A kind of cobalt lithium fluorophosphate coated with tin oxide and antimony and its surface deposition in-situ coating method and application

Abstract

The invention discloses a high-voltage electrode material and a preparation method for in-situ coating of tin antimony oxide on the surface of cobalt lithium fluorophosphate and its application in lithium secondary batteries. It is characterized in that the prepared method comprises the following steps: weighing a certain amount of cobalt lithium fluorophosphate precursor into a beaker, adding a dispersant, adding an antimony source and a tin source according to a certain mass ratio, dissolving in the dispersant, and adding an excessive amount of Precipitating agent, precipitating, centrifuging, washing, after the precursor is calcined and reacted in situ, the lithium cobalt fluorophosphate cathode material coated in situ with tin oxide and antimony is obtained. The lithium cobalt fluorophosphate cathode material coated with antimony tin oxide in situ prepared by this method has good crystallinity, good dispersion, uniform coating, high discharge platform and high energy density, and exhibits excellent electrochemical performance. The performance, especially after many charge-discharge cycles, still maintains a high discharge specific capacity and energy density, which will help further research and application of high-voltage and high-energy-density cathode materials.

Description

technical field

[0001] The invention relates to a preparation method for in-situ coating of tin and antimony oxide on the surface of lithium cobalt fluorophosphate, in particular to directly depositing tin ions and antimony ions on a lithium cobalt fluorophosphate precursor, and then calcining to synthesize tin and antimony oxide in-situ coating The lithium cobalt fluorophosphate cathode material is used to coat the surface of lithium cobalt fluorophosphate with antimony doped tin dioxide in situ to improve the conductivity of the cathode material, and further enhance its use as a high voltage lithium secondary battery. The electrochemical performance of a positive electrode material belongs to the technical field of lithium secondary batteries. Background technique

[0002] Since the emergence of lithium secondary batteries, they have been widely used in smart phones, electric vehicles, aerospace and other fields due to their advantages such as high specific capacity, good ...

Examples

Embodiment 1

[0027] Accurately weigh 0.02mol lithium hydroxide, 0.02mol cobalt acetate, 0.02mol phosphoric acid, and 0.02mol lithium fluoride, add them to 25 mL of deionized water, stir for 4 h and mix well, and then transfer them to the reaction kettle. Heat for 11 h, cool to room temperature, move it to a beaker to dry overnight, and grind it finely to obtain the precursor of lithium cobalt fluorophosphate. Weigh 1.0 g of lithium cobalt fluorophosphate precursor into a beaker, add 20 mL of deionized water, add 0.1900 g of tin tetrachloride and 0.0137 g of antimony trichloride while stirring, and slowly drop 8 mL of 1 mol / L sodium hydroxide, aged for 90 min, centrifuged at 6000 r / min for 8 min, washed with deionized water, and dried at 70 °C. Pre-calcined at 350 °C for 7 h under nitrogen protection, and calcined at 600 °C for 7 h. That is, the lithium cobalt fluorophosphate cathode material coated with antimony tin oxide in situ is obtained; the lithium cobalt fluorophosphate cathode ma...

Embodiment 2

[0029] Accurately weigh 0.04mol of lithium acetate, 0.02mol of cobalt oxalate, 0.02mol of phosphoric acid, and 0.02mol of ammonium fluoride, add them to 15 mL of deionized water, stir for 4 h and mix well, and then transfer them to the reaction kettle. After 10 h, it was cooled to room temperature, moved to a beaker to dry overnight, and ground finely to obtain the precursor of lithium cobalt fluorophosphate. Weigh 1.0 g lithium cobalt fluorophosphate precursor into a beaker, add 25 mL of dispersant (water: ethanol: methanol = 2:2:1), add 0.1470 g tin dichloride and 0.0096 g antimony triiodide while stirring, Slowly drop 7 mL of 1 mol L at 70°C -1 Precipitant (4 mL 1 mol / L sodium hydroxide + 3 mL concentrated ammonia water), aged for 80 min, centrifuged at 6500 r / min for 6 min, washed with deionized water, and dried at 80 °C. Pre-calcined at 300 °C for 6 h under argon protection and calcined at 680 °C for 4 h. That is, the lithium cobalt fluorophosphate cathode material coat...

Embodiment 3

[0031] Accurately weigh 0.02mol lithium hydroxide, 0.02mol cobalt nitrate, 0.02mol diammonium hydrogen phosphate, 0.02mol lithium fluoride, add them to 25 mL of deionized water, stir for 3 h and mix well, then transfer them to the reaction kettle, It was heated with water at 200 °C for 11 h, cooled to room temperature, moved to a beaker to dry overnight, and finely ground to obtain the precursor of lithium cobalt fluorophosphate. Weigh 1.0 g of lithium cobalt fluorophosphate precursor into a beaker, add 10 mL of ethanol, add 0.2130 g of tin sulfate and 0.0097 g of antimony tribromide while stirring, and slowly drop 12 mL of 1 mol / L lithium hydroxide at 70 °C , aged for 30 min, centrifuged at 5000 r / min for 10 min, washed with deionized water, and dried at 60 °C. Under the protection of mixed gas (argon: hydrogen = 8:2), pre-calcination at 300 °C for 7 h and 550 °C for 8 h. That is, an in-situ lithium cobalt fluorophosphate positive electrode material coated with tin and antim...

technical field

[0001] The invention relates to a preparation method for in-situ coating of tin and antimony oxide on the surface of lithium cobalt fluorophosphate, in particular to directly depositing tin ions and antimony ions on a lithium cobalt fluorophosphate precursor, and then calcining to synthesize tin and antimony oxide in-situ coating The lithium cobalt fluorophosphate cathode material is used to coat the surface of lithium cobalt fluorophosphate with antimony doped tin dioxide in situ to improve the conductivity of the cathode material, and further enhance its use as a high voltage lithium secondary battery. The electrochemical performance of a positive electrode material belongs to the technical field of lithium secondary batteries. Background technique

[0002] Since the emergence of lithium secondary batteries, they have been widely used in smart phones, electric vehicles, aerospace and other fields due to their advantages such as high specific capacity, good ...

Examples

Embodiment 1

[0027] Accurately weigh 0.02mol lithium hydroxide, 0.02mol cobalt acetate, 0.02mol phosphoric acid, and 0.02mol lithium fluoride, add them to 25 mL of deionized water, stir for 4 h and mix well, and then transfer them to the reaction kettle. Heat for 11 h, cool to room temperature, move it to a beaker to dry overnight, and grind it finely to obtain the precursor of lithium cobalt fluorophosphate. Weigh 1.0 g of lithium cobalt fluorophosphate precursor into a beaker, add 20 mL of deionized water, add 0.1900 g of tin tetrachloride and 0.0137 g of antimony trichloride while stirring, and slowly drop 8 mL of 1 mol / L sodium hydroxide, aged for 90 min, centrifuged at 6000 r / min for 8 min, washed with deionized water, and dried at 70 °C. Pre-calcined at 350 °C for 7 h under nitrogen protection, and calcined at 600 °C for 7 h. That is, the lithium cobalt fluorophosphate cathode material coated with antimony tin oxide in situ is obtained; the lithium cobalt fluorophosphate cathode ma...

Embodiment 2

[0029] Accurately weigh 0.04mol of lithium acetate, 0.02mol of cobalt oxalate, 0.02mol of phosphoric acid, and 0.02mol of ammonium fluoride, add them to 15 mL of deionized water, stir for 4 h and mix well, and then transfer them to the reaction kettle. After 10 h, it was cooled to room temperature, moved to a beaker to dry overnight, and ground finely to obtain the precursor of lithium cobalt fluorophosphate. Weigh 1.0 g lithium cobalt fluorophosphate precursor into a beaker, add 25 mL of dispersant (water: ethanol: methanol = 2:2:1), add 0.1470 g tin dichloride and 0.0096 g antimony triiodide while stirring, Slowly drop 7 mL of 1 mol L at 70°C -1 Precipitant (4 mL 1 mol / L sodium hydroxide + 3 mL concentrated ammonia water), aged for 80 min, centrifuged at 6500 r / min for 6 min, washed with deionized water, and dried at 80 °C. Pre-calcined at 300 °C for 6 h under argon protection and calcined at 680 °C for 4 h. That is, the lithium cobalt fluorophosphate cathode material coat...

Embodiment 3

[0031] Accurately weigh 0.02mol lithium hydroxide, 0.02mol cobalt nitrate, 0.02mol diammonium hydrogen phosphate, 0.02mol lithium fluoride, add them to 25 mL of deionized water, stir for 3 h and mix well, then transfer them to the reaction kettle, It was heated with water at 200 °C for 11 h, cooled to room temperature, moved to a beaker to dry overnight, and finely ground to obtain the precursor of lithium cobalt fluorophosphate. Weigh 1.0 g of lithium cobalt fluorophosphate precursor into a beaker, add 10 mL of ethanol, add 0.2130 g of tin sulfate and 0.0097 g of antimony tribromide while stirring, and slowly drop 12 mL of 1 mol / L lithium hydroxide at 70 °C , aged for 30 min, centrifuged at 5000 r / min for 10 min, washed with deionized water, and dried at 60 °C. Under the protection of mixed gas (argon: hydrogen = 8:2), pre-calcination at 300 °C for 7 h and 550 °C for 8 h. That is, an in-situ lithium cobalt fluorophosphate positive electrode material coated with tin and antim...

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