Silicon dioxide-coated fluorinated lithium cobalt phosphate and preparation method thereof

A technology of fluorinated cobalt lithium phosphate and silicon dioxide, applied in electrical components, battery electrodes, circuits, etc., can solve problems such as poor cycle performance, achieve improved electrochemical performance, good reaction reversibility and structural stability, excellent The effect of electrochemical performance

Active Publication Date: 2015-11-25
UNIV OF JINAN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The object of the present invention is to solve Li 2 CoPO 4 The problem of poor cycle performance of F, in ensuring the preparatio

Method used

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  • Silicon dioxide-coated fluorinated lithium cobalt phosphate and preparation method thereof
  • Silicon dioxide-coated fluorinated lithium cobalt phosphate and preparation method thereof
  • Silicon dioxide-coated fluorinated lithium cobalt phosphate and preparation method thereof

Examples

Experimental program
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Example Embodiment

[0022] Example 1

[0023] Add 0.02mol lithium fluoride, 0.02mol cobalt acetate, 0.02mol phosphoric acid, and 0.02mol lithium hydroxide into 35ml deionized water respectively, stir for 2h to make it evenly mixed, then transfer the mixed solution to the reaction kettle, and water at 210℃ Heat for 10h, then cool the reaction kettle to room temperature naturally, take out the product and dry it at 80℃ overnight, take out the tablet, and finally calcinate in a tube furnace at 350℃ for 6h and then 650℃ for 6h to obtain the product Li 2 CoPO 4 F. Then, weigh a certain amount of silica dispersion into a 50ml dry beaker, add 20ml of deionized water, magnetically stir until the mixture is uniform, and then add a certain amount of Li prepared by the above method 2 CoPO 4 F, continue to stir, then vacuum dry at 90°C overnight, take it out, and grind thoroughly in a quartz mortar to obtain silica-coated Li 2 CoPO 4 F material. For the X-ray powder diffraction pattern of the sample, see figur...

Example Embodiment

[0024] Example 2

[0025] Add 0.02mol of ammonium fluoride, 0.02mol of cobalt oxalate, 0.02mol of ammonium dihydrogen phosphate, and 0.02mol of lithium carbonate to 30ml of deionized water, stir for 2h to make them evenly mixed, and then transfer the mixed solution to the reaction kettle. Hydrothermally heated at ℃ for 14h, then the reaction kettle was naturally cooled to room temperature, the product was taken out and dried overnight at 80℃, taken out for grinding, tableting, and finally calcined at 300℃ for 6h in a tube furnace under a hydrogen / argon mixed gas atmosphere, and then Calcined at 640℃ for 6h to obtain the product Li 2 CoPO 4 F. Then, weigh a certain amount of silica particles into a 50ml dry beaker, add 20ml of hydrofluoric acid, manually stir and mix evenly, and then add a certain amount of Li prepared by the above method 2 CoPO 4 F, continue to stir, then dry at 90°C in a blast drying box, take it out, and grind it fully in an agate mortar to obtain silica-coated...

Example Embodiment

[0026] Example 3

[0027] 0.02mol lithium hydroxide, 0.02mol cobalt tetroxide, 0.02mol ammonium hydrogen phosphate were mixed and ball milled for 3h, and then calcined at 400℃ and 800℃ for 10h respectively to obtain LiCoPO 4 . Will get LiCoPO 4 Then mixed with LiF and ball milled and calcined at 700℃ for 1.5h under argon atmosphere to obtain the product Li 2 CoPO 4 F. Then, weigh a certain amount of silica powder and place it in a 100ml beaker, add 30ml of ethanol, mechanically stir and mix evenly, and then add a certain amount of Li prepared by the above method 2 CoPO 4 F, continue to stir, dry in a vacuum drying oven at 60°C, take it out, and grind it in an alumina mortar to obtain silica-coated Li 2 CoPO 4 F material.

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Abstract

The invention discloses silicon dioxide-coated fluorinated lithium cobalt phosphate and a preparation method thereof. The preparation method is characterized by comprising the following steps: weighing a certain amount of silicon dioxide and putting into a small beaker; adding 10-30ml of deionized water, and stirring and mixing the silicon dioxide evenly; adding a certain amount of fluorinated lithium cobalt phosphate prepared by a solid phase method or a hydrothermal method or a sol-gel method, further stirring the fluorinated lithium cobalt phosphate, and dying the mixture at 60-90 DEG C; and taking out and grinding the mixture, so as to obtain the silicon dioxide-coated fluorinated lithium cobalt phosphate. The silicon dioxide-coated fluorinated lithium cobalt phosphate prepared by the method is good in particle dispersity, small in particle size and uniform in size and morphology; and the structure of the fluorinated lithium cobalt phosphate is not destroyed. The cathode material prepared by the method is high in working voltage platform and shows excellent electrochemical property; particularly, after the battery is charged and discharged for dozens of circles, compared with an uncoated material, the specific discharge capacity is higher than 20%; and the capacity retention ratio can reach 100%, therefore, further research on high-voltage and high-energy density cathode materials is facilitated.

Description

Technical field [0001] The present invention relates to a hydrothermal method for preparing fluorinated cobalt phosphate lithium, in particular, the present invention relates to a method for optimizing the performance of a high-voltage, high-energy density cathode material fluorinated cobalt phosphate for lithium secondary batteries, and in particular to the use of nanometer two The method for coating the surface of fluorinated lithium cobalt phosphate cathode material with silicon oxide to obtain excellent electrochemical performance belongs to the technical field of lithium secondary battery materials. Background technique [0002] Fluorinated phosphate structure due to inductive effect of PO 4 3- And the stronger electronegative fluoride ion, the redox potential and structural stability of the material are significantly improved; in addition, because fluorination introduces a negative charge, considering the charge balance, it is expected to pass M in the fluorinated phosphate ...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/58H01M4/1397
CPCH01M4/1397H01M4/366H01M4/5825Y02E60/10
Inventor 常彩云冯季军李烨邹舟金钊赵玉燕
Owner UNIV OF JINAN
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