CN-122025586-A - Topological-softened sodium ion battery positive electrode material and preparation method and application thereof

CN122025586ACN 122025586 ACN122025586 ACN 122025586ACN-122025586-A

Abstract

A topology-softened sodium ion battery positive electrode material and a preparation method and application thereof relate to a sodium ion battery positive electrode material and a preparation method and application thereof. The method aims to solve the technical problems of limited bulk diffusion of Na + , increased voltage polarization, reduced available capacity and complex modification method of the existing sodium ion battery anode material under the condition of high-rate charge and discharge. The material is obtained by controllably introducing intrinsic vacancies and defects into the positive electrode material of the polyanionic sodium ion battery. Can be prepared by spray drying method, sol-gel method or solid phase synthesis method. By regulating and controlling the proportion of raw materials, sodium vacancy and anionic group defects are controllably introduced, a sodium ion transmission channel is optimized, and the steric hindrance and electrostatic repulsive force in the migration process are obviously reduced, so that the diffusion capacity of sodium ions is improved, the structural characteristics of the material are improved on the premise of keeping a stable frame of the material, and the rapid migration of the sodium ions under the high-rate charge and discharge working condition is promoted. Can be used in the fields of energy storage systems and power batteries.

Inventors

WANG ZHENBO
LV SHIZHONG
DENG LIANG
ZHENG YINQI
He Zaohui
ZHAO LEI
GU DAMING

Assignees

哈尔滨工业大学
江西金晖锂电材料股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260209

Claims (10)

1. The topologically softened sodium ion battery anode material is characterized in that the material is obtained by controllably introducing intrinsic vacancies and defects into a polyanion sodium ion battery anode material.
2. The topologically softened sodium ion battery positive electrode material of claim 1, wherein the polyanionic sodium ion battery positive electrode material is sodium vanadium fluorophosphate or sodium vanadium phosphate.
3. The topologically softened sodium ion battery positive electrode material according to claim 1 or 2, wherein the topologically softened sodium ion battery positive electrode material is Na 3-x V 2 (PO 4 ) 2-x/3 F 3 , wherein 0< x is less than or equal to 1.
4. The topologically softened sodium ion battery positive electrode material according to claim 1 or 2, wherein the topologically softened sodium ion battery positive electrode material is Na 3-y V 2 (PO 4 ) 3-y/3 , wherein 0< y is less than or equal to 1.
5. A method for preparing a topologically softened sodium ion battery positive electrode material according to claim 1, characterized in that the method is a spray drying method, a sol-gel method or a solid phase synthesis method.
6. The method for preparing the topologically softened sodium ion battery positive electrode material according to claim 5, wherein the method for preparing the topologically softened sodium ion battery positive electrode material by using a spray drying method is as follows: 1. Sequentially adding a carbon source, a phosphorus source, a sodium source, a vanadium source and a fluorine source into deionized water, heating, stirring and dissolving to obtain a mixed solution, wherein the adding amount of the phosphorus source, the sodium source, the vanadium source and the fluorine source is added according to the stoichiometric ratio of the topologically softened sodium ion battery anode material, the molecular expression of the topologically softened sodium ion battery anode material is Na 3-x V 2 (PO 4 ) 2-x/3 F 3 , wherein x is less than or equal to 1, or the molecular expression of the topologically softened sodium ion battery anode material is Na 3-y V 2 (PO 4 ) 3-y/3 , wherein y is less than or equal to 1, and the mass ratio of the carbon source to the vanadium source is (1-5): 1; 2. Transferring the mixed solution into spray drying equipment, setting the air inlet temperature to be 190-200 ℃ and the air outlet temperature to be 110-120 ℃, and carrying out spray drying on the solution with the inlet speed of 400-500 mL h -1 to obtain precursor powder; 3. Transferring the obtained precursor powder into a tube furnace, heating and calcining under a protective atmosphere, and naturally cooling to obtain the topologically softened sodium ion battery anode material, wherein the protective gas of the topologically softened sodium ion battery anode material Na 3-x V 2 (PO 4 ) 2-x/3 F 3 is argon, the calcining temperature is 550-600 ℃, the calcining time is 3-4 hours, the protective gas of the topologically softened sodium ion battery anode material Na 3-y V 2 (PO 4 ) 3-y/3 is hydrogen-argon mixed gas, the calcining temperature is 800-900 ℃, and the calcining time is 8-12 hours.
7. The method for preparing a topologically softened sodium ion battery positive electrode material according to claim 6, wherein the carbon source in the first step is oxalic acid and/or citric acid.
8. The method for preparing a topologically softened sodium ion battery positive electrode material according to claim 6 or 7, wherein the phosphorus source in the first step is one or a mixture of several of monoammonium phosphate, diammonium phosphate, sodium dihydrogen phosphate and disodium hydrogen phosphate.
9. The method for preparing a topologically softened sodium ion battery positive electrode material according to claim 6 or 7, wherein the sodium source in the first step is one or a mixture of several of sodium carbonate, sodium acetate and sodium nitrate.
10. The use of a topologically softened sodium ion battery positive electrode material as claimed in claim 1, wherein the topologically softened sodium ion battery positive electrode material is used for preparing a positive electrode of a sodium ion battery.

Description

Topological-softened sodium ion battery positive electrode material and preparation method and application thereof Technical Field The invention belongs to the field of electrochemical energy storage, and particularly relates to a sodium ion battery anode material, a preparation method and application thereof. Background Sodium ion batteries are considered as an important technical route for large-scale energy storage and medium-low cost power application because of abundant raw material resources, obvious cost advantages and good safety and environmental adaptability. The positive electrode material is used as a core component for determining energy density and power characteristics, and the positive electrode material is used for realizing charge transfer by reversible intercalation/deintercalation of Na + in the charge-discharge process. For most frame-type cathode materials, electrochemical performance is not only dependent on structural stability and reversible capacity, but is also largely limited by the mobility kinetics and polarization level of Na +. In particular, under engineering conditions of high-rate charge and discharge, low-temperature operation, thick electrode/high surface load and the like, na + bulk diffusion limitation can directly lead to voltage polarization increase, available capacity reduction, energy efficiency reduction and heating aggravation, thereby limiting the power output capability and the rapid charge and discharge capability of the battery in an actual scene. Therefore, the method for improving the ion transmission dynamics of the positive electrode material has remarkable practical value, and is one of key paths for realizing high-power and high-efficiency sodium ion batteries. In the prior art, strategies such as particle nanocrystallization, carbon coating, conductive network construction or coupling with an external composite material are often adopted for improving dynamics of a polyanion sodium ion battery anode material so as to shorten a diffusion distance and improve electron transmission and interface reaction dynamics, but the effects are concentrated on particle size or electrode/electrolyte interface layers, and the problems of complexity improvement of a preparation method and the like are often accompanied. In addition, element doping is also a common method for improving the performance of the material, and by introducing different elements to optimize the local structure and charge distribution, although the sodium ion migration energy barrier can be reduced and the conductivity of the material can be improved, the doping scheme often needs complex element screening, has specificity and is difficult to be universally applied to different anode materials. Therefore, how to improve the internal structure of the positive electrode material of the sodium ion battery in a simple and effective way, so as to fundamentally improve the dynamic performance of the positive electrode material, and the problem to be solved in the field is still needed. Disclosure of Invention The invention aims to solve the technical problems of increased polarization, reduced capacity, poor multiplying power performance and complex modification method of the existing sodium ion battery positive electrode material caused by limited sodium ion migration kinetics under the condition of high-multiplying power charge and discharge, and provides a topology-softened sodium ion battery positive electrode material, and a preparation method and application thereof. The topologically softened sodium ion battery anode material is a universal and simple material design based on raw material feeding ratio regulation. Intrinsic vacancies and defects are introduced by precisely regulating and controlling the internal structure of the material, the topological structure of the migration channel is reconstructed, the diffusion kinetics and the multiplying power performance of sodium ions are improved, the dynamics performance of the positive electrode material of the sodium ion battery is fundamentally improved, and the requirements of high power and quick charge application are met. The topologically softened sodium ion battery anode material is obtained by controllably introducing intrinsic vacancies and defects into the polyanion sodium ion battery anode material. The positive ion vacancy and the negative ion group defect of the positive electrode material of the sodium ion battery are regulated by a simple and effective internal structure regulation method, so that the migration channel and the topological structure of sodium ions are fundamentally optimized. The invention adjusts the flexibility of the local structure in the material and reconstructs the topological structure of the migration channel to form the material with lower migration energy barrier and higher ion conductivity, so as to effectively improve the diffusion rate of sodium ions in the material and improve the high-rate charge