MODIFIED SUPER-HYDROPHOBIC MATERIAL-COATED HIGH-NICKEL CATHODE MATERIAL FOR LITHIUM ION BATTERY AND PREPARATION METHOD THEREFOR

Abstract

A modified super-hydrophobic material-coated high-nickel cathode material for a lithium ion battery and a preparation method therefor. The surface of the high-nickel cathode material for a lithium ion battery is coated with a modified super-hydrophobic material, and particles are bridged with each other by the modified super-hydrophobic material. The modified super-hydrophobic material is obtained by depositing a nano material on the surface of a super-hydrophobic material. By the surface modification of the super-hydrophobic material, the hydrophobic and electrolyte-philic properties and the conductivity of the super-hydrophobic material are improved. Next the modified super-hydrophobic material is coated on the surface of the particles of the high-nickel cathode material for a lithium ion battery and between the particles, in the form of a three dimensional network. Thus the surface hydrophobic conductive treatment of the high-nickel cathode material is effectively realized; reducing the reaction of environmental water with surface free lithium and side reactions of trace water and an electrolyte, and improving the safety, cycle and storage performance of the high-nickel cathode material for a lithium ion battery in batteries.

Claims

1-11. (canceled)

12. A high-nickel cathode material for a lithium ion battery, wherein the surface of the high-nickel cathode material for a lithium ion battery is coated with a modified super-hydrophobic material, and particles are bridged by the modified super-hydrophobic material.

13. The high-nickel cathode material for a lithium ion battery of claim 12, wherein the modified super-hydrophobic material is a super-hydrophobic material with nano-material deposited on its surface.

14. The high-nickel cathode material for a lithium ion battery of claim 13, wherein the mass ratio of the super-hydrophobic material to the nano-material is 100:(0.01-50).

15. The high-nickel cathode material for a lithium ion battery of claim 13, wherein the super-hydrophobic material is any one selected from the group consisting of super-hydrophobic conductive polymer nanofiber, super-hydrophobic carbon nanotube array film, super-hydrophobic polyacrylonitrile nanofiber, super-hydrophobic carbon fiber film, conductive porous aerogel, and a mixture of at least two of them.

16. The high-nickel cathode material for a lithium ion battery of claim 13, wherein the nano-material is a nano-powder material; the nano-powder material is any one selected from the group consisting of nano-alumina, nano-titania, nano-magnesia, nano-zirconia, nano-zinc oxide, and a mixture of at least two of them.

17. The high-nickel cathode material for a lithium ion battery of claim 16, wherein the nano-powder material has a median particle diameter of 10-200 nm.

18. The high-nickel cathode material for a lithium ion battery of claim 12, wherein the high-nickel cathode material is any one selected from the group consisting of lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt oxide, and a mixture of at least two of them.

19. The high-nickel cathode material for a lithium ion battery of claim 18, wherein the high-nickel cathode material is a surface-coated high-nickel cathode material and/or a doped high-nickel cathode material.

20. The high-nickel cathode material for a lithium ion battery of claim 19, wherein the coating layer of the surface-coated high-nickel cathode material is any one selected from the group consisting of alumina, titania, magnesia, zirconia, and a mixture of at least two of them.

21. The high-nickel cathode material for a lithium ion battery of claim 19, wherein the doping element in the doped high-nickel cathode material is any one selected from the group consisting of sodium, aluminum, magnesium, titanium, vanadium, fluorine, and a mixture of at least two of them.

22. A method for preparing the high-nickel cathode material for a lithium ion battery of claim 12, comprising the following steps: (1) adding a high-nickel cathode material for a lithium ion battery and a modified super-hydrophobic material into a reaction kettle; (2) uniformly dispersing the modified super-hydrophobic material and the high-nickel cathode material for a lithium ion battery in an ethanol solution; (3) carrying out solid-liquid separation to the suspension obtained in step (2) and carrying out heat treatment to obtain a modified super-hydrophobic material-coated high-nickel cathode material for a lithium ion battery.

23. The method of claim 22, wherein the mass ratio of the high-nickel cathode material for a lithium ion battery to the modified super-hydrophobic material in step (1) is 100:(0.01-5).

24. The method of claim 22, wherein the modified super-hydrophobic material is obtained by depositing nano-material on the surface of super-hydrophobic material.

25. The method of claim 24, wherein the deposition is any one selected from the group consisting of vapor phase deposition, liquid phase deposition, electrochemical deposition, and a combination of at least two of them.

26. The method of claim 22, wherein the dispersion in step (2) is any one selected from the group consisting of ultrasonic dispersion, mechanical stirring, spray dispersion, and a combination of at least two of them.

27. The method of claim 22, wherein the solid-liquid separation method in step (3) is any one selected from the group consisting of suction filtration, spray drying, stewing, centrifugal separation, and a combination of at least two of them.

28. The method of claim 22, wherein the temperature for heat treatment in step (3) is 120-600 C.; the time for heat treatment is 4-24 h.

29. The method of claim 22, wherein the method comprises the following steps: (1) depositing a nano-material with a median particle size of 10-200 nm on the surface of a super-hydrophobic material to obtain a modified super-hydrophobic material, wherein the mass ratio of the super-hydrophobic material to the nano-material is 100:(0.01-50); (2) adding a high-nickel cathode material for a lithium ion battery and the modified super-hydrophobic material into a reaction kettle, wherein the mass ratio of the high-nickel cathode material for a lithium ion battery to the modified super-hydrophobic material is 100:(0.01-5); (3) ultrasonically dispersing the modified super-hydrophobic material into the high-nickel cathode material for a lithium ion battery; (4) centrifuging and separating the suspension obtained in step (2), and drying to obtain a modified super-hydrophobic material-coated high-nickel cathode material for a lithium ion battery.

30. A lithium ion battery, comprising the high-nickel cathode material for a lithium ion battery of claim 12.

Description

DESCRIPTION OF THE DRAWINGS

[0049] FIG. 1 shows a sectional view of the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material according to Example 1 of the present invention;

[0050] FIG. 2 shows XRD patterns of the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material and the LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material according to Example 1 of the present invention;

[0051] FIG. 3 shows first charge and discharge curves of the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material and the LiNi.sub.a6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material according to Example 1 of the present invention;

[0052] FIG. 4 shows cycle performance curves of the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material and the LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material according to Example 1 of the present invention;

[0053] FIG. 5 shows storage performance curves of the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material and the LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material according to Example 1 of the present invention;

[0054] FIG. 6 shows liquid absorption performance curves of the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material and the LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material according to Example 1 of the present invention.

[0055] In the figures: 1cathode material, 2super-hydrophobic carbon nanotubes, 3nano-titania, Amodified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, Bsuper-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, Cuncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material, DLiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material.

EMBODIMENTS

[0056] In order to facilitate the understanding of the present invention, examples of the present invention are listed in the following. It should be understood by those skilled in the art that the examples are merely used to help understand the present invention, and should not be construed as specifical limitations to the present invention.

Example 1

[0057] Dibutyl phthalate in a liquid form was gasified and then introduced by N.sub.2 carrier gas into a vapor phase deposition reactor charged with super-hydrophobic carbon nanotubes. The mass ratio of nano-titania to super-hydrophobic carbon nanotube array film was controlled to be 0.05:100, so that the resulting nano-titania (TiO.sub.2) was uniformly deposited on the surface of the super-hydrophobic carbon nanotube array film, to obtain modified super-hydrophobic carbon nanotubes.

[0058] The modified super-hydrophobic carbon nanotubes and LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 electrode material powder having a particle size of 7-60 m, and super-hydrophobic carbon nanotubes and LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 electrode material having a particle size of 7-60 m were dispersed in ethanol solution in a mass ratio of 0.25:100 respectively and mechanically stirred for 1 h, while LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 electrode material powder was dispersed in ethanol solution and mechanically stirred for 1 h. Then the above three samples were stewed at 200 C. until ethanol solution was completely removed, then solid materials were dried at 400 C. for 12 h to obtain a modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, a super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material and an uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material.

[0059] Uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material is a control experiment, which eliminates that the reasons for improvement is the treatment process and proves that it is coating which improves the properties of cathode material.

[0060] Storage performance test: 3-5 g of cathode material sample was weighted in a laboratory room with constant temperature (25 C.) and constant humidity (80% relative humidity) by a 1/10000 balance scale and placed in a weighing bottle which is exposed to air. The sample was weighted once every day until the mass of the sample did not change. Then the sample was weighted once every half a month. The change of the mass of the sample was expressed as weight gain rate. The lower the weight gain rate is, the better the storage performance of the cathode material is.

[0061] Liquid absorption performance test of pole pieces: 10 L of electrolyte was dropped on the surface of the produced cathode pole pieces, and the time required for complete absorption of liquid by cathode pole pieces is the liquid absorption time. The less the liquid absorption time is, the better the electrolyte-philic property of the cathode material is.

[0062] FIG. 1 shows a sectional view of the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material according to this example. FIGS. 2, 3, 4, 5, and 6 are respectively XRD patterns, first charge and discharge curves, cycle performance curves, storage performance curves and liquid absorption performance curves of the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material and the LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material according to this example.

[0063] In FIG. 1, nano-titania is deposited on the surface of the super-hydrophobic carbon nanotubes to form a nano-scale roughness. The surface of the high-nickel cathode material for a lithium ion battery is coated with the modified super-hydrophobic carbon nanotubes, and the particles of the high-nickel cathode material for a lithium ion battery are bridged with each other by super-hydrophobic carbon nanotubes.

[0064] As can be seen from FIG. 2, all the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material and LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material have diffraction peaks of LiNi.sub.a6Co.sub.0.2Mn.sub.0.2O.sub.2.

[0065] As can be seen from FIG. 3, all the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material and LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material have higher first specific discharge capacity.

[0066] As can be seen from FIG. 4, the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material and the LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material have a capacity retention after 40 cycles at 1C rate of 97.2%, 94.4%, 90.6% and 91.8% respectively. This demonstrates that the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material has the best cycle performance, the super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material has the second best cycle performance, and the uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material has a cycle performance which is comparable to that of LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material.

[0067] As can be seen from FIG. 5, the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material and LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material have a weight gain rate after storage for 60 days under environment having a relative humidity of 80% of 0.155 wt %, 0.39 wt %, 1.525 wt % and 1.685 wt %, respectively. This demonstrates that the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material has an improved storage performance.

[0068] As can be seen from FIG. 6, the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material, the uncoated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material and the LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 cathode material have a liquid absorption time of 2.2 min, 2.6 min, 4.2 min and 4.5 min, respectively. This demonstrates that the modified super-hydrophobic carbon nanotubes-coated LiNi.sub.0.6Co.sub.0.2Mn.sub.0.2O.sub.2 composite cathode material has a better electrolyte-philic property compared to the LiNi.sub.0.6Co.sub.a2Mn.sub.0.2O.sub.2 cathode material.

Example 2

[0069] 0.01 g of nano-zirconia having a particle size of 30 nm-100 nm was added to an ethanol dispersion of 100 g of super-hydrophobic carbon fiber film, and the mixture was strong mechanically stirred for 1.5 h, so that nano-zirconia was fully distributed on the surface of the super-hydrophobic carbon fiber film to obtain a nano-zirconia modified super-hydrophobic carbon fiber film material. 0.5 g of LiNi.sub.0.815Co.sub.0.15Al.sub.0.035O.sub.2 electrode material powder having a particle size of 3-50 m was dispersed in 20 mL of 10% modified super-hydrophobic carbon fiber film material dispersion and dispersed by ultrasonic wave for 1 hour to make the modified super-hydrophobic carbon fiber film uniformly coated on the surface of the electrode material. After separation by centrifugation, the solid was dried at 200 C. for 12 h to obtain a modified super-hydrophobic carbon fiber film-coated LiNi.sub.0.815Co.sub.0.15Al.sub.0.035O.sub.2 cathode material.

Example 3

[0070] 0.01 g of nano-MgO having a particle size of 30 nm-100 nm was added to an ethanol dispersion of 100 g of super-hydrophobic polyacrylonitrile nanofibers, and the mixture was subjected to ultrasonic dispersion for 30 min and then was stewed at 200 C. under mechanical stirring until ethanol was completely removed to obtain a nano-MgO surface modified super-hydrophobic polyacrylonitrile nanofibers. The above modified super-hydrophobic polyacrylonitrile nanofibers and LiNi.sub.0.8Co.sub.0.1Mn.sub.0.1O.sub.2 electrode material powder having a particle size of 10-100 m were dispersed into ethanol solution in a mass ratio of 0.25:100, and the mixture was mechanically stirred for 30 min, and then spray dried to obtain a modified super-hydrophobic polyacrylonitrile nanofibers-coated LiNi.sub.0.8Co.sub.0.1Mn.sub.0.1O.sub.2 electrode material. Then the electrode material was dried at 200 C. for 24 h to obtain a modified super-hydrophobic polyacrylonitrile nanofibers-coated LiNi.sub.0.8Co.sub.0.1Mn.sub.0.1O.sub.2 cathode material for a lithium ion battery having appropriate water content and specific surface area.

Example 4

[0071] 0.01 g of nano-zirconia having a particle size of 40 nm-100 nm and 0.05 g of nano-titania having a particle size of 30-50 nm were added to a dispersion of 100 g of super-hydrophobic carbon nanotube array film, and the mixture was strong mechanically stirred for 1 h, so that nano-zirconia and nano-titania were fully distributed on the surface of the super-hydrophobic carbon nanotube array film to obtain a nano-zirconia and nano-titania modified super-hydrophobic carbon nanotube array film material. 0.5 g of LiNi.sub.0.815Co.sub.0.15Al.sub.0.035O.sub.2 electrode material powder having a particle size of 3-50 m was dispersed in 20 mL of 10% modified super-hydrophobic carbon nanotube array film dispersion and dispersed by ultrasonic wave for 1 hour to make the modified super-hydrophobic carbon nanotube array film uniformly coated on the surface of the electrode material. After separation by centrifugation, the solid was dried at 200 C. for 4 h to obtain a modified super-hydrophobic carbon nanotube array film-coated LiNi.sub.0.815Co.sub.0.15Al.sub.0.035O.sub.2 cathode material.

Example 5

[0072] 0.02 g of nano-zirconia having a particle size of 80 nm-100 nm, 0.25 g of nano-titania having a particle size of 60-80 nm and 0.01 g of nano-magnesia having a particle size of 60-100 nm were added to a dispersion of 100 g of super-hydrophobic carbon nanotube array film, and the mixture was strong mechanically stirred for 1.5 h, so that nano-zirconia, nano-titania and nano-magnesia were fully distributed on the surface of the super-hydrophobic carbon nanotube array film to obtain a nano-zirconia, nano-titania and nano-magnesia modified super-hydrophobic carbon nanotube array film material. 0.5 g of LiNi.sub.0.815Co.sub.0.15Al.sub.0.035O.sub.2 electrode material powder having a particle size of 3-50 m was dispersed in 20 mL of 10% modified super-hydrophobic carbon nanotube array film dispersion and dispersed by ultrasonic wave for 1 hour to make the modified super-hydrophobic carbon nanotube array film uniformly coated on the surface of the electrode material. After separation by centrifugation, the solid was dried at 200 C. for 4 h to obtain a modified super-hydrophobic carbon nanotube array film-coated LiNi.sub.0.815Co.sub.0.15Al.sub.0.035O.sub.2 cathode material.

Example 6

[0073] 0.02 g of nano-magnesia having a particle size of 40-100 nm and 0.1 g of nano-titania having a particle size of 30-100 nm were added to a dispersion of 50 g of super-hydrophobic carbon nanotube array film and 50 g of super-hydrophobic carbon fiber film, and the mixture was strong mechanically stirred for 1 h, so that nano-magnesia and nano-titania were fully distributed on the surface of the super-hydrophobic carbon nanotube array film and super-hydrophobic carbon fiber film to obtain a nano-magnesia and nano-titania modified super-hydrophobic carbon nanotube array film and super-hydrophobic carbon fiber film material. 0.5 g of LiNi.sub.0.815Co.sub.0.15Al.sub.0.035O.sub.2 electrode material powder having a particle size of 3-50 m was dispersed in 20 mL of 10% modified super-hydrophobic carbon nanotube array film and super-hydrophobic carbon fiber film dispersion and dispersed by ultrasonic wave for 1 hour to make the modified super-hydrophobic carbon nanotube array film and super-hydrophobic carbon fiber film uniformly coated on the surface of the electrode material. After separation by centrifugation, the solid was dried at 400 C. for 8 h to obtain a modified super-hydrophobic carbon nanotube array film and super-hydrophobic carbon fiber film-coated LiNi.sub.0.815Co.sub.0.15Al.sub.0.035O.sub.2 cathode material.

Example 7

[0074] 10 g of nano-MgO having a particle size of 60 nm-150 nm was added to an ethanol dispersion of 60 g of super-hydrophobic polyacrylonitrile nanofibers and 40 g of super-hydrophobic conductive polymer nanofibers, and the mixture was subjected to ultrasonic dispersion for 30 min and then was stewed at 200 C. under mechanical stirring until ethanol was completely removed to obtain a nano-MgO surface modified super-hydrophobic polyacrylonitrile nanofibers and super-hydrophobic conductive polymer nanofibers. The above modified super-hydrophobic polyacrylonitrile nanofibers and super-hydrophobic conductive polymer nanofibers and LiNi.sub.0.8Co.sub.0.1Mn.sub.0.1O.sub.2 electrode material powder having a particle size of 10-100 m were dispersed into ethanol solution in a mass ratio of 0.25:100, and the mixture was mechanically stirred for 30 min, and then spray dried to obtain a modified super-hydrophobic polyacrylonitrile nanofibers and super-hydrophobic conductive polymer nanofibers-coated LiNi.sub.0.8Co.sub.0.1Mn.sub.0.1O.sub.2 electrode material. Then the electrode material was dried at 300 C. for 12 h to obtain a modified super-hydrophobic polyacrylonitrile nanofibers and super-hydrophobic conductive polymer nanofibers-coated LiNi.sub.0.8Co.sub.0.1Mn.sub.0.1O.sub.2 cathode material for a lithium ion battery having appropriate water content and specific surface area.

[0075] The applicant states that: the present invention illustrates the detailed method of the present invention by the above examples, but the present invention is not limited to the above detailed method, that is to say, it does not mean that the present invention must be conducted relying on the above detailed method. Those skilled in the art should understand that any modifications to the present invention, any equivalent replacements of each raw material of the products of the present invention and the additions of auxiliary ingredients, the selections of specific embodiments and the like all fall into the protection scope and the disclosure scope of the present invention.