Preparation method of high-capacity nano manganese oxide / polyelectrolyte composite membrane capacitor electrode
By forming a nano-manganese oxide layer on a carbon substrate through in-situ redox self-assembly and electrostatically assembling a polyelectrolyte, the problems of weak binding and slow ion transport of manganese oxide electrodes were solved, achieving high capacity and stable electrode performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HARBIN INST OF TECH
- Filing Date
- 2026-03-27
- Publication Date
- 2026-05-08
AI Technical Summary
Manganese oxide electrodes suffer from weak interfacial bonding, easy detachment of active materials, limited ion transport, and complex processes, making it difficult to achieve high capacity and stability using existing composite methods.
By using an in-situ redox self-assembly method, a layer of nano-manganese oxide was grown in situ on a carbon material substrate, and a multilayer composite film was formed by electrostatic assembly of polyelectrolytes. This achieved synergistic compositing of manganese oxide and polyelectrolytes, enhancing interfacial bonding and ion transport.
The structure stability and ion transport performance of high-capacity nano-manganese oxide/polyelectrolyte composite membrane electrodes have been achieved, improving the cycle life and electrochemical performance of the electrodes. The process is green and simple.
Smart Images
Figure CN122000212A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of flexible capacitor energy storage, specifically to a method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite membrane capacitor electrode. Background Technology
[0002] Supercapacitors, with their high power density, excellent cycle stability, and fast charge / discharge characteristics, have shown great application potential in portable electronic devices, hybrid vehicles, and wearable energy storage devices. Electrode materials are the core determinant of their performance. Manganese oxide (MnO) x Due to its advantages such as high theoretical specific capacitance, abundant resources, environmental friendliness, and low cost, it has become a research hotspot. However, it still faces multiple bottlenecks in practical applications: its low conductivity hinders electron transport, resulting in an actual specific capacitance far lower than the theoretical value; and it is prone to volume expansion and contraction and Mn content fluctuations during charging and discharging. 2+ Dissolution phenomena lead to structural instability and active material detachment, shortening cycle life. Simultaneously, in electrodes prepared by traditional physical mixing or coating methods, the interfacial bonding between manganese oxide and the substrate is weak, making it easily peeled off. Furthermore, the long ion diffusion path in thick electrodes results in poor rate performance. To address these issues, researchers have attempted to composite manganese oxide with conductive carbon materials such as graphene and carbon nanotubes, or conductive polymers. However, carbon material composites often restrict ion diffusion, while conductive polymers suffer from insufficient cycle stability. Polyelectrolytes (such as polydiallyldimethylammonium chloride and sodium polystyrene sulfonate) possess high ion conductivity, good film-forming properties, and tunable interfaces, but current composites with manganese oxide mostly employ physical blending or surface modification, resulting in weak interfacial bonding and low active site loading, making it difficult to fully realize synergistic effects. Therefore, there is an urgent need to develop a manganese oxide-based electrode material with strong interfacial bonding, controllable structure, fast ion transport, and excellent electrochemical performance, along with a green and simple preparation method. Summary of the Invention
[0003] The purpose of this invention is to solve the problems of weak interfacial bonding, easy shedding of active materials, limited ion transport, and complex processes in the prior art of manganese oxide electrodes, and to provide a method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite membrane capacitor electrode.
[0004] This invention provides an in-situ redox self-assembled nano-manganese oxide / polyelectrolyte composite membrane capacitor electrode. This method employs a two-step strategy of "in-situ growth + electrostatic assembly" to achieve the synergistic composite of nano-manganese oxide and polyelectrolyte, resulting in a composite membrane electrode with controllable structure, robust interface, and excellent ion conductivity.
[0005] A method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode is specifically carried out according to the following steps:
[0006] I. Hydrophilization pretreatment:
[0007] First, the carbon material substrate is immersed in anhydrous ethanol for ultrasonic cleaning, then washed with water, then immersed in sodium hydroxide solution, and then washed with water to obtain a hydrophilic carbon material substrate.
[0008] II. Charging process:
[0009] A hydrophilic carbon material substrate was immersed in a Mn(II) solution and reacted for a period of time. During the reaction, the hydroxyl groups on the surface of the carbon material substrate adsorbed Mn(II) through electrostatic interaction. After being removed, the substrate was dried with nitrogen gas to obtain a carbon material substrate adsorbed with Mn(II).
[0010] III. Discharge process:
[0011] A carbon material substrate adsorbed with Mn(II) was immersed in a solution of Mn(VII) ions and reacted for a period of time. During the reaction, Mn(VII) acted as a strong oxidant and reacted with Mn(II) on the surface of the carbon material substrate to undergo a redox reaction, generating manganese oxide nanoparticles in situ. After being removed, the substrate was dried with nitrogen gas.
[0012] IV. In-situ layer-by-layer self-assembly to achieve the charge-discharge cycle process:
[0013] Repeat steps two to three several times to form a continuous, porous nano-manganese oxide layer that is firmly bonded to the carbon material substrate through layer-by-layer self-assembly, thus obtaining a carbon material substrate with a nano-manganese oxide layer on its surface.
[0014] V. Self-assembly of the polyelectrolyte layer:
[0015] ① The carbon material substrate with a nano-manganese oxide layer on its surface is immersed in a polycationic solution for a period of time, and then washed with deionized water to obtain a carbon material substrate containing polycations.
[0016] ② The carbon material substrate containing polycations is immersed in a polyanion solution for a period of time, and then washed with deionized water to obtain a carbon material substrate with a deposited polyelectrolyte composite layer.
[0017] ③ Repeat steps ① to ② several times to deposit polycations and polyanions alternately on the surface of the nano-manganese oxide layer to form a polyelectrolyte composite layer, thus obtaining a high-capacity nano-manganese oxide / polyelectrolyte composite membrane capacitor electrode.
[0018] The principle of this invention:
[0019] In this invention, the nano-manganese oxide layer grown in situ on the surface of a carbon substrate forms the basis for subsequent charge-discharge cycles. During repeated charge-discharge cycles, subsequent Mn(II) is not only adsorbed onto the substrate surface but also enriched on the surface of the already formed manganese oxide nanoparticles; furthermore, the smaller the particle size of the manganese oxide and the larger its specific surface area, the more Mn(II) is enriched. This in-situ layer-by-layer self-assembly significantly increases the local Mn(II) concentration, thereby greatly accelerating the electron transfer rate between it and subsequently added Mn(VII). Ultimately, a continuous porous nanonetwork with a high specific surface area is formed, providing abundant active sites for electrochemical reactions. Based on this, utilizing the negatively charged surface of the nano-manganese oxide layer, a polyelectrolyte multilayer film is formed by electrostatic adsorption through alternating immersion in polycationic and polyanionic solutions of opposite charges. This polyelectrolyte layer is rich in ionizable groups, which, after dissociation in water, construct a three-dimensional continuous ion-conducting network, significantly reducing ion diffusion resistance. Flexible molecular chains tightly encapsulate MnO. x The particles enhance interfacial bonding through electrostatic interactions, inhibiting the shedding of active materials and the dissolution of Mn(II), while buffering volume changes during cycling. Furthermore, the layer thickness can be precisely controlled at the nanoscale through the number of assembly cycles. This design achieves a synergistic "ion-electron dual-pathway" transport system, where the nano-manganese oxide layer provides electronic conductivity and Faraday capacitance, while the polyelectrolyte provides ionic conductivity. The local electric field formed at the interface further promotes ion adsorption / desorption kinetics, and the flexibility of the polyelectrolyte endows the electrode with excellent mechanical flexibility. The entire preparation process is completed in an aqueous phase at room temperature, without the need for high temperature, high pressure, or complex equipment, possessing both green environmental protection and large-scale production potential. This solves key problems of existing manganese oxide electrodes, such as weak interfacial bonding, slow ion transport, and structural instability.
[0020] The beneficial effects of this invention are:
[0021] I. Strong interfacial bonding: The manganese oxide nanoparticle layer generated by the in-situ redox reaction of this invention forms a chemical bond with the hydroxyl groups on the surface of the carbon material substrate, resulting in a strong bond that is not easily peeled off after repeated bending, thus solving the problem of weak bonding of traditional physical coatings.
[0022] II. Excellent ion transport performance: The multilayer polyelectrolyte membrane constructs a three-dimensional ion-conducting network, reducing ion diffusion resistance and enabling rapid electron transfer;
[0023] III. Good structural stability: The polyelectrolyte flexibility acts as a buffer layer, inhibiting the dissolution of Mn(II) and significantly improving the cycle life of the electrode;
[0024] IV. Precise and controllable thickness: By adjusting the number of cycles and the number of assembled layers, this invention can precisely control the electrode structure at the nanoscale to adapt to different capacitance requirements;
[0025] V. Green and simple process: Except for hydrophilization pretreatment, the entire process of this invention is carried out in aqueous phase and at room temperature, without the need for organic solvents, high-temperature calcination or electrochemical equipment, which is low in cost and suitable for industrial production. Attached Figure Description
[0026] Figure 1 The images are SEM images. In the image, A is the SEM image of the carbon paper with a nano-manganese oxide layer on the surface prepared in Example 1, B is the high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode prepared in Example 1, and C is the high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode prepared in Example 2.
[0027] Figure 2 Electrochemical impedance spectroscopy (EIS) spectra of high-capacity nano-manganese oxide / polyelectrolyte composite membrane capacitor electrodes prepared in Examples 1-2 using carbon paper containing a nano-manganese oxide layer, at open-circuit potentials of 0.01-10. 6 A 5mV disturbance is applied within the Hz range;
[0028] Figure 3 The high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode, prepared using carbon paper containing a nano-manganese oxide layer and in Examples 1-2, was tested at a scan rate of 10 mV / s. -1 Cyclic volt-ampere curve at time. Detailed Implementation
[0029] Specific Implementation Method 1: This implementation method is a method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode, which is specifically completed according to the following steps:
[0030] I. Hydrophilization pretreatment:
[0031] First, the carbon material substrate is immersed in anhydrous ethanol for ultrasonic cleaning, then washed with water, then immersed in sodium hydroxide solution, and then washed with water to obtain a hydrophilic carbon material substrate.
[0032] II. Charging process:
[0033] A hydrophilic carbon material substrate was immersed in a Mn(II) solution and reacted for a period of time. During the reaction, the hydroxyl groups on the surface of the carbon material substrate adsorbed Mn(II) through electrostatic interaction. After being removed, the substrate was dried with nitrogen gas to obtain a carbon material substrate adsorbed with Mn(II).
[0034] III. Discharge process:
[0035] A carbon material substrate adsorbed with Mn(II) was immersed in a solution of Mn(VII) ions and reacted for a period of time. During the reaction, Mn(VII) acted as a strong oxidant and reacted with Mn(II) on the surface of the carbon material substrate to undergo a redox reaction, generating manganese oxide nanoparticles in situ. After being removed, the substrate was dried with nitrogen gas.
[0036] IV. In-situ layer-by-layer self-assembly to achieve the charge-discharge cycle process:
[0037] Repeat steps two to three several times to form a continuous, porous nano-manganese oxide layer that is firmly bonded to the carbon material substrate through layer-by-layer self-assembly, thus obtaining a carbon material substrate with a nano-manganese oxide layer on its surface.
[0038] V. Self-assembly of the polyelectrolyte layer:
[0039] ① The carbon material substrate with a nano-manganese oxide layer on its surface is immersed in a polycationic solution for a period of time, and then washed with deionized water to obtain a carbon material substrate containing polycations.
[0040] ② The carbon material substrate containing polycations is immersed in a polyanion solution for a period of time, and then washed with deionized water to obtain a carbon material substrate with a deposited polyelectrolyte composite layer.
[0041] ③ Repeat steps ① to ② several times to deposit polycations and polyanions alternately on the surface of the nano-manganese oxide layer to form a polyelectrolyte composite layer, thus obtaining a high-capacity nano-manganese oxide / polyelectrolyte composite membrane capacitor electrode.
[0042] Specific Implementation Method Two: The difference between this implementation method and Specific Implementation Method One is that the carbon material substrate mentioned in step one is carbon paper, carbon cloth, or carbon felt; the power of the ultrasonic cleaning mentioned in step one is 100W~200W.
[0043] The other steps are the same as in Specific Implementation Method 1.
[0044] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: the water washing in step one uses deionized water, and the washing is performed 2 to 4 times; the concentration of the sodium hydroxide solution in step one is 1 mol / L to 2 mol / L, and the temperature is 50℃ to 60℃. Other steps are the same as in Specific Implementation Method One or Two.
[0045] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: the Mn(II) solution mentioned in step two is a manganese chloride solution or a manganese sulfate solution; the concentration of the Mn(II) solution mentioned in step two is 1 mmol / L to 10 mmol / L. Other steps are the same as in Specific Implementation Methods One to Three.
[0046] Specific Implementation Method 5: The difference between this implementation method and Specific Implementation Methods 1 to 4 is that in step 2, the hydrophilic carbon material substrate is immersed in the Mn(II) solution and reacted for 5 to 10 minutes. The other steps are the same as in Specific Implementation Methods 1 to 4.
[0047] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that: the Mn(VII) ion solution mentioned in step three is a potassium permanganate solution; the concentration of the Mn(VII) ion solution mentioned in step three is 1.5 mmol / L to 15 mmol / L. The other steps are the same as in Specific Implementation Methods One to Five.
[0048] Specific Implementation Method Seven: The difference between this implementation method and Specific Implementation Methods One to Six is that in step three, the carbon material substrate adsorbed with Mn(II) is immersed in a Mn(VII) ion solution and reacted for 2 to 5 minutes. The other steps are the same as in Specific Implementation Methods One to Six.
[0049] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: Step Two to Three are repeated two to ten times in Step Four; the polycationic solution mentioned in Step Five① is a polyallylamine hydrochloride solution, a polyethyleneimine solution, or a polydiallyldimethylammonium chloride solution; the concentration of the polycationic solution mentioned in Step Five① is 1 g / L to 15 g / L. Other steps are the same as in Specific Implementation Methods One to Seven.
[0050] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: the soaking time in step five ① is 5 min to 15 min; the polyanionic solution in step five ② is a sodium polystyrene sulfonate solution or a polyacrylic acid solution. Other steps are the same as in Specific Implementation Methods One to Eight.
[0051] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that: the concentration of the polyanionic solution mentioned in step 5.② is 1 g / L to 15 g / L; the soaking time mentioned in step 5.② is 5 min to 15 min; and steps 5.① to 2.② are repeated two to ten times in step 5.③. Other steps are the same as in Specific Implementation Methods One to Nine.
[0052] The beneficial effects of the present invention are verified using the following embodiments:
[0053] Example 1: A method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode, specifically completed according to the following steps:
[0054] I. Hydrophilization pretreatment:
[0055] First, cut the carbon paper into 2cm×2cm pieces, then soak it in anhydrous ethanol and ultrasonically clean it for 5 minutes at an ultrasonic power of 100W. After taking it out, clean it twice with deionized water, then soak it in a 1mol / L sodium hydroxide solution for 1 hour. After taking it out, clean it twice with deionized water to obtain hydrophilic carbon paper.
[0056] II. Charging process:
[0057] Hydrophilic carbon paper was immersed in a 1 mmol / L manganese chloride solution for 5 min. During the reaction, the hydroxyl groups on the surface of the carbon paper adsorbed Mn(II) through electrostatic interaction, which enriched the carbon paper on the surface. After removal, nitrogen gas was used to blow dry the paper to remove the physically adsorbed Mn(II) ions that were not firmly bound to the membrane surface, thus obtaining carbon paper adsorbed with Mn(II).
[0058] III. Discharge process:
[0059] The carbon paper adsorbed with Mn(II) was immersed in a 7.5 mmol / L potassium permanganate solution for 3 min. During the reaction, Mn(VII) acted as a strong oxidant and reacted with Mn(II) on the surface of the carbon paper to undergo a redox reaction, generating brown-black manganese oxide nanoparticles in situ on the surface of the carbon paper and anchoring them firmly. After being removed, the paper was dried with nitrogen gas to complete one "adsorption-reaction" cycle.
[0060] IV. In-situ layer-by-layer self-assembly to achieve the charge / discharge cycle process:
[0061] Repeat steps two through three four times to form a continuous, porous layer of manganese oxide nanoparticles that is firmly bonded to the carbon substrate through layer-by-layer self-assembly, thus obtaining carbon paper with a surface containing the manganese oxide nanoparticle layer (denoted as [MnO2]). x ]4);
[0062] V. Self-assembly of the polyelectrolyte layer:
[0063] ① The carbon paper with a nano-manganese oxide layer on its surface is immersed in a 10 g / L polydiallyldimethylammonium chloride solution for 5 min. After being taken out, it is washed twice with deionized water to obtain carbon paper containing polycations.
[0064] ② Immerse the carbon paper containing polycations in a 10 g / L sodium polystyrene sulfonate solution for 5 minutes, then wash it twice with deionized water to obtain the carbon paper with the deposited polyelectrolyte composite layer.
[0065] ③ Repeat steps ① to ② twice, alternatingly depositing polycations and polyanions on the surface of the nano-manganese oxide layer to form a polyelectrolyte composite layer, thus obtaining a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode (denoted as [MnO4]). x ]4-[PEM]2).
[0066] Example 2: The difference between this example and Example 1 is that in step 5.3, steps 5.1-5.2 are repeated four times, and polycations and polyanions are alternately deposited on the surface of the nano-manganese oxide layer to form a polyelectrolyte composite layer, thus obtaining a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode (denoted as [MnO4]).x [4-[PEM]4). Other steps and parameters are the same as in Example 1.
[0067] Figure 1 The images are SEM images. In the image, A is the SEM image of the carbon paper electrode, B is the high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode prepared in Example 1, and C is the high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode prepared in Example 2.
[0068] from Figure 1 Image A shows the surface morphology of the nano-manganese oxide layer, revealing a porous structure formed by particle accumulation. Image B shows the polyelectrolyte uniformly covering the surface of the nano-manganese oxide, filling the interparticle gaps. Image C indicates that the film layer is more dense and uniform, with further optimized pore structure. SEM images demonstrate that the polyelectrolyte successfully fills the gaps between the nano-manganese oxide particles through electrostatic self-assembly, forming a continuous composite structure, enhancing interfacial bonding, and providing an effective channel for ion transport.
[0069] Figure 2 Electrochemical impedance spectroscopy (EIS) spectra of high-capacity nano-manganese oxide / polyelectrolyte composite membrane capacitor electrodes prepared in Examples 1-2 using carbon paper containing a nano-manganese oxide layer, at open-circuit potentials of 0.01-10. 6 A 5mV disturbance is applied within the Hz range;
[0070] Figure 2 The results show that as the number of polyelectrolyte assembly layers increases, the charge transfer resistance gradually decreases, indicating that the introduction of polyelectrolyte layers significantly improves the charge transport dynamics at the electrode / electrolyte interface and enhances the conductivity and electrochemical activity of the electrode.
[0071] Figure 3 The high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode, prepared using carbon paper containing a nano-manganese oxide layer and in Examples 1-2, was tested at a scan rate of 10 mV / s. -1 Cyclic volt-ampere curve at time;
[0072] from Figure 3 As can be seen, the current response of the high-capacity nano-manganese oxide / polyelectrolyte composite membrane capacitor electrode is significantly higher than that of the pure manganese oxide electrode. Furthermore, the area enclosed by the curves increases with the increase in the number of polyelectrolyte layers, indicating a significant improvement in specific capacitance. This is attributed to the synergistic enhancement effect of the three-dimensional ion transport network constructed by the polyelectrolyte layers and the interfacial double-layer structure.
Claims
1. A method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode, characterized in that... The preparation method is specifically carried out according to the following steps: I. Hydrophilization pretreatment: First, the carbon material substrate is immersed in anhydrous ethanol for ultrasonic cleaning, then washed with water, then immersed in sodium hydroxide solution, and then washed with water to obtain a hydrophilic carbon material substrate. II. Charging process: A hydrophilic carbon material substrate was immersed in a Mn(II) solution and reacted for a period of time. During the reaction, the hydroxyl groups on the surface of the carbon material substrate adsorbed Mn(II) through electrostatic interaction. After being removed, the substrate was dried with nitrogen gas to obtain a carbon material substrate adsorbed with Mn(II). III. Discharge process: A carbon material substrate adsorbed with Mn(II) was immersed in a solution of Mn(VII) ions and reacted for a period of time. During the reaction, Mn(VII) acted as a strong oxidant and reacted with Mn(II) on the surface of the carbon material substrate to undergo a redox reaction, generating manganese oxide nanoparticles in situ. After being removed, the substrate was dried with nitrogen gas. IV. In-situ layer-by-layer self-assembly to achieve the charge-discharge cycle process: Repeat steps two to three several times to form a continuous, porous nano-manganese oxide layer that is firmly bonded to the carbon material substrate through layer-by-layer self-assembly, thus obtaining a carbon material substrate with a nano-manganese oxide layer on its surface. V. Self-assembly of the polyelectrolyte layer: ① The carbon material substrate with a nano-manganese oxide layer on its surface is immersed in a polycationic solution for a period of time, and then washed with deionized water to obtain a carbon material substrate containing polycations. ② The carbon material substrate containing polycations is immersed in a polyanion solution for a period of time, and then washed with deionized water to obtain a carbon material substrate with a deposited polyelectrolyte composite layer. ③ Repeat steps ① to ② several times to deposit polycations and polyanions alternately on the surface of the nano-manganese oxide layer to form a polyelectrolyte composite layer, thus obtaining a high-capacity nano-manganese oxide / polyelectrolyte composite membrane capacitor electrode.
2. The method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode according to claim 1, characterized in that... The carbon material substrate mentioned in step one is carbon paper, carbon cloth, or carbon felt; the ultrasonic cleaning power mentioned in step one is 100W~200W.
3. The method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode according to claim 1, characterized in that... The water washing mentioned in step one is deionized water, and the number of washing cycles is 2 to 4; the concentration of the sodium hydroxide solution mentioned in step one is 1 mol / L to 2 mol / L, and the temperature is 50℃ to 60℃.
4. The method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode according to claim 1, characterized in that... The Mn(II) solution mentioned in step two is a manganese chloride solution or a manganese sulfate solution; the concentration of the Mn(II) solution mentioned in step two is 1 mmol / L to 10 mmol / L.
5. The method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode according to claim 1, characterized in that... In step two, the hydrophilic carbon material substrate is immersed in Mn(II) solution and reacted for 5 min to 10 min.
6. The method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode according to claim 1, characterized in that... The Mn(VII) ion solution mentioned in step three is a potassium permanganate solution; the concentration of the Mn(VII) ion solution mentioned in step three is 1.5 mmol / L to 15 mmol / L.
7. The method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode according to claim 1, characterized in that... In step three, the carbon material substrate adsorbed with Mn(II) is immersed in a Mn(VII) ion solution and reacted for 2 to 5 minutes.
8. The method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode according to claim 1, characterized in that... Step four is repeated two to ten times from step two to step three; the polycationic solution mentioned in step five① is a polyallylamine hydrochloride solution, a polyethyleneimine solution, or a polydiallyldimethylammonium chloride solution; the concentration of the polycationic solution mentioned in step five① is 1 g / L to 15 g / L.
9. The method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode according to claim 1, characterized in that... The soaking time mentioned in step 5① is 5 min to 15 min; the polyanionic solution mentioned in step 5② is sodium polystyrene sulfonate solution or polyacrylic acid solution.
10. The method for preparing a high-capacity nano-manganese oxide / polyelectrolyte composite film capacitor electrode according to claim 1, characterized in that... The concentration of the polyanionic solution mentioned in step 5② is 1 g / L to 15 g / L; the soaking time mentioned in step 5② is 5 min to 15 min; and steps 5① to 2② are repeated two to ten times in step 5③.