CN-122025621-A - High-entropy layered oxide material, preparation method and application

Abstract

The invention discloses a high-entropy layered oxide material, a preparation method and application thereof, wherein the chemical general formula of the high-entropy layered oxide material is NaMn a Ti 0.09 Cu 0.05 Me b O 2 , me is a transition metal element and is at least three selected from Ni, fe, co, zn, sn, sb, mg, al, a and b are 0.74-0.80,0.06-b-0.12, a+b-0.94, the high-entropy layered oxide material has a Pmnm space group structure, and an X-ray diffraction pattern of the high-entropy layered oxide material has characteristic diffraction peaks at the positions of 14.1+/-0.2 DEG and 23.8+/-0.2 DEG. The preparation method of the high-entropy layered oxide material is a stress control quenching method, and the richness and stability of the layered material structure are effectively improved.

Inventors

• LI JIAN
• Sheng Tiandu

Assignees

• 湖南省正源储能材料与器件研究所

Dates

Publication Date

20260512

Application Date

20260415

Claims (4)

1. 1. The high-entropy layered oxide material is characterized by having a chemical general formula of NaMn a Ti 0.09 Cu 0.05 Me b O 2 ; Wherein Me is a transition metal element selected from at least three of Ni, fe, co, zn, sn, sb, mg, al; The a and the b are satisfied that a is more than or equal to 0.74 and less than or equal to 0.80,0.06 and b is more than or equal to 0.12, and a+b=0.86; the high-entropy layered oxide material has a Pmnm space group structure, and an X-ray diffraction pattern of the high-entropy layered oxide material has characteristic diffraction peaks at the positions of 14.1 degrees+/-0.2 degrees and 23.8 degrees+/-0.2 degrees of 2 theta; in the crystal structure, transition metal atoms and oxygen atoms coordinate to form a polyhedron, so that a sodium atom layer and a transition metal polyhedron layer which are overlapped in sequence are formed, and the sodium atom layer and the transition metal polyhedron layer are arranged in a W shape.
2. 2. A method for preparing the high-entropy layered oxide material according to claim 1, wherein a stress control quenching method is adopted, and the method comprises the following specific steps: S1, weighing oxides of manganese, titanium, copper and three transition metal oxides as metal sources according to the stoichiometric ratio of a target product, wherein the three transition metal oxides are selected from at least three oxides of nickel, iron, cobalt, zinc, tin, antimony, magnesium and aluminum; S2, mixing the mixed precursor obtained in the step S1 with an organic solvent for wet ball milling, drying the obtained slurry to obtain precursor powder, unidirectionally pressing the precursor powder into a sheet under the pressure of 10-100 MPa, placing the pressed sheet in an air atmosphere, and performing heat treatment for 5-25 h at 600-1000 ℃; And S3, immediately taking out the sample after the heat treatment is finished, quenching, and then crushing, grinding and sieving the quenched sample to obtain the high-entropy layered oxide material as claimed in claim 1.
3. 3. The method according to claim 2, wherein the organic solvent in step S2 is absolute ethanol.
4. 4. Use of the high entropy layered oxide material according to claim 1, wherein the high entropy layered oxide material is used for a sodium ion secondary battery.

Description

High-entropy layered oxide material, preparation method and application Technical Field The invention relates to the technical field of battery energy materials, in particular to a preparation method and application of a high-entropy layered oxide material. Background The sodium ion battery has the advantages of abundant sodium resources, low cost, capability of using aluminum foil current collector and the like, and has great application prospect in the field of large-scale energy storage. However, the sodium ion battery in the prior art still faces the bottlenecks of low practical capacity, poor cycle performance and the like. In particular to a layered oxide positive electrode material, lattice distortion and crack expansion are easy to occur in the long circulation process, so that the structural stability is reduced, and meanwhile, the 'potential barrier-potential well' alternation phenomenon existing in a diffusion channel severely limits the rate capability. Therefore, a novel layered oxide structure capable of eliminating stress concentration and optimizing a diffusion channel is developed, and the novel layered oxide structure has important application value for improving the comprehensive performance of a sodium ion battery. Disclosure of Invention In order to solve the technical problems, the invention provides a high-entropy layered oxide material with high performance, a preparation method and application thereof. The material constructs a continuous W-shaped arrangement structure of atomic polyhedrons between layers through the synergistic effect of lattice distortion effect caused by high entropy components and a stress control quenching process. The unique structure effectively eliminates the local stress concentration of the layered material in the charge and discharge process, and the micro-nano thin strip shape formed by the layered material obviously shortens the diffusion path of sodium ions and improves the uniformity of lattice strain distribution, thereby breaking through the bottleneck that the traditional block-shaped anode material is easy to crack and has short cycle life. In a first aspect, the invention provides a high-entropy layered oxide material having a chemical formula of NaMn aTi0.09Cu0.05MebO2; Wherein Me is a transition metal element selected from at least three of Ni, fe, co, zn, sn, sb, mg, al; The a and the b are satisfied that a is more than or equal to 0.74 and less than or equal to 0.80,0.06 and b is more than or equal to 0.12, and a+b=0.86; the high-entropy layered oxide material has a Pmnm space group structure, and an X-ray diffraction pattern of the high-entropy layered oxide material has characteristic diffraction peaks at the positions of 14.1 degrees+/-0.2 degrees and 23.8 degrees+/-0.2 degrees of 2 theta; in the crystal structure, transition metal atoms and oxygen atoms coordinate to form a polyhedron, so that a sodium atom layer and a transition metal polyhedron layer which are overlapped in sequence are formed, and the sodium atom layer and the transition metal polyhedron layer are arranged in a W shape. In the crystal structure, the sodium atomic layer and the transition metal polyhedral layer are periodically arranged in a W-shaped wavy manner along the direction of the c axis, and the structure can be used as a buffer layer for absorbing volume expansion stress generated by sodium ion deintercalation. In a second aspect, the present invention provides a method for preparing a high entropy layered oxide material according to the first aspect, which adopts a stress control quenching method, and specifically comprises the following steps: S1, weighing oxides of manganese, titanium, copper and three transition metal oxides as metal sources according to the stoichiometric ratio of a target product, wherein the three transition metal oxides are selected from at least three oxides of nickel, iron, cobalt, zinc, tin, antimony, magnesium and aluminum; S2, mixing the mixed precursor obtained in the step S1 with an organic solvent for wet ball milling, drying the obtained slurry to obtain precursor powder, unidirectionally pressing the precursor powder into a sheet under the pressure of 10-100 MPa, placing the pressed sheet in an air atmosphere, and performing heat treatment for 5-25 h at 600-1000 ℃; And S3, immediately taking out the sample after the heat treatment is finished, quenching, and then crushing, grinding and sieving the quenched sample to obtain the high-entropy layered oxide material according to the first aspect. During the heat treatment, the Mn-O-Mn coordination bond in the trivalent manganese ion has extremely short bond length and extremely high bond strength in the b-axis direction, so that the lattice extension in the direction is limited, thereby forming the preferred orientation growth along the b-axis, and meanwhile, the c-axis direction shows a significantly faster growth kinetic rate. The huge growth rate difference between crystal fac