similar to the SEM spectrum of Example 1. The SEM spectrum shows that the particle shape of the synthesized product is ellipsoidal, the size is uniform, the average particle size is 4-13 m, and the tap density of the powder is 2.26 g/cm ³ . The electrochemical performance of the product has been tested with a Xinwei small current tester for the button cell. The first charge specific capacity of the material is 193.7749 mAh/g, the first discharge specific capacity is 164.783 mAh/g, and the coulombic efficiency is 85.02. %; After 100 cycles, the capacity retention rate was 96.47%, and the reversible capacity was 158.9327 mAh/g. The pulping and coating process of the pole piece were good. No gel appeared after 48 hours of slurry placement. The surface of the sheet is smooth and there is no dropping.

Example 4: Preparation and performance of positive active material LiNi^Coi A^Mno.osC Structural test: Nickel (Ni), cobalt (Co), aluminum (Al), manganese (taken by molar ratio 0.65:0.2:0.1:0.05) Mn) sulfate total 10 moles Under the condition of constant stirring, slowly add a buffer solution of pH 8.5 prepared by ammonia water and ammonium sulfate to obtain 10L of mixed ammonia complex solution. Under continuous stirring, it is simultaneously slow with 10L, 2.2M NaOH aqueous solution. A reaction vessel containing 7 L of an aqueous solution and adjusting its pH to 11.5 with a 2.2 M pure NaOH solution was added dropwise, the reaction temperature was 70 V, and the stirring speed was 300 rpm. After 5 hours, the Ni-Co-Al-Mn composite hydroxide was separated, aged for 4 hours, washed with distilled water for several times, and then dried at 120 ° C for 8 hours. After grinding and sieving, the precursor was prepared and the water was accurately measured. After the portion of lithium hydroxide monohydrate (LiOH * H ₂ 0) molar ratio 1: 1.07 mixed grinding and placed in an intelligent control muffle furnace, in a dry air at 2 ° C / min to 400 Ό and constant temperature for 6 hours The first heat treatment was carried out, and then the temperature was raised to 770 Torr at 2 ° C / min and the temperature was kept for 24 hours to carry out sintering, followed by natural cooling to room temperature, grinding, sieving and classification to obtain a positive electrode active material.

The structure and morphology test results of the product obtained in this example: The XRD pattern is similar to the XRD pattern of Example 1, the peak intensity ratio of 1003/1104 is about 1.4, and the structural peaks 006 and 102 and peaks 008 and 110 tend to be independent peaks. Existence, it can be considered that the synthesized product has a layered structure and the crystal form is well developed, the structure is complete, and the defects are few. The SEM spectrum was similar to the SEM spectrum of Example 1, and it was shown that the particle shape of the synthesized product was ellipsoidal, the size was uniform, the average particle size was 4-18 um, and the tap density of the powder was 2.17 g/cm ³ . The electrochemical performance of the product was tested with a Xinwei small current tester. The material has a first charge specific capacity of 189.6044 mAh/g, a first discharge specific capacity of 165.2592 m Ah7g, and a coulombic efficiency of 87.16%. After 100 cycles, the capacity retention rate was 96.13%, and the reversible capacity was 158.8637 mAh/g. The pulping and coating process of the pole piece were good. No gel appeared after 48 hours of slurry placement. The surface of the pole piece was produced. Smooth, no missing material.

Example 5: Preparation and performance of positive active material LiNio^CoojAlo Mno.cnCuo.iHCao.oi ^ Structural test molar ratio 0.65:0.3:0.02:0.01:0.01:0.01 Take nickel (Ni), cobalt (Co), aluminum (Al), manganese (Mn;), copper (Cu) and calcium (Ca) sulfates a total of 10 moles under constant stirring conditions slowly added to the buffer solution of pH 3⁄11 11 prepared from ammonia and oxalate A mixed ammonia complex solution of 10L was obtained, and while continuously stirring, it was slowly dropped into a 7 L aqueous solution with 10 L of a 2.2 M aqueous solution of NaOH, and the pH was adjusted to 11.0 with a 2.2 M pure NaOH solution. In the reaction vessel, the reaction temperature was 55 ° C and the stirring speed was 900 rpm. After 10 hours, the Ni-Co-Al-Mn-Cu-Ca composite hydroxide was separated, aged for 3 hours, washed several times with distilled water, dried at 50 ° C for 30 hours, ground and sieved to obtain a precursor, which was accurately measured. After the water, the anhydrous lithium nitrate is mixed with 1:1.07 and placed in an intelligent control muffle furnace. The first heat treatment is carried out in a dry air at TC/min to 550 ° C and constant temperature for 8 hours. Then, the temperature was raised to 770 ° C at 2 ° C / min and the temperature was kept for 20 hours to carry out sintering, followed by natural cooling to room temperature, grinding, sieving and classification to obtain a positive electrode active material. .

The structure and morphology test results of the product obtained in this example: The XRD pattern is similar to the XRD pattern of Example 1, the peak intensity ratio of 1003/1104 is about 1.4, and the structural peaks 006 and 102 and peaks 008 and 110 tend to be independent peaks. Existence, it can be considered that the synthesized product has a layered structure and the crystal form is well developed, the structure is complete, and the defects are few. The SEM spectrum was similar to the SEM spectrum of Example 1, and it was shown that the particle shape of the synthesized product was a nan spherical shape with a uniform size, an average particle diameter of 5-17 P m, and a tap density of the powder of 2.21 g/cm ³ . The electrochemical performance of the product has been tested with a Xinwei small current tester. The material has a first charge specific capacity of 191.6174 mAh/g, a first discharge specific capacity of 166.7329 mAh/g, and a coulombic efficiency of 87.01%. After 100 cycles, the capacity retention rate is 94.88%, and the reversible capacity is 158.1962 mAlVg. The pulping and coating process of the pole piece are good. No gel phenomenon occurs after the slurry is placed for 48 hours. The surface of the electrode piece is smooth. There is no dropping phenomenon.

Example 6: Positive active material

Preparation and performance structure testing

Nickel (Ni), cobalt (Co), aluminum (Al), manganese (Mn) sulfate in a molar ratio of 0.3:0.5:0.1:0.1, a total of 10 moles under constant stirring conditions, slowly added by ammonia and amine carbonate In a buffer solution with a pH of 8, 10 L of the mixed ammonia complex solution was prepared, and while continuously stirring, it was slowly dropped into a 7 L aqueous solution containing 10 L of 2.2 M NaOH solution and adjusted with 2.2 M pure NaOH solution. In a reaction vessel having a pH of 11.5, the reaction temperature was 70 ° C and the stirring speed was 950 rpm. After 10 hours, the Ni-Co-Al-Mn composite hydroxide was separated, aged for 3 hours, washed with distilled water for several times, dried at 80 ° C for 24 hours, ground and sieved to obtain a precursor, and the water was accurately measured. Waterless Lithium nitrate massage ratio 1: 1.05 was mixed and placed in an intelligent control muffle furnace, heated to 550 ° C at 5 ° C / min in dry air and heated for 8 hours for the first heat treatment, and then 2 ° C/min was heated to 770 ° C and kept at a constant temperature for 16 hours for sintering, and then naturally cooled to room temperature, ground, sieved and classified to obtain a positive electrode active material.

The structure and morphology test results of the product obtained in this example: The XRD pattern is similar to the XRD pattern of Example 1, the peak intensity ratio of 1003/1104 is about 1.53, and the structural peaks 006 and 102 and peaks 008 and 110 tend to be independent peaks. Existence, it can be considered that the synthesized product has a layered structure and the crystal form is well developed, the structure is complete, and the defects are few. The SEM spectrum was similar to the SEM spectrum of Example 1. It showed that the particle shape of the synthesized product was ellipsoidal, the size was uniform, the average particle size was 7-15 μ ηι, and the tap density of the powder was 2.34 g/cm ³ . The electrochemical performance of the product has been tested with a Xinwei small current tester. The material has a first charge specific capacity of 192.7129 mAh/g, a first discharge specific capacity of 172.6642 mAh/g, and a coulombic efficiency of 89.60%. After 100 cycles, the capacity retention rate is 96.21%, and the reversible capacity is 166.1202 mAh/g. The pulping and coating process of the pole piece are good. No gelation occurs after the paddle is placed for 96 hours. The surface is smooth and there is no material drop.

Claims

Claims, a cobalt-nickel-containing multicomponent oxide Li NibCoj M^Os, wherein M is at least one selected from the group consisting of iron (Fe), aluminum (Al), Mn (Mn), titanium (Ti), and copper (Cu) And the metal atom of calcium (Ca), a=0. 97 - 1. 07, 0. 3 b<l, 0<c^0. 5, 0. 8^b+c< lc

Multi-component oxide containing cobalt and nickel

The preparation method comprises the following steps:

0) preparing a mixed ammonia complex solution of nickel, cobalt and other metals M with ammonia in a buffer solution (Ni _b Co _c Mi. _b .c) (NH ₃ ) _ll (0<n^6);

And the alkali solution is slowly added to the reaction tank at the same time, coprecipitating to form Ni-Co-M composite hydroxide, aging, separating, washing and drying to obtain a precursor;

(c) mixing the precursor prepared in the step (b) with lithium oxychloride or lithium salt;

(d) heat-treating the mixture obtained after the mixing to remove the adsorbed water and the structural water at a temperature of 240 to 550. C, heat treatment time is 3-7. hours;

(e) Heat treatment step The product obtained in the step (d) is a lithium composite oxide having a heat treatment temperature of 650 to 85 (TC, heat treatment time of 5 to 18 hours).

The cobalt-containing nickel-containing multicomponent oxide according to claim 2.

The preparation method is characterized in that the metal M is at least one metal selected from the group consisting of iron (Fe:), aluminum (Al), manganese (Mn), titanium (Ti), copper (Cu), and calcium (Ca). Oxide or metal M salt.

The method for preparing a cobalt-containing nickel-containing multi-component oxide Li _a (Ni _b Co _e ) M ^ _e 02 according to claim 2, wherein the buffer solution is composed of ammonia and an amine salt or ammonia and Weak acid is formulated.

The cobalt-containing nickel-containing multicomponent oxide according to claim 4.

The preparation method is characterized in that the pH of the buffer solution is 8-11.

The cobalt-containing nickel-containing multicomponent oxide Li _a (Ni _b Co _e )M _b . according to claim 2. 0 ₂ preparation method, its special The temperature in the coprecipitation reaction in step (b) is 40-80 ° C, the stirring speed of the stirrer is 240-1000 rpm during the reaction, the pH of the solution is 10-12 during the reaction, and the time of the co-precipitation reaction is 4-11. hour.

a cobalt-nickel-containing multi-component oxide Li _a (Ni _b CojM _1-b- 0 ₂ as a positive electrode active material for a lithium ion secondary battery, wherein M is at least one selected from the group consisting of iron (Fe), aluminum Metal atoms of (Al), manganese (Mn), titanium (Ti), copper (Cu), and calcium (Ca), a = 0.97-1.07, 0.3^b<l, (Kc 0.5, 0.8 b+c<l.

A lithium ion battery comprising a positive electrode sheet, characterized in that: the positive electrode active material on the positive electrode sheet contains a multi-component oxide multi-component oxide Li _a (Ni _b Co.) M _lb- containing cobalt nickel. 0 ₂ , wherein M is at least one metal atom selected from the group consisting of iron (Fe), aluminum (Al), manganese (Mn;), titanium (Ti), copper (Cu), and calcium (Ca), a=0.97- 1.07, 0.3 b<l, 0<c^0.5, 0.8 b+c<l. ■