A preparation method of a manganese dioxide / MXene paper electrode suitable for a flexible aqueous zinc ion battery

Abstract

This invention discloses a method for preparing a manganese dioxide / MXene-like paper electrode suitable for flexible aqueous zinc-ion batteries. Potassium permanganate and ammonium chloride are dissolved in water to obtain a precursor solution, which is then heated to obtain one-dimensional (1D) manganese dioxide nanowires. The 1D manganese dioxide nanowires are immersed in a polydiallyldimethylammonium chloride (PDDA) solution and subjected to ultrasonic treatment. A two-dimensional (2D) MXene dispersion is then added and vigorously stirred to obtain a manganese dioxide / MXene heterojunction electrode material. The manganese dioxide / MXene suspension is then vacuum filtered to obtain a lightweight manganese dioxide / MXene-like paper electrode.

Description

Technical Field

[0001] This invention relates to a method for preparing a paper-like electrode, and more particularly to a method for preparing a manganese dioxide / MXene paper-like electrode suitable for flexible aqueous zinc-ion batteries. Background Technology

[0002] With the development of big data, the demand for real-time data acquisition from electronic devices is increasing in fields such as healthcare, automotive, and aviation. Among these, flexible and wearable electronic products, such as implantable medical devices, wearable health monitoring systems, flexible displays, and smart clothing, are receiving increasing attention. These smart devices need to continue functioning normally when bent and folded. Although significant progress has been made in the research of flexible and wearable electronics, the matching power source has become a bottleneck hindering their application. Currently, flexible batteries are the most suitable for this purpose.

[0003] Although lithium-ion batteries have been accepted by the market, their poor safety and high cost fail to meet the needs of flexible energy storage. Aqueous zinc-ion batteries, due to their high safety and simple manufacturing process, are considered a strong competitor for flexible energy storage devices. Flexible aqueous zinc-ion batteries, as a promising alternative, have attracted widespread attention. Developing high-energy-density flexible electrodes suitable for flexible aqueous zinc-ion batteries has become a top priority.

[0004] To obtain flexible electrodes, active energy storage materials are typically coated onto the surface of metal foil, plastic, or paper. However, this approach suffers from drawbacks such as heavy electrode weight, active material detachment, and poor conductivity. Alternatively, methods exist that combine other conductive flexible carriers with active materials to prepare flexible electrodes. For example, invention publication CN114613984A discloses a self-supporting manganese dioxide cathode material and its application in zinc / sodium batteries, where the self-supporting electrode uses an MXene flexible film to support manganese dioxide. These are all indirect flexible electrodes, where the proportion of inactive energy storage material is relatively high, leading to a decrease in the overall specific capacity of the flexible electrode. Summary of the Invention

[0005] To overcome the aforementioned defects in the prior art, this invention provides a method for preparing a manganese dioxide / MXene-type paper electrode suitable for flexible aqueous zinc-ion batteries. This method solves the problems of low overall specific capacity and poor electrochemical energy storage activity of current flexible electrodes, and can prepare a lightweight paper-like electrode with high energy density for use as the positive electrode of flexible aqueous zinc-ion batteries.

[0006] This invention provides a method for preparing a manganese dioxide / MXene-type paper electrode suitable for flexible aqueous zinc-ion batteries, comprising the following steps:

[0007] 1) Preparation of manganese dioxide nanowires: Potassium permanganate and ammonium chloride were dissolved in water to obtain a precursor solution, and the precursor solution was heated to react and obtain manganese dioxide nanowires;

[0008] 2) Preparation of manganese dioxide / MXene heterojunction electrode material: Manganese dioxide nanowires were immersed in polydiallyldimethylammonium chloride solution and ultrasonically treated, and then MXene dispersion was added and stirred vigorously to obtain manganese dioxide / MXene heterojunction electrode material.

[0009] 3) Preparation of manganese dioxide / MXene paper electrode: Manganese dioxide / MXene suspension was filtered under vacuum to obtain manganese dioxide / MXene paper electrode.

[0010] The precursor solution described in step 1) contains potassium ions and ammonium ions in a molar ratio of 1-2:1.

[0011] The heating growth temperature described in step 1) is 190-210℃, and the heating growth time is 72-120h.

[0012] The manganese dioxide nanowires obtained in step 1) have a length greater than 15 μm and a diameter of 20-100 nm.

[0013] The mass percentage concentration of the polydiallyldimethylammonium chloride solution in step 2) is 0.1%-1%, and the mass ratio of manganese dioxide to MXene in the manganese dioxide / MXene heterojunction electrode material is 10-100:1.

[0014] The concentration of the manganese dioxide / MXene suspension in step 3) is 0.1-0.4 mg / ml, and the vacuum filtration time is 0.5-3 h.

[0015] The thickness of the manganese dioxide / MXene paper electrode mentioned in step 3) is 10-50 μm.

[0016] Beneficial effects:

[0017] 1) The manganese dioxide / MXene paper electrode provided by the present invention has excellent flexibility and can be bent and wound at different angles without damaging the electrode structure.

[0018] 2) The manganese dioxide / MXene paper-like electrode provided by this invention constructs a heterogeneous interface between the MnO2 and MXene phases, enabling an internal electric field, reducing the ion diffusion energy barrier, and enhancing reaction kinetics and electrochemical energy storage activity. The lightweight manganese dioxide / MXene paper-like electrode provided by this invention exhibits high energy density, excellent cycle performance, and a simple, low-cost preparation method suitable for large-scale production. The main energy storage active material in the paper-like electrode constructed by this invention accounts for more than 90% of the total mass, resulting in a high overall specific capacity.

[0019] 3) The heterogeneous interface between the MnO2 and MXene phases in the manganese dioxide / MXene paper electrode provided by this invention can realize an internal electric field, reduce the ion diffusion energy barrier, and enhance reaction kinetics and electrochemical energy storage activity.

[0020] 4) The manganese dioxide / MXene paper-like electrode provided by this invention exhibits excellent electrochemical performance when applied to flexible aqueous zinc-ion batteries. The paper-like electrode of this invention is constructed by creating a heterostructure of 1D MnO2 nanowires and 2D MXene, and rationally designing and preparing a lightweight film as a direct flexible electrode. It not only exhibits excellent flexibility, but also has a high overall specific capacity with the main energy storage active material MnO2 accounting for more than 90%. The discharge specific capacity is as high as 339.4 mAh / g.

[0021] 5) Compared with indirect flexible electrodes based on metal foil, plastic, paper, and conductive materials, the manganese dioxide / MXene paper electrode provided by this invention overcomes the disadvantages of heavy electrode weight, easy shedding of active material, and high proportion of inactive material. Attached Figure Description

[0022] Figure 1 This is a SEM image of the manganese dioxide nanowires grown in step 1) of the present invention.

[0023] Figure 2 This is a TEM image of the manganese dioxide / MXene prepared in step 2) of Example 2 of the present invention.

[0024] Figure 3 This is a diagram illustrating the manganese dioxide / MXene paper electrode and its flexibility prepared in step 3) of Embodiment 2 of the present invention.

[0025] Figure 4 The charge-discharge curves of the manganese dioxide / MXene paper electrode prepared in Example 2 of this invention are shown in the figure.

[0026] Figure 5 The manganese dioxide / MXene paper electrode prepared in Example 2 of this invention is used to drive a small light bulb using a flexible quasi-solid-state zinc-ion battery. Detailed Implementation

[0027] The present invention will be further illustrated by detailed implementation examples below, making the technical solution and advantages of the present invention clearer. However, the technical parameters in the following implementation examples are not intended to limit the present invention.

[0028] A method for preparing a manganese dioxide / MXene-type paper electrode suitable for flexible aqueous zinc-ion batteries, the technical solution of which is as follows:

[0029] Step 1) Dissolve potassium permanganate and ammonium chloride in water to obtain a precursor solution, and heat the precursor solution to react and obtain manganese dioxide nanowires.

[0030] Step 2) Immerse manganese dioxide nanowires in 50 ml of polydiallyldimethylammonium chloride (PDDA) solution for ultrasonic treatment, then add MXene dispersion and stir vigorously to obtain manganese dioxide / MXene heterojunction electrode material.

[0031] Step 3) Obtain a manganese dioxide / MXene paper electrode by vacuum filtration of 50 ml of manganese dioxide / MXene suspension.

[0032] In the preparation scheme, preferably, the molar ratio of potassium ions to ammonium ions in the precursor solution in step 1) is 2:1 to 1:1.

[0033] In the preparation scheme, preferably, the heating growth temperature in step 1) is 190-210℃ and the heating growth time is 72-120h.

[0034] In the preparation scheme, preferably, the length of the manganese dioxide nanowires obtained in step 1) is greater than 15 μm and the diameter is 20-100 nm.

[0035] In the preparation scheme, preferably, the mass percentage concentration of the polydiallyl dimethylammonium chloride (PDDA) solution in step 2) is 0.1%-1%, and the mass ratio of manganese dioxide to MXene in the manganese dioxide / MXene heterojunction electrode material is 10:1-100:1.

[0036] In the preparation scheme, preferably, the concentration of the manganese dioxide / MXene suspension in step 3) is 0.1-0.4 mg / ml, and the vacuum filtration time is 0.5-3 h.

[0037] In the preparation scheme, preferably, the thickness of the manganese dioxide / MXene paper electrode in step 3) is 10-50 μm.

[0038] Example 1

[0039] This invention provides a method for preparing a manganese dioxide / MXene-based paper electrode suitable for flexible aqueous zinc-ion batteries, wherein the mass ratio of manganese dioxide to MXene is 100:1, and includes the following steps:

[0040] 1) Growth of manganese dioxide nanowires.

[0041] 1 mmol of potassium permanganate and 1 mmol of ammonium chloride were dissolved in 30 ml of deionized water and magnetically stirred for 30 min at room temperature to obtain a red transparent precursor solution. The precursor solution was poured into a 50 ml polytetrafluoroethylene high-pressure reactor and placed in a forced-air drying oven for heating and reaction at 200 °C for 96 h to obtain manganese dioxide nanowires.

[0042] 2) Preparation of manganese dioxide / MXene heterojunction electrode material.

[0043] 0.5 g of manganese dioxide nanowires were immersed in 50 ml of 0.5% polydiallyldimethylammonium chloride (PDDA) solution and sonicated for 30 min. Then, 1 ml of 5 mg / ml MXene dispersion was slowly added and stirred vigorously for 1 h. The product was washed with deionized water and ethanol, centrifuged three times, and vacuum dried at 60 °C overnight to obtain manganese dioxide / MXene heterojunction electrode material.

[0044] 3) Forming of manganese dioxide / MXene paper electrodes.

[0045] First, take 5 mg of manganese dioxide / MXene and magnetically disperse it in 50 ml of deionized water. Then, vacuum filter the 50 ml manganese dioxide / MXene suspension. Finally, vacuum dry the filter paper loaded with the manganese dioxide / MXene membrane overnight at 60°C to obtain a manganese dioxide / MXene paper electrode.

[0046] Example 2

[0047] This invention provides a method for preparing a manganese dioxide / MXene-based paper electrode suitable for flexible aqueous zinc-ion batteries, wherein the mass ratio of manganese dioxide to MXene is 100:5, and includes the following steps:

[0048] 1) Growth of manganese dioxide nanowires.

[0049] 1 mmol of potassium permanganate and 1 mmol of ammonium chloride were dissolved in 30 ml of deionized water. The solution was magnetically stirred for 30 min at room temperature to obtain a red, transparent precursor solution. The precursor solution was poured into a 50 ml polytetrafluoroethylene high-pressure reactor. The reactor was placed in a forced-air drying oven and heated at 200 °C for 96 h to obtain manganese dioxide nanowires. Figure 1 As shown, the 1D manganese dioxide nanowires are longer than 15 μm, and the interlacing of the ultra-long nanowires gives them flexibility.

[0050] 2) Preparation of manganese dioxide / MXene heterojunction electrode material.

[0051] 0.5 g of manganese dioxide nanowires were immersed in 50 ml of 0.5% polydiallyldimethylammonium chloride (PDDA) solution and sonicated for 30 min. Then, 5 ml of 5 mg / ml MXene dispersion was slowly added and stirred vigorously for 1 h. The product was washed with deionized water and ethanol, centrifuged three times, and vacuum dried overnight at 60 °C to obtain manganese dioxide / MXene heterojunction electrode material. Figure 2 As shown, 1D manganese dioxide nanowires and 2D MXene electrostatically assemble to form a heterostructure.

[0052] 3) Forming of manganese dioxide / MXene paper electrodes.

[0053] First, disperse 5 mg of manganese dioxide / MXene in 50 ml of deionized water using magnetic stirring. Then, vacuum filter the 50 ml manganese dioxide / MXene suspension. Finally, vacuum dry the filter paper loaded with the manganese dioxide / MXene membrane overnight at 60°C to obtain a manganese dioxide / MXene paper electrode. Figure 3 As shown, manganese dioxide / MXene paper electrodes have excellent flexibility and can be bent and wound at different angles without damaging the electrode structure.

[0054] The charge-discharge curves of the manganese dioxide / MXene-type paper electrode prepared in the examples applied to a quasi-solid-state zinc-ion battery are shown below. Figure 4 As shown, at a current density of 0.1 A / g, the initial discharge specific capacity is 339.4 mAh / g, and after 50 charge-discharge cycles, it still maintains a high specific capacity of 333.3 mAh / g. Figure 5 As shown, the quasi-solid-state zinc-ion battery assembled with manganese dioxide / MXene paper electrodes can be used to drive a small light bulb, indicating that this lightweight manganese dioxide / MXene paper electrode has promising applications.

[0055] Example 3

[0056] This invention provides a method for preparing a manganese dioxide / MXene-based paper electrode suitable for flexible aqueous zinc-ion batteries, wherein the mass ratio of manganese dioxide to MXene is 100:10, and includes the following steps:

[0057] 1) Growth of manganese dioxide nanowires.

[0058] 1 mmol of potassium permanganate and 1 mmol of ammonium chloride were dissolved in 30 ml of deionized water and magnetically stirred for 30 min at room temperature to obtain a red transparent precursor solution. The precursor solution was poured into a 50 ml polytetrafluoroethylene high-pressure reactor and placed in a forced-air drying oven for heating and reaction at 200 °C for 96 h to obtain manganese dioxide nanowires.

[0059] 2) Preparation of manganese dioxide / MXene heterojunction electrode material.

[0060] 0.5 g of manganese dioxide nanowires were immersed in 50 ml of 0.5% polydiallyldimethylammonium chloride (PDDA) solution and sonicated for 30 min. Then, 10 ml of 5 mg / ml MXene dispersion was slowly added and stirred vigorously for 1 h. The product was washed with deionized water and ethanol, centrifuged three times, and vacuum dried at 60 °C overnight to obtain manganese dioxide / MXene heterojunction electrode material.

[0061] 3) Forming of manganese dioxide / MXene paper electrodes.

[0062] First, take 5 mg of manganese dioxide / MXene and magnetically disperse it in 50 ml of deionized water. Then, vacuum filter the 50 ml manganese dioxide / MXene suspension. Finally, vacuum dry the filter paper loaded with the manganese dioxide / MXene membrane overnight at 60°C to obtain a manganese dioxide / MXene paper electrode.

Claims

1. A method for the preparation of a manganese dioxide / MXene paper-like electrode suitable for flexible aqueous zinc-ion batteries, characterized in that, The method comprises the following steps: 1) preparing manganese dioxide nanowires: dissolving potassium permanganate and ammonium chloride in water to obtain a precursor solution, and heating the precursor solution to obtain manganese dioxide nanowires with a length of greater than 15 μm and a diameter of 20-100 nm; the heating temperature is 190-210℃, and the heating time is 72-120 h; 2) preparing a manganese dioxide / MXene heterojunction electrode material: immersing the manganese dioxide nanowires in a polydiallyldimethylammonium chloride solution and performing ultrasonic treatment, and then adding a MXene dispersion liquid and stirring to obtain a manganese dioxide / MXene heterojunction electrode material; wherein the manganese dioxide nanowires and the MXene are electrostatically assembled to form a heterojunction; 3) preparing a manganese dioxide / MXene paper-like electrode: dispersing the manganese dioxide / MXene by magnetic stirring in deionized water to form a suspension, and then obtaining a manganese dioxide / MXene paper-like electrode by vacuum filtration, wherein the thickness of the manganese dioxide / MXene paper-like electrode is 10-50 μm.

2. The method according to claim 1, characterized in that, In step 1), the amount-of-substance ratio of potassium ions to ammonium ions in the precursor solution is 1-2:

1.

3. The method according to claim 1, characterized in that, In step 2), the mass percentage concentration of the polydiallyldimethylammonium chloride solution is 0.1%-1%, and the mass ratio of manganese dioxide to MXene in the manganese dioxide / MXene heterojunction electrode material is 10-100:

1.

4. The method according to claim 1, characterized in that, In step 3), the concentration of the manganese dioxide / MXene suspension is 0.1-0.4 mg / ml, and the vacuum filtration time is 0.5-3 h.

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