METHOD FOR PREPARING 3D CARBONITRIDE COATED VSE2 COMPOSITE (3D-VSe2@CN)

Abstract

The disclosure relates to a method for preparing a 3D sponge structured carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN), belonging to the technical fields of electrode materials and preparation of batteries. In the disclosure, carbon, nitrogen and VSe.sub.2 are composited by using NaCl as a template so as to construct a 3D sponge structured carbonitride coated VSe.sub.2 composite. The 3D sponge structure can increase the structure stability of the material in the cyclic process, and the carbocanitride can increase the electron conductivity and activity sites of the material, so as to allow easier diffusion of potassium ions. Meanwhile, the stable structure can cause the clustering of VSe.sub.2 all the time. Thus, the prepared composite has good and stable rate capability and cycle stability. The process method is simple, low in cost, environmental-friendly, and suitable for large-scale industrial production.

Claims

1. A method for preparing a 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN), comprising the following steps: 1) a vanadium oxide and a selenium oxide are weighed and dissolved into water or an organic solvent to be prepared into a solution having a concentration of 0.5˜2 mol/L, and stirring for 0.5 h to obtain a black green solution; 2) an organic acid is added into the salt solution obtained in step 1), and stirring is continued for 0.5 h to obtain a mixed solution; 3) the mixed solution obtained in step 2) is transferred into a Teflon lining high-pressure hydrothermal reactor, and heat preservation is performed for 20˜28 h at 180˜220° C.; 4) after the solution obtained in step 3) is cooled, the cooled solution is subjected to suction filtration and washing with deionized water and absolute ethyl alcohol to obtain a black metallic luster precipitate; 5) the black precipitate obtained in step 4) is dried for 12˜24 h at 80˜100° C. to obtain black powders; 6) the mixed solution is a 10˜20% citric acid/2˜8% melamine mixed aqueous solution, and the temperature is preferably controlled at about 25˜30° C.; 7) the products in step 5) and step 6) are blended and stirred, and the preferred control time is about 1˜2 h; 8) the mass of NaCl added into the blended solution in step 7) is preferably controlled to 5˜20 g, and the stirring time is preferably controlled to 18˜28 h; 9) the drying temperature is preferably controlled at 50˜100° C., and the heat preservation time is preferably controlled to 12˜24 h; and 10) the inert atmosphere is nitrogen, the temperature rising rate is preferably 10˜5° C./min; the first heat preservation temperature is 180˜300° C., and the heat preservation time is 1˜5 h; the second heat preservation temperature is 450˜800° C., and the heat preservation time is 2˜5 h; the 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN) is obtained after naturally cooling to room temperature.

2. The method for preparing a 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN) according to claim 1, wherein in the 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN), the mass percentage of VSe.sub.2 is 70%, and the mass percentage of carbonitride is 30%.

3. The method for preparing a 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN) according to claim 1, wherein in step 1), the vanadium oxide is vanadyl acetylacetonate (VO(acac).sub.2); the selenium oxide is selenium dioxide; the solvent is one of deionzied water and N-methylpyrrolidone;

4. The method for preparing a 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN) according to claim 1, wherein the organic acid in step 2) is formic acid.

5. The method for preparing a 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN) according to claim 1, wherein in step 3), the heat preservation temperature is preferably controlled at 180˜220° C., and the heat preservation time is preferably controlled to 20˜28 h.

6. The method for preparing a 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN) according to claim 1, wherein in step 5), the drying temperature is preferably controlled at 80˜100° C. , and the heat preservation time is preferably controlled to 12˜24 h.

7. The method for preparing a 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN) according to claim 1, wherein in step 6), the mixed solution is blended into 10˜20% citric acid (wt %)/2˜8% melamine mixed aqueous solution (wt %), and the temperature is preferably controlled at about 25˜30° C.

8. The method for preparing a 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN) according to claim 1, wherein in step 7), the blending and stirring time is preferably controlled to about 1˜2 h.

9. The method for preparing a 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN) according to claim 1, wherein in step 8), the mass of NaCl added into the blended solution is preferably controlled to 5˜20 g, and the stirring time is preferably controlled to 18˜28 h.

10. The method for preparing a 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN) according to claim 1, wherein in step 9), the drying temperature is preferably controlled at 50˜100° C., and the heat preservation time is preferably controlled to 12˜24 h.

11. The method for preparing a 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN) according to claim 1, wherein in step 10), the inert atmosphere is nitrogen; the temperature rising rate is preferably 10˜5° C./min; the first heat preservation temperature is preferably 180˜300° C., and the heat preservation time is preferably 1˜5 h; the second heat preservation temperature is preferably 450˜800° C., and the heat preservation time is preferably 2˜5 h; the 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN) is obtained after naturally cooling to the room temperature.

Description

DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 is an XRD (X-ray powder diffraction) pattern obtained by XRD analysis of 3D carbonitride coated VSe.sub.2 and pure VSe.sub.2 prepared in example 1 according to the disclosure, wherein a represents an XRD pattern of a 3D carbonitride coated VSe.sub.2 anode composite (3D-VSe.sub.2@CN) prepared in example 1, and b represents an XRD pattern of a pure layered VSe.sub.2 material prepared in example 1;

[0030] FIG. 2 is an SEM (scanning electron microscope) image of 3D carbonitride coated VSe.sub.2 (3D-VSe.sub.2@CN) prepared in example 1 according to the disclosure;

[0031] FIG. 3 is an SEM image of a pure layered VSe.sub.2 material prepared in example 1 according to the disclosure;

[0032] FIG. 4 is a TEM (transmission electron microscope) image of 3D carbonitride coated VSe.sub.2 (3D-VSe.sub.2@CN) prepared in example 1 according to the disclosure;

[0033] FIG. 5 is a TEM image of a pure layered VSe.sub.2 material prepared in example 1 according to the disclosure;

[0034] FIG. 6 is a charging and discharging cycle performance graph of button batteries respectively made of 3D carbonitride coated VSe.sub.2 (3D-VSe.sub.2@CN) prepared in example 1 and a pure layered VSe.sub.2 material prepared in comparative example 1 under the current density of 100 mAg.sup.−1;

[0035] FIG. 7 is a charging and discharging rate capability graph of button batteries respectively made of 3D carbonitride coated VSe.sub.2 (3D-VSe.sub.2@CN) prepared in example 1 and a pure layered VSe.sub.2 material prepared in comparative example 1 under the current density of 100 mAg.sup.−1;

[0036] FIG. 8 is a charging and discharging long-cycle performance graph of button batteries respectively made of 3D carbonitride coated VSe.sub.2 (3D-VSe.sub.2@CN) prepared in example 1 and a pure layered VSe.sub.2 material prepared in comparative example 1 under the current density of 500 mAg.sup.−1;

[0037] FIG. 9 is a charging and discharging cycle performance graph of a button battery made of 3D carbonitride coated VSe.sub.2 (3D-VSe.sub.2@CN) prepared in example 2 under the current density of 100 mAg.sup.−1;

[0038] FIG. 10 is a charging and discharging cycle performance graph of a button battery made of 3D carbonitride coated VSe.sub.2 (3D-VSe.sub.2@CN) prepared in example 3 under the current density of 100 mAg.sup.−1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0039] Next, the disclosure will be further described by taking a 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) as a specific example. However, the disclosure is not limited to these examples.

EXAMPLE 1

[0040] 1. Vanadyl acetylacetonate (VO(acac).sub.2) and vanadium diselenide were weighed and dissolved into a N-methylpyrrolidone solvent to be prepared into a solution having a concentration of 1 mol/L, and the above solution was stirred for 0.5 h to obtain a black green solution;

[0041] 2. formic acid was added into the salt solution obtained in step 1, and then continued to stir for 0.5 h to obtain a mixed solution;

[0042] 3. the mixed solution obtained in step 2 was transferred into a Teflon lining high-pressure hydrothermal reactor and underwent heat preservation for 24 h at 220° C.;

[0043] 4. when the solution obtained in step 3 was cooled to room temperature, the cooled solution was subjected to suction filtration and washing repeatedly with deionized water and absolute ethyl alcohol to obtain a black metal luster precipitate;

[0044] 5. the black metal luster precipitate obtained in step 4 was dried for 24 h at 80° C. to obtain black powders;

[0045] 6. the mixed solution was 10˜20% citric acid/2˜8% melamine mixed aqueous solution;

[0046] 7. the black powders and the mixed solution in step 5 and step 6 were blended, and stirred for 1˜2 h;

[0047] 8. a certain mass of NaCl was added into the blended solution in step 7, and continuously stirred for 18˜28 h;

[0048] 9. the black mixed solution obtained in step 8 was dried for 12˜24 h at 50˜100° C. to obtain black powders; and

[0049] 10. the black powers obtained in step 9 was heated to 180˜300° C. from 25° C. at 1˜5° C./min under the inert atmosphere and subjected to heat preservation of 1˜5 h, subsequently heated to 450˜800° C. at 1˜5° C./min and subjected to heat preservation of 2˜5 h, and naturally cooled to room temperature to obtain the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN).

[0050] XRD analysis and SEM/TEM analysis were performed on the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) obtained in example 1 and the pure layered VSe.sub.2 material obtained in example 1. It can be seen from XRD patterns that diffraction peaks of a carbon quantum dot/carbon coated VSe.sub.2 composite and the layered VSe.sub.2 material prior to modification are consistent, indicating that the 3D carbonitride coats the material phase structure of the VSe.sub.2 composite anode material (3D-VSe.sub.2@CN). The SEM image of the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) prepared in example 1 is shown in FIG. 2, and the SEM image of the pure layered VSe.sub.2 material used in example 1 is shown in FIG. 3. By comparing FIG. 2 with FIG. 3, it can be seen that after 3D configuration treatment of vanadium diselenide, a series of changes on the microstructure of the material occur. Pore ducts become more abundant and the surface becomes rougher.

[0051] The TEM image of the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) prepared in example 1 is shown in FIG. 4, and the TEM image of the pure layered VSe.sub.2 material used in example 1 is shown in FIG. 5. By comparing FIG. 4 with FIG. 5, it can be seen that after 3D configuration treatment, a large amount of 2˜5 nm carbonitrides are coated on the layered VSe.sub.2 material, indicating that carbonitrides are successfully coated on the VSe.sub.2 material.

[0052] The 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) prepared in example 1, acetylene black and binder PVDF were dissolved into N-methylpyrrolidone in a ratio of 7.5:1.5:1.5 and stirred. The obtained slurry was applied to copper foil and dried in vacuum for 12 h to obtain a cathode pole. Then, battery assembly was performed in a glove box filled with argon, a cathode is the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN), an anode is a potassium piece, a diaphragm is glass fiber, the electrolyte was 0.8M KPF.sub.6 in EC:DEC (1:1). The electrochemical performance test is performed on the assembled button battery.

[0053] FIG. 6 is a charging and discharging cycle performance graph of button batteries respectively made of the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) in example 1 and the pure layered VSe.sub.2 material prepared in comparative example 1 under the current density of 100 mAg.sup.−1. It can be seen from FIG. 6 that the capacity of the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) in example 1 after 100 cycles is 298 mAhg.sup.−1, however, the capacity of the pure layered VSe.sub.2 material after 100 cycles is only 198 mAhg.sup.−1. It can be seen from the above result that after the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) is adopted, the reversible capacity and cycle stability of the material can be effectively improved.

[0054] FIG. 7 is a charging and discharging rate capability graph of button batteries respectively made of 3D carbonitride coated VSe.sub.2 (3D-VSe.sub.2@CN) prepared in example 1 and a pure phase layered VSe.sub.2 material prepared in comparative example 1 under the current density of 100˜1000 mAg.sup.−1. It can be seen from FIG. 7 that the reversible capacities of the carbon quantum dot/carbon coated VSe.sub.2 composite (VSe.sub.2@CQD) prepared in example 1 under the current densities of 100, 200, 300, 500 and 1000 mAg.sup.−1 are 501.2, 390.2, 290, 210 100.2 mAhg.sup.−1. However, the capacities of the pure layered VSe.sub.2 material under the same rate capability current densities are 300, 228.9, 190.2, 98.8 and 47.8 mAhg.sup.−1. It can be seen from the above result that after the 3D carbonitride coated VSe.sub.2 (3D-VSe.sub.2@CN) is adopted, the capacity of the material under the large current density can be effectively improved.

[0055] FIG. 8 is a charging and discharging long-cycle performance graph of button batteries respectively made of 3D carbonitride coated VSe.sub.2 (3D-VSe.sub.2@CN) prepared in example 1 and a pure layered VSe.sub.2 material prepared in comparative example 1 under the current density of 500 mAg.sup.−1. It can be seen from FIG. 8 that the capacity of the 3D carbonitride coated VSe.sub.2 composite (3D-VSe.sub.2@CN) prepared in example 1 after 1000 cycles is maintained at 98.3 mAhg.sup.−1. Consequently, after the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) is adopted, the long-cycle stability and structure stability of the material can be effectively improved.

EXAMPLE 2

[0056] 1. Vanadyl acetylacetonate (VO(acac).sub.2) and vanadium diselenide were weighed and dissolved into a N-methylpyrrolidone solvent to be prepared into a solution having a concentration of 1.5 mol/L, and the above solution was stirred for 0.5 h to obtain a black green solution;

[0057] 2. formic acid was added into the salt solution obtained in step 1, and then further stirred for 0.5 h to obtain a mixed solution;

[0058] 3. the mixed solution obtained in step 2 was transferred into a Teflon lining high-pressure hydrothermal reactor and underwent heat preservation for 24 h at 200° C.;

[0059] 4. when the solution obtained in step 3 was cooled to room temperature, the cooled solution was subjected to suction filtration and washing repeatedly with deionized water and absolute ethyl alcohol to obtain a black metal luster precipitate;

[0060] 5. the black metal luster precipitate obtained in step 4 was dried for 24 h at 80° C. to obtain black powders;

[0061] 6. the mixed solution was 15% citric acid/3% melamine mixed aqueous solution;

[0062] 7. the black powders and the mixed solution in step 5 and step 6 were blended, and stirred for 1˜2 h;

[0063] 8. a certain mass of NaCl was added into the blended solution in step 7, and continuously stirred for 18˜28 h;

[0064] 9. the black mixed solution obtained in step 8 was dried for 12˜24 h at 50˜100° C. to obtain black powders; and

[0065] 10. the black powers obtained in step 9 was heated to 180˜300° C. from 25° C. at 1˜5° C./min under the inert atmosphere and subjected to heat preservation of 1˜5 h, subsequently heated to 450˜800° C. at 1˜5° C./min and subjected to heat preservation of 2˜5 h, and naturally cooled to room temperature to obtain the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2CN).

[0066] The 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) prepared in example 2, acetylene black and binder PVDF were dissolved into N-methylpyrrolidone in a ratio of 7.5:1.5:1.5 and stirred. The obtained slurry was applied to copper foil and dried in vacuum for 12 h to obtain a cathode pole. Then, battery assembly was performed in a glove box filled with argon, a cathode is the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN), an anode is a potassium piece, a diaphragm is glass fiber, and the electrolyte was 0.8M KPF.sub.6. The electrochemical performance test was performed between 0.01 V and 3.0V at 25° C., and the result indicates that the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) prepared in example 2 has excellent rate capability and cycle stability.

EXAMPLE 3

[0067] 1. Vanadyl acetylacetonate (VO(acac).sub.2) and vanadium diselenide were weighed and dissolved into a N-methylpyrrolidone solvent to be prepared into a solution having a concentration of 1.2 mol/L, and the above solution was stirred for 0.5 h to obtain a black green solution;

[0068] 2. formic acid was added into the salt solution obtained in step 1, then further stirred for 0.5 h to obtain a mixed solution;

[0069] 3. the mixed solution obtained in step 2 was transferred into a Teflon lining high-pressure hydrothermal reactor to undergo heat preservation for 24 h at 200° C.;

[0070] 4. when the solution obtained in step 3 was cooled to room temperature, the cooled solution was subjected to suction filtration and washing repeatedly with deionized water and absolute ethyl alcohol to obtain a black metal luster precipitate;

[0071] 5. the black metal luster precipitate obtained in step 4 was dried for 24 h at 80° C. to obtain black powders;

[0072] 6. the mixed solution was 15% citric acid/5% melamine mixed aqueous solution;

[0073] 7. the black powders and the mixed solution in step 5 and step 6 were blended, and stirred for 1˜2 h;

[0074] 8. a certain mass of NaCl was added into the blended solution in step 7, and continuously stirred for 18˜28 h;

[0075] 9. the black mixed solution obtained in step 8 was dried for 12˜24 h at 50˜100° C. to obtain black powders; and

[0076] 10. the black powers obtained in step 9 was heated to 180˜300° C. from 25° C. at 1˜5° C./min under the inert atmosphere and subjected to heat preservation of 1˜5 h, subsequently heated to 450˜800° C. at 1˜5° C./min and heat preservation of 2˜5 h, and naturally cooled to room temperature to obtain the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN).

[0077] The 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) prepared in example 3, acetylene black and binder PVDF were dissolved into N-methylpyrrolidone in a ratio of 7.5:1.5:1.5 and stirred. The obtained slurry was applied to copper foil and dried in vacuum for 12 h to obtain a cathode pole. Then, battery assembly was performed in a glove box filled with argon, a cathode is the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN), an anode is a potassium piece, a diaphragm is glass fiber, and the electrolyte was 0.8M KPF.sub.6. The electrochemical performance test was performed between 0.01 V and 3.0V at 25° C., and the result indicates that the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) prepared in example 3 has excellent rate capability and cycle stability.

EXAMPLE 4

[0078] 1. Vanadyl acetylacetonate (VO(acac).sub.2) and vanadium diselenide were weighed and dissolved into a N-methylpyrrolidone solvent to be prepared into a solution having a concentration of 1 mol/L, and the above solution was stirred for 0.5 h to obtain a black green solution;

[0079] 2. formic acid was added into the salt solution obtained in step 1, and then further stirred for 0.5 h to obtain a mixed solution;

[0080] 3. the mixed solution obtained in step 2 was transferred into a Teflon lining high-pressure hydrothermal reactor to undergo heat preservation for 24 h at 180° C.;

[0081] 4. when the solution obtained in step 3 was cooled to room temperature, the cooled solution was subjected to suction filtration and washing repeatedly with deionized water and absolute ethyl alcohol to obtain a black metal luster precipitate;

[0082] 5. the black metal luster precipitate obtained in step 4 was dried for 24 h at 80° C. to obtain black powders;

[0083] 6. the mixed solution was 20% citric acid/5% melamine mixed aqueous solution;

[0084] 7. the black powders and the mixed solution in step 5 and step 6 were blended, and stirred for 1˜2 h;

[0085] 8. a certain mass of NaCl was added into the blended solution in step 7, and continuously stirred for 18˜28 h;

[0086] 9. the black mixed solution obtained in step 8 was dried for 12˜24 h at 50˜100° C. to obtain black powders; and

[0087] 10. the black powers obtained in step 9 was heated to 180˜300° C. from 25° C. at 1˜5° C./min under the inert atmosphere and subjected to heat preservation of 1˜5 h, subsequently heated to 450˜800° C. at 1˜5° C./min and subjected to heat preservation of 2˜5 h, and naturally cooled to room temperature to obtain the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN).

[0088] The 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) prepared in example 4, acetylene black and binder PVDF were dissolved into N-methylpyrrolidone in a ratio of 7.5:1.5:1.5 and stirred. The obtained slurry was applied to copper foil and dried in vacuum for 12 h to obtain a cathode pole. Then, battery assembly was performed in a glove box filled with argon, a cathode is the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN), an anode is a potassium piece, a diaphragm is glass fiber, and the electrolyte was 0.8M KPF.sub.6. The electrochemical performance test was performed between 0.01 V and 3.0V at 25° C. , and the result indicates that the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) prepared in example 4 has excellent rate capability and cycle stability.

EXAMPLE 5

[0089] 1. Vanadyl acetylacetonate (VO(acac).sub.2) and vanadium diselenide were weighed and dissolved into a N-methylpyrrolidone solvent to be prepared into a solution having a concentration of 1 mol/L, and the above solution was stirred for 0.5 h to obtain a black green solution;

[0090] 2. formic acid was added into the salt solution obtained in step 1, and then continued to stir for 0.5 h to obtain a mixed solution;

[0091] 3. the mixed solution obtained in step 2 was transferred into a Teflon lining high-pressure hydrothermal reactor to undergo heat preservation for 24 h at 200° C.;

[0092] 4. when the solution obtained in step 3 was cooled to room temperature, the cooled solution was subjected to suction filtration and washing repeatedly with deionized water and absolute ethyl alcohol to obtain a black metal luster precipitate;

[0093] 5. the black metal luster precipitate obtained in step 4 was dried for 24 h at 80° C. to obtain black powders;

[0094] 6. the mixed solution was 10˜20% citric acid/2˜8% melamine mixed aqueous solution;

[0095] 7. the black powders and the mixed solution in step 5 and step 6 were blended, and stirred for 1˜2 h;

[0096] 8. a certain mass of NaCl was added into the blended solution in step 7, and continuously stirred for 18˜28 h;

[0097] 9. the black mixed solution obtained in step 8 was dried for 12˜24 h at 50˜100° C. to obtain black powders; and

[0098] 10. the black powers obtained in step 9 was heated to 180˜300° C. from 25° C. at 1˜5° C./min under the inert atmosphere and subjected to heat preservation of 1˜5 h, subsequently heated to 450˜800° C. at 1˜5° C./min and subjected to heat preservation of 2˜5 h, and naturally cooled to room temperature to obtain the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2CN).

[0099] The 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) prepared in example 5, acetylene black and binder PVDF were dissolved into N-methylpyrrolidone in a ratio of 7.5:1.5:1.5 and stirred. The obtained slurry was applied to copper foil and dried in vacuum for 12 h to obtain a cathode pole. Then, battery assembly was performed in a glove box filled with argon, a cathode is the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN), an anode is a potassium piece, a diaphragm is glass fiber, the electrolyte was 0.8M KPF.sub.6. The electrochemical performance test was performed between 0.01 V and 3.0V at 25° C. , and the result indicates that the 3D carbonitride coated VSe.sub.2 composite anode material (3D-VSe.sub.2@CN) prepared in example 5 has excellent rate capability and cycle stability.