CN-122010184-A - Manganese tetraoxide material and preparation method and application thereof

CN122010184ACN 122010184 ACN122010184 ACN 122010184ACN-122010184-A

Abstract

The application provides a manganous-manganic oxide material, a preparation method and application thereof, and belongs to the technical field of battery materials. The trimanganese tetroxide material has a sunflower-like structure, wherein the sunflower-like structure is formed by orderly assembling radially arranged flaky or columnar primary grains inside trimanganese tetroxide particles, and the cross section of the particles presents a sunflower-like shape radiating outwards from the center. The trimanganese tetroxide with the sunflower-like structure can maintain excellent capacity retention rate at normal temperature and high temperature, and provides powerful material support for the development of high-performance lithium ion batteries.

Inventors

TAN SIRUI
WANG TAO
ZHOU TONG
JIANG JIANBING
GAO XUGUANG
TANG PEIYUAN
HUANG XIANGPING
ZHOU YIJIE
MA BOKAI

Assignees

湘潭电化科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260410

Claims (9)

1. The trimanganese tetroxide material is characterized by having a sunflower-like structure, wherein the sunflower-like structure is formed by orderly assembling radially arranged flaky or columnar primary grains inside trimanganese tetroxide particles, and the cross section of the particles presents a sunflower-like shape radiating outwards from the center.
2. The trimanganese tetroxide material of claim 1, wherein the trimanganese tetroxide material has an average particle size D50 of 5-13 μm.
3. A method for preparing a trimanganese tetroxide material, characterized in that it is used for preparing trimanganese tetroxide according to claim 1 or 2, comprising the steps of: S1, preparing a manganous manganic oxide seed crystal, namely adding soluble manganese salt, a precipitator and a complexing agent into a base solution in parallel, and reacting in the presence of an oxidant to obtain the manganous manganic oxide seed crystal with the average particle size D50 of 2-5 mu m; S2, synthesizing the trimanganese tetroxide with the sunflower-like structure, namely adding soluble manganese salt, a precipitator and a complexing agent into a system containing the trimanganese tetroxide seed crystal in parallel flow, continuing to react in the presence of an oxidant, and controlling the dosage of the oxidant, the pH value and the concentration of the complexing agent in the reaction system to enable the trimanganese tetroxide crystal to grow in order along the radial direction to form the sunflower-like structure; S3, after the reaction is finished, solid-liquid separation, washing and drying are carried out to obtain the sunflower-like manganous oxide material.
4. The method for preparing a trimanganese tetroxide material according to claim 3, wherein the amount of the oxidizing agent used in the step S2 is 3-10 times the theoretical amount required for completely oxidizing Mn 2+ to Mn 3 O 4 .
5. The method for preparing the trimanganese tetroxide material according to claim 3, wherein the concentration of the complexing agent in the reaction system in the step S2 is 1-3 mol/L.
6. The method for preparing a trimanganese tetroxide material according to claim 3, wherein the pH value of the reaction system in the step S2 is 8.5-9.9.
7. The method for producing a trimanganese tetroxide material according to claim 3, wherein the S2 is controlled by controlling the amount O, pH of the oxidizing agent P and the concentration C of the complexing agent so that the S value defined by the following formula is not less than 0.68: S =[0.35 F(O) + 0.4 G(P) + 0.25 H(C) ] Φ(O, P, C) Wherein: The multiplying power O of the oxidant is in the range of 3-10 times, and F (O) is a normalization function of the dosage of the oxidant; the pH value P is in the range of 8.5-9.9, and G (P) is a normalization function of the pH value; The concentration of the complexing agent C is in the range of 1-3 mol/L, and H (C) is a normalization function of the concentration of the complexing agent; Φ (O, P, C) is a constraint function, Φ=1 when O, P, C are all within the above range, else Φ=0.
8. Use of a trimanganese tetroxide material according to claim 1 or 2 or a trimanganese tetroxide material prepared by the method according to any of claims 3-7 in the preparation of a lithium manganate positive electrode material.
9. The preparation method of the lithium manganate positive electrode material is characterized by comprising the steps of mixing the manganous manganic oxide material prepared by the method of claim 1 or 2 or the manganous manganic oxide material prepared by the method of any one of claims 3-7 with a lithium source, and calcining at 750-800 ℃ for 12-24 hours in air or oxygen atmosphere to obtain the lithium manganate positive electrode material.

Description

Manganese tetraoxide material and preparation method and application thereof Technical Field The application relates to the field of battery material operation, in particular to a trimanganese tetroxide material and a preparation method and application thereof. Background The LiMn 2O4 has low preparation cost, mature and simple production process and good safety. Unlike layered oxides and olivine-type lithium iron phosphate, spinel-type LiMn 2O4 is an ideal positive electrode material for energy storage devices because of its environmental friendliness, unique structure, good electrochemical stability, and high theoretical capacity. The precursor of the lithium manganate anode material used in the market at present mainly comprises electrolytic manganese dioxide and manganous manganic oxide, wherein manganese in the latter is in a low valence state and has high chemical activity, so that the temperature for synthesizing the lithium manganate is relatively low, the energy consumption is saved, meanwhile, the overgrowth of crystal grains and volatilization of manganese caused by high temperature can be effectively inhibited, the product with more uniform grain size and more proper specific surface area is obtained, the rapid deintercalation of lithium ions is facilitated, the multiplying power performance is improved, in addition, the manganic oxide and the lithium manganate are in a spinel structure, and in the sintering process, the structural similarity enables the atomic rearrangement to develop to regular spinel LiMn 2O4 more easily, and the anode material with higher crystallinity and fewer lattice defects is formed. When the manganese tetraoxide on the market is used for synthesizing a lithium manganate positive electrode material, the following problems are encountered that Mn 3+ in ① lithium manganate can undergo a disproportionation reaction (Mn 3+→ Mn2++ Mn4+) in electrolyte, and the generated Mn 2+ can be dissolved in the electrolyte. This directly leads to loss of active substance and destruction of the material structure. The larger the specific surface area of the particles, the larger the contact area with the electrolyte, and the more serious the dissolution of manganese. ② Under the action of Mn3 + in high valence state (especially at high temperature or deep discharge), the crystal lattice of the material is distorted, and the material is converted from cubic system to tetragonal system, so that structural stress is induced, microcracks are generated, and capacity fading is aggravated. The document CN119637941A discloses a preparation method and application of modified sea urchin type manganous oxide, ammonia water is used as a precipitator, aminocarboxylic acid is used as a complexing agent, al, mg, ti, zn and other elements are introduced through liquid phase doping, a coating layer is formed on the surface, and parameters such as pH, temperature, solid content and the like are controlled, so that the modified manganous oxide is obtained. This document can improve the cycle performance of lithium manganate, but the cycle performance of the manganous manganic oxide of this structure is poor under the high temperature condition. Disclosure of Invention The application is made in view of the above problems, and an object of the application is to provide a trimanganese tetroxide material, a preparation method and application thereof, wherein the trimanganese tetroxide product with a sunflower-like structure is prepared to improve the structural stability of lithium manganate and accelerate the diffusion rate of lithium ions, so that the high-temperature cycle performance is remarkably improved. The application particularly provides a trimanganese tetroxide material, which has a sunflower-like structure, wherein the sunflower-like structure is formed by orderly assembling radially arranged flaky or columnar primary grains inside trimanganese tetroxide particles, and the cross section of the particles presents a sunflower-like shape radiating outwards from the center. Further, the average particle diameter D50 of the manganous oxide material is 5-13 mu m. The second aspect of the application provides a method for preparing a trimanganese tetroxide material, comprising the following steps: S1, preparing a manganous manganic oxide seed crystal, namely adding soluble manganese salt, a precipitator and a complexing agent into a base solution in parallel, and reacting in the presence of an oxidant to obtain the manganous manganic oxide seed crystal with the average particle size D50 of 2-5 mu m; S2, synthesizing the trimanganese tetroxide with the sunflower-like structure, namely adding soluble manganese salt, a precipitator and a complexing agent into a system containing the trimanganese tetroxide seed crystal in parallel flow, continuing to react in the presence of an oxidant, and controlling the dosage of the oxidant, the pH value and the concentration of the complexing agent in the reaction syst