Lithium ion battery phosphatic composite cathode material and preparation method thereof

A composite positive electrode material and lithium-ion battery technology, applied in battery electrodes, circuits, electrical components, etc.

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

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  • Lithium ion battery phosphatic composite cathode material and preparation method thereof
  • Lithium ion battery phosphatic composite cathode material and preparation method thereof
  • Lithium ion battery phosphatic composite cathode material and preparation method thereof

Examples

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Embodiment 1

[0028] a. Prepare the core active material by one spray: use lithium acetate, ammonium vanadate, ammonium dihydrogen phosphate, and citric acid (added according to the residual carbon content of the product as 2%) as raw materials, add an appropriate amount of deionized water, and place in a constant temperature water bath at 80°C Stir for 6 hours to form a sol, then press LiFePO 4 with Li 3V 2 (PO 4 ) 3 The molar ratio of 10:1, adding nano-sized LiFePO 4 Powder, ultrasonically dispersed uniformly, the resulting mixture was spray-dried at 150°C, then calcined at 800°C for 4 hours in an inert atmosphere, cooled and ground to obtain the core LiFePO of lithium vanadium phosphate-coated lithium iron phosphate 4 / Li 3 V 2 (PO 4 ) 3 .

[0029] b. Secondary spraying to prepare a composite positive electrode material with a multi-nuclear core-shell structure: a certain amount of glucose (the quality of carbon contained in it is 5% of the quality of the inner core material) is...

Embodiment 2

[0031] a. Prepare the core active material by spraying once: take lithium carbonate, vanadyl oxalate, phosphoric acid, polyethylene glycol (according to the residual carbon content in the product is 3% to add) as raw material, add appropriate amount of deionized water, oil at 70 ℃ Stir in the bath for 10 hours to form a sol, then press LiFePO 4 with Li 3 V 2 (PO 4 ) 3 The molar ratio of 100:1, adding nano-sized LiFePO 4 Powder, magnetically stirred to disperse evenly, the resulting mixture was spray-dried at 200°C, then calcined at 550°C for 20 hours in an inert atmosphere, cooled and ground to obtain the nuclear active material LiFePO, which is lithium vanadium phosphate-coated lithium iron phosphate 4 / Li 3 V 2 (PO 4 ) 3 .

[0032] b. Secondary spraying to prepare a composite positive electrode material with a multi-nuclear core-shell structure: a certain amount of sucrose (the quality of carbon contained in it is 15% of the quality of the inner core material) is di...

Embodiment 3

[0034] a. Preparation of core active material by spraying once: using lithium hydroxide, triethanolamine vanadium peroxide, triammonium phosphate, oxalic acid (added according to the residual carbon content of the product as 1%) as raw materials, adding an appropriate amount of deionized water, and keeping the temperature at 60°C Stir in a water bath for 12 hours to form a sol, then press LiFePO 4 with Li 3 V 2 (PO 4 ) 3 The molar ratio of 5:1, adding nano-sized LiFePO 4 Powder, mechanically stirred and dispersed evenly, the resulting mixture was spray-dried at 250°C, then calcined at 900°C for 2 hours in an inert atmosphere, cooled and ground to obtain the core active material LiFePO, which is lithium vanadium phosphate-coated lithium iron phosphate 4 / Li 3 V 2 (PO 4 ) 3 .

[0035] b. Secondary spraying to prepare the composite positive electrode material of the polynuclear core-shell structure: a certain amount of citric acid (the quality of its contained carbon is ...

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Abstract

The invention discloses a lithium ion battery phosphatic composite cathode material and a preparation method thereof. The composite material is a multinuclear core shell structure composed of a plurality of cores and a housing layer, the cores are lithium iron phosphate particles wrapped by lithium vanadium phosphate and the housing layer is amorphous carbon. Preparation of the lithium iron phosphate particles wrapped by lithium vanadium phosphate comprises the following steps: preparing precursor sol with a sol gel method, adding lithium iron phosphate powder to disperse uniformly, carrying out spray drying on the above mixture, calcining the above resultant in inert gas, and followed by cooling and grinding to obtain the lithium iron phosphate particles wrapped by lithium vanadium phosphate. Preparation of the composite cathode material comprises the following steps: dissolving a carbon source compound into deionized water, adding core materials, dispersing the above resultant uniformly, carrying out second spray drying, calcining the above resultant in inert gas, and followed by cooling to obtain the composite cathode material. The composite material prepared in the invention has good electronic conduction performance, good ionic conduction performance and excellent electrochemistry performance. Because of existence of lithium vanadium phosphate, energetic density of a material is raised. Because of the multinuclear core shell structure like nano/micro structures, the composite material has good processing performance, and tap density of the material is greatly raised.

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 phosphate-based composite cathode material and a preparation method thereof. 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 electronic condu...

Claims

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Application Information

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IPC IPC(8): H01M4/58H01M4/1397
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河
Owner CENT SOUTH UNIV
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