CN-122000212-A - Preparation method of high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode

CN122000212ACN 122000212 ACN122000212 ACN 122000212ACN-122000212-A

Abstract

A preparation method of a high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode relates to the field of flexible capacitor energy storage. The invention aims to solve the problems of weak interface bonding, easy falling of active substances, limited ion transmission and complex process of a manganese oxide electrode in the prior art. The method comprises the steps of hydrophilization pretreatment, charging, discharging, in-situ layer-by-layer self-assembly to realize charging-discharging cycle, and self-assembly of polyelectrolyte layers. According to the invention, the synergistic combination of the nanometer manganese oxide and the polyelectrolyte is realized through the two-step strategy of 'in-situ growth and electrostatic assembly', and the composite membrane electrode with controllable structure, firm interface and excellent ion conduction is obtained. The whole process of the invention is operated at water phase and room temperature, does not need organic solvent, high-temperature calcination or electrochemical equipment, has low cost and is suitable for industrial production.

Inventors

WANG PANPAN
CAI YAJUAN
WANG HAN
ZHANG ZHILIN
JIN XINGYAN
MA JUN

Assignees

哈尔滨工业大学

Dates

Publication Date: 20260508
Application Date: 20260327

Claims (10)

1. The preparation method of the high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode is characterized by comprising the following steps of: 1. Hydrophilization pretreatment: Firstly, soaking a carbon material substrate in absolute ethyl alcohol, carrying out ultrasonic cleaning, then washing, soaking in a sodium hydroxide solution, taking out and washing to obtain a hydrophilized carbon material substrate; 2. And (3) charging: Immersing the hydrophilized carbon material substrate into Mn (II) solution for reaction for a period of time, adsorbing Mn (II) by hydroxyl groups on the surface of the carbon material substrate through electrostatic interaction in the reaction process, taking out, and drying by utilizing nitrogen to obtain the carbon material substrate adsorbed with Mn (II); 3. The discharging process comprises the following steps: immersing a carbon material substrate adsorbed with Mn (II) into Mn (VII) ion solution for reaction for a period of time, wherein Mn (VII) is used as a strong oxidant in the reaction process to perform oxidation-reduction reaction with Mn (II) on the surface of the carbon material substrate, manganese oxide nano particles are generated in situ, and the manganese oxide nano particles are taken out and dried by nitrogen; 4. the charge-discharge cycle process is realized by in-situ layer-by-layer self-assembly: repeating the second step to the third step for several times, forming a continuous porous nano manganese oxide layer firmly combined with the carbon material substrate in a layer-by-layer self-assembly mode, and obtaining the carbon material substrate with the nano manganese oxide layer on the surface; 5. self-assembly of polyelectrolyte layer: ① . Immersing a carbon material substrate with a nano manganese oxide layer on the surface in a polycation solution for a period of time, taking out, and washing with deionized water to obtain the carbon material substrate with polycation; ② . Immersing a carbon material substrate containing polycation in a polyanion solution for a period of time, taking out, and washing with deionized water to obtain the carbon material substrate on which the polyelectrolyte composite layer is deposited; ③ . Repeating the steps five ①~② times, alternately depositing polycation and polyanion on the surface of the nanometer manganese oxide layer to form a polyelectrolyte composite layer, and obtaining the high-capacity nanometer manganese oxide/polyelectrolyte composite membrane capacitor electrode.
2. The method for preparing the high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode according to claim 1, wherein the carbon material substrate in the first step is carbon paper, carbon cloth or carbon felt, and the ultrasonic cleaning power in the first step is 100-200W.
3. The preparation method of the high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode is characterized in that the water washing in the first step is carried out by using deionized water, the washing times are 2-4 times, the concentration of sodium hydroxide solution in the first step is 1-2 mol/L, and the temperature is 50-60 ℃.
4. The preparation method of the high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode is characterized in that the Mn (II) solution in the second step is a manganese chloride solution or a manganese sulfate solution, and the concentration of the Mn (II) solution in the second step is 1-10 mmol/L.
5. The method for preparing the high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode according to claim 1, wherein in the second step, a hydrophilized carbon material substrate is immersed in Mn (II) solution for reaction for 5-10 min.
6. The preparation method of the high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode is characterized in that Mn (VII) ion solution in the step three is potassium permanganate solution, and the concentration of Mn (VII) ion solution in the step three is 1.5 mmol/L-15 mmol/L.
7. The method for preparing the high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode according to claim 1, wherein in the third step, a carbon material substrate adsorbed with Mn (II) is immersed into Mn (VII) ion solution for reaction for 2-5 min.
8. The preparation method of the high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode is characterized in that the steps two to three times to ten times are repeated in the step four, the polycation solution in the step five ① is a polyallylamine hydrochloride solution, a polyethyleneimine solution or a polydiallyldimethyl ammonium chloride solution, and the concentration of the polycation solution in the step five ① is 1g/L to 15g/L.
9. The method for preparing the high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode according to claim 1, wherein the soaking time in the step five ① is 5 min-15 min, and the polyanion solution in the step five ② is sodium polystyrene sulfonate solution or polyacrylic acid solution.
10. The method for preparing the high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode according to claim 1, wherein the concentration of the polyanion solution in the step five ② is 1 g/L-15 g/L, the soaking time in the step five ② is 5 min-15 min, and the step five ③ is repeated for two to ten times with the step five ①~②.

Description

Preparation method of high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode Technical Field The invention relates to the field of flexible capacitance energy storage, in particular to a preparation method of a high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitance electrode. Background Super capacitors have great application potential in the fields of portable electronic equipment, hybrid electric vehicles, wearable energy storage devices and the like by virtue of the characteristics of high power density, excellent cycle stability and rapid charge and discharge, wherein an electrode material is a core for determining the performance of the super capacitors. Manganese oxide (MnO x) becomes a research hot spot due to the advantages of high theoretical specific capacitance, abundant resources, environmental friendliness, low cost and the like, but in practical application, multiple bottlenecks are still faced, namely, the conductivity of the manganese oxide is lower, electron transmission is blocked, the practical specific capacitance is far lower than the theoretical value, volume expansion shrinkage and Mn 2+ dissolution phenomena easily occur in the charge and discharge process, the structure is unstable, active materials fall off, the cycle life is shortened, meanwhile, in an electrode prepared by a traditional physical mixing or coating method, the binding force between the manganese oxide and a substrate interface is weak, the manganese oxide is very easy to peel, the ion diffusion path in a thick electrode is long, and the rate performance is poor. To solve these problems, researchers have tried to compound manganese oxide with conductive carbon materials such as graphene and carbon nanotubes or conductive polymers, however, the carbon material compound often limits ion diffusion, and the conductive polymers have a defect of insufficient cycle stability. Polyelectrolyte (such as polydiallyl dimethyl ammonium chloride and sodium polystyrene sulfonate) has high ion conductivity, good film forming property and interface controllability, but the existing composite of the polyelectrolyte and manganese oxide mostly adopts physical blending or surface modification, has weak interface binding force and low active site loading, and is difficult to fully exert synergistic effect. Therefore, there is a need to develop a manganese oxide-based electrode material with strong interface bonding, controllable structure, fast ion transmission and excellent electrochemical performance, and a green and simple preparation method thereof. Disclosure of Invention The invention aims to solve the problems of weak interface bonding, easy falling of active substances, limited ion transmission and complex process of a manganese oxide electrode in the prior art, and provides a preparation method of a high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode. The invention provides an in-situ redox self-assembled nano manganese oxide/polyelectrolyte composite membrane capacitor electrode. According to the method, the two-step strategy of 'in-situ growth and electrostatic assembly' is adopted to realize the synergistic combination of the nano manganese oxide and the polyelectrolyte, so that the composite membrane electrode with controllable structure, firm interface and excellent ion conduction is obtained. The preparation method of the high-capacity nano manganese oxide/polyelectrolyte composite membrane capacitor electrode is specifically completed by the following steps: 1. Hydrophilization pretreatment: Firstly, soaking a carbon material substrate in absolute ethyl alcohol, carrying out ultrasonic cleaning, then washing, soaking in a sodium hydroxide solution, taking out and washing to obtain a hydrophilized carbon material substrate; 2. And (3) charging: Immersing the hydrophilized carbon material substrate into Mn (II) solution for reaction for a period of time, adsorbing Mn (II) by hydroxyl groups on the surface of the carbon material substrate through electrostatic interaction in the reaction process, taking out, and drying by utilizing nitrogen to obtain the carbon material substrate adsorbed with Mn (II); 3. The discharging process comprises the following steps: immersing a carbon material substrate adsorbed with Mn (II) into Mn (VII) ion solution for reaction for a period of time, wherein Mn (VII) is used as a strong oxidant in the reaction process to perform oxidation-reduction reaction with Mn (II) on the surface of the carbon material substrate, manganese oxide nano particles are generated in situ, and the manganese oxide nano particles are taken out and dried by nitrogen; 4. the charge-discharge cycle process is realized by in-situ layer-by-layer self-assembly: repeating the second step to the third step for several times, forming a continuous porous nano manganese oxide layer firmly combined with the carbon material substra