Patent Application
20250122098
The present disclosure belongs to the technical field of lithium-ion battery (LIB) cathode materials, and in particular relates to a preparation method for an LIB cathode material precursor with a large channel.
LIBs are widely used in fields such as portable electronic products, electric vehicles, and energy storage systems due to their advantages such as high energy density, low self-discharge, no memory effect, long cycling life, and small environmental pollution. With the increasing market demand for high-performance (such as high energy density) batteries and the continuous popularization of electric vehicles, the market demand for battery cathode materials has presented a rapid growth trend. Ternary cathode materials are the most potential and promising materials among the current mass-produced cathode materials due to their characteristics such as high energy density, relatively-low cost, and excellent cycling performance.
The continuous intercalation and deintercalation of Li ions in a battery requires a cathode material to have relatively strong physical and chemical stability. Physical stability: a cathode material and an anode material are required to show structural stability during an electric conduction process and a charge-discharge process, that is, those materials each need to have an ion channel to ensure the smooth migration of Li ions, and also need to have the ability to prevent hole collapse during the deintercalation of Li ions, especially when a battery generates heat to get a high temperature after continuous charging and discharging. Chemical stability: as a temperature or a humidity in a battery changes, each component of an electrode material still maintains a preferable shape without affecting the intercalation, deintercalation, and transportation of Li ions. Therefore, it is of great significance to prepare a lithium battery cathode material with high physical and chemical stability.
At present, there are many methods to improve the cycling performance of ternary LIBs, for example, an LIB ternary (NCM) cathode material is improved by doping and coating to slow down the deterioration of a crystal structure of the cathode material during a cycling process. Although properly doping and coating a cathode material can reduce the contact between a cathode active material and an electrolyte to prevent the dissolution of the cathode material and can inhibit the decomposition of the electrolyte at a high electric potential, an ion channel of the cathode material cannot be changed. In addition, most of materials used for coating do not have the ability to accommodate lithium ions, and too-much coating will reduce a specific capacity of a cathode material.
A preparation method for an LIB cathode material in which LiV3O8 and LiNi0.4Co0.2Mn0.4O2 are blended for modification is disclosed in the related art. The cathode materials LiV3O8 and LiNi0.4Co0.2Mn0.4O2 are mixed in a mass ratio of 3:7 in a three-dimensional (3D) cone mixer, pre-sintered at 480° C. to 500° C. for 2 h, sintered at 650° C. to 675° C. for 4 h, sintered at 800° C. to 825° C. for 6 h, kept at the temperature for 8 h, then naturally cooled with a furnace, and crushed to finally obtain a blended material (LiV3O8 and LiNi0.4Co0.2Mn0.4O2). A ternary cathode material is blended with LiV3O8 for modification to obtain a cathode material with high compacted density, which can effectively improve the capacity performance according to test results. However, the simple physical mixing destroys a matrix structure of the ternary cathode material, and no chemical bond is generated between the mixed components, which is not conducive to the construction of a lithium ion channel.
In addition, the performance of a ternary LIB cathode material is 60% dependent on the performance of a precursor thereof, and there are few studies on the synthesis of the precursor to improve the performance of the cathode material.
The following is a summary of the subject matters described in detail herein. This summary is not intended to limit the scope of protection of claims.
The present disclosure provides a preparation method for a cathode material precursor with a large channel and use thereof. A precursor prepared by the method has a relatively large ion channel, which is conducive to the improvement of the performance of a subsequently-sintered cathode material.
According to an aspect of the present disclosure, a preparation method for a cathode material precursor with a large channel is provided, including the following steps:
In some embodiments of the present disclosure, in S1, the sodium hexanitrocobaltate aqueous solution may be prepared as follows: dissolving a soluble cobalt salt and sodium nitrite in water, and adding an oxidant and acetic acid to obtain the sodium hexanitrocobaltate aqueous solution. Further, the soluble cobalt salt may be at least one of a nitrate, a chloride, and a sulfate. A reaction equation for preparing sodium hexanitrocobaltate with the cobalt salt and sodium nitrite is as follows (hydrogen peroxide and oxygen are adopted as the oxidant, for example):
24NaNO2+4Co(NO3)2+2H2O2+4HAc=4Na3[Co(NO2)6]+8NaNO3+4NaAc+4H2O; and
24NaNO2+4Co(NO3)2+O2+4HAc=4Na3[Co(NO2)6]+8NaNO3+4NaAc+2H2O.
In some embodiments of the present disclosure, in S1, a molar ratio of cobalt ions in the soluble cobalt salt to sodium ions in the sodium nitrite may be 1:(6-8). Further, a molar ratio of the acetic acid to the cobalt ions in the soluble cobalt salt may be (1-1.5):1; and a molar concentration of cobalt in the sodium hexanitrocobaltate aqueous solution may be 0.01 mol/L to 0.2 mol/L.
In some embodiments of the present disclosure, in S1, the oxidant may be at least one of hydrogen peroxide, oxygen, and air.
In some embodiments of the present disclosure, in S1, a total molar concentration of metal ions in the nickel-manganese mixed salt solution may be 0.01 mol/L to 2.0 mol/L.
In some embodiments of the present disclosure, in S1, the nickel-manganese mixed salt solution may be prepared by dissolving soluble salts of nickel and manganese in water; and the soluble salts of nickel and manganese may be at least one of a nitrate, a chloride, and a sulfate.
In some embodiments of the present disclosure, in S1, the oxalic acid may have a concentration of 0.01 mol/L to 0.5 mol/L; and the aqueous ammonia may have a concentration of 1.0 mol/L to 6.0 mol/L.
In some embodiments of the present disclosure, in S1, the reaction may be conducted at a temperature of 45° C. to 65° C., a pH of 8.1 to 8.3, and an ammonia concentration of 2.0 g/L to 5.0 g/L. A molar ratio of metal elements in the precursor is controlled by controlling addition flow rates of the sodium hexanitrocobaltate aqueous solution and the nickel-manganese mixed salt solution.
In some embodiments of the present disclosure, in S1, the particle size may reach a D50 of 2.0 μm to 15.0 μm.
In some embodiments of the present disclosure, in S2, the calcination may be conducted at 200° C. to 250° C. Further, the calcination may be conducted for 1 h to 4 h. The calcination may be conducted in an air or oxygen atmosphere.
In some embodiments of the present disclosure, in S3, a ratio of a volume of the water to a mass of the calcined material may be 5,000 to 8,000 L/t.
In some embodiments of the present disclosure, in S3, the soaking may be conducted for 1 h to 2 h.
The present disclosure also provides use of the preparation method described above in the preparation of an LIB.
According to a preferred embodiment of the present disclosure, the present disclosure at least has the following beneficial effects.
Na3[Co(NO2)6]+2NH4+=(NH4)2Na[Co(NO2)6]↓+2Na+
Ni2++C2O42−=NiC2O4↓
Mn2++C2O42−=MnC2O4↓
Through the co-precipitation, a eutectic alloy is formed, the eutectic alloy is further sintered such that an ammonium group, a nitro group, and an oxalate group therein are decomposed into gases to obtain a calcined material of nickel, cobalt, manganese, and sodium oxides, and the calcined material is soaked in pure water to remove sodium, dried, sieved, and demagnetized to obtain the LIB cathode material precursor with a large channel.
Other aspects can be obvious upon reading and understanding the drawings and detailed description.
The drawings are used to provide a further understanding of the technical solution herein and form part of the description, and are used together with the examples of the present application to interpret the technical solution herein, and do not constitute a limitation on the technical solution herein. The present application is further described below in conjunction with the accompanying drawings and examples, wherein:
The concepts and technical effects of the present disclosure are clearly and completely described below in conjunction with examples, so as to allow the objectives, features and effects of the present disclosure to be fully understood. Apparently, the described examples are merely some rather than all of the examples of the present disclosure. All other examples obtained by those skilled in the art based on the examples of the present disclosure without creative efforts should fall within the protection scope of the present disclosure.
In this example, an LIB cathode material precursor with a large channel was prepared by the following specific process:
The precursor had a chemical formula of Ni0.8Co0.1Mn0.1O.
In this example, an LIB cathode material precursor with a large channel was prepared by the following specific process:
The precursor had a chemical formula of Ni0.5Co0.2Mn0.3O, which had a spherical or spheroidic particle morphology and can be used as a raw material for subsequent sintering to prepare a ternary cathode material.
In this example, an LIB cathode material precursor with a large channel was prepared by the following specific process:
The precursor had a chemical formula of Ni0.6Co0.2Mn0.2O, which had a spherical or spheroidic particle morphology and can be used as a raw material for subsequent sintering to prepare a ternary cathode material.
In this comparative example, a precursor Ni0.8Co0.1Mn0.1O was prepared by the following specific process, which was different from the process in Example 1 in that the sodium hexanitrocobaltate aqueous solution was not prepared:
In this comparative example, a precursor Ni0.5Co0.2Mn0.3O was prepared by the following specific process, which was different from the process in Example 2 in that the sodium hexanitrocobaltate aqueous solution was not prepared:
In this comparative example, a precursor Ni0.6Co0.2Mn0.2O was prepared by the following specific process, which was different from the process in Example 3 in that the sodium hexanitrocobaltate aqueous solution was not prepared:
The precursor materials obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were each sintered with a lithium source to prepare a ternary cathode material. The cathode material was subjected to an electrochemical performance test, and test results were shown in Table 1.
It can be seen from Table 1 that, compared with the precursors of the comparative examples, the precursors of the examples led to better cycling performance and rate performance. In the preparation of each of the precursors of the examples, co-precipitation was first conducted with sodium and ammonium; then sintering was conducted, such that an ammonium group, a nitro group, and an oxalate group therein were decomposed into gases to obtain a calcined material of nickel, cobalt, manganese, and sodium oxides; and the calcined material was soaked in pure water to remove sodium, such that a larger ion channel was left and a diffusion channel of lithium ions was widened in a nickel-cobalt-manganese precursor skeleton because sodium ions had a larger radius than lithium ions, which facilitated the deintercalation of lithium ions in a chemically-sintered cathode material, resulted in a more stable crystal structure, and significantly improved the rate performance and cycling performance of the material.
The present disclosure is above described in detail with reference to the accompanying drawings and examples, but the present disclosure is not limited to the above examples. Within the scope of knowledge possessed by those of ordinary skill in the technical field, various changes can also be made without departing from the purpose of the present disclosure. In addition, the examples in the present disclosure and features in the examples may be combined with each other in a non-conflicting situation.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202210077149.4 | Jan 2022 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2022/135660 | 11/30/2022 | WO |
