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CN-116364897-B - Lithium-rich lithium ferrite material and preparation method and application thereof

CN116364897BCN 116364897 BCN116364897 BCN 116364897BCN-116364897-B

Abstract

The application discloses a lithium ferrite material rich in lithium, a preparation method and application thereof. The lithium-rich lithium ferrite material comprises lithium-rich lithium ferrite particles and rare earth metal oxide particles coated on the surfaces of the lithium-rich lithium ferrite particles, and a heterostructure is formed between the interfaces of the lithium-rich lithium ferrite and the rare earth metal oxide particles. The application adopts rare earth metal oxide to construct a heterogeneous interface, reduces the resistance of electron migration, increases the electron mobility, adopts microwave sintering to reduce the temperature and time required by the reaction, has few small defects of the prepared lithium-rich lithium ferrite composite material particles, and has low defect concentration of the small particles, thereby being beneficial to reducing polarization, improving capacity and improving the particle size adaptation degree with the anode material.

Inventors

  • LI MINGMING
  • JIA XUEYING
  • LIU XINGLIANG
  • ZHOU BO
  • WANG QIAN

Assignees

  • 合肥国轩高科动力能源有限公司

Dates

Publication Date
20260512
Application Date
20230512

Claims (8)

  1. 1. The lithium-rich lithium ferrite material comprises lithium-rich lithium ferrite particles and rare earth metal oxide particles coated on the surfaces of the lithium-rich lithium ferrite particles, wherein a heterostructure is formed between the interfaces of the lithium-rich lithium ferrite and the rare earth metal oxide particles; Wherein the rare earth metal oxide is selected from one of Y 2 O 3 、Sc 2 O 3 ; the mass ratio of the rare earth metal oxide to the lithium ferrite particles is 1 (99.5-99.9); The method for preparing the lithium-rich lithium ferrite material comprises the following steps: 1) Mixing a lithium source and an iron source in a high mixing mode, performing microwave sintering to obtain lithium-rich lithium ferrite, and crushing the obtained lithium-rich lithium ferrite to obtain lithium-rich lithium ferrite powder; 2) Ball-milling and mixing the obtained lithium-rich lithium ferrite powder with the rare earth metal oxide, sieving the obtained mixture, and reserving sieving and discharging; 3) Microwave sintering the obtained screen blanking under the protection of atmosphere to obtain a lithium-rich lithium ferrite material coated with rare earth metal oxide; in the ball milling treatment, the ball-material ratio is 5:1, the rotating speed is 300rpm, and the time is 2 hours; in the step 3), the temperature of the microwave sintering is 400 ℃ and the time is 5h.
  2. 2. The lithium-rich lithium ferrite material of claim 1, wherein in step 1), the lithium source comprises one or more of Li 2 O,LiOH,Li 2 C 2 O 4 ,Li 2 CO 3 ; The iron source comprises one or more of Fe 2 O 3 ,Fe 2 (C 2 O 4 ) 3 ,Fe（NO 3 ） 3 ; The lithium source and the iron source are added according to the molar ratio of lithium to iron element (5.0-5.5): 1.
  3. 3. The lithium-rich lithium ferrite material according to claim 1, wherein in the step 1), the temperature of the microwave sintering is 400-600 ℃, the time is 5-10h, the microwave power is 1-3kW, and the heating rate is 5-10 ℃ per minute; in the step 3), the microwave power is 1-3kW, and the heating rate is 5-10 ℃ per minute; in the steps 1) and 3), the microwave sintering is carried out under the protection of inert gas; In the step 1), the crushing is jet crushing, and the particle size D50 of the lithium-rich lithium ferrite powder obtained after the crushing is 3-5 mu m.
  4. 4. The lithium ferrite material according to claim 1, wherein in the step 2), the rare earth metal oxide is added according to a mass ratio of the rare earth metal oxide to the lithium ferrite powder of 1 (99.5-99.9).
  5. 5. The lithium ferrite material according to claim 1, wherein the mesh number of the sieving screen is 300-500 mesh.
  6. 6. The use of the lithium ferrite material rich in lithium of claim 1 as a lithium supplementing material in the preparation of lithium ion batteries.
  7. 7. The method of claim 6, wherein the lithium-rich ferrite material is used as a positive electrode lithium-supplementing agent of a lithium ion battery.
  8. 8. A lithium ion battery is characterized in that the lithium ion battery contains the lithium ferrite material rich in lithium as set forth in claim 1.

Description

Lithium-rich lithium ferrite material and preparation method and application thereof Technical Field The application belongs to the field of batteries, relates to a positive electrode lithium supplementing material, and in particular relates to a lithium-rich lithium ferrite material, and a preparation method and application thereof. Background With the rapid development of electronic technology, mobile phones, notebook computers, cameras, electric bicycles and electric vehicles are increasingly used as electric equipment, and become an indispensable part in daily life, and with the increase of portability requirements, the requirements for energy storage batteries are also increasingly increased. Therefore, developing an energy storage battery with high energy storage capacity, good safety performance and long service life is an urgent task. Compared with lead-acid batteries and cadmium-nickel batteries, the lithium ion battery has wide application due to the advantages of high energy density, high power density, long service life, good safety, low self-discharge, wide temperature application range and the like. In the first charge and discharge process of the lithium ion battery, a Solid Electrolyte Interface (SEI) film layer is formed on the surface of the negative electrode, a large amount of active lithium is converted into lithium carbonate, lithium fluoride and alkyl lithium, so that lithium loss of a positive electrode material is caused, and the first coulomb efficiency and the battery capacity of the battery are reduced. In lithium ion battery systems using graphite cathodes, the initial charge consumes about 10% of the lithium source. The consumption of positive lithium sources is further exacerbated when high specific capacity negative electrode materials are employed, such as alloys (silicon, tin, etc.), oxides (silicon oxide, tin oxide), and amorphous carbon negative electrodes. In order to further improve the energy density of the lithium ion battery, pre-supplementing lithium to the positive electrode or the negative electrode is an effective method. However, the current negative electrode lithium supplementing materials have the defects that the activity is too high and the materials cannot be stably stored for a long time, so that the operation difficulty and the production risk are increased. The positive electrode lithium supplementing material has high potential, good compatibility with the existing processing technology of the lithium ion battery, and safer and more convenient operation, so that more and more attention is paid to academia and industry. However, the existing positive electrode lithium supplementing materials (such as lithium L-ascorbate, lithium D-isoascorbate, lithium metabisulfite, lithium sulfite, lithium phytate, etc.) are easily oxidized in air, are difficult to synthesize in large quantities, and are unfavorable for large-scale industrial production. Disclosure of Invention One of the purposes of the application is to provide a lithium-rich lithium ferrite material. The lithium-rich lithium ferrite material provided by the application comprises lithium-rich lithium ferrite particles and rare earth metal oxide particles coated on the surfaces of the lithium-rich lithium ferrite particles, wherein a heterostructure is formed between the interfaces of the lithium-rich lithium ferrite and the rare earth metal oxide particles; The rare earth metal oxide is selected from one or more of ：Y2O3、Sc2O3、La2O3、Ce2O3、Rb2O、Yb2O3; the mass ratio of the rare earth metal oxide to the lithium ferrite particles is 1 (99.5-99.9), specifically can be 1:99.5, 1:99.7 or 1:99.9, and more specifically can be 1:99.5. The application also provides a method for preparing the lithium-rich lithium ferrite material. The method for preparing the lithium-rich lithium ferrite material provided by the application comprises the following steps: 1) Mixing a lithium source and an iron source in a high mixing mode, performing microwave sintering to obtain lithium-rich lithium ferrite, and crushing the obtained lithium-rich lithium ferrite to obtain lithium-rich lithium ferrite powder; 2) Ball-milling and mixing the obtained lithium-rich lithium ferrite powder with rare earth metal oxide, sieving the obtained mixture, and reserving sieving and discharging; 3) And carrying out microwave sintering on the obtained screen blanking under the protection of atmosphere to obtain the lithium-rich lithium ferrite material coated with the rare earth metal oxide. In the method step 1), the lithium source comprises one or more of Li 2O,LiOH,Li2C2O4,Li2CO3; The iron source comprises one or more of Fe 2O3,Fe2(C2O4)3,Fe(NO3)3; the lithium source and the iron source are added according to the molar ratio of lithium to iron element (5.0-5.5): 1; The rotation speed of the high mixing can be 500-800rpm, and the high mixing time can be 5-10min; Preferably, the particle diameter D50 of the lithium source and the iron source i