A uniform spherical transition metal oxide positive electrode material and its preparation and application
By doping antimony into lithium cobalt oxide, uniform spherical layered lithium cobalt oxide is synthesized, which solves the problem of structural collapse under high voltage and improves the cycle and rate performance of lithium-ion batteries.
Patent Information
- Application Number
- CN202111000327.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-08-27
- Publication Date
- 2025-09-05
- Estimated Expiration
- 2041-08-27
AI Technical Summary
The structural collapse of layered lithium cobalt oxide under high voltage leads to rapid capacity decay, and the irregular morphology of undoped materials affects the efficiency of lithium ion transmission.
By doping antimony into the crystal structure of lithium cobalt oxide, uniform spherical layered lithium cobalt oxide is synthesized, the lattice spacing is increased, and the stability of the material and the lithium ion transmission efficiency are improved.
It improves the cycle performance and rate performance of lithium-ion batteries, and achieves stability and excellent battery performance at high voltage.
Smart Images
Figure CN115732687B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of lithium-ion battery positive electrode materials, and relates to a spherical transition metal oxide positive electrode material for lithium-ion batteries with uniform morphology and its application, and specifically to a modified lithium cobalt oxide material and its preparation method. Background Art
[0002] Lithium-ion batteries are electrochemical energy storage devices that convert electrical energy into chemical energy. Energy transfer and conversion is achieved through the intercalation and extraction of lithium ions and electrons within electrode materials. As lithium ions and electrons are transferred, the intrinsic physicochemical parameters of the battery's internal materials, such as the Gibbs free energy and Fermi surface, change. This is reflected in macroscopic battery parameters as changes in battery voltage and capacity.
[0003] Compared with traditional lead-acid batteries, lithium-ion batteries are widely used in portable electronic devices and electric vehicles due to their advantages such as high charge and discharge voltage, no memory effect, high energy density, low self-discharge, and long cycle life. Since Sony first used lithium cobalt oxide as a positive electrode material for lithium-ion batteries, lithium cobalt oxide has always been the main positive electrode material for lithium-ion secondary batteries. Layered lithium cobalt oxide has high voltage (3.6V), stable discharge, and high theoretical specific capacity (274mAh g -1 ), excellent cycle performance, good rate performance, simple preparation process, etc., and is considered to be an ideal positive electrode material for small lithium-ion batteries. As the requirements of small batteries for capacity, cycle and safety performance gradually increase, lithium cobalt oxide materials are driven to develop in the direction of high capacity and high rate.
[0004] Layered transition metal oxides are widely used as cathode materials for lithium-ion batteries, with lithium cobalt oxide being a representative example. Layered lithium cobalt oxide has a reversible capacity of 140 mAh / g at 4.2V. Increasing the discharge voltage can increase the discharge capacity, but high voltages can lead to transitional delithiation of the lithium cobalt oxide, causing the layered lithium cobalt oxide structure to collapse and resulting in rapid capacity decay. Summary of the Invention
[0005] To address these issues, the present invention synthesizes a uniformly spherical layered lithium cobalt oxide by doping it with antimony. This improves the stability of the lithium cobalt oxide at high voltages and enhances the battery's cycling performance. The antimony doping also increases the lattice spacing of the lithium cobalt oxide, improving rate performance. The lattice spacing of the (003) crystal plane of undoped lithium cobalt oxide is 0.467-0.472 nm, while the lattice spacing of the (003) crystal plane of lithium cobalt oxide after antimony doping increases to 0.486-0.492 nm.
[0006] The technical solutions of the present invention are as follows:
[0007] On the one hand, the present invention provides a lithium ion battery positive electrode material, the positive electrode material composition is LiCo 1- x Sb x O2, wherein x=0.001-0.02; the positive electrode material is a spherical structure with uniform morphology.
[0008] Based on the above solution, preferably, the lattice spacing of the (003) crystal plane of the positive electrode material is 0.486-0.492 nm; and the particle size of the spherical particles of the positive electrode material is 7-11 um.
[0009] Based on the above solution, preferably, in the positive electrode material, x=0.01-0.02.
[0010] In another aspect, the present invention provides a method for preparing the above-mentioned positive electrode material, wherein the positive electrode material is prepared by a high-temperature solid-phase method, specifically comprising the following steps:
[0011] 1) mixing a lithium-containing compound, a cobalt-containing compound, and an antimony-containing compound in a molar ratio of (1.01-1.20):(0.999-0.98):(0.001-0.02) in a mortar, sintering the mixture in a box furnace at 750-1100° C. for 1-20 hours, and crushing the mixture to obtain a primary sintered product;
[0012] 2) Grind the primary sintered product evenly in a mortar, put it into a box furnace again, and sinter it at 500-900℃ for 1-20h. Grind the product thoroughly in a mortar to obtain a transition metal oxide positive electrode material LiCo with a uniform spherical shape. 1- x Sb x O2.
[0013] Based on the above scheme, preferably, in step 1), the lithium-containing compound is one or two or more of lithium carbonate, lithium acetate, lithium oxalate, lithium nitrate, lithium bicarbonate, lithium hydroxide, and lithium sulfate; the cobalt-containing compound is one or two or more of cobalt nitrate, cobalt acetate, cobalt tetroxide, cobalt oxide, cobalt hydroxide, cobalt oxalate, and cobalt sulfate; and the antimony-containing compound is antimony oxide, one or two or more of antimony trioxide, antimony tetroxide, antimony pentoxide, and antimony oxide.
[0014] Based on the above solution, preferably, in step 1), the sintering temperature is 900-1000° C., and the sintering time is 10-15 hours.
[0015] Based on the above solution, preferably, in step 2), the sintering temperature is 800-900° C., and the sintering time is 10-15 hours.
[0016] Based on the above scheme, preferably, in step 1), the molar ratio of lithium, cobalt and antimony is (1.03-1.05):(0.995-0.980):(0.005-0.020).
[0017] In another aspect, the present invention provides a lithium-ion battery, comprising the lithium-ion battery positive electrode material prepared above.
[0018] Specifically, the prepared spherical layered transition metal oxide cathode material LiCo 1-x Sb x O2 is used as the positive electrode, metal lithium sheet is used as the negative electrode, ceramic diaphragm is used as the diaphragm, electrolyte is TC-E9201-B purchased from Tianci, carbon-coated aluminum foil is used as the current collector, and a button-type lithium-ion battery is assembled by stacking and pressing in the order of negative electrode shell, negative electrode, electrolyte, diaphragm, electrolyte, positive electrode, positive current collector, and positive electrode shell through a CR2016 button-type shell.
[0019] The cycle performance of the lithium-ion battery is 179.1 mAh g at 1C. -1 , the capacity after 100 cycles is maintained at >87%; the rate performance of the battery can reach 95.9mAh g at 10℃. -1 .
[0020] The present invention has the following advantages:
[0021] 1) The synthesis method is a high-temperature solid-phase method, which does not require a post-processing process. The synthesis method is simple and easy to perform and can be easily industrialized.
[0022] 2) The synthetic antimony-doped lithium cobalt oxide is a spherical particle with uniform and controllable size. It has excellent fluidity, dispersibility, and processability, and has a higher packing density, which is beneficial for improving the energy density of lithium-ion batteries. The morphology of lithium cobalt oxide without antimony doping remains unchanged, and it has an amorphous structure. At the same time, the amount of antimony doping must be appropriate. Research has found that lithium cobalt oxide doped with excessive antimony will form some uneven protrusions on the surface of the spherical particles, resulting in uneven contact between the lithium cobalt oxide particles and hindered lithium ion transmission, which adversely affects the performance of the positive electrode material.
[0023] 3) The present invention controls the morphology of the synthesized antimony-doped lithium cobaltate by designing the morphology of the cobalt-containing compound precursor. By using a spherical cobalt-containing compound, the sintering temperature is controlled during the synthesis process to allow the antimony-containing compound to dissolve and penetrate the cobalt-containing compound, maintaining the spherical morphology, before reacting with the lithium-containing compound to form the lithium cobaltate.
[0024] 4) Synthesize antimony-doped spherical lithium cobalt oxide with uniform morphology, which has excellent cycle performance and rate performance.
[0025] Beneficial effects of the present invention
[0026] Spherical layered transition metal oxide positive electrode material LiCo 1-x Sb x O2 is synthesized by a high-temperature solid-phase method, and the resulting positive electrode material is spherical particles with uniform morphology. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 : SEM image of the undoped transition metal oxide positive electrode material LiCoO2 prepared in Comparative Example 1.
[0028] Figure 2 : The transition metal oxide positive electrode material LiCo doped with 0.01 nickel prepared in Comparative Example 2 0.99 Ni 0.01 SEM image of O2.
[0029] Figure 3 : In comparative example 3, a transition metal oxide positive electrode material LiCo doped with 0.03 antimony was prepared. 0.97 Sb 0.03 SEM image of O2.
[0030] Figure 4 : The transition metal oxide positive electrode material LiCo prepared in Example 1 0.99 Sb 0.01 SEM image of O2.
[0031] Figure 5 : Comparison of the cycle performance curves of the lithium ion batteries prepared in Comparative Example 1, Comparative Example 2, Comparative Example 3, Example 1, Example 2, and Example 3.
[0032] Figure 6 : Comparison of rate performance curves of the lithium ion batteries prepared in Comparative Example 1, Comparative Example 2, Comparative Example 3, Example 1, Example 2, and Example 3. DETAILED DESCRIPTION
[0033] The present invention will be further described in detail below through specific comparative examples and embodiments in conjunction with the accompanying drawings, but the present invention is not limited thereto.
[0034] Comparative Example 1 (Preparation of undoped transition metal oxide positive electrode material LiCoO2 by high temperature solid phase method)
[0035] Lithium carbonate and cobalt trioxide (Co3O4) with a Li:Co molar ratio of 1.05:1 were added to a 20 cm diameter mortar and ground thoroughly. The resulting mixture was then added to a corundum boat, placed in a box furnace, and heated to 1000°C at a rate of 5°C / min in an air atmosphere. The mixture was then fired at 1000°C for 10 hours. After cooling to room temperature, the mixture was removed from the mortar and ground again. The mixture was then returned to the corundum boat and heated to 900°C at a rate of 5°C / min in an air atmosphere. The mixture was fired at 900°C for 10 hours. After cooling to room temperature, the mixture was ground into a powder, resulting in lithium cobalt oxide. The lattice spacing of the (003) crystal plane of lithium cobalt oxide is 0.469 nm, and the particle size is 18 μm.
[0036] Comparative Example 2 (Preparation of 0.01% nickel-doped transition metal oxide positive electrode material LiCo by high temperature solid phase method) 0.99 Ni 0.01 O2)
[0037] Lithium carbonate, cobalt oxide, and nickel carbonate (at a Li:Co:Ni molar ratio of 1.05:0.99:0.01) were added to a 20 cm diameter mortar and ground thoroughly. The resulting mixture was added to a corundum boat, placed in a box furnace, and heated to 1000°C at a rate of 5°C / min in air. The mixture was then sintered at 1000°C for 10 hours. After cooling to room temperature, the mixture was removed from the mortar and ground again. The mixture was then returned to the corundum boat and heated to 900°C at a rate of 5°C / min in air. The mixture was sintered at 900°C for 10 hours. After cooling to room temperature, the mixture was ground into powder to form lithium cobalt oxide (LiCO) doped with 0.01% nickel. The morphology of the 0.01% nickel-doped LiCO was irregular particles with a (003) lattice spacing of 0.475 nm and a particle size of 16 μm.
[0038] Comparative Example 3 (Preparation of 0.03% antimony-doped transition metal oxide positive electrode material LiCo by high temperature solid phase method) 0.97 Sb 0.03 O2)
[0039] Lithium carbonate, cobalt tetroxide, and antimony trioxide (antimony trioxide) in a Li:Co:Sb molar ratio of 1.05:0.97:0.03 were added to a 20 cm diameter mortar and ground thoroughly. The resulting mixture was added to a corundum boat, placed in a box furnace, and heated to 1000°C at a rate of 5°C / min in an air atmosphere. It was then fired at 1000°C for 10 hours. After cooling to room temperature, the mixture was removed from the mortar and ground again. The mixture was then returned to the corundum boat and heated to 900°C at a rate of 5°C / min in an air atmosphere. It was fired at 900°C for 10 hours. After cooling to room temperature, it was ground into powder to obtain lithium cobalt oxide, a transition metal oxide doped with 0.03% antimony. The (003) crystal plane had a lattice spacing of 0.492 nm, and the particle size was 13 μm.
[0040] Example 1 (Preparation of 0.01% antimony-doped transition metal oxide positive electrode material LiCo by high temperature solid phase method) 0.99 Sb 0.01 O2)
[0041] Lithium carbonate, cobalt tetroxide, and antimony trioxide, with a Li:Co:Sb molar ratio of 1.05:0.99:0.01, were added to a 20 cm diameter mortar and ground thoroughly. The resulting mixture was added to a corundum boat, placed in a box furnace, and heated to 1000°C at a rate of 5°C / min in air. It was then fired at 1000°C for 10 hours. After cooling to room temperature, the mixture was removed from the mortar and ground again. The mixture was then returned to the corundum boat and heated to 900°C at a rate of 5°C / min in air. It was fired at 900°C for 10 hours. After cooling to room temperature, it was ground into powder to obtain lithium cobalt oxide, a transition metal oxide doped with 0.01 antimony. The (003) crystal plane had a lattice spacing of 0.488 nm, and the particle size was 11 μm.
[0042] Example 2 (Preparation of 0.015 Antimony-doped Transition Metal Oxide Positive Electrode Material LiCo by High-Temperature Solid-Phase Method) 0.985 Sb 0.015 O2)
[0043] Lithium carbonate, cobalt tetroxide, and antimony trioxide (antimony trioxide) in a Li:Co:Sb molar ratio of 1.05:0.985:0.015 were added to a 20 cm diameter mortar and ground thoroughly. The resulting mixture was added to a corundum boat, placed in a box furnace, and heated to 1000°C at a rate of 5°C / min in an air atmosphere. It was then fired at 1000°C for 10 hours. After cooling to room temperature, the mixture was removed from the mortar and ground again. The mixture was then returned to the corundum boat and heated to 900°C at a rate of 5°C / min in an air atmosphere. It was fired at 900°C for 10 hours. After cooling to room temperature, it was ground into powder to obtain lithium cobalt oxide, a transition metal oxide doped with 0.015 antimony. The (003) crystal plane had a lattice spacing of 0.488 nm, and the particle size was 11 μm.
[0044] Example 3 (Preparation of 0.02% antimony-doped transition metal oxide positive electrode material LiCo by high temperature solid phase method) 0.98 Sb 0.02 O2)
[0045] Lithium carbonate, cobalt tetroxide, and antimony trioxide (antimony trioxide) in a Li:Co:Sb molar ratio of 1.05:0.98:0.02 were added to a 20 cm diameter mortar and ground thoroughly. The resulting mixture was added to a corundum boat, placed in a box furnace, and heated to 1000°C at a rate of 5°C / min in an air atmosphere. It was then fired at 1000°C for 10 hours. After cooling to room temperature, the mixture was removed from the mortar and ground again. The mixture was then returned to the corundum boat and heated to 900°C at a rate of 5°C / min in an air atmosphere. It was fired at 900°C for 10 hours. After cooling to room temperature, it was ground into powder to obtain lithium cobalt oxide (lithium cobalt oxide) doped with 0.02% antimony. The lattice spacing of the (003) crystal plane was 0.488 nm, and the particle size of the lithium cobalt oxide particles was 11 μm.
[0046] Figure 1-4 LiCoO2, LiCo 0.99 Ni 0.01 O2、LiCo 0.97 5b 0.03 O2、LiCo 0.99 5b 0.01 SEM image of O2, from Figure 1 and Figure 2 It can be seen that the undoped lithium cobalt oxide and the lithium cobalt oxide doped with 0.01 nickel have smooth surface and irregular morphology particles, large particle size (9-18μm), and long lithium ion transmission path, which leads to poor battery performance of the material; Figure 3 It is lithium cobalt oxide doped with 0.03 antimony. The surface of the spherical particles has irregular protrusions, the particles are not in uniform contact, and the lithium ion transmission is hindered, resulting in poor battery performance of the material; Figure 4 It is lithium cobalt oxide doped with 0.02 antimony. It is a spherical particle with a flat surface, small size and uniform morphology. The lithium ion transmission path is short and the battery performance of the material is excellent. Figure 5 and 6 They are the cycle performance and rate performance of the synthesized positive electrode materials, among which the battery performance of lithium cobalt oxide doped with 0.02 antimony is the best.
Claims
1. A lithium-ion battery positive electrode material, characterized in that The positive electrode material is composed of LiCo 1-x Sb x O2, wherein x=0.02; the positive electrode material is a spherical structure with uniform morphology; The lattice spacing of the (003) crystal plane of the positive electrode material is 0.488 nm; the particle size of the spherical particles of the positive electrode material is 11 μm; The positive electrode material is prepared by a high-temperature solid phase method, which specifically includes the following steps: 1) uniformly mixing a lithium-containing compound, a cobalt-containing compound, and an antimony-containing compound in a molar ratio of 1.05:0.98:0.02, sintering at 1000° C. for 10 hours, and crushing to obtain a primary sintered product; 2) Grind the primary sintered product evenly, sinter at 900°C for 10 hours to obtain a secondary sintered product, and grind the secondary sintered product thoroughly to obtain the positive electrode material LiCo 1-x Sb x O2.
2. The lithium-ion battery cathode material according to claim 1, wherein: In step 1), the lithium-containing compound is one or more of lithium carbonate, lithium acetate, lithium oxalate, lithium nitrate, lithium bicarbonate, lithium hydroxide, and lithium sulfate; the cobalt-containing compound is one or more of cobalt nitrate, cobalt acetate, cobalt tetroxide, cobalt oxide, cobalt hydroxide, cobalt oxalate, and cobalt sulfate; and the antimony-containing compound is one or more of antimony trioxide, antimony tetroxide, antimony pentoxide, and antimony oxide.
3. A lithium-ion battery, characterized in that: The lithium-ion battery comprises the lithium-ion battery positive electrode material according to any one of claims 1 to 2.