Cathode materials, batteries and electronic devices

Abstract

To provide a positive electrode material, a battery and an electronic apparatus.SOLUTION: A first aspect of the present invention provides a positive electrode material which is Lin-xNaxCo1-yMeyO2 where 0.7≤n≤1, 0<x≤0.15 and 0≤y≤0.15 are satisfied, and Me represents one or more selected from Al, Mg, Ti, Zr, Ni, Mn, Y, La, Sr, W, Sc, Ce, P, Nb, V, Ta, and Te. An X-ray diffraction pattern of the positive electrode material includes a peak 002 corresponding to a crystal plane 002, a peak 004 corresponding to a crystal plane 004, a peak 101 corresponding to a crystal plane 101, a peak 102 corresponding to a crystal plane 102, and a peak 103 corresponding to a crystal plane 103, and when a peak intensity ratio of the peak 101 to the peak 004 is m, m≥1.5 is satisfied. The positive electrode material provided by the present invention has higher discharge gram capacity and a relatively stable structure, which is helpful to improve capacity and cycle performance of the battery.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to cathode materials, batteries and electronic devices, and to the field of electrochemical technology. [Background technology]

[0002] As consumer electronic products such as mobile phones and tablets become thinner, the demand for battery energy density is also increasing. Currently, lithium cobalt oxide is the cathode material used to increase energy density. One effective way to achieve this is to increase the end-of-charge voltage of lithium cobalt oxide. However, when the charging voltage exceeds 4.55V (vs. Li), lithium cobalt oxide with a general structure undergoes an irreversible phase change, namely, from the O3 phase to the H1-3 phase. The poor ionic and electronic conductivity of the H1-3 phase causes the capacity of the lithium cobalt oxide to decrease, thereby affecting the battery's cycle performance.

[0003] One way to improve the structural stability of lithium cobalt oxide is to increase the content of doping elements in the lithium cobalt oxide. However, as the content of the doping elements increases, the improvement in capacity per gram is not significant. For example, the capacity per gram of lithium cobalt oxide at 4.5 V is 186 mAh / g (vs. C / 0.2C), and the capacity per gram at 4.53 V is 189 mAh / g (vs. C / 0.2C). Therefore, how to improve the structure of lithium cobalt oxide to improve the capacity per gram and structural stability of the positive electrode material, thereby improving the capacity and cycle performance of the battery, is a challenge that must be solved by those skilled in the art. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a positive electrode material, which can be used to improve the capacity per gram and structural stability of the positive electrode material, and to improve the capacity and cycle performance of the battery.

[0005] The present invention further provides a battery and an electronic device including the above positive electrode material.

Means for Solving the Problems

[0006] In a first aspect of the present invention, a positive electrode material is provided, and the positive electrode material is Li + , 1-y , y , n-x , x ,

[0007] , , , Na x Co 1-y Me y O2 (where 0.7 ≤ n ≤ 1, 0 < x ≤ 0.15, 0 ≤ y ≤ 0.15, and Me is one or more selected from Al, Mg, Ti, Zr, Ni, Mn, Y, La, Sr, W, Sc, Ce, P, Nb, V, Ta, Te), the X-ray diffraction pattern of the positive electrode material has a 002 peak corresponding to the 002 crystal plane, a 004 peak corresponding to the 004 crystal plane, a 101 peak corresponding to the 101 crystal plane, a 102 peak corresponding to the 102 crystal plane, and a 103 peak corresponding to the 103 crystal plane, the peak intensity ratio of the 101 peak to the 004 peak is m, and m ≥ 1.5.

[0007] The present invention provides a positive electrode material, and its structural formula is Li n-x Na x Co 1-y Me y O2 (where 0.7 ≤ n ≤ 1, 0 < x ≤ 0.15, 0 ≤ y ≤ 0.15, and Me is one or more selected from Al, Mg, Ti, Zr, Ni, Mn, Y, La, Sr, W, Sc, Ce, P, Nb, V, Ta, Te). In addition, for the positive electrode material, the n value is different in different delithiated states. Before forming the positive electrode sheet of the positive electrode material and performing a capacity test, the n value in the positive electrode material (powder state) is 1. After forming the positive electrode sheet and performing a capacity test, when the operating voltage is 3.6 - 4.0 V, the n value decreases to 0.70 - 1. This is mainly because during the first charge and discharge of the battery, some lithium ions are used to form the CEI film and SEI film, which are the protective layers on the positive and negative electrode surfaces, and a part of the Li +Therefore, the Li content of the positive electrode material in the positive electrode sheet after formation and capacity testing decreases due to irreversible loss of Li. Furthermore, the X-ray diffraction pattern of the positive electrode material shows a 002 peak corresponding to the 002 crystal plane, a 004 peak corresponding to the 004 crystal plane, a 101 peak corresponding to the 101 crystal plane, a 102 peak corresponding to the 102 crystal plane, and a 103 peak corresponding to the 103 crystal plane. The 002 peak corresponding to the 002 crystal plane, the 102 peak corresponding to the 102 crystal plane, and the 103 peak corresponding to the 103 crystal plane indicate that the positive electrode material provided by the present invention has characteristic peaks different from those of common lithium cobalt oxide materials, and has a distinct layered structure, forming multiple small charge / discharge platforms during charge / discharge. It can be expressed as follows: under the same charge / discharge end voltage and charge / discharge rate conditions, the positive electrode material has a higher capacity per gram and a stable structure; and the greater the peak intensity ratio m between the 101 peak and the 004 peak, the more favorable the structural stability of the positive electrode material is, which is more favorable for lithium ion desorption and absorption; otherwise, the positive electrode material may have poor structural stability, and the electrochemical performance may be reduced due to conditions such as incomplete reaction or poor crystallinity. Therefore, the positive electrode material provided in the present invention is useful for improving the capacity and cycle performance of the battery, thereby meeting the demand for thinner batteries.

[0008] In one specific embodiment, the diffraction angle 2θ corresponding to the 002 peak is 18.6°±0.5°, the diffraction angle 2θ corresponding to the 102 peak is 41.7°±0.5°, and the diffraction angle 2θ corresponding to the 103 peak is 47.1°±0.5°.

[0009] Measurement using a Malvern laser granulometer reveals that the particle size of the positive electrode material is 6 to 18 μm, where the particle size is the size of the particles of the positive electrode material.

[0010] Through testing, the specific capacity per gram of the positive electrode material at 0.1C is ≥196 mAh / g (3.0 - 4.5V, vs. Li), and when charging and discharging at a rate of 0.1C within the voltage range of 3.0 - 4.5V, the discharge specific capacity per gram obtained is defined as C0 mAh / g. The discharge specific capacity per gram from the start of discharge to 4.4V is C1 mAh / g, the specific capacity per gram within the voltage range of 3.8V - 3.7V is C2 mAh / g, and C1 / C0 ≥ 9% and C2 / C0 ≥ 25%.

[0011] In the present invention, further provided is a method for manufacturing the above positive electrode material. Specifically, it includes a compound Na containing at least Co and Na elements x Step 1 of manufacturing CoO2 (0.68 < x < 0.74), and a compound Na containing Co and Na x Disperse CoO2 and a compound containing lithium element in deionized water, conduct an ion exchange reaction, and replace part of the Na ions in Na x CoO2 with Li ions to obtain a positive electrode material, including Step 2.

[0012] In one specific embodiment, the manufacturing of the positive electrode material specifically includes Step 1 - 1, Step 1 - 2, and Step 2.

[0013] In Step 1 - 1, after weighing a cobalt - element - containing compound and a sodium - element - containing compound in required stoichiometric ratios, use one of the mixing devices such as a high - speed mixing device, a sand mill device, a ball mill device, a colter mixing device, or an inclined - type mixing device to mix thoroughly until uniform to obtain a mixed material. During mixing, water, alcohol, or other solvents can be added, and after uniform mixing, it can be dried.

[0014] Here, the cobalt - element - containing compound can be one or more of cobalt hydroxide, tricobalt tetraoxide, doped tricobalt tetraoxide, cobalt oxide, cobalt oxyhydroxide, cobalt nitrate, and cobalt sulfate. The sodium - element - containing compound can be one or more of sodium - containing oxide, sodium carbonate, sodium nitrate, sodium hydroxide, sodium bicarbonate, and sodium sulfate. In addition, a compound containing a doping element Me can be further added. The doping element Me includes one or more of Al, Mg, Ti, Zr, Ni, Mn, Y, La, Sr, W, Sc, Ce, P, Nb, V, Ta, Te. Specifically, it can be a compound containing a doping element such as basic magnesium carbonate, magnesium hydroxide, zirconium oxide, aluminum oxide, yttrium oxide, lanthanum oxide, etc. Furthermore, the cobalt-containing compound, sodium-containing compound, and Me-containing compound follow Na:Co:Me = x:(1 - y):y, where 0.68 < x < 0.74 and 0 ≤ y ≤ 0.15. To sufficiently mix until the compounds are homogeneous, the mixing time is at least 4 h, and those skilled in the art can observe the mixing state of the compounds with a SEM electron microscope.

[0015] In step 1-2, after loading the mixed material produced in step 1-1 into a crucible, it is placed in a high-temperature sintering device such as a muffler furnace, tunnel furnace, roller hearth kiln, tubular furnace, etc., and high-temperature sintering is performed in an air or oxygen atmosphere to obtain the first compound Na x Co 1-y Me y O2, where 0.68 < x < 0.74 and 0 ≤ y ≤ 0.15.

[0016] Furthermore, the sintering temperature is 700 - 900 °C and the time is 8 - 50 h.

[0017] In step 2, the first compound synthesized and obtained in step 1-2 and the lithium element-containing compound are mixed in a required ratio and dispersed in deionized water, and an ion exchange reaction is carried out. Due to the free migration and diffusion of sodium ions and lithium ions in the aqueous solution, most of the Na ions in the first compound are replaced by Li ions. After the reaction is completed, the reaction product is washed and dried to obtain a cathode material.

[0018] The lithium element-containing compound may be one or more of lithium carbonate, lithium chloride, lithium bromide, lithium iodide, lithium nitrate, lithium hydroxide, lithium fluoride, and if necessary, any carbon-containing compound or fast ion conductor compound, etc. may be added to improve the conductivity of the cathode material.

[0019] The mass ratio of the lithium-containing compound to the first compound is ≧1, and preferably 1-3, and the mass ratio of the solvent to the first compound is ≧5, and preferably 20-150.

[0020] The reaction equipment used includes sealed vessel equipment with sealing function and stirring ability, such as wet coating reaction equipment and coprecipitation reaction equipment, the stirring speed during the reaction is 10-200 rpm, the reaction temperature is 70-125°C, and the reaction time is ≥ 5 hours, and further, the reaction time is 10-15 hours; The equipment used for drying, such as a blower oven, vacuum drying oven, rotary furnace, and disk dryer, has a drying temperature of 80 to 180°C and a drying time of ≥ 10 hours.

[0021] In a second aspect of the present invention, there is provided a battery including a positive electrode sheet including a positive electrode current collector and a positive electrode active layer provided on at least one surface of the positive electrode current collector, the positive electrode active layer including any one of the positive electrode materials described above.

[0022] The present invention provides a battery, specifically, a battery is obtained by preparing a positive electrode sheet using the above-mentioned positive electrode material, and assembling the same together with a negative electrode sheet, a separator, and an electrolyte solution. Specifically, the positive electrode sheet includes a positive electrode current collector and a positive electrode active layer provided on the surface of the positive electrode current collector. The positive electrode active layer includes the above-mentioned positive electrode material, a conductive agent, and an adhesive, and the adhesive is one or more selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), and polylithium acrylate (PAALi). the conductive agent is one or more selected from conductive carbon black, acetylene black, ketjen black, conductive graphite, conductive carbon fiber, carbon nanotubes, single-arm carbon nanotubes, and multi-arm carbon nanotubes; the mass ratio of the positive electrode material, conductive agent, and adhesive in the positive electrode active layer is (70 to 99):(0.5 to 15):(0.5 to 15), and further, the mass ratio of the positive electrode material, conductive agent, and adhesive is (80 to 98):(1 to 10):(1 to 10).

[0023] During the preparation of the positive electrode sheet, the above-mentioned positive electrode material, conductive agent and adhesive are mixed in a certain ratio, and then dispersed in a solvent to obtain a positive electrode active layer slurry, which is then applied to the surface of a positive electrode current collector to obtain a positive electrode sheet, and the positive electrode current collector may be an aluminum foil.

[0024] The negative electrode sheet includes a negative electrode current collector and a negative electrode active layer provided on the surface of the negative electrode current collector. The negative electrode active layer includes a negative electrode material, a conductive agent, and an adhesive. The negative electrode material is one or more selected from artificial graphite, natural graphite, hard carbon, mesocarbon microbeads, lithium titanate, silicon carbon, and silicon oxide. The types of the conductive agent and adhesive are the same as those of the positive electrode active layer. The mass ratio of the negative electrode material, conductive agent, and adhesive is (70 to 99):(0.5 to 15):(0.5 to 15), and further, the mass ratio of the negative electrode material, conductive agent, and adhesive is (80 to 98):(1 to 10):(1 to 10).

[0025] During the preparation of the negative electrode sheet, the above-mentioned negative electrode material, conductive agent, and adhesive are mixed in a certain ratio, and then dispersed in a solvent to obtain a negative electrode active layer slurry, which is then applied to the surface of a negative electrode current collector to obtain a negative electrode sheet, and the negative electrode current collector may be copper foil.

[0026] The separator may be a material common in the art, such as a polypropylene based material, or an adhesive coated separator with a ceramic coating on one or both sides.

[0027] The electrolyte is a common material in the art and includes an organic solvent including ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), and fluoroethylene carbonate (FEC), a lithium salt, and an additive having the structure shown in the following formula, the weight of which is 0.1 to 10% of the total weight of the electrolyte. [ka]

[0028] The positive electrode material provided by the present invention is applied to high voltage batteries, and the operating voltage of the batteries is specifically 3.0 to 4.5V.

[0029] In a third aspect of the present application, there is further provided an electronic device comprising the battery provided in the second aspect of the present invention. The battery can be used as a power source or energy storage unit for the electronic device. The device may be, but is not limited to, a mobile device (e.g., a mobile phone, a tablet computer, a laptop, etc.), an electric vehicle (e.g., a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), etc.

[0030] Mobile devices such as mobile phones, tablet computers, and notebook computers are typically required to be thin, and can use lithium-ion batteries as their power source. [Effects of the Invention]

[0031] Implementation of the present invention has at least the following advantages:

[0032] 1. The positive electrode material provided in the present invention has a special phase structure, which can present multiple small charge / discharge platforms during charging and discharging. Under the conditions of the same charge / discharge end voltage and charge / discharge rate, it has a higher capacity per gram and a relatively stable structure, which helps to improve the capacity and cycle performance of the battery, thereby meeting the requirements for thinner batteries.

[0033] 2. The battery provided by the present invention has good capacity and cycle performance. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 2 is an XRD test data diagram of the positive electrode material provided in Example 1 of the present invention. [Figure 2] 1 is a graph showing the charge / discharge of the positive electrode material provided in Example 1 of the present invention at 3.0-4.5 V (vs. Li) and 0.1 C rate. DETAILED DESCRIPTION OF THE INVENTION

[0035] In order to clarify the purpose, technical solutions and advantages of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Any other embodiments that a person skilled in the art can obtain based on the embodiments of the present invention without creative efforts also fall within the protection scope of the present invention.

[0036] Unless otherwise specified, the experimental methods used in the following examples are all common methods, and the reagents and materials used in the following examples are all commercially available unless otherwise specified. Example 1

[0037] The method for producing the positive electrode material provided in this example includes the following steps (1) to (4).

[0038] (1) Weigh out 3.656 kg of sodium carbonate powder and 29.105 kg of cobalt nitrate hexahydrate powder, put them into a high-speed mixer, mix at 300 rpm for 3 minutes, then mix at 500 rpm for 5 minutes, and then mix at 1000 rpm for 10 minutes. After that, take out the mixture and check that there are no small white dots of white sodium carbonate in the mixture. After that, the materials are considered to be uniformly mixed.

[0039] (2) 30g of the mixture was taken and loaded into a ceramic crucible. It was then sintered at high temperature using a pit-type muffle furnace, model number VBF-1200X. The temperature rise rate of the sintering temperature graph was 5℃ / min. After the temperature rose to 750℃, constant temperature sintering was carried out for 10 hours. After sintering, the sample was allowed to cool naturally to room temperature, and the cobalt- and sodium-containing compound Na was removed from the sintered sample. 0.69 Obtain CoO2.

[0040] (3) 200 ml of deionized water, 10.49 g of lithium hydroxide monohydrate, and 10.59 g of lithium chloride were added to a reaction vessel, and the mixture was stirred for 5 minutes at a water temperature of 78°C and a rotation speed of 20 rpm. After that, 10 g of the cobalt- and sodium-containing compound Na obtained in step 2 was added. 0.69 CoO2 is weighed out, and the reaction is continued for 8 hours under conditions of 78°C and a rotation speed of 20 rpm.

[0041] (4) After the reaction was completed, the reaction product was taken out, suctioned, filtered, and washed with deionized water three times, and then dried in a 90°C air drying oven for 8 hours to obtain the positive electrode material. Example 2

[0042] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0043] (3) 200 ml of deionized water, 10.49 g of lithium hydroxide monohydrate, and 21.71 g of lithium bromide were added to a reaction vessel, and the mixture was stirred for 5 minutes at a water temperature of 78°C and a rotation speed of 20 rpm. After that, 10 g of the cobalt- and sodium-containing compound Na obtained in step 2 was added. 0.69 CoO2 is weighed out, and the reaction is continued for 8 hours under conditions of 78°C and a rotation speed of 20 rpm. Example 3

[0044] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0045] (3) 200 ml of deionized water, 10.49 g of lithium hydroxide monohydrate, and 33.46 g of lithium iodide were added to a reaction vessel, and the mixture was stirred for 5 minutes at a water temperature of 78°C and a rotation speed of 20 rpm. After that, 10 g of the cobalt- and sodium-containing compound Na obtained in step 2 was added. 0.69 CoO2 is weighed out, and the reaction is continued for 8 hours under conditions of 78°C and a rotation speed of 20 rpm. Example 4

[0046] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0047] (3) 200 ml of deionized water, 10.49 g of lithium hydroxide monohydrate, and 6.48 g of lithium fluoride were added to a reaction vessel, and the mixture was stirred for 5 minutes at a water temperature of 78°C and a rotation speed of 20 rpm. After that, 10 g of the cobalt- and sodium-containing compound Na obtained in step 2 was added. 0.69 CoO2 is weighed out, and the reaction is continued for 8 hours under conditions of 78°C and a rotation speed of 20 rpm. Example 5

[0048] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0049] (3) 200 ml of deionized water, 16.78 g of lithium hydroxide monohydrate, and 3.69 g of lithium carbonate were added to a reaction vessel, and the mixture was stirred for 5 minutes at a water temperature of 78°C and a rotation speed of 20 rpm. After that, 10 g of the cobalt- and sodium-containing compound Na obtained in step 2 was added. 0.69 CoO2 is weighed out, and the reaction is continued for 8 hours under conditions of 78°C and a rotation speed of 20 rpm. Example 6

[0050] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0051] (3) 200 ml of deionized water, 16.78 g of lithium hydroxide monohydrate, and 16.96 g of lithium chloride were added to a reaction vessel, and the mixture was stirred for 5 minutes at a water temperature of 78°C and a rotation speed of 20 rpm. After that, 10 g of the cobalt- and sodium-containing compound Na obtained in step 2 was added. 0.69 CoO2 is weighed out, and the reaction is continued for 8 hours under conditions of 78°C and a rotation speed of 20 rpm. Example 7

[0052] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0053] (3) 200 ml of deionized water, 16.78 g of lithium hydroxide monohydrate, and 4.24 g of lithium chloride were added to a reaction vessel, and the mixture was stirred for 5 minutes at a water temperature of 78°C and a rotation speed of 20 rpm. After that, 10 g of the cobalt- and sodium-containing compound Na obtained in step 2 was added. 0.69 CoO2 is weighed out, and the reaction is continued for 8 hours under conditions of 78°C and a rotation speed of 20 rpm. Example 8

[0054] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0055] (3) 200 ml of deionized water, 10.49 g of lithium hydroxide monohydrate, and 10.59 g of lithium chloride were added to a reaction vessel, and the mixture was stirred for 5 minutes at a water temperature of 78°C and a rotation speed of 30 rpm. After that, 10 g of the cobalt- and sodium-containing compound Na obtained in step 2 was added. 0.69 CoO2 is weighed out, and the reaction is continued for 8 hours under conditions of 78°C and a rotation speed of 30 rpm. Example 9

[0056] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0057] (1) Weigh out 2.138 kg of sodium oxide powder and 29.105 kg of cobalt nitrate hexahydrate powder, put them into a high-speed mixer, mix at 300 rpm for 3 minutes, then mix at 500 rpm for 5 minutes, and then mix at 1000 rpm for 10 minutes. After that, take out the mixture and check that there are no small white dots of white sodium oxide in the mixture. After that, the materials are considered to be uniformly mixed. Example 10

[0058] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0059] (1) Weigh out 3.656 kg of sodium carbonate powder and 7.493 kg of cobalt oxide powder, put them into a high-speed mixer, mix at 300 rpm for 3 minutes, then mix at 500 rpm for 5 minutes, and then mix at 1000 rpm for 10 minutes. After that, take out the mixture and check that there are no small white dots of white sodium oxide in the mixture. After that, the materials are considered to be uniformly mixed. Example 11

[0060] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0061] (1) Weigh out 3.656 kg of sodium carbonate powder and 9.293 kg of cobalt hydroxide powder, put them into a high-speed mixer, mix at 300 rpm for 3 minutes, then mix at 500 rpm for 5 minutes, and then mix at 1000 rpm for 10 minutes. After that, take out the mixture and check that there are no small white dots of white sodium carbonate in the mixture. After that, the materials are considered to be uniformly mixed. Example 12

[0062] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0063] (1) Weigh out 3.656 kg of sodium carbonate powder and 8.026 kg of tricobalt tetroxide powder, put them into a high-speed mixer, mix at 300 rpm for 3 minutes, then mix at 500 rpm for 5 minutes, and then mix at 1000 rpm for 10 minutes. After that, take out the mixture and check that there are no small white dots of white sodium carbonate in the mixture. After that, the materials are considered to be uniformly mixed. Example 13

[0064] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0065] (1) Weigh out 3.656 kg of sodium carbonate powder, 9.200 kg of cobalt hydroxide powder, and 50.98 g of nano-alumina powder, place them in a high-speed mixer, mix at 300 rpm for 3 minutes, then at 500 rpm for 5 minutes, and then at 1000 rpm for 10 minutes. After that, remove the mixture and check that there are no small white dots of white sodium carbonate in the mixture. The materials are considered to be uniformly mixed. Example 14

[0066] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0067] (1) Weigh out 3.656 kg of sodium carbonate powder, 9.014 kg of cobalt hydroxide powder, and 152.94 g of nano-alumina powder, place them in a high-speed mixer, mix at 300 rpm for 3 minutes, then at 500 rpm for 5 minutes, and then at 1000 rpm for 10 minutes. After that, remove the mixture and check that there are no small white dots of white sodium carbonate in the mixture. The materials are considered to be uniformly mixed. Example 15

[0068] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0069] (1) Weigh out 3.656 kg of sodium carbonate powder, 8.828 kg of cobalt hydroxide powder, and 254.9 g of nano-alumina powder, place them in a high-speed mixer, mix at 300 rpm for 3 minutes, then at 500 rpm for 5 minutes, and then at 1000 rpm for 10 minutes. After that, remove the mixture and check that there are no small white dots of white sodium carbonate in the mixture. After that, the materials are considered to be uniformly mixed. Example 16

[0070] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0071] (1) Weigh out 3.656 kg of sodium carbonate powder, 9.200 kg of cobalt hydroxide powder, and 40.30 g of nano-magnesium oxide powder, place them in a high-speed mixer, mix at 300 rpm for 3 minutes, then at 500 rpm for 5 minutes, and then at 1000 rpm for 10 minutes. After that, remove the mixture and check that there are no small white dots of white sodium carbonate in the mixture. The materials are considered to be uniformly mixed. Example 17

[0072] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0073] (1) Weigh out 3.656 kg of sodium carbonate powder, 9.014 kg of cobalt hydroxide powder, and 120.91 g of nano-magnesium oxide powder, place them in a high-speed mixer, mix at 300 rpm for 3 minutes, then mix at 500 rpm for 5 minutes, and then mix at 1000 rpm for 10 minutes. After that, remove the mixture and check that there are no small white dots of white sodium carbonate in the mixture. The materials are considered to be uniformly mixed. Example 18

[0074] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0075] (1) Weigh out 3.656 kg of sodium carbonate powder, 8.828 kg of cobalt hydroxide powder, and 201.52 g of nano-magnesium oxide powder, place them in a high-speed mixer, mix at 300 rpm for 3 minutes, then at 500 rpm for 5 minutes, and then at 1000 rpm for 10 minutes. After that, remove the mixture and check that there are no small white dots of white sodium carbonate in the mixture. The materials are considered to be uniformly mixed. Example 19

[0076] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0077] (1) Weigh out 2.138 kg of sodium oxide powder and 9.293 kg of cobalt hydroxide powder, put them into a high-speed mixer, mix at 300 rpm for 3 minutes, then mix at 500 rpm for 5 minutes, and then mix at 1000 rpm for 10 minutes. After that, take out the mixture and check that there are no small white dots of white sodium oxide in the mixture. After that, the materials are considered to be uniformly mixed. Example 20

[0078] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0079] (1) Weigh out 2.138 kg of sodium oxide powder, 9.200 kg of cobalt hydroxide powder, and 50.98 g of nano-alumina powder, place them in a high-speed mixer, mix at 300 rpm for 3 minutes, then at 500 rpm for 5 minutes, and then at 1000 rpm for 10 minutes. After that, remove the mixture and check that there are no small white dots of white sodium oxide in the mixture. The materials are considered to be uniformly mixed. Example 21

[0080] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0081] (1) Weigh out 2.138 kg of sodium oxide powder, 9.014 kg of cobalt hydroxide powder, and 152.94 g of nano-alumina powder, place them in a high-speed mixer, mix at 300 rpm for 3 minutes, then mix at 500 rpm for 5 minutes, and then mix at 1000 rpm for 10 minutes. After that, remove the mixture and check that there are no small white dots of white sodium carbonate in the mixture. The materials are considered to be uniformly mixed. Example 22

[0082] The manufacturing method of the positive electrode material provided in this example can refer to Example 1, with the following differences:

[0083] (1) Weigh out 2.138 kg of sodium oxide, 8.828 kg of cobalt hydroxide powder, and 254.9 g of nano-alumina powder, place them in a high-speed mixer, mix at 300 rpm for 3 minutes, then mix at 500 rpm for 5 minutes, and then mix at 1000 rpm for 10 minutes. After that, remove the mixture and check that there are no small white dots of white sodium oxide in the mixture. After that, the materials are considered to be uniformly mixed. Comparative Example 1

[0084] The cathode material provided in this comparative example is a common non-doped lithium cobalt oxide, and its chemical composition is Li 1.003 The compound is CoO2, and the production method includes the following steps (1) to (4).

[0085] (1) Weigh out lithium carbonate in a molar ratio of Li:Co=100.3:100 and commercially available undoped spherical Co3O4 particles. Using the same stirring equipment as in the examples, mix the two substances at 300 rpm for 3 minutes, then at 500 rpm for 5 minutes, and finally at 1000 rpm for 10 minutes. After removing the mixture, check that there are no small white dots of lithium carbonate in the mixture, and the materials are considered to be uniformly mixed.

[0086] (2) 30g of the mixture was taken and loaded into a ceramic crucible. The VBF-1200X pit-type muffle furnace was used for high-temperature sintering. The temperature rise rate of the sintering temperature graph was 5℃ / min. After the temperature rose to 1050℃, constant temperature sintering was carried out for 10 hours. After sintering, the sample was allowed to cool to room temperature naturally. The cobalt- and lithium-containing compound Li was then removed from the sintered sample. 1.003 Obtain CoO2.

[0087] (3) After the sintered lithium cobalt oxide was crushed and polished, the powder was placed in a muffle furnace and sintered at 950°C for 8 hours. The sintered product was then crushed to obtain a Li SiO 2 powder with no doping coating and a D50 of 15.2 μm. 1.003 Obtain CoO2. Comparative Example 2

[0088] The cathode material provided in this comparative example is a high-voltage doped lithium cobalt oxide, whose chemical composition is Li 1.0028 Co 0.982 Al 0.014 Mg 0.002 La 0.002 It is O2.

[0089] The method for producing the positive electrode material includes steps (1) to (3).

[0090] (1) Weigh out lithium carbonate and commercially available spherical Co3O4 particles doped with Al and La in a molar ratio of Li:Co:Mg=100.28:98.2:0.2, and magnesium oxide particles. The stoichiometric ratio of the Co3O4 particles is Co:Al:La=98.2:1.4:0.2. Using the same stirring equipment as in the examples, mix the two substances at 300 rpm for 3 minutes, then at 500 rpm for 5 minutes, and finally at 1000 rpm for 10 minutes. After removing the mixture and confirming that there are no small white dots of lithium carbonate in the mixture, the materials are deemed to be uniformly mixed.

[0091] (2) 30g of the mixture was taken and loaded into a ceramic crucible. The VBF-1200X pit-type muffle furnace was used for high-temperature sintering. The temperature rise rate of the sintering temperature graph was 5℃ / min. After the temperature rose to 1030℃, constant temperature sintering was carried out for 10 hours. After sintering, the sample was allowed to cool naturally to room temperature, and then the cobalt- and sodium-containing compound Li was removed from the sintered sample. 1.0028 Co 0.982 Al 0.014 Mg 0.002 La 0.002 Get O2.

[0092] (3) After the sintered lithium cobalt oxide was crushed and polished, it was weighed with titanium dioxide in a molar ratio of Co:Ti=98.2:0.2. The two materials were then placed in a high-speed mixer and mixed at 300 rpm for 3 minutes, then at 500 rpm for 5 minutes, and finally at 1000 rpm for 10 minutes. The mixture was then removed and placed in a muffle furnace again to be sintered at 950°C for 8 hours. The sintered product was then crushed to obtain a doped high-voltage lithium cobalt oxide material with a D50 of 14.8 μm. 1.0028 Co 0.982 Al 0.014 Mg 0.002 La 0.002 Ti 0.002 Get O2. Comparative Example 3

[0093] The manufacturing method of the positive electrode material provided in this comparative example can be referred to Example 1, with the following differences:

[0094] (3) 10.49 g of lithium hydroxide monohydrate, 10.59 g of lithium chloride, and 10 g of the cobalt- and sodium-containing compound Na obtained in step 2 0.69 CoO2 is weighed and placed in a mixer, mixed uniformly, and then sintered at a high temperature of 300°C for 5 hours. Comparative Example 4

[0095] The manufacturing method of the positive electrode material provided in this comparative example can be referred to Example 1, with the following differences:

[0096] (3) 10.49 g of lithium hydroxide monohydrate, 10.59 g of lithium chloride, and 10 g of the cobalt- and sodium-containing compound Na obtained in step 2 0.69 CoO2 is weighed and placed in a mixer, and after uniformly mixing, high-temperature sintering is carried out at 250°C for 5 hours.

[0097] XRD tests were performed on the positive electrode materials provided in Examples 1 to 22 and Comparative Examples 1 to 4. FIG. 1 is an XRD test date diagram of the positive electrode material provided in Example 1 of the present invention. As can be seen from FIG. 1, the XRD diagram of the positive electrode material provided in Example 1 includes a 002 peak corresponding to the 002 crystal plane, a 102 peak corresponding to the 102 crystal plane, a 103 peak corresponding to the 103 crystal plane, a 101 peak corresponding to the 101 crystal plane, and a 004 peak corresponding to the 004 crystal plane. The corresponding diffraction angles and peak intensities are listed as shown in Table 1.

[0098] [Table 1-1] [Table 1-2]

[0099] As can be seen from the XRD data provided in Examples 1 to 12 in Table 1, different manufacturing raw materials and proportional relationships have certain effects on the peak positions and peak intensities of the phases of the positive electrode material. As can be seen from the XRD data provided in Examples 13 to 22, with an increase in the content of doping elements, the peak intensity ratio of the 101 crystal plane to the 004 crystal plane of the positive electrode material increases significantly. As can be seen from Comparative Examples 3 and 4, compared with the case of performing an ion exchange reaction using the sintering method, the peak intensity ratio m of the 101 crystal plane / 004 crystal plane of the positive electrode material prepared by the solution method provided in the present invention is significantly higher.

[0100] The positive electrode materials prepared in Examples 1 to 22 and Comparative Examples 1 to 4 were subjected to a button battery capacity test. The button battery was manufactured as follows: The positive electrode materials prepared in Examples 1 to 22 and Comparative Examples 1 to 2 were mixed with conductive carbon black (SP) and PVDF in a weight ratio of 80:10:10, and dispersed in a solvent to obtain a positive electrode slurry. The slurry was applied to an aluminum foil current collector and rolled to produce a positive electrode sheet. The positive electrode sheet was then punched into mini-wafers with a diameter of 12 mm using a mold, dried, and weighed. After that, a button battery was assembled using a 2025 button battery case in an Ar protective atmosphere in a glove box, and a negative electrode was formed using a Li metal wafer. A common high-voltage lithium cobalt oxide electrolyte was added to the button battery. After the button battery was manufactured, it was left to stand for 4 hours under normal conditions, and then an initial charge / discharge capacity test was conducted. The test conditions were: charging at 0.1C to 4.5V, charging at a constant voltage to 0.025C, and then stopping. After standing for 3 minutes, it was discharged at 0.1C to 3.0V. The charge / discharge curve of the positive electrode material provided in Example 1 is shown in FIG. 2. The initial charge capacity per gram and the initial discharge capacity per gram, C0mAh / g, were recorded. The discharge capacity per gram within the voltage termination range from the start of discharge to 4.4V, C1mAh / g, was defined. In terms of discharge capacity, the capacity per gram discharged within the discharge voltage range of 3.8V to 3.7V, was C2mAh / g. The initial efficiency, C1 / C0 and C2 / C0, were calculated, and the results are shown in Table 2.

[0101] The cathode materials provided in Examples 1 to 22 and Comparative Examples 1 to 4 were subjected to a certain amount of amplification, and then mixed with conductive carbon black and PVDF in a weight ratio of 96:2:2, and dispersed in a solvent to prepare a cathode active layer slurry. This was then applied to the surface of an aluminum cathode current collector to obtain a cathode sheet, which was then combined with an anode sheet, a separator, and an electrolyte to obtain a lithium ion battery. The specific manufacturing method is as follows:

[0102] Artificial graphite (charge cut-off voltage is 4.5V), styrene-diene rubber (SBR), sodium carboxymethyl cellulose, and conductive carbon black are mixed in a weight ratio of 94:3:2:1, dispersed in water, and mixed in a revolution-rotation mixer to obtain anode active layer slurry, which is then applied to the anode copper current collector to obtain anode sheet.

[0103] The electrolyte contains organic solvents including ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), and fluoroethylene carbonate (FEC), and an additive having the structure shown below. [ka]

[0104] Next, the cycle performance of the lithium-ion battery was tested. The cycle performance test procedure was as follows: at 25°C, the battery was charged at a constant current of 1C to 4.50V, then charged at a constant voltage of 0.05C to 4.50V, and then discharged at a discharge rate of 1C to 3.0V. This charge / discharge cycle was repeated 500 times, and the discharge capacity at the first cycle and the 500th cycle was measured. The post-cycle capacity retention was calculated as follows: (discharge capacity at the 500th cycle) / (discharge capacity at the first cycle) * 100%. The results are shown in Table 2.

[0105] [Table 2-1] [Table 2-2]

[0106] From Table 2, it can be seen that the positive electrode materials provided in Examples 1 to 22 of the present invention are advantageous in improving the capacity and cycle performance of lithium-ion batteries compared to Comparative Examples 1 to 4, with the capacity retention rate after 500 cycles being at least 80% or more. Furthermore, as can be seen from Examples 13 to 22 and Comparative Examples 3 and 4, the cycle performance of lithium-ion batteries also improves to some extent with the improvement in peak intensity ratio m. In summary, the positive electrode materials provided by the present invention enable lithium-ion batteries to achieve high discharge capacity per gram and excellent cycle performance at high voltages, and can meet the demand for thinner lithium-ion batteries.

[0107] Finally, it should be understood that the above embodiments are only used to explain the technical solutions of the present invention, and are not limiting. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art may modify the technical solutions described in the above embodiments or make equivalent substitutions for part or all of the technical features thereof, without departing from the essence of the technical solutions of the embodiments of the present invention through such modifications or substitutions.

Claims

1. A battery comprising: a positive electrode sheet including a positive electrode current collector and a positive electrode active layer including a positive electrode material and provided on at least one surface of the positive electrode current collector; and an electrolyte; The positive electrode material is Lin-xNaxCo1-yMeyO2 (0.7≦n≦1, 0<x≦0.15, 0≦y≦0.15, and Me is one or more selected from Al, Mg, Ti, Zr, Ni, Mn, Y, La, Sr, W, Sc, Ce, P, Nb, V, Ta, and Te), an X-ray diffraction pattern of the positive electrode material having a 002 peak corresponding to a 002 crystal plane, a 004 peak corresponding to a 004 crystal plane, a 101 peak corresponding to a 101 crystal plane, a 102 peak corresponding to a 102 crystal plane, and a 103 peak corresponding to a 103 crystal plane; The peak intensity ratio between the 101 peak and the 004 peak is m, and m≧1.695; The diffraction angle 2θ corresponding to the 002 peak is 18.6°±0.5°, the diffraction angle 2θ corresponding to the 102 peak is 41.7°±0.5°, and the diffraction angle 2θ corresponding to the 103 peak is 47.1°±0.5°, The electrolyte solution includes an organic solvent, a lithium salt, and an additive having a structure represented by the following formula, the additive having a mass of 0.1 to 10% of the total mass of the electrolyte solution: 【Chemistry 1】 A battery characterized by:

2. The battery of claim 1, wherein the positive electrode material is subjected to an initial charge-discharge capacity test, the test conditions being charging at 0.1 C to 4.5 V, charging at a constant voltage to 0.025 C, and then stopping the charge. After allowing to stand for 3 minutes, the positive electrode material is discharged at 0.1 C to 3.0 V. The capacity per gram of the positive electrode material is ≥ 196 mAh / g at a voltage of 3.0 to 4.5 V, and the discharge capacity per gram at a rate of 0.1 C is C0 mAh / g, the discharge capacity per gram from the start of discharge to 4.4 V is C1 mAh / g, and the discharge capacity per gram at 3.8 V to 3.7 V is C2 mAh / g, with C1 / C0 ≥ 10.30% and C2 / C0 ≥ 28.9%.

3. 2. The battery according to claim 1, wherein the mass of the positive electrode material is 70 to 99% of the total mass of the positive electrode active layer.

4. The battery according to claim 1 , wherein the positive electrode active layer comprises an adhesive and a conductive agent.

5. 5. The battery of claim 4, wherein the adhesive is one or more selected from polyvinylidene fluoride, polytetrafluoroethylene, and lithium polyacrylate, and / or the conductive agent is one or more selected from conductive carbon black, acetylene black, ketjen black, conductive graphite, conductive carbon fiber, carbon nanotubes, single-arm carbon nanotubes, and multi-arm carbon nanotubes.

6. The battery according to claim 4, wherein the mass of the adhesive is 0.5 to 15% of the total mass of the positive electrode active layer, and the mass of the conductive agent is 0.5 to 15% of the total mass of the positive electrode active layer.

7. An electronic device comprising the battery according to any one of claims 1 to 6.

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