Composite lithium vanadium phosphate positive material, and preparation method and applications thereof

A technology of compounding lithium vanadium phosphate and cathode material, which is applied in the directions of phosphate, phosphorus oxyacid, chemical instruments and methods, etc., to achieve the effect of improving electrochemical performance, enhancing cycle life and cycle stability, and preventing structure collapse

Active Publication Date: 2019-06-07
LANGFANG GREEN IND TECH CENT +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Although the above method has improved the electrochemical performance of lithium vanadium phosphate to a certain extent, there is still room for further improvement in its performance.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0075] The mass ratio of sulfur and graphene in the sulfur-doped graphene selected in this embodiment is 0.05:1, and the mass ratio of sulfur-doped graphene and polypyrrole in the first carbon source is 1:6; The mass fraction of nitrogen in the compound is 0.05%, and the chemical formula of the oxygen-containing compound is Li 0.06 B 0.98 PO 4 ; The mass fraction of nitrogen in the second carbon source (nitrogen and phosphorus co-doped carbon material) is 0.1%, and the mass fraction of phosphorus is 0.3%.

[0076] Prepare composite lithium vanadium phosphate positive electrode material according to the following method:

[0077] (1) the first carbon source, V 2o 5 , potassium phosphate, templating agent SBA-15 and oxalic acid mixed, control V 2 o 5 , the molar ratio of oxalic acid and template is 1:3:1, at 25 ℃ with the power of 200W after ultrasonic treatment for 1h drying, to obtain a dry mixture;

[0078] (2) heating the dried mixture obtained in step (1) to 650° C. ...

Embodiment 2

[0084] The mass ratio of sulfur and graphene in the sulfur-doped graphene selected in this embodiment is 0.12:1, and the mass ratio of sulfur-doped graphene and polyoxyethylene in the first carbon source is 1:4; The mass fraction of nitrogen in the oxygen compound is 0.3%, and the oxygen-containing compound is copper oxide and Li 0.03 B 0.99 PO 4 The mass fraction of nitrogen in the second carbon source (nitrogen, phosphorus co-doped carbon material) is 0.2%, and the mass fraction of phosphorus is 0.08%.

[0085] Prepare composite lithium vanadium phosphate positive electrode material according to the following method:

[0086] (1) The first carbon source, NH 4 VO 3 , sodium phosphate, template KIT-6 and oxalic acid mixed to control NH 4 VO 3 , the molar ratio of oxalic acid and the template is 1:4.5:0.8, 10h drying after ultrasonic treatment with a power of 30W at 100°C, to obtain a dry mixture;

[0087] (2) heating the dry mixture obtained in step (1) to 450° C. and r...

Embodiment 3

[0093] The mass ratio of sulfur and graphene in the sulfur-doped graphene selected in this embodiment is 0.01:1, and the mass ratio of sulfur-doped graphene and polythiophene in the first carbon source is 1:6; The mass fraction of nitrogen in the compound is 0.5%, and the chemical formula of the oxygen-containing compound is Li 0.09 B 0.97 PO 4 ; The mass fraction of nitrogen in the second carbon source (nitrogen and phosphorus co-doped carbon material) is 0.8%, and the mass fraction of phosphorus is 0.5%.

[0094] Prepare composite lithium vanadium phosphate positive electrode material according to the following method:

[0095] (1) the first carbon source, V 2 o 3 , triammonium phosphate, templating agent SBA-15 and oxalic acid mixed, control V 2 o 3 , the molar ratio of oxalic acid and the template is 1:5:3, 5h drying after ultrasonic treatment with a power of 120W at 80°C, to obtain a dry mixture;

[0096] (2) heating the dry mixture obtained in step (1) to 350° C. ...

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Abstract

The invention relates to a composite lithium vanadium phosphate positive material, and a preparation method and applications thereof. The composite lithium vanadium phosphate positive material can beprepared by adopting two kinds of different carbon sources through two steps of in-situ coating; ion doping can be performed on a lithium vanadium phosphate positive material by doping an oxygen-containing compound; and through the utilization of a synergistic effect formed between a coating layer and an adulterant, the electrochemical performance of a lithium vanadium phosphate material can be further improved. The obtained composite lithium vanadium phosphate positive material has a mesoporous structure; the discharge specific capacity of the composite positive material is greater than 150 mAh/g at 5C multiplying power; capacity retention rate is greater than 91% after 1,000 cycles; and therefore, the composite lithium vanadium phosphate positive material has excellent specific capacity,rate performance and cyclic stability, and is suitable for large-scale popularization and application.

Description

technical field [0001] The invention belongs to the technical field of preparation of cathode materials for lithium ion batteries, and in particular relates to a composite lithium vanadium phosphate cathode material and a preparation method and application thereof. Background technique [0002] Lithium vanadium phosphate has a monoclinic structure of Li 3 V 2 (PO 4 ) 3 compounds, not only have good security, but also have higher Li + Ion diffusion coefficient, higher discharge voltage and energy density, both the advantages of lithium cobalt oxide and lithium vanadium phosphate, and overcome the shortcomings of the above two, so it is considered to be better than LiCoO 2 Better cathode materials. [0003] Due to its good electrical conductivity, high theoretical specific capacity, high operating voltage platform, and good safety and stability, lithium vanadium phosphate has attracted great attention. However, the electron transport ability inside lithium vanadium phosp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58H01M10/0525H01M4/583H01M4/62C01B25/26C01B25/45C01B25/37
CPCY02E60/10
Inventor 谭强强徐宇兴
Owner LANGFANG GREEN IND TECH CENT
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