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Decarburization reconstruction method for lithium iron phosphate with high carbon and low rate capability

A lithium iron phosphate, low-magnification technology, applied in the direction of chemical instruments and methods, phosphorus compounds, active material electrodes, etc., can solve the problem of high processing cost, and achieve the effect of low production cost, wide range of raw materials, and low internal resistance

Active Publication Date: 2021-11-30
ZHUZHOU SMELTER GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the method for lithium iron phosphate recovery in the prior art is generally to prepare lithium salt and iron sulfate by wet method first, and then use the sulfate railway line to prepare; at present, Zhuzhou Smelting Group Co., Ltd. has industrially applied lithium iron phosphate waste recycling is Lithium iron phosphate products are obtained through direct repair. Although this method produces medium and high-quality lithium iron phosphate, the preparation cost is equivalent to that of the orthophosphate railway line, and there is a defect that the processing cost is relatively high. Therefore, it is necessary to overcome the recycling of lithium iron phosphate waste to prepare phosphoric acid. For this defect of lithium iron cathode material, it is necessary to prepare lithium iron phosphate material with excellent performance by changing the raw and auxiliary materials, improving the preparation process of lithium iron phosphate and optimizing the technical conditions.

Method used

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  • Decarburization reconstruction method for lithium iron phosphate with high carbon and low rate capability

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Step A, pyrolysis separation: Take the waste lithium iron phosphate electrode sheet without electrolyte solution and pyrolyze it under the conditions of 420°C, 8 hours, and 1500ppm oxygen concentration under the protective atmosphere of nitrogen, and the completely pyrolyzed waste electrode sheet is The 3-mesh screen added with zirconium balls is the upper vibrating sieve, and the lithium iron phosphate waste powder with an Al content of 0.1% is obtained;

[0034] Step B, airflow crushing: mix the lithium iron phosphate waste powder obtained in step A with zinc oxide powder of 0.3 times the molar number of F, and carry out airflow crushing, and sieve the crushed material with a 100-mesh sieve to obtain a median particle size of 0.5μm mixed lithium iron phosphate waste powder with high carbon and low performance;

[0035] Step C, carbon reduction: the mixed lithium iron phosphate waste powder obtained in step B is sintered in a mixed gas containing argon with a molar rat...

Embodiment 2

[0038] Step A. Pyrolysis and separation: Take the waste lithium iron phosphate electrode sheet without electrolyte solution and pyrolyze it under the protective atmosphere of argon at a temperature of 500°C, for 3 hours, and with an oxygen concentration of 10ppm. The waste electrode sheet that has been pyrolyzed completely Add the 35 mesh sieves of rubber balls as upper vibrating sieve, obtain the lithium iron phosphate waste powder that Al content is 0.05%;

[0039] Step B, airflow crushing: mix the lithium iron phosphate waste powder obtained in step A with zinc oxide powder of 0.35 times the molar number of F, and carry out airflow crushing, and sieve the crushed material with a 100-mesh sieve to obtain a median particle size of 10μm mixed lithium iron phosphate waste powder with high carbon and low performance;

[0040] Step C, carbon reduction: Sinter the mixed lithium iron phosphate waste powder obtained in step B in a mixed gas containing nitrogen with a molar ratio of ...

Embodiment 3

[0043] Step A. Pyrolysis and separation: Take the waste lithium iron phosphate electrode sheet without electrolyte solution and pyrolyze it under the protective atmosphere of helium at a temperature of 480°C, for 5 hours, and with an oxygen concentration of 100ppm, and completely pyrolyze the waste electrode sheet Adding stainless steel balls to the 25-mesh sieve for vibratory sieving to obtain Al content of 0.07% lithium iron phosphate waste powder;

[0044] Step B, airflow crushing: mix the lithium iron phosphate waste powder obtained in step A with zinc oxide powder of 0.33 times the molar number of F, and carry out airflow crushing, and carry out 100 mesh sieve screening to the crushed material to obtain a medium particle size of 5μm high-carbon and low-performance mixed lithium iron phosphate waste powder;

[0045] Step C, carbon reduction: Sinter the mixed lithium iron phosphate waste powder obtained in step B in a mixed gas containing helium with a molar ratio of carbon...

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Abstract

A decarburization reconstruction method for lithium iron phosphate with high carbon and low rate performance comprises the following steps of: pyrolyzing lithium iron phosphate waste pole pieces without electrolyte under a protective atmosphere, and vibrating and screening the completely pyrolyzed waste pole pieces to obtain lithium iron phosphate waste powder; mixing the lithium iron phosphate waste powder with a certain amount of zinc oxide powder, carrying out airflow crushing, and screening the crushed material to obtain high-carbon and low-performance mixed lithium iron phosphate waste powder; and sintering the mixed lithium iron phosphate waste powder in mixed gas according to the sintering schedule that the F removal temperature of the lithium iron phosphate is 680-720 DEG C, the decarburization temperature is 820-880 DEG C, and the purification temperature is 740-780 DEG C, then cooling the sintering product to 100 DEG C or below and discharging the sintering product out of a furnace. The method is simple in process and short in flow, and the prepared lithium iron phosphate positive electrode material has the characteristics of good consistency, high electrochemical performance and the like.

Description

technical field [0001] The invention relates to the technical field of lithium ion battery materials, in particular to a method for decarburization and reconstruction of lithium iron phosphate with high carbon and low rate performance. Background technique [0002] Lithium iron phosphate (LiFePO 4 , referred to as LFP) as a lithium-ion battery cathode material, its theoretical specific capacity is 170mAh g-1, the actual specific capacity exceeds 140mAh g-1 (0.2C, 25 ℃), it has the advantages of low price and good thermal stability, and Environmental protection, high safety and superior cycle performance. At present, lithium iron phosphate is widely used in fields such as electric buses, special vehicles, electric bicycles, ships, energy storage, and 5G base stations. It is still relatively expensive. In the future, only when the price of lithium batteries per 1WH is lower than 0.6 yuan will they have strong competitiveness. Therefore, the performance of lithium iron phosph...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/45H01M4/58H01M10/0525H01M10/54
CPCC01B25/45H01M4/5825H01M10/0525H01M10/54H01M2004/028C01P2006/40Y02W30/84Y02E60/10
Inventor 廖贻鹏林文军周玉琳张桂海王勇
Owner ZHUZHOU SMELTER GRP