Positive electrode material composition, positive electrode sheet, and lithium ion battery
By using a combination of graphene-like carbon nitride materials, conductive additives, and binders, the resource and environmental problems of inorganic cathode materials and the performance deficiencies of organic cathode materials have been solved, achieving high-potential, high-capacity, and high-stability lithium-ion battery performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING INST OF NANOENERGY & NANOSYST
- Filing Date
- 2026-02-26
- Publication Date
- 2026-05-29
AI Technical Summary
Existing inorganic cathode materials face challenges such as resource depletion, environmental pollution, high toxicity of transition metals, and the trade-off between energy density and stability. Organic cathode materials, on the other hand, suffer from poor rate performance, rapid capacity decay, and short cycle life in practical applications.
A positive electrode material composition is prepared by thermal polymerization using a combination of graphene-like carbon nitride material, conductive additives and binders, and then applied to positive electrode sheets and lithium-ion batteries. The composition utilizes CN bonds to bind anions in the electrolyte to provide high potential, high capacity and high stability.
It achieves high-potential, high-capacity, and high-stability lithium-ion battery performance, with an initial specific capacity of 235.2 mAh g-1, which remains at 211.4 mAh g-1 after 1000 cycles and 152.9 mAh g-1 after 5000 cycles.
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Figure CN122117899A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of energy storage materials technology, specifically to a cathode material composition, a cathode sheet, and a lithium-ion battery. Background Technology
[0002] Lithium-ion batteries, with their superior performance such as high energy density, high output power, and long cycle life, have become an indispensable part of modern energy storage systems, powering portable electronic devices, electric vehicles (EVs), and grid-scale energy storage facilities. However, traditional inorganic cathode materials, such as layered transition metal oxides (e.g., LiCoO2, LiNiO2), multi-anionic compounds (e.g., LiFePO4), and ternary layered oxides (e.g., LiNi...), are limited. 0.8 Co 0.1 Mn 0.1 Inorganic cathode materials, particularly those containing oxygen (O2), typically face challenges such as resource depletion, environmental pollution, high toxicity of transition metals, and high mining costs. Furthermore, inorganic cathode materials involve a trade-off between energy density and stability; for example, nickel-based ternary materials and cobalt-based oxides offer high energy density but poor thermal stability, while LiFePO4 prioritizes safety at the expense of energy density. These drawbacks hinder their scalability for large-scale applications. In contrast, organic cathode materials offer a promising alternative, composed of abundant and low-toxicity light elements (C, H, O, and N), offering advantages such as environmental friendliness, low production costs, high theoretical capacity, diverse and tunable structures, and the ability to optimize redox activity and stability through custom design. However, due to limited electronic and ionic conductivity and susceptibility to dissolution, organic cathode materials often suffer from poor rate performance, rapid capacity decay, and short cycle life in practical applications.
[0003] Based on the type of redox reaction during charging and discharging, organic cathode materials can be classified into n-type (reduced) and p-type (oxidized). n-type materials undergo a reduction reaction during discharge, gaining electrons and then intercalating with cations (such as Li). + Na + These capacitors achieve charge compensation, characterized by high capacity achieved through multiple electron transfers. However, they have relatively low operating voltages (1.5-3.0 V vs. Li / Li). + Furthermore, they are readily soluble in organic electrolytes, leading to poor cycle stability, such as carbonyl compounds (cyclohexanone, anthraquinone), pyrazine derivatives, etc. p-type materials lose electrons through oxidation reactions and intercalate anions (e.g., PF6). - ClO4 - This achieves charge compensation and is characterized by a relatively high operating voltage (3.0-4.5 V vs. Li / Li). +They have fast kinetics but generally low capacity, such as triphenylamine derivatives, phenothiazine derivatives, pyrazole derivatives, polyaniline, polypyrrole, and graphite. Summary of the Invention
[0004] The purpose of this invention is to overcome the problem of low capacity of p-type organic materials in existing technologies, and to provide a cathode material composition, a cathode sheet, and a lithium-ion battery. According to the technical solution of this invention, the prepared cathode sheet and lithium-ion battery exhibit high potential, high capacity, and high stability.
[0005] To achieve the above objectives, the present invention provides a positive electrode material composition comprising a graphene-like carbon nitride material, a conductive additive, and a binder, wherein the mass ratio of the graphene-like carbon nitride material, the conductive additive, and the binder is (6-8):(1-3):1.
[0006] Preferably, the graphene-like carbon nitride material has the structure shown in formula (1). Equation (1).
[0007] Preferably, the graphene-like carbon nitride material is prepared by the following process: under an inert atmosphere, hexaaminobenzene trihydrochloride is subjected to a thermal polymerization reaction.
[0008] Preferably, the conditions for the thermal polymerization reaction include: a temperature of 300-500℃ and a time of 2-6 hours.
[0009] Preferably, the conductive additive is at least one selected from Ketjen black, conductive carbon black, acetylene black, graphene, conductive graphite, and carbon nanotubes.
[0010] Preferably, the adhesive is at least one selected from polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, and sodium alginate.
[0011] A second aspect of the present invention provides a positive electrode sheet comprising a current collector and a positive electrode material composition coated on the current collector, wherein the positive electrode material composition is the positive electrode material composition described above.
[0012] Preferably, the current collector is a carbon-coated aluminum foil.
[0013] A third aspect of the present invention provides a lithium-ion battery comprising the positive electrode sheet described above.
[0014] Preferably, the electrolyte in the electrolyte of the lithium-ion battery is at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium bis(trifluoromethanesulfonyl)imide.
[0015] According to the technical solution of this invention, graphene-like carbon nitride material is used as the positive electrode material. The CN bonds in the graphene-like carbon nitride material can bind to anions in the electrolyte during charging and discharging, providing capacity. The prepared positive electrode exhibits high potential, high capacity, and high stability in lithium-ion batteries. Specifically, the positive electrode of this invention has a capacity of 0.1 A g. -1 The initial specific capacity was 235.2 mAh g. -1 It still maintains 211.4 mAh g after 1000 cycles. -1 The specific capacity is [value missing], the average charging voltage is 3.86V, the discharging voltage is 3.70V, and it still maintains 152.9 mAh g after 5000 cycles. -1 Specific capacity. Attached Figure Description
[0016] Figure 1 A photograph of the hexaaminobenzene trihydrochloride in Example 1 of this invention; Figure 2 A photograph of the graphene-like carbon nitride material in Embodiment 1 of the present invention; Figure 3 This is a scanning electron microscope image of the graphene-like carbon nitride material in Example 1 of the present invention; Figure 4 The energy spectrum of the graphene-like carbon nitride material in Example 1 of the present invention is shown, where (a) is the EDS mapping of carbon and (b) is the EDS mapping of nitrogen. Figure 5 This is the solid-state carbon NMR spectrum of the graphene-like carbon nitride material in Example 1 of this invention; Figure 6 The infrared spectrum of the graphene-like carbon nitride material in Example 1 of this invention; Figure 7 The X-ray diffraction pattern of the graphene-like carbon nitride material in Example 1 of this invention; Figure 8 This is a cyclic voltammetry diagram of the positive electrode sheet prepared in Example 1 of the present invention; Figure 9 This is a charge-discharge curve of the positive electrode sheet prepared in Example 1 of the present invention; Figure 10 The rate performance diagram of the positive electrode prepared in Example 1 of this invention; Figure 11 The positive electrode sheet prepared for Example 1 of this invention was prepared at 0.1 A g. -1 Cyclic performance at current density; Figure 12 The positive electrode sheet prepared in Example 1 of this invention was subjected to a reaction at 1 A g. -1 Cyclic performance at current density. Detailed Implementation
[0017] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.
[0018] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0019] The cathode material composition of the present invention contains a graphene-like carbon nitride material, a conductive additive, and a binder, wherein the mass ratio of the graphene-like carbon nitride material, the conductive additive, and the binder is (6-8):(1-3):1.
[0020] In the cathode material composition of the present invention, preferably, the mass ratio of the graphene-like carbon nitride material, the conductive additive, and the binder is (6.2-7.8):(1.2-2.8):1. In a more preferred embodiment, the mass ratio of the graphene-like carbon nitride material, the conductive additive, and the binder is (6.5-7.5):(1.5-2.5):1.
[0021] In the cathode material composition of the present invention, preferably, the graphene-like carbon nitride material has the structure shown in formula (1).
[0022] Equation (1) In the cathode material composition of the present invention, preferably, the graphene-like carbon nitride material has the chemical formula C3N. All nitrogen elements in the molecular structure of the graphene-like carbon nitride material are graphite nitrogen atoms, resulting in the graphene-like carbon nitride material having a 3V (vs. Li / Li) property. + It has a high potential of 536.0 mA h / g and a theoretical specific capacity of 536.0 mA h / g.
[0023] In the cathode material composition of the present invention, preferably, the graphene-like carbon nitride material is prepared by the following process: thermal polymerization of hexaaminobenzene trihydrochloride under an inert atmosphere. The inert atmosphere may be provided by at least one of nitrogen, argon, and helium. In the most preferred embodiment, the inert atmosphere is provided by argon.
[0024] In the cathode material composition of the present invention, the conditions for the thermal polymerization reaction may include: a temperature of 300-500°C and a time of 2-6 hours. Preferably, the conditions for the thermal polymerization reaction include: a temperature of 350-450°C and a time of 3-5 hours. The heating rate of the thermal polymerization reaction may be 6-10°C / min, preferably 7-9°C / min. The thermal polymerization reaction process can be carried out in a tube furnace.
[0025] The thermal polymerization process of this invention further includes: performing a Soxhlet extraction on the product of the thermal polymerization reaction using water and ethanol, followed by drying the obtained product. The Soxhlet extraction time can be 12-48 hours, preferably 20-30 hours. The Soxhlet extraction process is used to remove soluble impurities. In a preferred embodiment, the drying conditions include: a temperature of 70-90°C, a time of 12-48 hours, and a vacuum degree of -0.08 to -0.1 MPa. The drying process can be carried out in a vacuum oven.
[0026] In the cathode material composition of the present invention, the conductive additive may be at least one selected from Ketjen black, conductive carbon black, acetylene black, graphene, conductive graphite, and carbon nanotubes. In the most preferred embodiment, the conductive additive is Ketjen black.
[0027] In the cathode material composition of the present invention, the binder may be at least one selected from polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, and sodium alginate. In the most preferred embodiment, the binder is polyvinylidene fluoride. In a specific embodiment, the polyvinylidene fluoride has a weight-average molecular weight of 8 × 10⁻⁶. 5 Up to 1×10 6 The polyvinylidene fluoride (PVDF) is available from Dongguan Kelude New Energy Technology Co., Ltd., and its brand name is HSV-900. The weight-average molecular weight of the polytetrafluoroethylene (PTFE) can be 4 × 10⁻⁶. 4 Up to 5×10 4 The polytetrafluoroethylene (PTFE) is available from Dongguan Kelude New Energy Technology Co., Ltd., with the grade MA-EN-BI-0001. The polyvinylidene fluoride-hexafluoropropylene copolymer is available from Dongguan Kelude New Energy Technology Co., Ltd., with the grade MA-EN-SS-0075.
[0028] The positive electrode sheet of the present invention includes a current collector and a positive electrode material composition coated on the current collector, wherein the positive electrode material composition is the positive electrode material composition described above.
[0029] In the positive electrode sheet described in this invention, preferably, the current collector is a carbon-coated aluminum foil.
[0030] The method for preparing the positive electrode sheet according to the present invention includes: mixing the graphene-like carbon nitride material, the conductive additive, and the binder to obtain a slurry; coating the slurry onto the current collector; drying the slurry; and then cutting the resulting product into discs as positive electrode sheets. The mixing process can be carried out under grinding conditions. Preferably, the grinding time is 20-40 minutes. The grinding process is carried out in N-methyl-2-pyrrolidone. The grinding process can be carried out in a mortar. The coating method can be a doctor blade coating method. Under preferred conditions, the drying conditions include: a temperature of 50-70°C and a time of 10-15 hours. The diameter of the disc can be 10-15 mm, preferably 11-13 mm, and more preferably 15 mm. The loading of the active material on the disc can be 1.5-2 mg·cm³. -2 The preferred concentration is 1.6-1.8 mg·cm³. -2 .
[0031] The lithium-ion battery of the present invention includes the above-mentioned positive electrode sheet. In the lithium-ion battery of the present invention, the electrolyte in the electrolyte solution of the lithium metal ion battery can be at least one selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium bis(trifluoromethanesulfonyl)imide. In the most preferred embodiment, the electrolyte in the electrolyte solution of the lithium metal ion battery is lithium hexafluorophosphate. The lithium-ion battery of the present invention can be prepared according to conventional methods in this technical field.
[0032] The following examples further illustrate the positive electrode material composition, positive electrode sheet, and lithium-ion battery of the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.
[0033] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.
[0034] Example 1 Preparation of graphene-like carbon nitride materials: 1 g of hexaaminobenzene trihydrochloride was placed in an alumina crucible and then placed in a tube furnace. The furnace was evacuated and then purged with argon gas. The degassing-purging process was repeated three times to ensure an argon environment. The furnace temperature was slowly increased to 450°C at a rate of 8°C / min and held at this temperature for 3 hours under an argon gas flow to prevent oxidation. The sample was then slowly cooled to room temperature, and the argon gas was turned off. The sample was collected and subjected to Soxhlet extraction with water and ethanol, respectively, for 24 hours each time. The extracted product was then dried at 80°C under a vacuum of 0.1 MPa for 24 hours. The resulting black powder was the graphene-like carbon nitride material A1. Figure 1A photograph of the hexaaminobenzene trihydrochloride; Figure 2 Photograph of the graphene-like carbon nitride material A1.
[0035] Preparation of positive electrode sheet: The graphene-like carbon nitride material A1, Ketjen Black (purchased from Suzhou Shengernuo Energy Technology Co., Ltd., grade ECP-600JD, hereinafter the same), and polyvinylidene fluoride (purchased from Dongguan Kelude New Energy Technology Co., Ltd., grade HSV-900, hereinafter the same) were mixed and ground in N-methyl-2-pyrrolidone at a mass ratio of 7:2:1 for 30 min. The resulting slurry was then coated onto carbon-coated aluminum foil using a doctor blade coating method and dried in a vacuum oven at 60°C for 12 h. The aluminum foil coated with the slurry was cut into circular pieces with a diameter of 12 mm, which served as the positive electrode plate B1.
[0036] Example 2 Preparation of graphene-like carbon nitride materials: 1 g of hexaaminobenzene trihydrochloride was placed in an alumina crucible and then placed in a tube furnace. After the furnace was evacuated, argon gas was introduced. The degassing-purging process was repeated three times to ensure an argon environment. The furnace temperature was slowly increased to 350°C at a rate of 9°C / min and held at this temperature for 4 hours under an argon gas flow to prevent oxidation. The sample was then slowly cooled to room temperature, and the argon gas was turned off. The sample was collected and subjected to Soxhlet extraction with water and ethanol, respectively, for 24 hours each time. The extracted product was then dried at 70°C and a vacuum of -0.08 MPa for 24 hours. The resulting black powder was the graphene-like carbon nitride material A2.
[0037] Preparation of positive electrode sheet: The graphene-like carbon nitride material A2, Ketjen Black (purchased from Suzhou Shengernuo Energy Technology Co., Ltd., brand name ECP-600JD), and polyvinylidene fluoride (purchased from Dongguan Kelude New Energy Technology Co., Ltd., brand name HSV-900) were mixed and ground in N-methyl-2-pyrrolidone at a mass ratio of 6.5:2.5:1 for 30 min. The resulting slurry was then coated onto carbon-coated aluminum foil using a doctor blade coating method and dried in a vacuum oven at 70°C for 12 h. The aluminum foil coated with the slurry was cut into circular pieces with a diameter of 12 mm, which served as the positive electrode sheet B2.
[0038] Example 3 Preparation of graphene-like carbon nitride materials: 1 g of hexaaminobenzene trihydrochloride was placed in an alumina crucible and then placed in a tube furnace. After the furnace was evacuated, argon gas was introduced. The degassing-purging process was repeated three times to ensure an argon environment. The furnace temperature was slowly increased to 400°C at a rate of 8°C / min and held at this temperature for 5 hours under an argon gas flow to prevent oxidation. The sample was then slowly cooled to room temperature, and the argon gas was turned off. The sample was collected and subjected to Soxhlet extraction with water and ethanol, respectively, for 24 hours each time. The extracted product was then dried at 90°C under a vacuum of -0.1 MPa for 24 hours. The resulting black powder was the graphene-like carbon nitride material A3.
[0039] Preparation of positive electrode sheet: The graphene-like carbon nitride material A3, Ketjen Black (purchased from Suzhou Shengernuo Energy Technology Co., Ltd., brand name ECP-600JD), and polyvinylidene fluoride (purchased from Dongguan Kelude New Energy Technology Co., Ltd., brand name HSV-900) were mixed and ground in N-methyl-2-pyrrolidone at a mass ratio of 7.5:1.5:1 for 30 min. The resulting slurry was then coated onto carbon-coated aluminum foil using a doctor blade method and dried in a vacuum oven at 70°C for 12 h. The aluminum foil coated with the slurry was cut into circular pieces with a diameter of 12 mm, which served as the positive electrode sheet B3.
[0040] Example 4 Preparation of positive electrode: The positive electrode sheet was prepared according to the method of Example 1, except that Ketjen Black was replaced with acetylene black (purchased from Shenzhen Kejing Zhida Technology Co., Ltd., brand name 06000101), resulting in positive electrode sheet B4.
[0041] Example 5 Preparation of positive electrode: The positive electrode sheet was prepared according to the method in Example 1, except that Ketjen Black was replaced with graphene (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., brand name G302114) to obtain positive electrode sheet B5.
[0042] Example 6 Preparation of positive electrode: The positive electrode sheet was prepared according to the method of Example 1, except that Ketjen Black was replaced with conductive graphite (purchased from Shenzhen Kejing Zhida Technology Co., Ltd., grade 06001201), resulting in positive electrode sheet B6.
[0043] Example 7 Preparation of positive electrode: The positive electrode sheet was prepared according to the method in Example 1, except that Ketjen Black was replaced with carbon nanotubes (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., grade C369044), resulting in positive electrode sheet B7.
[0044] Example 8 Preparation of positive electrode: The positive electrode sheet was prepared according to the method in Example 1, except that polyvinylidene fluoride was replaced with polytetrafluoroethylene (purchased from Dongguan Kelude New Energy Technology Co., Ltd., brand name MA-EN-BI-0001), resulting in positive electrode sheet B8.
[0045] Example 9 Preparation of positive electrode: The positive electrode sheet was prepared according to the method of Example 1, except that the polyvinylidene fluoride was replaced with polyvinylidene fluoride-hexafluoropropylene copolymer (purchased from Dongguan Kelude New Energy Technology Co., Ltd., brand name MA-EN-SS-0075), resulting in positive electrode sheet B9.
[0046] Example 10 Preparation of positive electrode: The positive electrode sheet was prepared according to the method in Example 1, except that polyvinylidene fluoride was replaced with sodium alginate (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., brand name S100128), resulting in positive electrode sheet B10.
[0047] Example 11 Preparation of positive electrode: The positive electrode was prepared according to the method of Example 1, except that the mass ratio of graphene-like carbon nitride material A1, Ketjen black and polyvinylidene fluoride was adjusted to 5.5:3.5:1 to obtain positive electrode B11.
[0048] Example 12 Preparation of positive electrode: The positive electrode was prepared according to the method of Example 1, except that the mass ratio of graphene-like carbon nitride material A1, Ketjen black and polyvinylidene fluoride was adjusted to 8.5:0.5:1 to obtain positive electrode B12.
[0049] Test case (1) Morphological and structural characterization: The morphology and structure of graphene-like carbon nitride material A1 were characterized by scanning electron microscopy. Figure 3 Scanning electron microscope image of graphene-like carbon nitride material A1.
[0050] (2) Energy spectrum test: Energy dispersive X-ray spectroscopy was used to test the energy spectrum of graphene-like carbon nitride material A1. Figure 4 (a) in the figure represents the EDS mapping of carbon. Figure 4 (b) in the figure represents the EDS mapping of nitrogen.
[0051] (3) Solid-state NMR test: Solid-state NMR test was performed on graphene-like carbon nitride material A1 using solid-state NMR spectroscopy. Figure 5This is the solid-state carbon NMR spectrum of graphene-like carbon nitride material A1.
[0052] (4) Infrared spectroscopy test: Infrared spectroscopy test was performed on graphene-like carbon nitride material A1 using an infrared spectrometer. Figure 6 The infrared spectrum of graphene-like carbon nitride material A1.
[0053] (5) X-ray diffraction test: X-ray diffraction test was performed on graphene-like carbon nitride material A1 using an X-ray diffractometer. Figure 7 The X-ray diffraction pattern of graphene-like carbon nitride material A1.
[0054] (6) Electrochemical Testing: Coin cells were assembled in an argon-filled glove box with moisture and oxygen content both below 0.1 ppm. Lithium foil was used as the negative electrode and reference electrode, and a polypropylene membrane (Celgard 2500) was used as the separator. The electrolyte was a 1M LiPF6 solution of ethylene carbonate (EC) / diethyl carbonate (DEC) (volume ratio 1:1). 15 μL of electrolyte was added per milligram of electrode material. The cycle stability and rate performance of the battery were tested in a constant temperature chamber at 25°C using a LAND-CT3001A battery testing system within a potential range of 2.4–4.6 V. Cyclic voltammetry (CV) measurements were performed using a CHI760E electrochemical workstation within a potential range of 2.4–4.6 V at a scan rate of 0.1 mV s. -1 Electrochemical impedance spectroscopy (EIS) measurements were performed using a 5 mV AC oscillation with a frequency range of 100 kHz to 0.01 Hz. All electrochemical measurements were performed after the battery was assembled and allowed to stand at room temperature for 12 hours. Figure 8 This is the cyclic voltammetry diagram for the positive electrode B1. Figure 9 This is the charge-discharge curve of the positive electrode B1. Figure 10 This is a rate performance diagram for the positive electrode B1. Figure 11 For the positive electrode B1 at 0.1 A g -1 Cyclic performance at current density. Figure 12 For the positive electrode B1 at 1 A g -1 Cyclic performance at current density.
[0055] The performance parameters of the above embodiments are shown in Table 1 below.
[0056] Table 1
[0057] As can be seen from the results in Table 1, the positive electrode and lithium metal ion battery prepared according to the method of the present invention have significantly higher discharge plateau, initial specific capacity and remaining specific capacity after 1000 cycles.
[0058] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.
Claims
1. A positive electrode material composition, characterized in that, The cathode material composition contains a graphene-like carbon nitride material, a conductive additive, and a binder, wherein the mass ratio of the graphene-like carbon nitride material, the conductive additive, and the binder is (6-8):(1-3):
1.
2. The cathode material composition according to claim 1, characterized in that, The graphene-like carbon nitride material has the structure shown in formula (1). Equation (1).
3. The cathode material composition according to claim 1 or 2, characterized in that, The graphene-like carbon nitride material is prepared by the following process: under an inert atmosphere, hexaaminobenzene trihydrochloride is subjected to a thermal polymerization reaction.
4. The cathode material composition according to claim 3, characterized in that, The conditions for the thermal polymerization reaction include: a temperature of 300-500℃ and a time of 2-6 hours.
5. The positive electrode material composition according to claim 1, characterized in that, The conductive additive is at least one of Ketjen black, conductive carbon black, acetylene black, graphene, conductive graphite, and carbon nanotubes.
6. The cathode material composition according to claim 1, characterized in that, The adhesive is at least one of polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene fluoride-hexafluoropropylene copolymer, and sodium alginate.
7. A positive electrode sheet, comprising a current collector and a positive electrode material composition coated on the current collector, characterized in that, The cathode material composition is the cathode material composition according to claim 1.
8. The positive electrode sheet according to claim 7, characterized in that, The current collector is a carbon-coated aluminum foil.
9. A lithium-ion battery, characterized in that, The lithium-ion battery includes the positive electrode as described in claim 7 or 8.
10. The lithium-ion battery according to claim 9, characterized in that, The electrolyte in the lithium-ion battery is at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium bis(trifluoromethanesulfonyl)imide.