Sheet-shaped nitrogen-phosphorus co-doped porous carbon material and method for preparation thereof and use thereof

Abstract

Provided is a sheet-shaped nitrogen-phosphorus co-doped porous carbon material, prepared and obtained according to the following method: mixing aniline and hexachlorocyclotriphosphazene, undergoing a closed reaction for 2-24 h at a pressure of 1-10 MPa and a temperature of 140-260 C., then pressure is released to atmospheric pressure and steam drying is performed to obtain a solid substance; under inert gas protection, the obtained solid substance is treated for 1-6 h at a high temperature of 400-1000 C., and the finished product is obtained; the sheet-shaped nitrogen-phosphorus co-doped porous carbon material thus provided has excellent electrical properties and may be used for fabricating capacitor electrodes and especially supercapacitor electrodes; thus it may be used in capacitors and especially supercapacitors, and has great application potential and industrial value in the field of energy storage.

Claims

1. A sheet-shaped nitrogen-phosphorus co-doped porous carbon material, wherein prepared and obtained according to the following method: (1) mixing aniline and hexachlorocyclotriphosphazene, undergoing a closed reaction for 2-24 h at a pressure of 1-10 MPa and a temperature of 140-260 C., then pressure is released to atmospheric pressure and steam drying is performed to obtain a solid substance; the volume of the aniline is 3-300 mL/g by the mass of the hexachlorocyclotriphosphazene; (2) under inert gas protection, the obtained solid substance in step (1) is treated for 1-6 h at a high temperature of 400-1000, and the sheet-shaped nitrogen-phosphorus co-doped porous carbon material is obtained.

2. The sheet-shaped nitrogen-phosphorus co-doped porous carbon material of claim 1, wherein the volume of the aniline in step (1) is 10-200 mL/g by the mass of the hexachlorocyclotriphosphazene.

3. The sheet-shaped nitrogen-phosphorus co-doped porous carbon material of claim 1, wherein the reaction pressure in step (1) is 1-3 MPa.

4. The sheet-shaped nitrogen-phosphorus co-doped porous carbon material of claim 1, wherein the reaction temperature in step (1) is 180-220 C.

5. The sheet-shaped nitrogen-phosphorus co-doped porous carbon material of claim 1, wherein the reaction time is 2-10 h.

6. The sheet-shaped nitrogen-phosphorus co-doped porous carbon material of claim 1, wherein the temperature of the high-temperature treatment in step (2) is 800-1000 C.

7. The sheet-shaped nitrogen-phosphorus co-doped porous carbon material of claim 1, wherein the time of the high-temperature treatment in step (2) is 2-5 h.

8. A capacitor electrode or supercapacitor electrode formed by the method comprising using the sheet-shaped nitrogen-phosphorus co-doped porous carbon material of claim 1.

9. The capacitor electrode of claim 8, wherein the capacitor electrodes is prepared and obtained according to the following method: mixing the sheet-shaped nitrogen-phosphorus co-doped porous carbon material, acetylene black, PTFE emulsion and nitromethylpyrrolidone uniformly, stirring to starchiness and coating on the foamed nickel, the coating amount is 1-8 mg/cm.sup.2, and then desiccating, drying and preforming the coated foamed nickel to obtain capacitor electrodes; the mass ratio of the sheet-shaped nitrogen-phosphorus co-doped porous carbon material, acetylene black and PTFE emulsion is 80:10:10.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Description of the Drawings

(1) FIG. 1: a scanning electron microscope (SEM) diagram showing the sheet-shaped nitrogen-phosphorus co-doped porous carbon materials obtained in Embodiment 1;

(2) FIG. 2: a XRD diagram showing the sheet-shaped nitrogen-phosphorus co-doped porous carbon materials obtained in Embodiment 1;

(3) FIG. 3: a XPS diagram showing the sheet-shaped nitrogen-phosphorus co-doped porous carbon materials obtained in Embodiment 1;

(4) FIG. 4: the cyclic voltammograms showing the capacitor electrodes obtained in Embodiment 11 at different scan rates, wherein (a) is cyclic voltammogram at a scan rate of 1-100 mv/s, and (b) is cyclic voltammogram at a scan rate of 200-2000 mv/s;

(5) FIG. 5: the constant-current charge-discharge diagrams showing the capacitor electrodes obtained in Embodiment 11 at different current densities, wherein (a) is constant-current charge-discharge diagram with a current density of 0.5 to 5 Ag.sup.1, and (b) is constant-current charge-discharge diagram with a current density of 1080 Ag.sup.1;

(6) FIG. 6: a diagram showing the cycle stability of the capacitor electrodes obtained in Embodiment 11 at different current densities;

(7) FIG. 7: a Ragone plot showing the cycle stability of the capacitor electrodes obtained in Embodiment 11 at different current densities.

THE PREFERRED EMBODIMENTS OF THE INVENTION

Description of the Preferred Embodiments

(8) (1) mixing 30 ml of aniline and 0.17 g of hexachlorocyclotriphosphazene, undergoing a closed reaction for 5 h at a pressure of 2 MPa and a temperature of 200 C., then pressure is released to atmospheric pressure and steam vaporizing and eliminating extra aniline to obtain a solid substance;

(9) (2) under inert nitrogen protection, the obtained solid substance in step (1) is treated for 2 h at a high temperature of 900 C., and the sheet-shaped nitrogen-phosphorus co-doped porous carbon material is obtained.

(10) Weighing 30 mg of the sheet-shaped nitrogen-phosphorus co-doped porous carbon materials, 0.375 mg of acetylene black and 0.375 mg of PTFE (polytetrafluoroethylene) emulsion (Purchased from Shanghai Aladdin Reagent Co., Ltd.) prepared in Embodiment 1, the mass ratio thereof is 80:10:10, adding 2 g of nitromethylpyrrolidone and mixing uniformly, stirring to starchiness and coating on the foamed nickel (size 11 cm) at a coating amount of 3 mg/cm.sup.2, and then desiccating, drying and preforming the coated foamed nickel to obtain capacitor electrodes.

(11) The properties of the sheet-shaped nitrogen-phosphorus co-doped porous carbon materials and the capacitor electrodes obtained in the above embodiment are characterized as follows, thereby demonstrating that the treatment temperature in the step (2) was preferably at 900 C.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the Invention

(12) The invention is described in detail below with reference to the specific embodiments thereof, but the embodiments are not intended to limit the scope of the invention, and the scope of the invention is not limited thereto.

Embodiment 1

(13) (1) mixing aniline of 30 ml and hexachlorocyclotriphosphazene of 0.17 g, undergoing a closed reaction for 5 h at a pressure of 2 MPa and a temperature of 200 C., then pressure is released to atmospheric pressure and steam vaporizing and eliminating extra aniline to obtain a solid substance;

(14) (2) under inert nitrogen protection, the obtained solid substance in step (1) is treated for 2 h at a high temperature of 900 C., and the sheet-shaped nitrogen-phosphorus co-doped porous carbon material is obtained, named C1.

Embodiments 2 to 7: Investigation of Reaction Temperature in Step (1)

(15) Except that the reaction temperatures in step (1) are replaced by 180 C., 220 C., 160 C., 240 C., 140 C., and 260 C., respectively, other operations are unchanged, thereafter Embodiments 2 to 7 are sequentially performed, and named C2 to C7, respectively.

Embodiments 8 to 10: Investigation of the Temperature of the High-Temperature Treatment in Step (2)

(16) Except that the temperatures of the high-temperature treatment in step (2) are replaced by 800 C., 900 C., and 1000 C., respectively, other operations are unchanged, thereafter Embodiments 8 to 10 are sequentially performed, and named C8 to C10, respectively.

Embodiment 11: The Preparation Method of Capacitor Electrodes

(17) Weighing 30 mg of the sheet-shaped nitrogen-phosphorus co-doped porous carbon materials, 0.375 mg of acetylene black and 0.375 mg of PTFE (polytetrafluoroethylene) emulsion (Purchased from Shanghai Aladdin Reagent Co., Ltd.) prepared in Embodiment 1, the mass ratio thereof is 80:10:10, adding 2 g of nitromethylpyrrolidone and mixing uniformly, stirring to starchiness and coating on the foamed nickel (size 11 cm) at a coating amount of 3 mg/cm.sup.2, and then desiccating, drying and preforming the coated foamed nickel to obtain capacitor electrodes.

(18) The properties of the sheet-shaped nitrogen-phosphorus co-doped porous carbon materials and the capacitor electrodes obtained in the above embodiments are characterized as follows.

(19) (I) Microscopic characterization of the sheet-shaped nitrogen-phosphorus co-doped porous carbon materials obtained in Embodiment 1.

(20) The sheet-shaped nitrogen-phosphorus co-doped porous carbon materials obtained in Embodiment 1 are microscopically characterized by various means, and the results are as follows:

(21) FIG. 1 is a scanning electron microscope (SEM) diagram showing the sheet-shaped nitrogen-phosphorus co-doped porous carbon materials obtained in Embodiment 1, wherein the materials are sheet-shaped.

(22) FIG. 2 is a XRD diagram showing that the sheet-shaped nitrogen-phosphorus co-doped porous carbon material is an amorphous structure, which is more conducive to the rapid embedding and derivation of ions or protons, and suitable for electrode materials.

(23) FIG. 3 is a XPS diagram showing that the sheet-shaped nitrogen-phosphorus co-doped porous carbon material contains carbon, nitrogen, phosphorus and oxygen.

(24) (II) Electrochemical Properties Testing

(25) FIG. 4 is the cyclic voltammograms showing the capacitor electrodes obtained in Embodiment 11 at different scan rates.

(26) In FIG. 4, the rate of each closed curve from top to below from left side (ie, arranged downward from the highest point of the left half) is 1 mv/s, 5 mv/s, 10 mv/s, 50 mv/s, 100 mv/s, 200 mv/s, 400 mv/s, 600 mv/s, 800 mv/s, 1000 mv/s and 2000 mv/s respectively. As can be seen therefrom, the material still has a good pattern at a rate of 100 mv/s, and the capacity is formula calculated 188.7 F/g at the rate of 100 mv/s.

(27) FIG. 5 is the constant-current charge-discharge diagrams showing the capacitor electrodes obtained in Embodiment 11 at different current densities.

(28) In the left figure of FIG. 5, the current densities from right to left are 0.5 A/g, 1 A/g, 2 A/g, and 5 A/g, respectively; in the right figure thereof, the current densities from right to left are 10 A/g, 20 A/g, 40 A/g, 50 A/g and 80 A/g, respectively.

(29) The constant-current charge-discharge diagram shows that calculated capacitance is still 122.2 F/g when the material is charged and discharged at a current density of 80 A/g, and the calculated capacitance is 400.5 F/g at a current density of 0.5 A/g, thereby demonstrating that the material can be charged and discharged at a large current density and has excellent charge-discharge property.

(30) FIG. 6 shows a diagram of the cycle stability of the capacitor electrodes obtained in Embodiment 11 at different current densities, as can be seen therefrom, the material has excellent cycle stability at high current densities; the material shows almost no attenuation after 35,000 cycles, thereby showing excellent cycle stability.

(31) FIG. 7 is a Ragone plot showing the capacitor electrodes obtained in Embodiment 11 at different current densities. As can be seen therefrom, at a current density of 0.5 A/g (top triangle), the materials have an energy density of 85.4 Wh/kg; at a current density of 80 A/g (top triangle), the materials have an power density of 49.9 kW/kg. Compared with published nitrogen-phosphorus co-doped porous carbon materials, the material of the invention has higher energy density and power density.

(32) As can be seen in FIGS. 4-7, the sheet-shaped nitrogen-phosphorus co-doped porous carbon materials of the invention have excellent electrochemical properties, and can be applied into the field of capacitors, especially into the supercapacitors field, and have excellent application prospects and industrial potential.

(33) Microscopic characterization of composite materials obtained in Embodiments 2 to 7, and 8 to 10.

(34) A. The characterization of C2-C7 found that the microscopic morphology thereof is highly similar to that of C1, and the electrochemical property thereof is also highly similar to that of C1. However, due to the high degree of similarity and for the sake of brevity, all diagrams of microscopic characterization and electrochemical property are not listed in the disclosure.

(35) B. From the characterization of C8C10, it is found that the microscopic morphology thereof is highly similar to that of C1, and the electrochemical property thereof is lower than that of C1; Table 1 below shows the capacitance of 100 mv/s at different temperatures of the high-temperature treatment, thereby demonstrating that the treatment temperature in step (2) was preferably at 900 C.

(36) TABLE-US-00001 TABLE 1 the capacitance of 100 mv/s at different temperatures T ( C.) C (F/g) 800 29.88 900 188.7 1000 51.39

(37) It is to be understood that the embodiments is merely to illustrate the invention and is not intended to limit the scope of the invention. In addition, it should be clear that various changes, modifications, and/or variations of the invention may be made by those skilled in the art after reading the technical content of the invention, all equivalent forms in the art without departing from the scope and spirit of the invention should still be covered by the appended claims of the invention.

INDUSTRIAL APPLICABILITY OF THE INVENTION

(38) The invention synthesizes a sheet-shaped nitrogen-phosphorus co-doped porous carbon material by selecting suitable reactants and conditions. It is found through research that the composite material has excellent electrochemical property, and has great industrial application potential and market value.