Positive pole active substance, positive pole and battery

A positive electrode active material and a positive electrode technology, applied in the field of positive electrodes and batteries including the positive electrodes, can solve the problems of low electronic conductivity, poor cycle performance, and low specific capacity of batteries

Active Publication Date: 2009-07-08
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the disadvantages of the existing positive electrode active material, such as the low electronic conductivity, the low mass specific capacity and poor cycle performance of the battery made of the positive electrode active material, and provide a battery with high electronic conductivity. The positive electrode active material and the positive electrode comprising the positive electrode active material and the battery comprising the positive electrode, the positive electrode active material can significantly improve the mass specific capacity and cycle performance of the battery

Method used

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  • Positive pole active substance, positive pole and battery
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  • Positive pole active substance, positive pole and battery

Examples

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preparation example Construction

[0033] The preparation method of the positive electrode can adopt various methods commonly used in the art, for example, a positive electrode active material, a binder and a conductive agent optionally contained are prepared into a positive electrode slurry with a solvent, and then the prepared positive electrode slurry is drawn The slurry is coated on the positive electrode current collector, dried and pressed, and then cut into pieces to obtain the positive electrode. The drying temperature may be 100-150° C., and the drying time may be 2-10 hours.

[0034]The solvent used in the positive electrode slurry can be various solvents used in the prior art, such as can be selected from N-methylpyrrolidone (NMP), dimethylformamide (DMF), diethylformamide (DEF) , dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), and one or more of water and alcohols. The amount of the solvent added is well known to those skilled in the art, and can be flexibly adjusted according to the viscosity an...

Embodiment 1

[0046] LiFePO 4 and LiNiO 2 Mix evenly according to the molar ratio of 1:0.02, then add starch as a carbon source according to the content of carbon in the positive electrode active material generated as 5% by weight, ball mill for 10 hours, and mix evenly; After drying, the dried powder was heated up to 600°C at a rate of 10°C / min in an argon atmosphere, and then sintered at a constant temperature for 20 hours to obtain the positive electrode active material LiFePO 4 / LiNiO 2 / C mixed crystals.

[0047] The XRD diffraction pattern of this positive electrode active material measured by the D / MAX-2200 / PC type X-ray powder diffractometer of Rigaku company is as follows figure 1 shown, from figure 1 It can be seen that in the diffraction peaks of the positive active material obtained after sintering, except for LiFePO 4 and LiNiO 2 No new characteristic peaks were found except for the characteristic peaks of the positive electrode active material, thus indicating that the L...

Embodiment 2

[0049] LiFePO 4 and LiCoO 2 Mix evenly according to the molar ratio of 1:0.04, then add acetylene black as carbon source according to the content of carbon in the positive electrode active material generated as 2% by weight, ball mill for 10 hours, and mix evenly; °C drying, and then the dried powder was heated to 500 °C at a heating rate of 5 °C / min in an argon atmosphere, and then sintered at a constant temperature for 30 hours to obtain the positive electrode active material LiFePO 4 / LiCoO 2 / C mixed crystals.

[0050] The XRD diffraction pattern of this positive electrode active material measured by the D / MAX-2200 / PC type X-ray powder diffractometer of Rigaku company is as follows figure 2 shown, from figure 2 It can be seen that in the diffraction peaks of the positive active material obtained after sintering, except for LiFePO 4 and LiCoO 2 No new characteristic peaks were found except for the characteristic peaks of the positive electrode active material, thus ...

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Abstract

The invention provides a positive electrode active substance, a positive electrode containing the positive active substance and a battery including the positive electrode. The positive active substance contains a crystal mixture containing a first crystal and a second crystal, wherein the first crystal is selected from one or more of compounds represented by LixxM'yy (XO4) zz, LiM'XO5, LiM'XO6, and LiM'X2O7, where the ratio of xx to zz is larger than 0 and not larger than 1, and the ratio of yy to zz is larger than 0 and not larger than 1.1; and the second crystal is one or more of compounds represented by LiDcO2, LiiNi(1-d-e)CodMneO2, LiNi(1-f-g) CofAlgO2, LixNi(1-y) CoO2 and LimMn(2-n)EnOj, where D is one element selected from B, Mg, Al, Ti, Cr, Fe, Cu, Zn, Ga, Y, La and V, c is larger than 0 and not larger than 3, i is not less than 0.9 and not larger than 1.2, d is not less than 0 and not larger than 0.5, e is larger than 0 and not larger than 0.3, f is not less than 0 and not larger than 0.5, g is not less than 0 and not larger than 0.3, x is not less than 0.9 and not larger than 1.1, y is not less than 0 and not larger than 1; E is one of B, Mg, Al, Ga and a transition metal except Mn, m is not less than 0.9 and not larger than 1.1, n is not less than 0 and not larger than 1, and j is larger than 1 and less than 6. The positive active substance has an electron conductivity of 0.001 to 10 S/cm at 25 DEG C, and can remarkably improve the specific discharge capacity and the cycle performance of the battery.

Description

technical field [0001] The present invention relates to a positive electrode active material, a positive electrode comprising the positive electrode active material and a battery comprising the positive electrode, in particular to a positive electrode active material of a lithium secondary battery, a positive electrode comprising the positive electrode active material and a battery comprising the positive electrode Battery. Background technique [0002] Lithium secondary batteries using lithium intercalation compounds as positive active materials have been widely used in various portable electronic products and communication tools due to their advantages such as high battery voltage, high specific energy, long cycle life, and small self-discharge. Developed as a clean power source for electric vehicles. [0003] LiCoO is currently used as the positive electrode active material of lithium secondary batteries 2 Due to the advantages of high open circuit voltage, large specif...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/02H01M10/36
CPCY02E60/12Y02E60/10
Inventor 席小兵程堂利田野白璐尹晓丽
Owner BYD CO LTD
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