CN105280393B - A kind of amorphous carbon material of nano tunnel and preparation method thereof - Google Patents

Abstract

The invention discloses a nano-tunnel amorphous carbon material and a preparation method thereof. Including: first reducing potassium permanganate under hydrothermal conditions to prepare nano-rod-shaped manganese dioxide; then using nano-rod-shaped manganese dioxide as a template to mix evenly with the precursor of biochar to form a stable hydrogel; The glue is vacuum-dried and carbonized; finally, the manganese dioxide in the carbon material is removed with acid, and further activated to obtain the nano-tunnel amorphous carbon material. The nano-tunnel amorphous carbon material prepared by this method has high specific surface area and porosity; at the same time, ions can diffuse in the liquid phase in the tunnel, which greatly improves the diffusion speed of ions, reduces the mass transfer resistance, and improves the electrode performance. Electrochemical capacitive properties of materials. As an electrode material for supercapacitors, this nano-tunnel carbon material has the advantages of high specific capacity, long cycle life and high specific energy.

Description

A nano-tunnel amorphous carbon material and preparation method thereof

technical field

The invention relates to the fields of material science and chemical power supply, in particular to a nano-tunnel amorphous carbon material and a preparation method thereof.

Background technique

Supercapacitor is a new type of energy storage device between secondary batteries and traditional capacitors. It has the advantages of high energy density of secondary batteries and high power density of traditional capacitors. In addition, supercapacitors also have the advantages of long cycle life, good safety performance, and low environmental pollution. It has broad application prospects in new energy electric vehicles, information technology, national defense and military industry, and some small electronic devices. According to different charge storage mechanisms, supercapacitors can be divided into electric double layer supercapacitors and pseudocapacitor supercapacitors. At present, commercial supercapacitors are mainly electric double layer capacitors. The electric double layer capacitor mainly uses the electric double layer formed at the interface between the electrode and the electrolyte to store energy, and its electrode material is mainly carbon material.

Carbon materials have been widely used in commercial supercapacitors due to their stable cycle life, high specific surface area, and low price. The relationship between the microstructure of carbon materials and the specific capacity of supercapacitors is complicated. Theoretically, it is believed that the larger the specific surface area of the carbon material, the higher the capacity, but in fact the specific capacity is also related to the pore size distribution, internal resistance and surface functional groups of the material. Many researchers have studied the transport and storage of ions in hierarchical pores of carbon materials (DW Wang et al, Angew.Chem. Int. Ed., 2008, 47 : 373-376), the energy storage model in subnanopores (R Mysyk et al. al, Electrochem. Commun., 2009, 11 : 554－556) and aperture matching (L Wang et al, Electrochim. Acta, 2007, 53 : 882－886) and other theoretical issues in electric double layer energy storage, so as to provide The preparation and structure optimization of carbon materials provide a good guiding significance. An ideal carbon material should have high specific surface area, high bulk density, high porosity and high cost performance at the same time. Patent No. 201010277238.0 discloses a method of preparing hemispherical activated carbon by hydrothermal treatment with glucose and foaming agent, followed by high-temperature carbonization. The experimental steps are simple and the reaction conditions are relatively mild. The specific surface area of the carbon material can reach 851.75 m ² g ^-1 , and the specific capacitance is 267.83 F g ^-1 when the current density is 20 mA cm ^-2 . The patent No. 200510031195.7 discloses a method for preparing activated carbon with high specific surface area. Petroleum tar is used as raw material and mixed with KOH for carbonization. The specific surface area of the prepared activated carbon is between 2000 and 3000 m ² g ^-1 , but the specific capacitance is only 84 F g ^-1 .

In the present invention, an amorphous microporous carbon with nano-tunnels is synthesized by using nano-rod manganese dioxide as a template. The material has high specific surface area and porosity. Since the width of the nanotunnel is between 20 and 80 nm, and the length is between 0.2 and 3 μm, it indicates that there are some mesopores in the material. After chemical activation, the carbon material will have many micropores. Ions can diffuse in the liquid phase in the nano-tunnel, which greatly increases the ion diffusion speed, reduces the mass transfer resistance, makes it easier for the ions to reach the micropores, and improves the utilization of the micropores. The presence of micropores facilitates the adsorption of ions, thus forming a stable electric double layer. The carbon material synthesized by this method not only has good electrochemical capacitive performance, but more importantly, this method is more environmentally friendly, cheap and safe.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a nano-tunnel amorphous carbon material and its preparation method, which is used in supercapacitors. Due to the particularity of the nano-tunnel microporous carbon structure, the performance of supercapacitors is improved. specific capacity and specific energy.

A nano-tunnel amorphous carbon material prepared by the following method:

(1) Reducing potassium permanganate under hydrothermal conditions to prepare nanorod-shaped manganese dioxide;

(2) ultrasonically disperse the manganese dioxide powder obtained in step (1) in deionized water to form a uniform suspension; then dissolve the biomass carbon precursor and surfactant in water to form a stable mixed solution; Under the condition of certain temperature and stirring, the manganese dioxide suspension is added dropwise to the mixed solution of the biomass carbon precursor and the surfactant, and stirred at constant temperature. When the mixed solution is cooled to room temperature, a stable brown water coagulation is formed. glue;

(3) After vacuum drying the hydrogel obtained in step (2), transfer it to a porcelain boat; carry out carbonization in a tube furnace under inert gas protection conditions; remove manganese dioxide in the carbon material with acid after carbonization , washed several times with deionized water, and then dried;

(4) The product in step (3) is uniformly mixed with an activator, and then chemically activated at high temperature to obtain an amorphous carbon material with nano-tunnels.

Preferably, the conditions for reducing potassium permanganate in the step (1) are as follows: the hydrothermal temperature is between 120-200°C, and the hydrothermal time is 1-20 h; the reducing agents used are MnCl ₂ , MnSO ₄ Or one of HCl; the molar ratio of potassium permanganate and reducing agent is between 1:1 and 1:20.

Preferably, in the step (2), the mass concentration of manganese dioxide is 1 g L ^-1 ~ 20 g L ^-1 , and the biomass carbon precursor is one of glucose, agar, chitosan, sucrose and starch The mass concentration is 20 g L ^-1 ~ 50 g L ^-1 ; the surfactant is one of polyvinyl alcohol, hydroxymethyl cellulose and cyclodextrin, and the mass concentration is 1 g L ^-1 ~ 10 g L ^-1 .

Preferably, in the step (2), when the temperature is 40-80°C, the manganese dioxide suspension is added dropwise to the mixed solution of the biomass carbon precursor and the surfactant, and the dropping rate is 60-120°C. Drop every minute; when the two are mixed evenly, stir for 2 to 12 hours at 40 to 80°C. Finally cooled to room temperature to obtain a stable tan hydrogel.

Preferably, the conditions for vacuum drying of the hydrogel in the step (3) are as follows: the drying temperature is between 40°C and 80°C, and the drying time is between 5 and 24 hours.

Preferably, the carbonization conditions in the step (3) are as follows: under an inert atmosphere, the dried hydrogel is firstly kept at 200-400°C for 1-3 hours at a constant temperature, and then carbonized at 600-900°C for 1-3 hours. 3 h, the heating rate is 2 ~ 5 ℃min ^-1 .

Preferably, the conditions for removing manganese dioxide in the step (3) are as follows: cool the product obtained after carbonization to room temperature, and wash with acid to remove manganese dioxide in the material; the acid used is hydrochloric acid, oxalic acid, sulfuric acid One, the concentration is between 0.1mol L ^-1 and 2mol L ^-1 .

Preferably, the activation conditions in the step (4) are as follows: the selected activator is one of H ₃ PO ₃ , ZnCl ₂ , and KOH, and the mass ratio of the carbon material to the activator is 1:1 to 1:4 Between, the activation temperature is between 500 ~ 800 ℃.

A kind of supercapacitor electrode material, electrode material comprises above-mentioned nano-tunnel amorphous carbon material, binder and conductive agent; Wherein: the quality of nano-tunnel amorphous carbon material is 80% of the total mass of electrode material, the quality of binder The mass of the conductive agent is 10% of the total mass of the electrode material, and the mass of the conductive agent is 10% of the total mass of the electrode material.

The preparation method of the above-mentioned supercapacitor electrode material: the slurry prepared by the above-mentioned proportioning material is coated on the stainless steel net collector fluid, or coated on the aluminum foil; the quality of the electrode active material obtained after drying is 1 ~ 3 mg.

The prepared electrodes were vacuum-dried at 60 °C for 12 h, and electrochemical tests were performed in 1 M H ₂ SO ₄ electrolyte. Pt and Hg/Hg ₂ SO ₄ are counter and reference electrodes, respectively. The cyclic voltammetry test was carried out at a potential window of -0.5 ~ 0.3 V and a scan rate of 100 mV s ^-1 , and the specific capacity was calculated. The prepared electrode sheets were assembled into a symmetrical supercapacitor. The electrolyte was bicyclobutylammonium tetrafluorosalt/acetonitrile. The potential window was 0 ~ 3 V and the current density was 1 A g ^-1 . The specific capacity and specific energy.

Compared with the prior art, the present invention has the following beneficial effects: the carbon material prepared by the present invention is amorphous activated carbon, which contains many criss-cross nano-tunnels with a width of 20-80 nm and a length of 0.2-3 μm ; Moreover, this carbon material has a high specific surface area (>1200 m ² g ^-1 ), and the material has both microporous and mesoporous properties. The experimental conditions of the present invention are relatively mild; the manganese dioxide nanorods are easily removed by acid and leave many nano tunnels inside the carbon material; the experimental method is safe, environmentally friendly and cheap.

Description of drawings

Fig. 1 is the picture of hydrogel among the present invention;

Fig. 2 is the transmission electron microscope figure of manganese dioxide nanorod among the present invention;

Fig. 3 is the transmission electron microscope figure of the nano-tunnel microporous carbon of the present invention;

Fig. 4 is the cyclic voltammogram of the nano-tunnel carbon material prepared in Example 1 of the present invention during the three-electrode test.

detailed description

Example 1:

a. Preparation of nanorod-shaped MnO ₂ : Dissolve 20 g of KMnO ₄ in 1 L of water, add 15 ml of HCl, stir evenly, transfer to a hydrothermal reactor, and keep the temperature at 140 °C for 16 h. Cool to room temperature, wash with deionized water three times, and dry in a forced air oven for 24 h to obtain nanorod-shaped MnO ₂ powder.

b. Preparation of nanotunnel microporous carbon materials: 10 g MnO ₂ was ultrasonically dispersed in 1 L deionized water. Take 20 g of agar and dissolve it in 1 L of deionized water with stirring at 70°C, add 5 g of hydroxymethylcellulose and stir evenly. Under the condition of stirring at 70 °C, the MnO ₂ suspension was added dropwise to the mixed solution of agar and hydroxymethyl cellulose at a rate of 60 drops per minute, and then the stirring was continued at 70 °C for 2 h. After cooling to room temperature, a uniform and stable tan hydrogel was obtained. The hydrogel was vacuum-dried at 60°C for 12 h, then transferred to a porcelain boat, and heated to 300°C for 2 h at a heating rate of 3°C min ^-1 and then to 800°C for 2 h. When cooled to room temperature, the MnO ₂ in the carbon material was removed with 1 M HCl, and washed three times with deionized water. Finally, the dried carbon material was mixed with KOH at a mass ratio of 1:2, and activated at 700 °C for 1 h. After cooling, it was washed four times with deionized water and dried to obtain nanotunneled microporous carbons.

c. Electrochemical test: (three electrodes) take nano-tunnel microporous carbon, acetylene black and PVDF with a mass ratio of 80:10:10, grind evenly, add nitrogen methyl pyrrolidone to make slurry, coat on stainless steel mesh, 60°C Electrochemical tests were performed after vacuum drying for 12 h. The electrolyte was 1 MH ₂ SO ₄ , and the cyclic voltammetry test was carried out at a potential window of -0.5 ~ 0.3 V and a sweep rate of 100 mV s ^-1 , and the specific capacity was 200 F g ^-1 . (Two electrodes) Take nano-tunnel microporous carbon, acetylene black and PVDF with a mass ratio of 80:10:10, grind them evenly, add nitrogen methyl pyrrolidone to make a paste, and evenly coat them on aluminum foil, vacuum dry at 60°C, and roll , sliced, and assembled into symmetrical supercapacitors in a glove box. The electrolyte is bicyclobutylammonium tetrafluorosalt/acetonitrile, and the constant current charge and discharge test is carried out when the potential window is 0~3 V. When the current density is 1 A g ^-1 , the specific energy is as high as 31 Wh kg ^-1 .

Example 2:

a. Preparation of nanorod-shaped MnO ₂ : Dissolve 20 g of KMnO ₄ in 1 L of water, add 15 ml of HCl, stir evenly, transfer to an autoclave, and keep the temperature at 140 °C for 16 h. Cool to room temperature, wash with deionized water three times, and dry in a forced air oven for 24 h to obtain nanorod-shaped MnO ₂ powder.

b. Preparation of nano-tunneled microporous carbon materials: 10 g of MnO ₂ was ultrasonically dispersed in 1 L of deionized water. Take 20 g of starch and dissolve it in 1 L of deionized water with stirring at 70 °C, add 5 g of hydroxymethyl cellulose and stir well. Under the condition of stirring at 70 °C, the MnO ₂ suspension was added dropwise to the mixed solution of starch and hydroxymethyl cellulose at a rate of 60 drops per minute, and then the stirring was continued at 70 °C for 2 h. After cooling to room temperature, a uniform and stable tan hydrogel was obtained. After the hydrogel was vacuum-dried at 60°C for 12 h, it was transferred to a porcelain boat and heated to 300°C for 2 h at a heating rate of 3°C min ^-1 and then to 800°C for 2 h. When cooled to room temperature, the MnO ₂ in the carbon material was removed with 1 M HCl, and washed three times with deionized water. Finally, the dried carbon material was mixed with KOH at a mass ratio of 1:2, and activated at 700 °C for 1 h. After cooling, it was washed four times with deionized water and dried to obtain nanotunneled microporous carbons.

c. Electrochemical test: (Three electrodes) Take nano-tunnel microporous carbon, acetylene black and PVDF with a mass ratio of 80:10:10, grind them evenly, add nitrogen methyl pyrrolidone to make slurry, coat them on stainless steel mesh, 60°C Electrochemical tests were performed after vacuum drying for 12 h. The electrolyte was 1 MH ₂ SO ₄ , and the cyclic voltammetry test was carried out at a potential window of -0.5 ~ 0.3 V and a sweep rate of 100 mV s ^-1 , and the specific capacity was 196 F g ^-1 . (Two electrodes) Take nano-tunnel microporous carbon, acetylene black and PVDF with a mass ratio of 80:10:10, grind them evenly, add nitrogen methyl pyrrolidone to make a paste, and evenly coat them on aluminum foil, vacuum dry at 60°C, and roll , sliced, and assembled into symmetrical supercapacitors in a glove box. The electrolyte is bicyclobutylammonium tetrafluorosalt/acetonitrile, and the constant current charge and discharge test is carried out when the potential window is 0~3 V. When the current density is 1 A g ^-1 , the specific energy is as high as 29 Wh kg ^-1 .

Example 3:

a. Preparation of nanorod-shaped MnO ₂ : Dissolve 20 g of KMnO ₄ in 1 L of water, add 15 ml of HCl, stir evenly, transfer to an autoclave, and keep the temperature at 140 °C for 16 h. Cool to room temperature, wash with deionized water three times, and dry in a forced air oven for 24 h to obtain nanorod-shaped MnO ₂ powder.

b. Preparation of nanotunnel microporous carbon materials: 10 g MnO ₂ was ultrasonically dispersed in 1 L deionized water. Take 40 g of agar and dissolve it in 1 L of deionized water with stirring at 70°C, add 5 g of hydroxymethylcellulose and stir evenly. Under the condition of stirring at 70 °C, the MnO ₂ suspension was added dropwise to the mixed solution of agar and hydroxymethyl cellulose at a rate of 60 drops per minute, and then the stirring was continued at 70 °C for 2 h. After cooling to room temperature, a uniform and stable tan hydrogel was obtained. The hydrogel was vacuum-dried at 60°C for 12 h, then transferred to a porcelain boat, and heated to 300°C for 2 h at a heating rate of 3°C min ^-1 and then to 800°C for 2 h. When cooled to room temperature, the MnO ₂ in the carbon material was removed with 1 M HCl, and washed three times with deionized water. Finally, the dried carbon material was mixed with KOH at a mass ratio of 1:2, and activated at 700 °C for 1 h. After cooling, it was washed four times with deionized water and dried to obtain nanotunneled microporous carbons.

c. Electrochemical test: (three electrodes) take nano-tunnel microporous carbon, acetylene black and PVDF with a mass ratio of 80:10:10, grind evenly, add nitrogen methyl pyrrolidone to make slurry, coat on stainless steel mesh, 60°C Electrochemical tests were performed after vacuum drying for 12 h. The electrolyte was 1 MH ₂ SO ₄ , and the cyclic voltammetry test was carried out at a potential window of -0.5 ~ 0.3 V and a sweep rate of 100 mV s ^-1 , and the specific capacity was 167 F g ^-1 . (Two electrodes) Take nano-tunnel microporous carbon, acetylene black and PVDF with a mass ratio of 80:10:10, grind them evenly, add nitrogen methyl pyrrolidone to make a paste, and evenly coat them on aluminum foil, vacuum dry at 60°C, and roll , sliced, and assembled into symmetrical supercapacitors in a glove box. The electrolyte is bicyclobutylammonium tetrafluorosalt/acetonitrile, and the constant current charge and discharge test is carried out when the potential window is 0~3 V. When the current density is 1 A g ^-1 , the specific energy is as high as 21 Wh kg ^-1 .

Example 4:

a. Preparation of nanorod-shaped MnO ₂ : Dissolve 20 g of KMnO ₄ in 1 L of water, add 15 ml of HCl, stir evenly, transfer to an autoclave, and keep the temperature at 140 °C for 16 h. Cool to room temperature, wash with deionized water three times, and dry in a forced air oven for 24 h to obtain nanorod-shaped MnO ₂ powder.

b. Preparation of nanotunnel microporous carbon materials: 10 g MnO ₂ was ultrasonically dispersed in 1 L deionized water. 20 g of agar was stirred and dissolved in 1 L of deionized water at 70°C, and 5 g of cyclodextrin was added and stirred evenly. Under the condition of stirring at 70 °C, the MnO ₂ suspension was added dropwise to the mixed solution of agar and cyclodextrin at a rate of 60 drops per minute, and then the stirring was continued at 70 °C for 2 h. After cooling to room temperature, a uniform and stable tan hydrogel was obtained. After the hydrogel was vacuum-dried at 60 °C for 12 h, it was transferred to a porcelain ark and heated to 300 °C for 2 h at a heating rate of 3 °C min ^-1 and then to 800 °C for 2 h. When cooled to room temperature, the MnO ₂ in the carbon material was removed with 1 M HCl, and washed three times with deionized water. Finally, the dried carbon material was mixed with KOH at a mass ratio of 1:2, and activated at 700 °C for 1 h. After cooling, it was washed four times with deionized water and dried to obtain nanotunneled microporous carbons.

c. Electrochemical test: Electrochemical test: (three electrodes) take nano-tunnel microporous carbon, acetylene black and PVDF with a mass ratio of 80:10:10, grind them evenly, add nitrogen methyl pyrrolidone to make slurry, and coat them on stainless steel Electrochemical tests were performed after vacuum drying at 60°C for 12 h on the Internet. The electrolyte was 1 MH ₂ SO ₄ , and the cyclic voltammetry test was carried out at a potential window of -0.5 ~ 0.3 V and a sweep rate of 100 mV s ^-1 , and the specific capacity was 215 F g ^-1 . (Two electrodes) Take nano-tunnel microporous carbon, acetylene black and PVDF with a mass ratio of 80:10:10, grind them evenly, add nitrogen methyl pyrrolidone to make a paste, and evenly coat them on aluminum foil, vacuum dry at 60°C, and roll , sliced, and assembled into symmetrical supercapacitors in a glove box. The electrolyte is bicyclobutylammonium tetrafluorosalt/acetonitrile, and the constant current charge and discharge test is carried out when the potential window is 0 ~ 3 V. When the current density is 1 A g ^-1 , the specific energy is as high as 33 Wh kg ^-1 .

Example 5:

a. Preparation of nanorod-shaped MnO ₂ : Dissolve 20 g of KMnO ₄ in 1 L of water, add 15 ml of HCl, stir evenly, transfer to an autoclave, and keep the temperature at 140 °C for 16 h. Cool to room temperature, wash with deionized water three times, and dry in a forced air oven for 24 h to obtain nanorod-shaped MnO ₂ powder.

b. Preparation of nanotunnel microporous carbon materials: 10 g MnO ₂ was ultrasonically dispersed in 1 L deionized water. Take 20 g of agar and dissolve it in 1 L of deionized water with stirring at 70°C, add 5 g of hydroxymethylcellulose and stir evenly. Under the condition of stirring at 70 °C, the MnO ₂ suspension was added dropwise to the mixed solution of agar and hydroxymethyl cellulose at a rate of 60 drops per minute, and then the stirring was continued at 70 °C for 2 h. After cooling to room temperature, a uniform and stable tan hydrogel was obtained. After the hydrogel was vacuum-dried at 60°C for 12 h, it was transferred to a porcelain ark and heated to 300°C for 2 h at a heating rate of 3°C min ^-1 and then to 600°C for 2 h. When cooled to room temperature, the MnO ₂ in the carbon material was removed with 1 M HCl, and washed three times with deionized water. Finally, the dried carbon material was mixed with KOH at a mass ratio of 1:2, and activated at 700 °C for 1 h. After cooling, it was washed four times with deionized water and dried to obtain nanotunneled microporous carbons.

c. Electrochemical test: (three electrodes) take nano-tunnel microporous carbon, acetylene black and PVDF with a mass ratio of 80:10:10, grind evenly, add nitrogen methyl pyrrolidone to make slurry, coat on stainless steel mesh, 60°C Electrochemical tests were performed after vacuum drying for 12 h. The electrolyte was 1 MH ₂ SO ₄ , and the cyclic voltammetry test was carried out at a potential window of -0.5 ~ 0.3 V and a sweep rate of 100 mV s ^-1 , and the specific capacity was 183 F g ^-1 . (Two electrodes) Take nano-tunnel microporous carbon, acetylene black and PVDF with a mass ratio of 80:10:10, grind them evenly, add nitrogen methyl pyrrolidone to make a paste, and evenly coat them on aluminum foil, vacuum dry at 60°C, and roll , sliced, and assembled into symmetrical supercapacitors in a glove box. The electrolyte is bicyclobutylammonium tetrafluorosalt/acetonitrile, and the constant current charge and discharge test is carried out when the potential window is 0~3 V. When the current density is 1 A g ^-1 , the specific energy is as high as 26 Wh kg ^-1 .

Claims (10)

1. an amorphous carbon material of a nano-tunnel, characterized in that it is prepared by the following method: Step (1) reducing potassium permanganate under hydrothermal conditions to prepare nanorod manganese dioxide; Step (2) ultrasonically dispersing the manganese dioxide powder obtained in step (1) in deionized water to form a uniform suspension; then dissolving the biomass carbon precursor and surfactant in water to form a stable mixed solution; Under certain temperature and stirring conditions, the manganese dioxide suspension was added dropwise to the mixed solution of the biomass carbon precursor and the surfactant, and stirred at a constant temperature. When the mixed solution was cooled to room temperature, a stable brown water was formed. gel; Step (3) After the hydrogel obtained in step (2) is vacuum-dried, it is transferred to a porcelain boat; in a tube furnace, carbonization is carried out under inert gas protection conditions; after carbonization, acid is used to remove the carbon dioxide in the carbon material Manganese, washed several times with deionized water and dried; In step (4), the product in step (3) is uniformly mixed with an activator, and then chemically activated at high temperature to obtain an amorphous carbon material with nano-tunnels. 2. The nano-tunnel amorphous carbon material according to claim 1, characterized in that the conditions for reducing potassium permanganate in the step (1) are as follows: the hydrothermal temperature is between 120 and 200°C, and the hydrothermal The time is 1 ~ 20 h; the reducing agent used is one of MnCl ₂ , MnSO ₄ or HCl; the molar ratio of potassium permanganate and reducing agent is between 1:1 ~ 1:20. 3. The nano-tunnel amorphous carbon material according to claim 1, characterized in that in the step (2), the mass concentration of manganese dioxide is 1 g L ^-1 ~ 20 g L ^-1 , and the biomass carbon The precursor is one of glucose, agar, chitosan, sucrose and starch, and its mass concentration is 20 g L ^-1 ~ 50 g L ^-1 ; the surfactant is polyvinyl alcohol, hydroxymethyl cellulose and cyclic A kind of dextrin, its mass concentration is 1 g L ^-1 ~ 10 g L ^-1 . 4. The nano-tunnel amorphous carbon material according to claim 1, characterized in that in the step (2), when the temperature is 40-80°C, the manganese dioxide suspension is added dropwise to the biomass carbon precursor In the mixed solution of solid and surfactant, the dropping rate is 60-120 drops per minute; when the two are evenly mixed, stir at 40-80°C for 2-12 hours, and finally cool to room temperature to obtain a stable brown Brown hydrogel. 5. The nano-tunnel amorphous carbon material according to claim 1, characterized in that the conditions for vacuum drying of the hydrogel in the step (3) are as follows: the drying temperature is between 40 and 80°C, and the drying time is 5 ~ 24 h. 6. The nano-tunnel amorphous carbon material according to claim 1, characterized in that the carbonization conditions in the step (3) are as follows: under an inert atmosphere, the dried hydrogel is firstly heated at 200-400°C , constant temperature for 1 ~ 3 h, followed by carbonization at 600 ~ 900°C for 1 ~ 3 h, with a heating rate of 2 ~ 5°C min ^-1 . 7. The nano-tunnel amorphous carbon material according to claim 1, characterized in that the conditions for removing manganese dioxide in the step (3) are as follows: the product obtained after carbonization is cooled to room temperature, and the material is removed by washing with acid Manganese dioxide in the solution; the acid used is one of hydrochloric acid, oxalic acid, and sulfuric acid, and the concentration is between 0.1 mol L ^-1 and 2 mol L ^-1 . 8. The nano-tunnel amorphous carbon material according to claim 1, characterized in that the activation conditions in the step (4) are as follows: the selected activator is one of H ₃ PO ₃ , ZnCl ₂ , and KOH , the mass ratio of carbon material to activator is between 1:1 and 1:4, and the activation temperature is between 500 and 800°C. 9. A supercapacitor electrode material, characterized in that the electrode material comprises the nano-tunnel amorphous carbon material, binding agent and conductive agent according to any one of claims 1-8; wherein: the nano-tunnel amorphous carbon material The mass is 80% of the total mass of the electrode material, the mass of the binder is 10% of the total mass of the electrode material, and the mass of the conductive agent is 10% of the total mass of the electrode material. 10. the preparation method of supercapacitor electrode material described in claim 9 is characterized in that, the slurry prepared by the material of above-mentioned proportioning is coated on the stainless steel mesh current collector, or is coated on the aluminum foil; After drying, obtain The mass of the electrode active material is 1 ~ 3 mg.