Nanometer lithium zirconate modified lithium iron phosphate composite material and preparation method thereof

A technology of lithium iron phosphate and composite materials, applied in the direction of phosphorus compounds, chemical instruments and methods, inorganic chemistry, etc., can solve the problems of lithium iron phosphate hindering the application and development, low temperature and poor rate performance, and no continuity, etc. Excellent electrical conductivity and cycle stability, high rate and low temperature performance, and the effect of improving electronic conductivity

Inactive Publication Date: 2013-11-20
YANTAI ZHUONENG BATTERY MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, there are many technical problems in pure phase lithium iron phosphate, which hinder its application and development.
Lithium iron phosphate has an olivine structure, and lithium ions are conducted in one-dimensional tunnels, making the ion diffusion coefficient only 10 -16 ~10 -14 cm 2 / s, much lower than lithium cobalt oxide 10 -9 cm 2 / s, and 10 of lithium manganate -11 cm 2 / s; there is no continuous FeO in the lithium iron phosphate structure 6 Octahedral network, electrons can only rely on Fe-O-Fe conduction, resulting in an electronic conductivity of only 10 -10 ~10 -9 S / cm, very poor conductivity
Therefore, the actual specific capacity of pure-phase lithium iron phosphate is only 60% of its theoretical specific capacity, and the low temperature and rate performance are poor.

Method used

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  • Nanometer lithium zirconate modified lithium iron phosphate composite material and preparation method thereof
  • Nanometer lithium zirconate modified lithium iron phosphate composite material and preparation method thereof
  • Nanometer lithium zirconate modified lithium iron phosphate composite material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Weigh 42.38 g of lithium hydroxide (monohydrate), 176.29 g of ferrous oxalate (dihydrate), 122.50 g of 80% phosphoric acid, and 1.53 g of nano-lithium zirconate, and add them to a reaction kettle with 2L of deionized water, stir Mix for 1.5 hours, then add 1.60g of citric acid, adjust the pH to 6.8 with 20% ammonia water, the filling degree is 60%, close the reaction kettle and stir vigorously, adjust the temperature to 90°C for 4 hours, then raise the temperature to 180°C for 7 hours , and then cooled to room temperature. The reaction product was evaporated to dryness at 70°C, then dried at 110°C for 2.5 hours, and 15.82g of microcrystalline cellulose was added, mixed in a high-speed mixer for 40 minutes, and then heated to 700°C at a heating rate of 10°C / min. ℃, in a nitrogen atmosphere for 6 hours, after crushing and sieving, the composition is Li 1.01 Fe 0.98 PO 4 0.01 Li 2 ZrO 3 / C lithium iron phosphate composite material, the carbon content is 2.5% as tested...

Embodiment 2

[0035] Weigh 59.39 g of lithium acetate, 156.54 g of ferrous acetate, 115.02 g of ammonium dihydrogen phosphate and 15.31 g of nano-lithium zirconate, and add them to a reaction kettle with 2.5 L of deionized water, stir and mix for 1.5 hours, then add poly Ethylene glycol 0.33g, adjust the pH=6 with 20% ammonia water, the filling degree is 50%, close the reaction kettle and stir vigorously, adjust the temperature to 50°C for 3 hours, then raise the temperature to 140°C for 5 hours, then cool to room temperature . The reaction product was evaporated to dryness at 90°C, then dried at 100°C for 2 hours, added 50.04 g of glucose, mixed in a high-speed mixer for 30 minutes, and then heated to 650°C at a rate of 10°C / min. Insulated under air atmosphere for 12 hours, after pulverization and sieving, the composition of Li 0.9 Fe 0.9 PO 4 0.1 Li 2 ZrO 3 / C lithium iron phosphate composite material, the carbon content is 5.5% as tested by the carbon sulfur analyzer.

[0036] Acco...

Embodiment 3

[0038] Weigh 40.64 g of lithium carbonate, 269.44 g of ferric citrate, 132.06 g of diammonium hydrogen phosphate and 3.06 g of nano-lithium zirconate, and add them to a reaction kettle with 3.5 L of deionized water, stir and mix for 2 hours, then add laurel Acid 6.68g, use 20% ammonia water to adjust pH=9, filling degree is 70%, close the reaction kettle and continue to stir, adjust the temperature to 100°C for 3 hours, then raise the temperature to 200°C for 8 hours, then cool to room temperature. Evaporate the reaction product to dryness at 80°C, then dry it at 110°C for 2.5 hours, add 8.35g of methylcellulose, mix it in a high-speed mixer for 1 hour, and then raise the temperature to 800°C at a heating rate of 10°C / min , kept under an argon atmosphere for 12 hours, after crushing and sieving, the composition of Li 1.1 Fe 1.1 PO 4 0.02Li 2 ZrO 3 / C lithium iron phosphate composite material, the carbon content is 1.5% as tested by the carbon sulfur analyzer.

[0039] Acc...

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PUM

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Abstract

The invention discloses a nanometer lithium zirconate modified lithium iron phosphate composite material and a preparation method thereof. The structural formula of the composite material is LixFeyPO4.zLi2ZrO3 / C, and the composite material comprises lithium iron phosphate, nanometer lithium zirconate and organic matter pyrolysis carbon. The composite material is characterized by being prepared by virtue of any one of the following methods: (1) preparing a precursor mixed liquor containing nanometer lithium zirconate through a hydrothermal reaction, drying, adding an organic carbon source, mixing, and calcining at a high temperature in an inert atmosphere; (2) preparing the precursor mixed liquor through the hydrothermal reaction, drying, calcining at a low temperature in the inert atmosphere, then adding the organic carbon source and nanometer lithium zirconate, mixing, and calcining at a high temperature in the inert atmosphere. The preparation method is simple; the prepared lithium iron phosphate composite material has the advantages of high conductivity, excellent multiplying power and low temperature performance, good cycle performance and the like, and can be widely applied to field of power batteries.

Description

technical field [0001] The invention relates to the technical field of cathode materials for lithium ion batteries, in particular to a lithium iron phosphate composite material modified with nanometer lithium zirconate and a preparation method thereof. Background technique [0002] In 1997, Professor Goodenough of the University of Texas reported for the first time the olivine-type structure of lithium iron phosphate (LiFePO 4 ), it has excellent electrochemical performance, the theoretical specific capacity is 170 mAh / g, and the voltage to lithium platform is 3.4V, which is low cost, environmentally friendly, long cycle life, good safety at high temperature, taking into account the LiCoO 2 , LiNiO 2 , LiMnO 2 The main advantages of the material, as a positive electrode material for lithium-ion batteries, can better solve the problems of cost, environment and safety, and has received widespread attention. LiFePO 4 The emergence of is considered to be a sign of "the arri...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/1397C01B25/45
CPCY02E60/122Y02E60/10
Inventor 周舟杨志宽
Owner YANTAI ZHUONENG BATTERY MATERIAL
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