CN102306781A - Doped graphene electrode material, macro preparation method and application of doped graphene electrode material - Google Patents

Abstract

The invention relates to the field of graphene electrode materials, in particular to a doped graphene electrode material and its macro-preparation method and application in large-capacity, high-rate lithium-ion batteries. Using graphene as raw material, through the protective gas and controlling the heating rate, under the condition of high temperature, the atmosphere containing nitrogen or boron elements with different concentrations is introduced to realize the doping of graphene heteroatoms and obtain nitrogen or boron doping Graphene; mix doped graphene, conductive carbon black, binder, add solvent, grind and apply on the current collector, after drying, shearing, and pressing, it will be the working electrode, and the lithium sheet will be used as the counter electrode/ The reference electrode is added with an electrolyte containing lithium salt, assembled into a button-type lithium-ion half battery in a glove box, and subjected to constant current charge and discharge tests under high current density conditions. The invention improves the electrode stability of the material under the condition of high current density, realizes that the doped graphene has a high specific capacity in a short period of time, and has excellent cycle performance.

Description

A kind of doped graphene electrode material and its macro preparation method and application

Technical field:

The invention relates to the field of graphene electrode materials, in particular to a doped graphene electrode material and its macro-preparation method and application in large-capacity, high-rate lithium-ion batteries.

Background technique:

The two major problems of environmental pollution and energy crisis have made the demand for high-power and high-energy energy storage devices increasingly urgent in modern society, especially renewable energy, various portable mobile devices and new energy hybrid electric vehicles, plug-in electric vehicles and pure electric vehicles. Development of electric vehicles. Lithium-ion batteries using traditional electrode materials such as graphite and lithium cobaltate as electrodes can only provide low power, far lower than supercapacitors, and can no longer meet the needs of society. At present, simultaneously achieving high specific power and specific energy in a short charging and discharging time (minutes to seconds) for lithium-ion batteries is still one of the great challenges in this research field. The power performance of lithium-ion batteries strongly depends on the transport speed of lithium ions and electrons in the electrolyte and bulk electrodes. An important method to improve the power performance of electrode materials is to use nanomaterials to improve the transmission speed of lithium ions and electrons on the surface and inside of electrodes, and to reduce the transmission paths of lithium ions and electrons inside electrodes. Unlike traditional lithium-ion batteries, carbon-based supercapacitors can achieve high power characteristics by improving the charge on the electrode surface and the reaction between the electrode and the electrolyte interface. Therefore, improving the power characteristics of lithium-ion batteries can be achieved by designing and synthesizing carbon materials with different nanostructures, improving the conductivity of the materials to promote the electron transfer rate, and improving the three-dimensional structure of the materials so that they have a large surface area and a well-developed pore structure. The rapid diffusion of ions realizes the rapid transport of ions and electrons and improves the power characteristics of lithium-ion batteries.

Graphene has a special two-dimensional nanostructure and excellent physical and chemical properties, especially high conductivity and developed flexible pore structure, which indicates that graphene may be a high specific power and high specific energy electrode material. Theoretical calculations show that graphene has a high chemical diffusion rate, reaching 10 ^-7 -10 ^-6 cm ² s ^-1 , and is an ideal high specific power electrode material. At present, several methods for producing graphene have been proposed, among which chemical exfoliation is a low-cost, mass-produced method for graphene, which is expected to meet the macro-material demand for lithium-ion battery applications. It is reported that graphene prepared by chemical exfoliation has a high reversible specific capacity, for example, at a low current density such as 100mA g ^-1 , the specific capacity can reach 1264mAh g ^-1 , but graphene prepared by chemical exfoliation has a relatively high There are large capacity fluctuations in rapid charge and discharge at a large initial current density of 500mA g ^-1 or greater. The main reason is that there are oxygen-containing functional groups on the surface of graphene prepared by chemical methods, which greatly reduces its electrical conductivity and thermal stability. During delithiation, the electrolyte will react with the oxygen on the graphene surface, which may lead to the instability of the electrochemical reaction process of the electrode.

Invention content:

The object of the present invention is to provide a doped graphene electrode material and its macro-scale preparation method and its application in large-capacity, high-rate lithium-ion batteries to solve the instability problem of graphene electrodes prepared by chemical exfoliation.

Technical scheme of the present invention is:

Graphene with different carbon/oxygen ratios prepared by the chemical exfoliation method is used as raw material. By protecting the gas and controlling the heating rate, under high temperature conditions, different concentrations of nitrogen or boron-containing gas are introduced, and the processing time is adjusted to realize the graphene. Doping of heteroatoms to obtain nitrogen or boron doped graphene.

Lithium-ion half-cell assembly: mix doped graphene, conductive carbon black, and binder. In terms of mass percentage, doped graphene accounts for 50% to 98% of the electrode material, and conductive carbon black and binder account for 50%-98% of the electrode material. The contents of the electrode materials are 25% to 1% respectively; adding a solvent accounting for 50 to 1000wt% of the mixture, grinding and coating on the current collector, drying, shearing, and tableting are used as working electrodes, and lithium sheets are used as the counter electrode. Electrode/reference electrode, add lithium salt-containing electrolyte, and assemble into a button-type lithium-ion half-cell in a glove box;

Lithium-ion half-battery test: constant current charge and discharge test under the condition of initial large current density.

In the present invention, the lateral dimension of the graphene prepared by the chemical exfoliation method is 50nm～200μm (preferably 500nm～50μm), the number of layers is 1～3 layers, the thickness is 0.8～2.3nm, and the electrical conductivity is ^10-4 ～ 10 ⁴ S/cm (preferably 10 to 10 ³ S/cm). The C/O atomic ratio is 1:1 to 50:1 (preferably the ratio is 5:1 to 20:1). Wherein, the graphite raw material is oxidized by the Hummer method to obtain graphite oxide, and the oxidation time is 20min-72h, preferably 1h-24h.

"Hummer's method" see literature: Hummers W, Offman R. Journal of The American Chemical Society 1958, 80:1339.

In the present invention, the high temperature condition is 200-1600°C, preferably 500-1000°C.

In the present invention, the gas mixing volume ratio of the atmosphere containing corresponding nitrogen or boron doping elements and other protective gases is 1:50-50:1, preferably the gas mixing volume ratio is 1:10-1:1; Nitrogen gas: N ₂ , NH ₃ , N ₂ O, NO, N ₂ O ₅ or N ₂ O ₃ etc.; boron-containing gas is BCl ₃ , BF ₃ , BBr ₃ or B ₂ H ₆ etc.; protective gas For argon or helium etc.

In the present invention, the protective gas is argon, helium or nitrogen, etc.; the heating rate is 1°C/min～50°C/min, preferably the heating rate is 10°C/min～40°C/min; the high temperature treatment time is 0.1 to 24 hours, preferably 1 to 10 hours.

In the present invention, the doping of heterogeneous atoms of graphene is realized, wherein the doping content of nitrogen or boron atoms is 0.1-30 at%, preferably 0.5-5 at%.

In the present invention, the doped graphene, conductive carbon black, and binder polyvinylidene fluoride are mixed in a certain mass ratio, wherein the doped graphene accounts for 50% to 98% of the electrode material content (the preferred content is 70%-90%), and the contents of the conductive carbon black and the binder in the electrode material are respectively 25%-1% (the preferred content is 20%-5%).

In the present invention, the solvent includes ethanol, acetone or N-methylpyrrolidone, etc.; the current collector includes copper foil, aluminum foil, titanium sheet, stainless steel plate or platinum sheet, etc.

In the present invention, the lithium salt-containing electrolyte lithium salt includes LiPF ₆ , LiClO ₄ or LiAsF ₆ , etc., the lithium salt-containing organic solvent is used as the electrolyte, and the molar concentration of the electrolyte is 0.1-3mol/L, organic The solvent is propylene carbonate (PC), dimethyl carbonate (DMC) or ethylene carbonate (EC).

In the present invention, the constant current charge and discharge test condition is 10mAg ^-1 ~ 50A g ^-1 under the condition of the initial high current density, preferably the high current density is 200mA g ^-1 ~ 30A g ^-1 . Under low current density (range 10mA g ^-1 ~ 100mA g ^-1 ), the charge and discharge time is more than 10 hours, the specific capacity is 600 ~ 2000mAh g ^-1 , preferably the specific capacity range is 800 ~ 1600mAh g ^-1 ; Under high current density (ranging from 100mA g ^-1 to 50A g ^-1 ), the charging and discharging time is within 1 hour to tens of seconds, and the specific capacity is 100 to 600mAh g ^-1 .

Features and beneficial effects of the present invention are:

1. The present invention adopts the graphene prepared by the chemical exfoliation method as a raw material. Under the condition of high temperature, the atmosphere containing corresponding nitrogen or boron doping elements and other protective gases are introduced, and different processing times are regulated to obtain different nitrogen or boron element contents. doped graphene;

2. The present invention adopts the doped graphene prepared by high-temperature gas phase doping as the electrode material of lithium ion battery, which significantly improves the electrical conductivity and thermal stability of the electrode material, and provides more reversible active sites for lithium storage. Doped graphene is a A promising high-capacity, high-rate electrode material that can be applied under fast charge-discharge conditions;

3. The present invention has the advantages of simple technological process, easy operation, low cost, fast doping efficiency, high electrochemical performance and promising mass production.

In short, by using graphene prepared by chemical exfoliation as raw material, nitrogen or boron doped graphene is obtained by high temperature gas phase doping, which not only achieves the doping of nitrogen or boron heteroatoms in the graphene lattice, but also further removes the Oxygen functional groups improve the electrical conductivity and thermal stability of graphene, increase the reversible active sites for lithium storage, and obtain a large-capacity, high-rate graphene electrode material.

Description of drawings:

Figure 1. (a) transmission electron microscopy and (b) scanning electron microscopy images of nitrogen-doped graphene.

Figure 2. (a) transmission electron microscopy and (b) scanning electron microscopy images of boron-doped graphene.

Figure 3. The (a) scanning transmission electron microscope photo of nitrogen-doped graphene and the distribution of (b) carbon and (c) nitrogen elements in the boxed area of figure (a); (d) of boron-doped graphene Scanning transmission electron microscope photo and the distribution of (e) carbon and (f) boron elements in the boxed area of figure (d); (g) N1s XPS spectrum of nitrogen-doped graphene, the inset is in the graphene lattice Schematic diagram of nitrogen-doped form, N1 is pyridinic nitrogen, N2 is pyrrolic nitrogen, (h) B1s XPS spectrum of boron-doped graphene, inset is a schematic diagram of boron-doped form in graphene lattice, B1 is BC Type ₃ boron, B2 is BC ₂ O type boron.

Figure 4. (a) galvanostatic charge-discharge voltage curves and (b) cycle performance and Coulombic efficiency of nitrogen-doped graphene at low current density; (c) galvanostatic charge-discharge voltage of boron-doped graphene at low current density Curves and (d) Cycling performance and Coulombic efficiency. The current density was 50 mAg ^-1 .

Figure 5. Constant current charge and discharge voltage curves of (a) nitrogen-doped and (b) boron-doped graphene under high current density, the current density is 50mAg ^-1 ; (c) nitrogen-doped and ( d) Rate performance and cycle performance curves of boron-doped graphene at current densities ranging from 0.5Ag ^-1 to 25Ag ^-1 .

Detailed ways:

Example 1

Graphene prepared by the chemical exfoliation method with a lateral size of 500nm-1μm, a layer number of 1-3 layers, and an electrical conductivity of 1×10 ³ S/cm is used as a raw material, and the C/O ratio (carbon-to-oxygen atomic ratio) is 10. Graphene (50 mg) was placed in a SiC tube (length 1.5 m, outer diameter 40 mm), under the protection of argon, the temperature was raised to 650 ° C at a heating rate of 10 ° C / min, and NH ₃ (volume purity ~ 99.0%), keep NH ₃ and the mixing volume ratio of argon is 1: 2, react 1h, obtain the nitrogen-doped graphene that nitrogen content is 2.0at%. Mix nitrogen-doped graphene, conductive carbon black, and polyvinylidene fluoride binder in a certain mass ratio (80:10:10), add N-methylpyrrolidone accounting for 200wt% of the mixture, and grind to form Uniform paste, then apply the slurry on Cu foil, dry at 100°C for 5h, make N-methylpyrrolidone volatilize, cut and press into tablets, dry at 100°C for 20h under vacuum as the working electrode, and use a lithium sheet as the counter Electrode/reference electrode, with ethylene carbonate EC/dimethyl carbonate DMC (volume ratio 1:1) solution of 1M (mol/L) LiPF ₆ as electrolyte, assembled into a button-type lithium-ion half-cell in a glove box , and then conduct constant current charge and discharge tests under different current density conditions. At a low current density of 50mA g ^-1 , the first reversible specific capacity is 950mAh g ^-1 ; at a high current density of 25A g ^-1 , the reversible specific capacity is 125mAhg ^-1 .

Example 2

The difference from Example 1 is:

Graphene prepared by the chemical exfoliation method with a transverse dimension of 500nm-5μm, a layer number of 1-3 layers, and an electrical conductivity of 2×10 ³ S/cm is used as a raw material, and graphene (50mg) with a C/O ratio of 9, Put it into a SiC tube (length 1.5m, outer diameter 40mm), under the protection of helium, raise the temperature to 700°C at a heating rate of 20°C/min, feed in NH ₃ (volume purity ~99.0%), and keep NH The mixing volume ratio of ₃ and argon was 1:3, and the reaction was carried out for 2 hours to obtain nitrogen-doped graphene with a nitrogen content of 3.1 at%. Mix nitrogen-doped graphene, conductive carbon black, and polyvinylidene fluoride binder in a certain mass ratio (80:10:10), add N-methylpyrrolidone accounting for 300wt% of the mixture, and grind it into Uniform paste, then apply the slurry on Cu foil, dry at 100°C for 5h, make N-methylpyrrolidone volatilize, cut and press into tablets, dry at 100°C for 20h under vacuum as the working electrode, and use a lithium sheet as the counter Electrode/reference electrode, with 1M LiPF ₆ ethylene carbonate EC/dimethyl carbonate DMC (volume ratio 1:1) solution as electrolyte, assembled into a button-type lithium-ion half-cell in a glove box, and then in different The constant current charge and discharge test was carried out under the condition of current density. At a low current density of 50mA g ^-1 , the first reversible specific capacity is 1040mAh g ^-1 ; at a high current density of 25A g ^-1 , the reversible specific capacity is 199mAh g ^-1 .

Example 3

The difference from Example 1 is:

Graphene (150 mg) with a lateral dimension of 500nm to 5 μm, a layer number of 1 to 3 layers, and an electrical conductivity of 2×10 ³ S/cm prepared by chemical exfoliation is used as a raw material, and the C/O ratio is 9. Put it into a SiC tube (length 1.5m, outer diameter 40mm), under the protection of helium, heat up to 600°C at a heating rate of 30°C/min, feed in NH ₃ (volume purity ~99.0%), and keep NH The mixing volume ratio of ₃ and argon is 1:4, react for 4 hours, and obtain nitrogen-doped graphene with a nitrogen content of 3.2 at%. Mix nitrogen-doped graphene, conductive carbon black, and polyvinylidene fluoride binder in a certain mass ratio (70:15:15), add N-methylpyrrolidone accounting for 400wt% of the mixture, and grind it into Uniform paste, then apply the paste on Cu foil, dry at 110°C for 2h, make N-methylpyrrolidone volatilize, cut, press into pieces, dry at 100°C for 24h in vacuum as working electrode, and use lithium sheet as counter Electrode/reference electrode, using 1M LiClO ₄ propylene carbonate PC solution as the electrolyte, assembled into a button-type lithium-ion half-cell in a glove box, and then carried out constant current charge and discharge tests under different current density conditions. At a low current density of 50mA g ^-1 , the first reversible specific capacity is 1020mAh g ^-1 ; at a high current density of 20A g ^-1 , the reversible specific capacity is 209mAh g ^-1 .

Example 4

The difference from Example 1 is:

Graphene (50 mg) with a lateral dimension of 500nm to 10 μm, a layer number of 1 to 3 layers, and an electrical conductivity of 2×10 ³ S/cm prepared by a chemical exfoliation method is used as a raw material, and the C/O ratio is 10. Put it into a SiC tube (length 1.5m, outer diameter 40mm), under the protection of argon, raise the temperature to 800°C at a heating rate of 30°C/min, pass in BCl ₃ (volume purity ~99.99%), keep BCl The mixing volume ratio of ₃ and argon is 1:5, react for 2 hours, and obtain boron-doped graphene with a boron content of 0.9 at%. Mix boron-doped graphene, conductive carbon black, and polyvinylidene fluoride binder in a certain mass ratio (80:10:10), add N-methylpyrrolidone accounting for 300wt% of the mixture, and grind it into Uniform paste, then apply the slurry on Cu foil, dry at 100°C for 6h, make N-methylpyrrolidone volatilize, cut and press into tablets, dry at 120°C for 15h under vacuum as the working electrode, and use a lithium sheet as the counter Electrode/reference electrode, using 0.5M LiPF ₆ propylene carbonate PC solution as electrolyte, assembled into a button-type lithium-ion half-cell in a glove box, and then carried out constant current charge and discharge tests under different current density conditions. At a low current density of 50mA g ^-1 , the first reversible specific capacity is 1500mAh g ^-1 ; at a high current density of 25A g ^-1 , the reversible specific capacity is 210mAh g ^-1 .

Example 5

The difference from Example 1 is:

Graphene (100mg) with a lateral dimension of 500nm to 10μm, a layer number of 1 to 3 layers, and an electrical conductivity of 1×10 ³ S/cm prepared by chemical exfoliation is used as a raw material, and the C/O ratio is 8. Put it into a SiC tube (length 1.5m, outer diameter 40mm), under the protection of argon, raise the temperature to 850°C at a heating rate of 5°C/min, pass in BCl ₃ (volume purity ~99.99%), keep BCl ₃ and argon in a volume ratio of 1:4, reacted for 4 hours, and obtained boron-doped graphene with a boron content of 1.5 at%. Mix boron-doped graphene, conductive carbon black, and polyvinylidene fluoride binder in a certain mass ratio (90:5:5), add N-methylpyrrolidone accounting for 350wt% of the mixture, and make Uniform paste, then apply the slurry on Cu foil, dry at 100°C for 5h, make N-methylpyrrolidone volatilize, cut and press into tablets, dry at 100°C for 20h under vacuum as the working electrode, and use a lithium sheet as the counter Electrode/reference electrode, using 1.5M LiClO ₄ propylene carbonate PC solution as the electrolyte, assembled into a button-type lithium-ion half-cell in a glove box, and then carried out constant current charge and discharge tests under different current density conditions. At a low current density of 50mA g ^-1 , the first reversible specific capacity is 1300mAh g ^-1 ; at a high current density of 20A g ^-1 , the reversible specific capacity is 230mAh g ^-1 .

Example 6

The difference from Example 1 is:

Graphene (50 mg) with a lateral dimension of 500nm to 5 μm, a layer number of 1 to 3 layers, and an electrical conductivity of 1×10 ³ S/cm prepared by chemical exfoliation is used as a raw material, and the C/O ratio is 7. Put it into a SiC tube (length 1.5m, outer diameter 40mm), under the protection of argon, heat up to 800°C at a heating rate of 15°C/min, pass in BCl ₃ (volume purity ~99.99%), keep BCl The mixing volume ratio of ₃ and argon is 1:2, react for 2 hours, and obtain boron-doped graphene with a boron content of 2.1 at%. Mix Peng-doped graphene, conductive carbon black, and polyvinylidene fluoride binder in a certain mass ratio (70:15:15), add N-methylpyrrolidone accounting for 500wt% of the mixture, and grind it into Uniform paste, then apply the slurry on Cu foil, dry at 120°C for 2h, volatilize N-methylpyrrolidone, cut and press into tablets, dry at 100°C for 20h in vacuum as working electrode, and use lithium sheet as counter Electrode/reference electrode, with 1M LiPF ₆ ethylene carbonate EC/dimethyl carbonate DMC (volume ratio 1:1) solution as the electrolyte, assembled into a button-type lithium-ion half-cell in a glove box, and then at different currents Constant current charge and discharge test under density conditions. At a low current density of 50mA g ^-1 , the first reversible specific capacity is 1200mAh g ^-1 ; at a high current density of 20A g ^-1 , the reversible specific capacity is 220mAhg ^-1 .

As shown in Figure 1, the transmission electron micrograph (a) of nitrogen-doped graphene shows that doped graphene still has an ultrathin two-dimensional structure, good flexibility and transparency; scanning electron micrograph (b) shows The doped graphene is in a free distribution state and stacked disorderly to form an overlapping conductive network and a rich pore structure.

As shown in Figure 2, the transmission electron micrograph (a) of boron-doped graphene shows that doped graphene still has an ultrathin two-dimensional structure, good flexibility and transparency; scanning electron micrograph (b) shows The doped graphene is in a free distribution state and stacked disorderly to form an overlapping conductive network and a rich pore structure.

As shown in Figure 3, high-angle annular dark-field scanning transmission microscopy images of nitrogen- or boron-doped graphene (Fig. c and Figure 3e, f) analysis shows that, in addition to carbon, nitrogen (Figure 3c) or boron (Figure 3f) is uniformly distributed on the graphene surface, indicating that under high temperature heat treatment conditions, heterogeneous atomic nitrogen Or the uniform doping of boron on graphene planes. From the XPS energy spectrum analysis of nitrogen (Figure 3g) or boron (Figure 3h) elements, it can be seen that graphene not only realizes the doping of heteroatoms, but also realizes the reduction of graphene to a certain extent.

As shown in Figure 4, nitrogen-doped (Figure 4a, b) and boron-doped (Figure 4c, d) graphene at a lower current density of 50mA g ^-1 constant current charge and discharge voltage curves and cycle performance, Coulombic efficiency can be known , doped graphene exhibits excellent electrochemical performance at low current densities. Doped graphene not only has high reversible capacity, but also improves the first-time Coulombic efficiency and capacity retention of electrode materials.

As shown in Fig. 5, the rate capability and cycle performance of nitrogen-doped (Fig. 5a, c) and boron-doped (Fig. 3b, d) graphene at high current densities (0.5A g ^-1 to 25A g ^-1 ) The stability curve shows that doped graphene has excellent fast charge and discharge performance, high specific capacity, excellent rate performance and cycle stability at high current density.

The results of the examples show that the present invention further improves the conductivity and thermal stability of the graphene by doping the graphene prepared by the chemical exfoliation method, and provides more reversible active sites for lithium storage. , significantly improved the electrochemical lithium storage performance of graphene, and obtained graphene electrode materials with large capacity and high rate. The biggest advantage of doped graphene is that it improves the electrode stability of the material under the condition of high current density, realizes that doped graphene has a high specific capacity in a short period of time, and has excellent cycle performance. Its electrochemical performance is significantly better than graphene and other carbon materials prepared by chemical exfoliation, revealing that doped graphene is a promising electrode material.

Claims (10)

1. A doped graphene electrode material, characterized in that, in the doped graphene electrode material, the doping content of nitrogen or boron atoms is 0.1 to 30 at%. 2. according to the described doped graphene electrode material of claim 1, it is characterized in that, the chemical exfoliation method that described graphene adopts is prepared, and the lateral dimension of graphene is 50nm～200 μ m, and number of layers is 1～3 layers, and thickness 0.8 to 2.3 nm, electrical conductivity of 10 ^-4 to 10 ⁴ S/cm, and carbon/oxygen atomic ratio of 1:1 to 50:1. 3. according to the macro preparation method of doped graphene electrode material as claimed in claim 1, it is characterized in that, the graphene of the different carbon/oxygen ratio that adopts chemical exfoliation method to prepare is raw material, by protective gas and control heating rate, Under high temperature conditions, different concentrations of nitrogen or boron-containing gas are introduced, and the processing time is adjusted to realize the doping of graphene heteroatoms, and obtain nitrogen or boron-doped graphene. 4. according to the macro-preparation method of doped graphene electrode material described in claim 3, it is characterized in that: described shielding gas is argon, helium or nitrogen; Heating rate is 1 ℃/min～50 ℃/min , the high temperature condition is 200-1600°C. 5. according to the macro-preparation method of doped graphene electrode material according to claim 3, it is characterized in that: in described step (1), the gas containing nitrogen element is: N ₂ , NH ₃ , N ₂ O, NO, N ₂ O ₅ or N ₂ O ₃ ; the boron-containing gas is BCl ₃ , BF ₃ , BBr ₃ or B ₂ H ₆ ; the volume ratio of the corresponding nitrogen or boron-containing gas to the protective gas is 1 :50～50:1. 6 . The method for preparing a doped graphene electrode material in large quantities according to claim 3 , characterized in that: in the step (1), the doping treatment time under high temperature conditions is 0.1 to 48 hours. 7. according to the application of the described doped graphene electrode material of claim 1, it is characterized in that, (1) the assembling of lithium ion half cell: doped graphene, conductive carbon black, binding agent are mixed, by mass percentage In total, doped graphene accounts for 50% to 98% of the electrode material, and the conductive carbon black and binder account for 25% to 1% of the electrode material; add a solvent that accounts for 50 to 1000 wt% of the mixture, grind After being coated on the current collector, after drying, shearing, and tableting, it is used as a working electrode, and a lithium sheet is used as a counter electrode/reference electrode, and an electrolyte containing lithium salt is added, and a button-type lithium-ion semi-conductor is assembled in a glove box. Battery; (2) Lithium-ion half-battery test: constant current charge and discharge test is carried out under the condition of initial large current density. 8. according to the application of the described doped graphene electrode material of claim 7, it is characterized in that: described solvent is ethanol, acetone or N-methylpyrrolidone; Described current collector is copper foil, aluminum foil, titanium sheet, stainless steel plate or platinum sheet. 9. According to the application of the doped graphene electrode material according to claim 7, it is characterized in that: in the electrolyte solution containing lithium salt, lithium salt is LiPF ₆ , LiClO ₄ or LiAsF ₆ , the electrolyte solution containing lithium salt The molar concentration is 0.1-3mol/L. 10. The application of the doped graphene electrode material according to claim 7, characterized in that: the constant current charging and discharging test condition under the condition of the initial high current density is 10mA g ^-1 ~ 50A g ^-1 .

Images