Method for improving tap density of composite anode material xLiFePO4.yLi3V2(PO4)3 of lithium ion battery

A composite positive electrode material and lithium-ion battery technology, applied in battery electrodes, circuits, electrical components, etc., to achieve the effects of increased tap density, improved energy density, and excellent electrochemical performance

Active Publication Date: 2011-11-16
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

So far, there is no information about using this method to prepare lithium-ion battery composite positive electrode material xLiFePO 4 ·yLi 3 V 2 (PO 4 ) 3 report

Method used

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  • Method for improving tap density of composite anode material xLiFePO4.yLi3V2(PO4)3 of lithium ion battery
  • Method for improving tap density of composite anode material xLiFePO4.yLi3V2(PO4)3 of lithium ion battery
  • Method for improving tap density of composite anode material xLiFePO4.yLi3V2(PO4)3 of lithium ion battery

Examples

Experimental program
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Embodiment 1

[0024] Using lithium acetate, ferrous oxalate, ammonium vanadate and phosphoric acid as raw materials, press 0.8LiFePO 4 0.2 Li 3 V 2 (PO 4 ) 3 The stoichiometric ratio of ingredients, adding citric acid (the molar amount of which is 1 times the total molar number of metal ions), and then adding an appropriate amount of deionized water to make the pH of the mixed solution 4, stirred in a constant temperature water bath at 80°C for 10 hours until the formation of Sol, the resulting sol is diluted with deionized water (the amount of deionized water is 10 times the volume of the sol), spray-dried at 150°C, and then the obtained powder is calcined at 800°C for 4 hours in an argon atmosphere to obtain a composite positive electrode material 0.8LiFePO 4 0.2 Li 3 V 2 (PO 4 ) 3 , its tap density reaches 1.92g / cm 2 .

Embodiment 2

[0026] Using lithium carbonate, iron phosphate, vanadium peroxalate and diammonium hydrogen phosphate as raw materials, press 0.5LiFePO 4 0.5 Li 3 V 2 (PO 4 ) 3 The stoichiometric ratio of ingredients, adding polyethylene glycol (its molar weight is 0.5 times the total molar number of metal ions), then adding an appropriate amount of ethanol to make the pH of the mixed solution is 2, stirred in a constant temperature oil bath at 70 ° C for 0.5 hours to Form a sol, dilute the obtained sol with deionized water (the amount of deionized water is 20 times the volume of the sol), spray dry it at 300°C, and then calcinate the obtained powder at 650°C for 12 hours in an argon atmosphere to obtain a composite positive electrode Material 0.5LiFePO 4 0.5Li 3 V 2 (PO 4 ) 3 , its tap density reaches 1.87g / cm 2 .

Embodiment 3

[0028] Using lithium hydroxide, ferric oxide, triethanolamine vanadium peroxide, and triammonium phosphate as raw materials, press 0.01LiFePO 4 0.99 Li 3 V 2 (PO 4 ) 3 The stoichiometric ratio of ingredients, adding oxalic acid (its molar mass is 3 times the total molar mass of metal ions), then adding an appropriate amount of acetone to make the pH value 6, stirring in a constant temperature oil bath at 20°C for 12 hours until a sol was formed, and the resulting sol Dilute with deionized water (the amount of deionized water is 50 times the volume of the sol), spray dry at 100°C, and then calcinate the obtained powder at 850°C for 2 hours in an argon atmosphere to obtain a composite positive electrode material 0.01LiFePO 4 0.99 Li 3 V 2 (PO 4 ) 3 , its tap density reaches 1.90g / cm 2 .

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Abstract

The invention discloses a method for improving the tap density of a composite anode material xLiFePO4.yLi3V2(PO4)3 of a lithium ion battery. A combined sol gel-spray drying-carbon thermal reduction method is adopted to prepare the composite anode material xLiFePO4.yLi3V2(PO4)3 of the lithium ion battery, comprising the following concrete steps: mixing a lithium source, an iron source and a vanadium source with phosphate groups in a stoichiometric ratio; adding a solvent and a coordinating agent containing carbon to stir to form sols; carrying out spray drying on the sols; and roasting the obtained powder for 2-24 hours in an argon or nitrogen atmosphere at the temperature of 500-850 DEG C to obtain the composite anode material xLiFePO4.yLi3V2(PO4)3. The tap density of the prepared composite material is 1.50-2.00g / cm<3> and the electrochemical performance of the prepared composite material is good.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery materials and preparation methods thereof, and relates to a lithium-ion battery composite cathode material xLiFePO 4 ·yLi 3 V 2 (PO 4 ) 3 The tap density method. Background technique [0002] In recent years, the compound LiMPO with olivine structure 4 (M=Fe, Mn, Ni and Co, etc.) has become a research hotspot in the field of cathode materials for lithium-ion batteries. Among these compounds, LiFePO 4 Because of its high theoretical specific capacity, low cost, safety, and environmental protection, it has become a very promising cathode material for lithium-ion batteries. However, LiFePO 4 Has a very low electronic conductivity (10 -9 ~10 -10 S cm -1 ) and lithium ion diffusion rate (1.8×10 -14 cm 2 ·s -1 ), resulting in poor electrochemical performance at high rates. Therefore, the current LiFePO 4 The focus and hotspots of modification research are focused on improving its electr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1397
CPCY02E60/122Y02E60/12Y02E60/10
Inventor 郭华军张晓萍李新海王志兴彭文杰胡启阳张云和伍凌
Owner CENT SOUTH UNIV
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