CN105551815B - A kind of lithium-ion capacitor and preparation method thereof - Google Patents

Abstract

The invention relates to a lithium ion capacitor, which comprises a positive pole piece, a negative pole piece, a diaphragm interposed between the positive and negative pole pieces, and an electrolytic solution. The positive electrode includes a positive electrode current collector and a positive electrode material coated on the positive electrode current collector. The positive electrode material is composed of a positive electrode active material and a binder, wherein the positive electrode active material is made of metal oxide and porous graphene, porous graphyne or porous carbon fiber One or more of the material mixtures are formed by in-situ compounding; the negative electrode sheet includes a negative electrode current collector and a negative electrode material coated on the negative electrode current collector, and the negative electrode material is composed of a negative electrode active material and a binder, wherein the negative electrode active material It is one of spherical natural graphite, graphitized mesophase carbon microspheres, and graphitized polyimide carbon microspheres with in-situ growth of carbon nanotubes or nano-metal nitrides on the surface after pore-forming and nitriding treatment; the above-mentioned lithium Ion capacitors have the advantages of high working voltage, good power characteristics, high energy density, and safe use. In addition, a preparation method of the lithium ion capacitor is also provided.

Description

A kind of lithium ion capacitor and preparation method thereof

technical field

The invention relates to an electrochemical energy storage device, in particular to a lithium ion capacitor and a preparation method thereof.

Background technique

The increasing energy crisis and environmental problems have accelerated the rapid development of the new energy industry. Under the current situation, the environment-friendly electrochemical energy storage technology that maximizes green energy supply and low-carbon energy conservation and emission reduction has attracted more and more attention. Recently, the state has proposed to establish a near-zero carbon emission project based on the Energy Internet, the core content of which includes renewable energy power generation, distributed energy storage technology, etc., which puts forward higher requirements for new and efficient energy storage technologies. In addition, new energy Electrochemical energy storage devices with high energy density and high power density are also required in fields such as electric vehicles, low-temperature starting power supplies, high-speed rail/urban rail transit braking energy recovery, marine ship platforms, underwater submersible power supplies, and UPS uninterruptible power supplies. .

At present, there are two most mature commercialized electrochemical energy storage technologies, one is lithium-ion battery, the positive electrode uses lithium-containing metal oxide as the active material, and the negative electrode uses graphite as the activated carbon material, through which the positive and negative electrodes electrochemically intercalate lithium to store energy , the energy density of a single cell can reach more than 150 Wh/kg, but its power density is only 100~500 W/kg, the power performance is poor, the cycle life is only 1000 times, and the low temperature performance is poor; the other is an electric double layer supercapacitor, The device uses activated carbon with high specific surface area as the positive and negative active materials, and stores energy through physical adsorption of charges, so its power density can reach more than 5000 W/kg, the cycle life can reach more than 100000 times, and it can realize low temperature -50 ℃ charge and discharge, however Its energy density is only 2~5Wh/kg, its battery life is limited, and it cannot supply power for a long time. Lithium-ion capacitors, that is, capacitive batteries, which have the advantages of both of the above, have become a research hotspot.

Patent 201110320933.5 discloses a supercapacitor battery. The anode active material of the capacitor battery is a mixture of activated carbon, carbon aerogel, carbon nanotubes or pyrolytic carbon and the anode material of the lithium ion battery. Although the specific surface area of activated carbon and carbon aerogel High, but the conductivity is still unsatisfactory. Carbon nanotubes are one-dimensional conductive materials with a relatively low specific surface area, while pyrolytic carbon is relatively poor in terms of specific surface area and conductivity, and cannot greatly improve power performance. The negative electrode active material is a mixture of silicon nanowires, carbon nanotubes and graphene. Silicon materials have a huge volume expansion and contraction effect when used as lithium intercalation materials, which is not conducive to long-term cycle performance. The specific surface area of graphene disclosed is only 200~600m ² /g. Patent 201010114612.5 discloses a supercapacitor battery. The negative electrode active material of the capacitor battery is hard carbon material, but the discharge voltage of hard carbon material varies greatly with capacity, and the first charge and discharge efficiency is low, and the discharge voltage hysteresis is obvious. The positive electrode active material is lithium The mixture of ion intercalation compounds and porous carbon materials (activated carbon, carbon cloth, carbon fiber, carbon felt, carbon aerogel, carbon nanotubes) has the same problems as patent 201110320933.5. Patent 201510130056.3 discloses a lithium supercapacitor battery negative electrode. The method is to sprinkle lithium powder on the surface of negative graphite or hard carbon material, and then roll to obtain the negative electrode. The disadvantage of this method is that the amount of lithium powder spread is harsh. What is more serious is the use of metallic lithium. There are potential safety hazards in the long-term charging and discharging process. Lithium dendrites are likely to be caused by a little carelessness, which will break through the diaphragm and cause a short circuit. In addition, there are two common problems in the three patents disclosed above. One is that the power performance cannot be maximized due to the limitation of the structure of the negative electrode active material. Conduction increases the difficulty of the positive and negative slurry mixing process.

Contents of the invention

One of the objects of the present invention is to provide a lithium ion capacitor.

Another object of the present invention is to provide a preparation method of a lithium ion capacitor.

In order to achieve the above object, the technical scheme of the present invention is as follows:

A lithium ion capacitor, comprising a positive electrode sheet, a negative electrode sheet, a separator between the positive and negative electrode sheets and an electrolyte, characterized in that the positive electrode includes a positive electrode collector and a positive electrode material coated on the positive electrode collector, the positive electrode The material is composed of a positive electrode active material and a binder, wherein the positive electrode active material is composed of one or more of the mixture of metal oxide and porous graphene, porous graphyne or porous carbon fiber material through in-situ composite; the negative electrode sheet includes The negative electrode current collector and the negative electrode material coated on the negative electrode current collector, the negative electrode material is composed of negative electrode active material and binder, wherein the negative electrode active material is the in-situ growth of carbon nanotubes or nano metals on the surface after pore making and nitriding treatment It is one of nitride spherical natural graphite, graphitized mesophase carbon microspheres, and graphitized polyimide carbon microspheres.

The lithium ion capacitor described above, the metal oxide is MxOy, one or more of M=Mn, Co, Ni, x is 1, 2, 3, 4 or 5, y is 1, 2, 3, 4 or 5.

In the described lithium ion capacitor, the mass ratio of metal oxide to porous graphene, porous graphyne or porous carbon fiber material is 1-30: 70-99.

In the lithium ion capacitor, the specific surface area of the porous graphene, porous graphyne or porous carbon fiber material is 500-3000 m ² /g.

In the lithium ion capacitor described above, after the surface is pore-forming and nitriding, the mass content of nitrogen in spherical natural graphite, graphitized mesophase carbon microspheres, and graphitized polyimide carbon microspheres is 1 to 9%. .

The lithium ion capacitor described above, after the surface is pore-forming and nitriding, carbon nanotubes or nano-metal nitrides grown in situ on the surface and spherical natural graphite, graphitized mesophase carbon microspheres, graphitized polyimide The mass ratio of amine-carbon microspheres is 0.5~5 : 95~99.5.

In the lithium ion capacitor, the diaphragm material is one of polyimide, polysulfone amide, polysulfone ether, melamine, polyaramid, and polyphenylene sulfide, and the thickness is 5-30 μm.

The lithium ion capacitor described above, the electrolyte in the electrolyte is lithium hexafluorophosphate (LiPF ₆ ), lithium perchlorate (LiClO ₄ ), lithium hexafluoroarsenate (LiAsF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), bisoxalic acid Lithium borate (LiBOB), lithium difluorooxalate borate (LiDFOB), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), lithium bisfluorosulfonylimide (LiFSI), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium hexafluoroantimonate (LiSbF ₆ ), and lithium tris(pentafluoroethyl)trifluorophosphate (LiFAP).

The lithium ion capacitor described above, the solvent in the electrolyte is dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), propylene carbonate (PC), ethylene carbonate (EC ), methyl propyl carbonate (MPC), gamma-butyrolactone (GBL), fluoroethylene carbonate (FEC), ethyl acetate (EA), trimethyl ethyl acetate (TMEA), methyl butyrate ( MB), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), propyl acetate (PA), methyl acetate (MA), ethyl acetoacetate (EAA), three One or more of methyl methyl acetate.

In the present invention, porous graphene, porous graphyne or porous carbon fiber materials are used to improve the power performance of the positive electrode, the specific surface area is as high as 1000-3000 m ² /g, and the conductivity is excellent, and no additional conductive agent is needed; the negative electrode active material is made of spherical natural stone Ink, graphitized mesophase carbon microspheres, and graphitized polyimide carbon microspheres are used as the base materials. After making pores on the surface, the ion diffusion rate is increased, and after nitriding treatment, the nitrogen content in the material is increased, thereby Improve the reversible lithium intercalation capacity of the material, and further adopt the in-situ growth of carbon nanotubes or nano-metal nitride technology on the surface to improve the conductivity of the material, thus eliminating the need for additional conductive agents other than the material body, reducing the cost of mixing the negative electrode slurry Complexity, process simplification. In the present invention, polyimide and polysulfone amide materials are also used as diaphragm materials, which can greatly improve the safety of lithium-ion capacitor devices; in addition, high-voltage resistant electrolytes are added to the electrolytic solution, so that the voltage application range can be improved, and the same effect can be achieved. To improve the safety and service life of lithium-ion capacitors.

The preparation scheme of a kind of lithium ion capacitor provided by the invention is as follows:

A method for preparing a lithium ion capacitor, comprising the steps of:

(1) Mix the positive electrode active material and the binder in a stirrer and stir for 60-300 minutes, during which the viscosity of the slurry is adjusted to an appropriate level by adding N-methylpyrrolidone. Add the negative electrode active material into the binder, stir for 60~300min, and adjust the viscosity of the slurry to a suitable level by adding water during this period;

(2) Mix the conductive carbon black and the binder evenly, and coat the positive electrode porous aluminum foil collector and the negative electrode porous copper foil collector respectively. The porous copper foil current collector of the negative electrode has a porosity of 20-60% and a thickness of 10-30μm;

(3) Coating the positive electrode slurry and negative electrode slurry described in step (1) on the porous aluminum foil current collector and porous copper foil current collector filled with conductive agent described in step (2), drying and compacting, Cutting pieces, spot welding tabs;

(4) The lithium auxiliary electrode is obtained by compacting lithium and filling it in a copper mesh, titanium mesh or stainless steel mesh collector fluid, and drawing it out through tabs. Lithium is in the form of flakes or powder.

(5) According to the sequence of lithium auxiliary electrode/diaphragm/negative electrode/diaphragm/positive electrode/diaphragm/negative electrode/diaphragm/positive electrode/diaphragm/negative electrode, the cells are assembled in order by lamination or winding process, and the cells are placed in In the aluminum-plastic film packaging, liquid injection, impregnation, charge and discharge formation, secondary liquid injection, vacuum sealing, to obtain a lithium ion capacitor device.

According to the preparation method of a lithium ion capacitor, the mass ratio of the positive or negative active material to the binder is: 80-95: 5-10.

The preparation method of a lithium ion capacitor, the binder is polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), hydroxypropyl methylcellulose (HPMC), sodium carboxymethylcellulose (CMC ) and one or more of styrene-butadiene rubber (SBR).

In the above preparation method, the positive and negative electrodes do not need to add any additional conductive agent, which reduces the complexity of the positive and negative electrode slurry mixing process, and uses the positive and negative electrode porous current collectors, which is conducive to the rapid transmission of ions, and the conductive material is coated on the current collectors. agent, which is beneficial to reduce the internal resistance and improve the power performance of lithium-ion capacitors.

The present invention further optimizes the preparation process of the lithium ion capacitor by optimizing the structure of the positive and negative electrode materials, the composition of the electrode material, and the composition of the electrolyte, which is conducive to the performance of the power performance of the lithium ion capacitor, and at the same time improves the energy density, safety and charge and discharge life. It can be widely used in renewable energy power generation, distributed energy storage technology, new energy electric vehicles, low-temperature starting power supply, high-speed rail/urban rail transit braking energy recovery, marine ship platform, underwater submersible power supply, UPS uninterruptible power supply and other fields .

Detailed ways

The lithium ion capacitor and its preparation method will be further described below through specific examples.

Example 1

Positive electrode: (1) Put graphene in potassium hydroxide solution, and prepare a porous graphene material with a specific surface area of 2500m ² /g by chemical activation method; (2) Dissolve the obtained porous graphene in N,N - in dimethylformamide, then add manganese acetylacetonate and nickel acetylacetonate in a certain proportion, after stirring, put the above mixed solution in a polytetrafluoroethylene-lined stainless steel autoclave, keep it warm at 200°C for 20h, cool and wash to obtain oxidation Manganese-nickel/porous graphene composite, wherein the mass ratio of manganese-nickel oxide to porous graphene is 20:80; (3) Stir and mix this mixture with the binder PVDF at a mass ratio of 90:10, and add NMP to adjust Slurry viscosity; (4) Coat the slurry on a porous aluminum foil containing a conductive agent with a thickness of 6 μm, the thickness of the porous aluminum foil is 20 μm, and the porosity is 30%; , and vacuum-dried at 120° C. for 24 hours to obtain a positive electrode sheet.

Negative electrode: (1) Use the Hummer method to oxidize graphitized mesophase carbon microspheres (particle size ~10μm) to form pores, then place them in an ammonia-protected atmosphere furnace for high-temperature nitriding treatment, and the mass content of nitrogen is 2% , and then use the CVD method to grow carbon nanotubes on the surface, and control the mass ratio of carbon nanotubes and graphitized mesophase carbon microspheres to 3:97 by controlling the growth time; (2) combine the material obtained in (1) with the binder CMC and SBR are stirred and mixed according to the mass ratio of 93:2.5:4.5, and an appropriate amount of water is added to adjust the viscosity of the slurry; (3) The slurry is coated on a porous copper foil containing a 6 μm thick conductive agent, and the thickness of the porous copper foil is 10 μm. The porosity is 35%; (4) The above-mentioned electrode sheet is dried, rolled, cut into pieces, and vacuum-dried at 120°C for 24 hours to obtain the negative electrode sheet.

Lithium auxiliary electrode: A metal lithium sheet with a thickness of 100 μm is compacted on a stainless steel mesh, and a nickel strip is welded on the tab.

According to the sequence of lithium auxiliary electrode/diaphragm/negative electrode/diaphragm/positive electrode/diaphragm/negative electrode, the winding core is formed by stacking sheets, placed in an aluminum-plastic case and placed in an aluminum-plastic film package, and the diaphragm is made of polyimide film. The thickness is 15 μm.

Dissolve LiPF ₆ and LiBOB electrolytes in EC and DMC solvents according to a certain mass ratio. The film-forming additives are vinylene carbonate (VC) and high-voltage overcharge protection agent biphenyl (BP). The electrolyte solution is injected into the core, After impregnation, first pass the positive electrode and lithium sheet through an external circuit to intercalate lithium, so that the positive electrode metal oxide is converted into a lithium-containing metal oxide; then pass the negative electrode and lithium sheet through an external circuit to perform lithium intercalation, and the amount of lithium intercalation is the negative electrode It can accommodate 80% of the highest capacity; second injection, vacuum sealing, to obtain a lithium ion capacitor device.

After charging and discharging tests, the obtained lithium ion capacitor has an energy density of 75 Wh/kg, a maximum power density of 7000W/kg, 20,000 continuous charge and discharge cycles, and a capacity retention rate of 95%.

Example 2

Positive electrode: (1) Put graphyne in potassium hydroxide solution, and prepare a porous graphyne material with a specific surface area of 2000m ² /g by chemical activation; (2) Dissolve the obtained porous graphyne in N,N - in dimethylformamide, then add manganese acetylacetonate and cobalt acetylacetonate, after stirring, place the above mixed solution in a polytetrafluoroethylene-lined stainless steel autoclave, keep it warm at 220°C for 24h, cool and wash to obtain cobalt manganese oxide/ Porous graphyne composite, wherein the mass ratio of manganese cobalt oxide to porous graphyne is 15:85; (3) Stir and mix this composite with binder PVDF at a mass ratio of 90:10, and add NMP to adjust the slurry Viscosity; (4) Coat the slurry on a porous aluminum foil containing a 6 μm thick conductive agent, the thickness of the porous aluminum foil is 20 μm, and the porosity is 30%; (5) The above pole piece is dried, rolled, and cut into pieces, and the Vacuum drying at 120° C. for 24 hours to obtain a positive electrode sheet.

Negative electrode: (1) Use the Hummer method to oxidize spherical natural graphite (particle size ~15μm) to form pores, mix it with n-butyl titanate in ethanol, add distilled water for hydrolysis, and drop nitric acid to adjust the appropriate pH to 2.0 to control Hydrolysis speed, after drying, put it in an ammonia-protected atmosphere furnace for high-temperature nitriding treatment, and obtain a spherical natural graphite composite material coated with nano-metal titanium nitride on the surface, with a nitrogen content of 3%; (2) (1) Stir and mix the obtained material with the binder CMC and SBR according to the mass ratio of 93:2.5:4.5, and add an appropriate amount of water to adjust the viscosity of the slurry; (3) Coat the slurry on a porous copper foil containing a 6μm thick conductive agent Above, the thickness of the porous copper foil is 10 μm, and the porosity is 35%; (4) The above-mentioned electrode sheet is dried, rolled, cut into pieces, and vacuum-dried at 120°C for 24 hours to obtain the negative electrode sheet.

Lithium auxiliary electrode: A metal lithium sheet with a thickness of 100 μm is compacted on a stainless steel mesh, and a nickel strip is welded on the tab.

According to the sequence of lithium auxiliary electrode/diaphragm/negative electrode/diaphragm/positive electrode/diaphragm/negative electrode, the winding core is formed in a laminated manner, placed in an aluminum-plastic case, and a polysulfoneamide membrane is used as a separator with a thickness of 15 μm.

Dissolve LiPF ₆ and LiDFOB electrolytes in EC and DMC solvents according to a certain mass ratio, and the additives are fluoroethylene carbonate (FEC) and high-voltage overcharge protection agent biphenyl (BP). After impregnation, first pass the positive electrode and lithium sheet through an external circuit to intercalate lithium, so that the positive electrode metal oxide is converted into a lithium-containing metal oxide; then pass the negative electrode and lithium sheet through an external circuit to intercalate lithium. It holds 80% of the highest capacity; after charging and discharging, liquid is injected for the second time, and the seal is vacuumed to obtain a lithium-ion capacitor device.

After charging and discharging tests, the obtained lithium ion capacitor has an energy density of 70 Wh/kg, a maximum power density of 6500 W/kg, 20,000 continuous charge and discharge cycles, and a capacity retention rate of 93%.

Example 3

Positive electrode: (1) Put the carbon fiber in potassium hydroxide solution, and prepare a porous carbon fiber material with a specific surface area of 2200m ² /g by chemical activation; (2) Dissolve the obtained porous carbon fiber in N,N - in dimethylformamide, then add cobalt acetylacetonate, after stirring, place the above mixed solution in a polytetrafluoroethylene-lined stainless steel autoclave, keep it at 200°C for 24h, cool and wash to obtain a cobalt oxide/porous graphyne composite , wherein the mass ratio of cobalt oxide to porous graphene is 20:80; (3) Stir and mix this composite with binder PVDF at a mass ratio of 90:10, and add NMP to adjust the viscosity of the slurry; (3) mix The slurry is coated on a porous aluminum foil containing a conductive agent with a thickness of 6 μm. The thickness of the porous aluminum foil is 20 μm and the porosity is 30%. (4) The above-mentioned pole pieces are dried, rolled, and cut into pieces, and dried in vacuum at 120°C for 24 hours , to obtain the positive electrode sheet.

Negative electrode: (1) Using the Hummer method, graphitized polyimide carbon microspheres (particle size ~5 μm) were oxidized to form pores, and then placed in an ammonia-protected atmosphere furnace for high-temperature nitriding treatment. The mass content of nitrogen was 2%, and then use CVD to grow carbon nanotubes on the surface, and control the mass ratio of carbon nanotubes and graphitized mesophase carbon microspheres to 5:95 by controlling the growth time; (2) mix the material obtained in (1) with the The binder CMC and SBR are stirred and mixed according to the mass ratio of 93:2.5:4.5, and an appropriate amount of water is added to adjust the viscosity of the slurry; (3) The slurry is coated on a porous copper foil containing a 6 μm thick conductive agent, and the thickness of the porous copper foil is 10 μm , The porosity rate is 35%; (4) The above-mentioned electrode sheet is dried, rolled, cut into pieces, and vacuum-dried at 120°C for 24 hours to obtain the negative electrode sheet.

Using the lamination process, the positive electrode, diaphragm, and negative electrode laminations are assembled into roll cores in sequence, and placed in aluminum-plastic film packaging. The diaphragm is made of polyimide film with a thickness of 15 μm;

Dissolve LiPF ₆ and LiBOB electrolytes in EC and DMC solvents according to a certain mass ratio. The film-forming additives are vinylene carbonate (VC) and high-voltage overcharge protection agent biphenyl (BP). The electrolyte solution is injected into the core, , after impregnation, first pass the positive electrode and lithium sheet through an external circuit to intercalate lithium, so that the positive electrode metal oxide is converted into a lithium-containing metal oxide; then pass the negative electrode and lithium sheet through an external circuit to perform lithium intercalation, and the amount of lithium intercalation is The negative electrode can hold 80% of the highest capacity; after charging and discharging, liquid is injected for the second time, and the seal is vacuumized to obtain a lithium ion capacitor device.

After charging and discharging tests, the obtained lithium ion capacitor has an energy density of 68 Wh/kg, a maximum power density of 7200W/kg, 20,000 continuous charge and discharge cycles, and a capacity retention rate of 93%.

Example 4

The raw material of the positive electrode active material in Example 1 is replaced by nickel acetylacetonate, and finally a nickel oxide/porous graphene composite electrode material is obtained. After lithium intercalation, the oxide in the positive electrode becomes lithium-containing metal nickel oxide, and the diaphragm is replaced by polysulfone Ether, the rest are the same as in Example 1. After charge and discharge tests, the energy density of the obtained lithium ion capacitor is 50 Wh/kg, the maximum power density is 7500W/kg, and the capacity retention rate is 95% after 20,000 continuous charge and discharge cycles.

Example 5

The raw material of positive electrode active material in embodiment 2 is changed into manganese acetylacetonate, finally obtains manganese oxide/porous graphyne composite electrode material, the oxide in the positive electrode becomes lithium-containing metal manganese oxide after intercalating lithium, and diaphragm is replaced by melamine, The rest is the same as in Example 2. After charging and discharging tests, the obtained lithium ion capacitor has an energy density of 55 Wh/kg, a maximum power density of 6000 W/kg, and a capacity retention rate greater than 92% for 20,000 continuous charge and discharge cycles.

The above-mentioned embodiments only represent several implementation modes in the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (9)

1. A lithium ion capacitor, comprising a positive electrode sheet, a negative electrode sheet, a separator between the positive and negative electrode sheets and an electrolyte, characterized in that the positive electrode sheet includes a positive electrode collector and a positive electrode coated on the positive electrode collector Material, the positive electrode material is composed of positive electrode active material and binder, wherein the positive electrode active material is composed of one or more of the mixture of metal oxide and porous graphene, porous graphyne or porous carbon fiber material through in-situ composite; The negative electrode sheet includes a negative electrode current collector and a negative electrode material coated on the negative electrode current collector. The negative electrode material is composed of a negative electrode active material and a binder, wherein the negative electrode active material is spherical natural graphite, graphitized mesophase carbon microspheres or graphitized polycarbonate. The surface of imide carbon microspheres is pore-forming, then nitriding, and finally grows carbon nanotubes or nano-metal nitrides in situ. 2. A kind of lithium ion capacitor according to claim 1, it is characterized in that described metal oxide is MxOy, one or more in M=Mn, Co, Ni, x is 1,2,3, 4 or 5, y is 1, 2, 3, 4 or 5. 3. a kind of lithium ion capacitor according to claim 1, it is characterized in that the mass ratio of described metal oxide and porous graphene, porous graphyne or porous carbon fiber material is 1～30: 70～99. 4. A lithium ion capacitor according to claim 1, characterized in that the specific surface area of the porous graphene, porous graphyne or porous carbon fiber material is 500-3000 m ² /g. 5. A kind of lithium ion capacitor according to claim 1, it is characterized in that after the surface is pore-forming and nitriding treatment, in spherical natural graphite, graphitized mesophase carbon microspheres, graphitized polyimide carbon microspheres The mass content of nitrogen element is 1~9%. 6. A kind of lithium ion capacitor according to claim 1, is characterized in that spherical natural graphite, graphitized mesophase carbon microsphere or graphitized polyimide carbon microsphere surface are through making holes, then nitriding treatment The mass ratio of the quality of the obtained material to the carbon nanotubes or nano-metal nitrides grown in situ on the surface of spherical natural graphite, graphitized mesophase carbon microspheres or graphitized polyimide carbon microspheres is: 95 ~ 99.5: 0.5~5. 7. A lithium ion capacitor according to claim 1, wherein the diaphragm material is one of polyimide, polysulfone amide, polysulfone ether, melamine, polyaramid, and polyphenylene sulfide species, with a thickness of 5-30 μm. 8. A lithium ion capacitor according to claim 1, characterized in that the electrolyte in the electrolyte is lithium hexafluorophosphate (LiPF ₆ ), lithium perchlorate (LiClO ₄ ), lithium hexafluoroarsenate (LiAsF ₆ ) , lithium tetrafluoroborate (LiBF ₄ ), lithium bisoxalate borate (LiBOB), lithium difluorooxalate borate (LiDFOB), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), lithium bisfluorosulfonylimide (LiFSI), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium hexafluoroantimonate (LiSbF ₆ ), and lithium tris(pentafluoroethyl)trifluorophosphate (LiFAP). 9. A lithium ion capacitor according to claim 1, characterized in that the solvent in the electrolyte is dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), Propylene carbonate (PC), ethylene carbonate (EC), methylpropyl carbonate (MPC), gamma-butyrolactone (GBL), fluoroethylene carbonate (FEC), ethyl acetate (EA), trimethyl Ethyl acetate (TMEA), methyl butyrate (MB), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), propyl acetate (PA), methyl acetate ( MA), ethyl acetoacetate (EAA), trimethylmethyl acetate or one or more.