CN-117416998-B - Acid etching auxiliary metal oxide coated high-nickel ternary positive electrode material and preparation method and application thereof

Abstract

The invention belongs to the field of electrochemical energy storage batteries, and particularly relates to an acid etching auxiliary metal oxide coated high-nickel ternary positive electrode material, and a preparation method and application thereof. According to the invention, the Ni 1‑x‑y Co x Mn y (OH) 2 ternary precursor, the strong acid weak alkali salt and the high polymer are mixed and dissolved to obtain the ternary precursor coated by the high polymer auxiliary strong acid weak alkali salt, and then the ternary precursor and the lithium source are uniformly mixed and then subjected to heat treatment in an oxygen atmosphere, so that the final acid etching auxiliary metal oxide coated high nickel ternary anode material is obtained. The positive electrode material enables the high molecular polymer to be uniformly adsorbed on the surface of the ternary material precursor, thereby promoting the uniform coating of the metal oxide on the surface of the high-nickel ternary positive electrode material, effectively preventing the direct contact between the high-nickel positive electrode material and electrolyte and side reactions thereof, having better cycle performance and multiplying power performance and being expected to promote the industrialized application of the high-nickel ternary positive electrode material.

Inventors

• SUN FUGEN
• WANG LIBO
• JIANG WEIWEI
• YUE ZHIHAO
• ZHOU LANG

Assignees

• 南昌大学

Dates

Publication Date

20260512

Application Date

20231127

Claims (2)

1. 1. The preparation method of the acid etching auxiliary metal oxide coated high-nickel ternary positive electrode material is characterized by comprising the following steps of: S1, mixing and dissolving a 3.00 gNi 1-x-y Co x Mn y (OH) 2 ternary precursor, 0.4 g strong acid weak alkali salt and 0.03 g high molecular polymer in water, fully stirring uniformly, filtering, and drying to obtain a Ni 1-x-y Co x Mn y (OH) 2 ternary precursor coated by the high molecular polymer auxiliary strong acid weak alkali salt; S2, uniformly mixing the ternary precursor obtained in the step S1 with a lithium source, and then performing heat treatment in an oxygen atmosphere to finally obtain the acid etching auxiliary metal oxide coated high-nickel ternary positive electrode material; The molecular formula of the acid etching auxiliary metal oxide coated high-nickel ternary positive electrode material is LiNi 1-x-y Co x Mn y O 2 , wherein x is 0.4, y is 0.4, and 1-x-y is more than or equal to 0.6, and the mass fraction of the metal oxide coating layer in the acid etching auxiliary metal oxide coated high-nickel ternary positive electrode material is less than 10.0%; In the step S2, the dosage ratio of the ternary precursor to the lithium source is 1:1.05; the specific process of the heat treatment comprises the steps of firstly heating to 400-500 ℃ at the rate of 1-5 ℃ per minute, preserving heat for 3 h-10 h, then heating to 700-800 ℃ at the rate of 1-5 ℃ per minute, and preserving heat for 10 h-20 h; The strong acid weak alkali salt is one of magnesium nitrate, aluminum nitrate, zirconium nitrate, lanthanum nitrate and zinc nitrate; The high molecular polymer is polyvinylpyrrolidone.
2. 2. The method of claim 1, wherein the lithium source is at least one of lithium hydroxide monohydrate, lithium carbonate, lithium nitrate, or lithium acetate.

Description

Acid etching auxiliary metal oxide coated high-nickel ternary positive electrode material and preparation method and application thereof Technical Field The invention belongs to the field of electrochemical energy storage batteries, and particularly relates to an acid etching auxiliary metal oxide coated high-nickel ternary positive electrode material, and a preparation method and application thereof. Background As the problems of global warming and environmental pollution caused by carbon emissions become more serious, the demands of society for renewable energy and clean energy are also increasing. The demand promotes the wide application of the electrochemical energy storage device in the electric energy conversion, storage and use, and covers the fields of electric automobiles, electronic products, smart grids, large-scale energy storage and the like. Thus, the development of electrochemical energy storage devices is critical to achieving sustainable development and reducing adverse effects on the environment. With the continuous development and improvement of technology, the electrochemical energy storage device is expected to become an important component in the future clean energy field, drive energy conversion and build a green low-carbon society. Among various positive electrode materials, the layered positive electrode material LiNi xCoyMn1-x-yO2 combines the advantages of LiNiO 2,LiCoO2 and LiMnO 2, and becomes a research hotspot in the field of lithium ion batteries. In the LiNi xCoyMn1-x-yO2 cathode material, three transition metals play different roles in crystal structure and electrochemical properties. In general, ni provides a majority of reversible capacity, while Co provides good electron conductivity and enhances lamellar structure ordering, has improved rate capability and provides the effect of additional capacity, mn stabilizes the local structure to achieve stable cycling performance. In the NCM family, liNi 0.8Co0.1Mn0.1O2 (NCM 811) has been gradually applied to electric and hybrid automobiles because it has a high discharge capacity, medium cycle performance and low production cost, and is one of the most promising positive electrode materials today. However, the problems of dislocation and mixing of Li/Ni cations, dissolution of transition metals, residual lithium on the surface, side reactions and the like of the NCM811 anode prevent the large-scale application of the NCM anode. To address these challenges, scientists have improved material properties through surface modification, lattice doping, and building core-shell structures. The coating is used as a surface modification method, which can increase the diffusion rate of lithium ions, inhibit the dissolution of transition metals and inhibit the occurrence of side reactions, thereby improving the electrochemical performance of LNCM 811. The concentration gradient structure modification can effectively improve the interface stability and structural integrity of the LNCM811, reduce the occurrence of side reactions and inhibit the volume change of the material. Ion doping is another method of structural modification. By introducing other ions to dope LNCM811 lattice to inhibit cation mixing and subsequent phase change, inhibit lattice distortion and further appearance of microcracks, and improve the cycle performance of the material. Wherein surface modification by a coating material is considered to be a highly efficient strategy for improving the electrochemical performance of NCM811 cathode materials. The surface coating effectively reduces the direct contact area of the NCM811 with the electrolyte, prevents HF from eroding the highly delithiated NCM811, mitigates dissolution of the transition metal, and inhibits unwanted side reactions on the surface of the NCM811, thereby improving cycle stability. The interface coating can reduce the exposed area of the material in the air, thereby reducing the side reaction of the high nickel surface and H 2O/CO2 and reducing the formation of LiOH/Li 2CO3 impurities. The metal oxide is used as a coating material, has low cost and good coating effect, and is a feasible solution to the problems. However, it still has some drawbacks. The binding energy between the metal oxide and the high nickel LiNi 1-x-yCoxMnyO2 cathode material is weak, so that it is difficult for the coating layer to achieve the effect of uniformly and completely coating the whole surface of the particles by a small amount. If the thickness of the coating layer is thinner, the coating layer may slowly drop off during the charge and discharge process of the material, and the coating effect of the material is lost. If the thickness of the coating layer is large, the coating layer itself, which is not an active material, may reduce the specific capacity of the material. However, because of its good coating effect, metal oxides still have great advantages in the coating material. Therefore, how to build a uniform and proper a