A mxene / conductive cellulose / conductive polymer high-conductive ink, a preparation method thereof and application thereof in flexible micro-supercapacitors

Abstract

The patent provides a MXene / CC / PEDOT:PSS high-conductivity ink and a preparation method thereof, and further prepares a high-performance flexible micro-supercapacitor through a 3D printing technology.The application takes the conductive polymer PEDOT:PSS as a spacer between MXene nanosheets, effectively prevents the stacking of MXene nanosheets, and provides more conductive paths.The mutual interaction between CC and MXene through hydrogen bonds and ionic bonds promotes the interface bonding force between them, resulting in high yield stress and unique shear thinning behavior.The "soft inside and hard outside" structure of CC improves the mechanical properties of the electrode and provides a certain capacity.The micro-supercapacitor prepared by the 3D printing technology has excellent electrochemical performance due to the synergistic effect of the electrode material and the unique structure, and has great application potential in the field of flexible energy storage.

Description

Technical Field

[0001] This invention relates to a method for preparing an MXene / conductive cellulose / conductive polymer ink, belonging to the field of functional electrode materials, and is mainly used in devices such as flexible micro supercapacitors. Background Technology

[0002] With the rapid development of portable wearable electronic products, there is an urgent need to develop miniaturized flexible new energy storage devices to match them. Miniature supercapacitors (MSCs) have attracted widespread attention in various energy storage systems due to their high power density, fast charge / discharge capability, ultra-long cycle life, and easy miniaturization and integration. However, achieving large-scale production of high-performance MSCs mainly depends on energy density. High-resolution 3D printing technology can precisely increase thickness during layer-by-layer manufacturing, effectively improving the device's surface capacitance and surface energy density. Currently, the challenge of 3D printing lies in preparing inks with excellent rheological properties.

[0003] Ti3C2T x MXene, a family of two-dimensional transition metal carbides / nitrides, is considered a promising electrode material for flexible supercapacitors due to its inherent metallic conductivity, large specific surface area, and high packing density. MXene also possesses abundant surface functional groups, such as -O, -OH, and -F, which endow it with hydrophilic properties, enabling it to effectively form suspensions for use as inks. However, at high concentrations, MXene nanosheets readily recombine due to van der Waals forces, and the weak interactions between adjacent nanosheets result in poor flexibility and mechanical properties in pure MXene materials, severely limiting its practical application in flexible electronic devices. To address these stacking issues, an effective strategy is to introduce spacers between MXene nanosheets. Poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS) has proven effective as both an interlayer spacer and a binder, forming a stable three-dimensional network structure and thus improving its electrochemical performance. Existing methods to improve mechanical properties include adding cellulose nanofibers to MXene inks, but this results in a loss of some electrochemical properties, leading to a decrease in the performance of the resulting supercapacitor.

[0004] The following publicly available patents and documents were found through a search: CN 113004556A discloses a method for preparing CNF / MXene-silver nanowire composite films, comprising five steps: Step 1, synthesizing a layered MXene dispersion using HCl / LiF according to etching and ultrasonic layering methods; Step 2, ultrasonically dispersing CNF in deionized water to obtain a uniformly dispersed CNF dispersion; Step 3, obtaining a uniform MXene / CNF mixed dispersion by ultrasonic dispersion and mechanical stirring of Step 1 and Step 2; Step 4, dispersing AgNWs solution in cellulose nanofiber dispersion to obtain a uniform AgNWs / CNF mixed dispersion; Step 5, using vacuum-assisted filtration, sequentially filtering the AgNWs / CNF mixed dispersion and the MXene / CNF mixed dispersion onto a mixed fiber membrane to obtain a multilayer CNF / MXene-silver nanowire composite film. This patent application utilizes a layered structure design to prepare an ultrathin film with high mechanical strength and efficient electromagnetic shielding performance; however, the use of easily oxidized silver nanowires in this film affects its electrical resistance. CN 113817230A discloses a method for preparing a CNF-MXene-PEI high-strength, high-conductivity material, comprising three steps: Step 1, using acid hydrolysis to prepare a cellulose nanofiber dispersion from palm fibers; Step 2, using etching and ultrasonic layering methods to synthesize a layered MXene dispersion using HCl / LiF; Step 3, polyethyleneimine-induced self-assembly of cellulose nanofibers and MXene nanosheets, followed by filtration and drying to obtain the CNF-MXene-PEI high-strength, high-conductivity material. The CNF-MXene-PEI high-strength, high-conductivity material prepared by this invention exhibits excellent mechanical and electrical properties. However, the cellulose nanofibers in this patent only provide certain mechanical properties and do not optimize electrical properties. Summary of the Invention

[0005] To address the problems existing in the prior art, this patent provides a highly conductive ink based on MXene / conductive cellulose / conductive polymer and its preparation method, and further utilizes 3D printing technology to fabricate high-performance micro supercapacitors. This invention utilizes the "flexible exterior, rigid interior" structure of conductive cellulose (CC) to improve mechanical properties and provide a certain capacitance. The interaction of hydrogen and ionic bonds between CC and MXene promotes interfacial bonding, thereby improving mechanical properties. This interaction leads to high yield stress and unique shear thinning behavior, giving the ink excellent 3D printing capabilities. This invention first homogenizes MXene, CC, and PEDOT:PSS using a physical mixing method, and then obtains a high-quality MXene / CC / PEDOT:PSS electrode material with a high mass loading using 3D printing technology. In the MXene / CC / PEDOT:PSS highly conductive ink, the mass ratio of MXene to CC is 8:1, and the amount of PEDOT:PSS added is 0% to 100% of the mass of CC. Specifically, the technical solution adopted by this invention is:

[0006] A method for preparing the MXene / CC / PEDOT:PSS highly conductive ink as described in claim 1, comprising the following steps:

[0007] S1, Preparation of CC;

[0008] S2. Preparation of MXene nanosheet dispersion;

[0009] S3, MXene, CC, and PEDOT:PSS are physically mixed and concentrated to obtain MXene / CC / PEDOT:PSS highly conductive ink for use as an electrode material in micro supercapacitors.

[0010] The conductive polymer PEDOT:PSS, acting as an interlayer spacer, effectively reduces the stacking of MXene sheets, providing an efficient pathway for ion transport and diffusion. Importantly, the "flexible exterior, rigid interior" structure of CC is cleverly utilized to improve mechanical properties and provide certain electrochemical performance. The interaction between CC and MXene via hydrogen and ionic bonds promotes interfacial bonding, thereby enhancing mechanical properties. This interaction leads to high yield stress and unique shear-thinning behavior, making it an excellent 3D printing ink.

[0011] The preparation of CC in step S1 includes the following steps:

[0012] X1. Conductive cellulose materials were prepared by confined carbonization using bamboo powder, corn stalks, sawdust, and flax fiber as raw materials.

[0013] X2. Place 0.5-1.25g of bamboo powder in a three-necked flask and dissolve it in 80mL of 64wt% sulfuric acid. Note that the temperature should be between 10-25℃. Seal the flask completely with a rubber stopper and purge it with nitrogen gas for 30-60 minutes.

[0014] X3. Heat the reaction to 40-50°C and stir for 30 minutes. Ensure the entire process is sealed and protected with high-throughput N2.

[0015] X4. Next, perform self-confined carbonization of the nano-surface by raising the temperature to 90-100℃ and stirring rapidly for 1-4 hours. Note that the process should be completely sealed and protected with high-throughput N2.

[0016] X5. After the reaction is complete, the mixture is rapidly cooled to room temperature in a cold water bath, then dialyzed to neutral, and freeze-dried to obtain conductive cellulose.

[0017] The preparation of the MXene nanosheet dispersion in step S2 includes the following steps:

[0018] W1. Etch 1g Ti3AlC2 with 9-12mol / L hydrochloric acid and 1-1.2g lithium fluoride for 24-48h;

[0019] W2. After the reaction in step W1 is completed, centrifuge and wash the mixture until the pH value is 5-7.

[0020] W3. Collect the precipitate and sonicate it at 100-400W power for 20-60 minutes. Note that this process requires the introduction of inert gas for protection and an ice-water bath for protection.

[0021] W4. After sonication, centrifuge at 3500 r / min for 20-60 min, collect the supernatant to obtain a 5-15 mg / mL MXene nanosheet dispersion.

[0022] The preparation of the MXene / CC / PEDOT:PSS highly conductive ink in step S3 includes the following steps:

[0023] S3-1. Mix the conductive cellulose from step S1 and the MXene nanosheet dispersion from step S2 evenly, and add PEDOT:PSS dropwise while stirring to obtain a homogeneous dispersion of MXene / CC / PEDOT:PSS. The mass ratio of MXene, CC and PEDOT:PSS is 8:1:(0~1).

[0024] S3-2. The homogeneous dispersion in step S3-1 is concentrated using a superabsorbent polymer to obtain MXene / CC / PEDOT:PSS ink suitable for 3D printing.

[0025] The present invention also provides an electronic device comprising the above-described MXene-based micro supercapacitor.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] (1) The conductive cellulose used in this invention does not require high-temperature calcination for preparation. The process is simple and the cost is low. The resulting conductive cellulose has certain electrochemical properties and can achieve a high loading of electrochemical substances.

[0028] (2) The experimental design of this invention is ingenious. The conductive polymer PEDOT:PSS is introduced as an interlayer spacer, which prevents the stacking of MXene nanosheets through interaction forces. This provides more conductive pathways in the system, which is conducive to the transport of electrolyte ions and ensures the high electrochemical performance of the material. On this basis, the mechanical and electrochemical properties are improved by utilizing CC. Moreover, this interaction force leads to high yield stress and unique shear thinning behavior, which makes the ink have excellent 3D printing capabilities.

[0029] (3) The micro supercapacitor prepared by the present invention using 3D printing technology has excellent electrochemical performance due to the unique structure of the microelectrode. It has high areal capacitance, energy density and power density, and has great application potential in the field of flexible energy storage. Attached Figure Description

[0030] Figure 1 This is an optical photograph of the micro supercapacitor prepared in Example 1 of the present invention.

[0031] Figure 2 The electrochemical performance test of the micro supercapacitor prepared in Example 1 of the present invention is shown in (a) as the cyclic voltammetry curve of Example 1 and (b) as the constant current charge-discharge curve of Example 1.

[0032] Figure 3 The electrochemical performance test of the micro supercapacitor prepared in Example 2 of the present invention is shown in (a) as the cyclic voltammetry curve of Example 2 and (b) as the constant current charge-discharge curve of Example 2.

[0033] Figure 4 The electrochemical performance test of the micro supercapacitor prepared in Example 3 of the present invention is shown in (a) as the cyclic voltammetry curve of Example 3 and (b) as the constant current charge-discharge curve of Example 3.

[0034] Figure 5 This is a comparison of the areal capacitance of the micro supercapacitors prepared in Examples 1, 2 and 3 of this invention. Detailed Implementation

[0035] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0036] Example 1

[0037] This embodiment provides a method for preparing an MXene / CC / PEDOT:PSS highly conductive ink. First, MXene, CC, and PEDOT:PSS are homogeneously mixed using a physical mixing method. Then, 3D printing technology is used to obtain an MXene / CC / PEDOT:PSS electrode material with a high mass loading. In the MXene / CC / PEDOT:PSS highly conductive ink, the mass ratio of MXene to CC is 8:1, and the amount of PEDOT:PSS added is 25% of the mass of CC.

[0038] The preparation method of the MXene / CC / PEDOT:PSS high conductivity ink is as follows:

[0039] S1. Preparation of conductive cellulose; specifically including the following steps:

[0040] X1. Conductive cellulose materials were prepared by confined carbonization using bamboo powder as raw material.

[0041] X2. Place 0.75g of bamboo powder in a three-necked flask, dissolve it in 80mL of 64wt% sulfuric acid at 15℃, seal it completely with a rubber stopper, and purge with nitrogen for 30min.

[0042] X3. Heat the reaction to 50°C and stir for 30 minutes. Ensure the entire process is sealed and protected with high-throughput N2.

[0043] X4. Next, perform self-confined carbonization of the nano-surface by raising the temperature to 90°C and stirring rapidly for 1 hour. Note that the entire process should be sealed and protected with high-throughput N2.

[0044] X5. After the reaction is complete, the mixture is rapidly cooled to room temperature in a cold water bath, then dialyzed to neutral, and freeze-dried to obtain conductive cellulose.

[0045] S2. Preparation of MXene nanosheet dispersion; specifically including the following steps:

[0046] W1. Etch 1g Ti3AlC2 with 9mol / L hydrochloric acid and 1g lithium fluoride for 24h;

[0047] W2. After the reaction in step W1 is completed, centrifuge and wash the mixture until the pH value is 5-7.

[0048] W3. Collect the precipitate and sonicate it at 100-400W power for 20-60 minutes. Note that this process requires the introduction of inert gas for protection and an ice-water bath for protection.

[0049] W4. After sonication, centrifuge at 3500 r / min for 20 min, collect the supernatant to obtain an 8 mg / mL MXene nanosheet dispersion.

[0050] The preparation of the MXene / CC / PEDOT:PSS highly conductive ink in step S3 includes the following steps:

[0051] S3-1. Mix the conductive cellulose from step S1 and the MXene nanosheet dispersion from step S2 evenly, and add PEDOT:PSS dropwise while stirring to obtain a homogeneous dispersion of MXene / CC / PEDOT:PSS, with a mass ratio of MXene, CC and PEDOT:PSS of 8:1:0.25.

[0052] S3-2. The homogeneous dispersion in step S3-1 is concentrated using a superabsorbent polymer to obtain MXene / CC / PEDOT:PSS ink suitable for 3D printing.

[0053] 1 g of polyvinyl alcohol (PVA) was added to 10 mL of 1 M H2SO4 solution and stirred at 95 °C for 2 h to dissolve, thus obtaining PVA / H2SO4 electrolyte.

[0054] Using PET as a substrate, ink was loaded onto the substrate by 3D printing and freeze-dried for 24 hours to obtain a microelectrode; then, PVA / H2SO4 electrolyte was coated onto the microelectrode to obtain a flexible micro supercapacitor, denoted as MCP-1.

[0055] Electrochemical performance tests were performed on a CHI660E electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd.). All tests were conducted at room temperature, with linear sweep voltammetry curves ranging from 0 to 0.6 V at scan rates of 10–100 mV / s. Constant current charge-discharge curves were performed in the range of 0.2–2 mA / cm². -2 The current density was measured.

[0056] Figure 1 a is an optical photograph of a micro supercapacitor 3D printed using the MXene / CC / PEDOT:PSS highly conductive ink prepared in this embodiment. Figure 2 This is an electrochemical performance test of the micro supercapacitor prepared in the embodiments of the present invention. Figure 2 Cyclic voltammetry yielded an approximately rectangular cyclic voltammetry curve, exhibiting good capacitive behavior at scan rates from 10 mV / s to 100 mV / s. Figure 2The constant current charge-discharge curve exhibits an isosceles triangle shape, demonstrating good coulombic efficiency.

[0057] Example 2

[0058] This embodiment provides a method for preparing an MXene / CC / PEDOT:PSS highly conductive ink. First, MXene, CC, and PEDOT:PSS are homogeneously mixed using a physical mixing method. Then, 3D printing technology is used to obtain an MXene / CC / PEDOT:PSS electrode material with a high mass loading. In the MXene / CC / PEDOT:PSS highly conductive ink, the mass ratio of MXene to CC is 8:1, and the amount of PEDOT:PSS added is 50% of the mass of CC.

[0059] The preparation method of the MXene / CC / PEDOT:PSS high conductivity ink is as follows:

[0060] S1. Preparation of conductive cellulose; specifically including the following steps:

[0061] X1. Conductive cellulose materials were prepared by confined carbonization using bamboo powder as raw material.

[0062] X2. Take 1g of bamboo powder and place it in a three-necked flask. Dissolve it in 80mL of 64wt% sulfuric acid at 10℃. Seal the flask completely with a rubber stopper and purge it with nitrogen for 40min.

[0063] X3. Heat the reaction to 45°C and stir for 30 minutes. Ensure the entire process is sealed and protected with high-throughput N2.

[0064] X4. Next, perform self-confined carbonization of the nano-surface. Raise the temperature to 100℃ and stir rapidly for 1 hour. Note that the entire process should be sealed and protected with high-throughput N2.

[0065] X5. After the reaction is complete, the mixture is rapidly cooled to room temperature in a cold water bath, then dialyzed to neutral, and freeze-dried to obtain conductive cellulose.

[0066] S2. Preparation of MXene nanosheet dispersion; specifically including the following steps:

[0067] W1. Etch 1g Ti3AlC2 with 12mol / L hydrochloric acid and 1.2g lithium fluoride for 36h;

[0068] W2. After the reaction in step W1 is completed, centrifuge and wash the mixture until the pH value is 5-7.

[0069] W3. Collect the precipitate and sonicate it at 100-400W power for 20-60 minutes. Note that this process requires the introduction of inert gas for protection and an ice-water bath for protection.

[0070] W4. After sonication, centrifuge at 3500 r / min for 30 min, collect the supernatant to obtain a 10 mg / mL MXene nanosheet dispersion.

[0071] The preparation of the MXene / CC / PEDOT:PSS highly conductive ink in step S3 includes the following steps:

[0072] S3-1. Mix the conductive cellulose from step S1 and the MXene nanosheet dispersion from step S2 evenly, and add PEDOT:PSS dropwise while stirring to obtain a homogeneous dispersion of MXene / CC / PEDOT:PSS, with a mass ratio of MXene, CC and PEDOT:PSS of 8:1:0.5.

[0073] S3-2. The homogeneous dispersion in step S3-1 is concentrated using a superabsorbent polymer to obtain MXene / CC / PEDOT:PSS ink suitable for 3D printing.

[0074] 1 g of polyvinyl alcohol (PVA) was added to 10 mL of 1 M H2SO4 solution and stirred at 95 °C for 2 h to dissolve, thus obtaining PVA / H2SO4 electrolyte.

[0075] Using PET as a substrate, ink was loaded onto the substrate by 3D printing and freeze-dried for 24 hours to obtain a microelectrode; then, a PVA / H2SO4 electrolyte was coated onto the microelectrode to obtain a flexible micro supercapacitor, denoted as MCP-2.

[0076] Electrochemical performance tests were performed on a CHI660E electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd.). All tests were conducted at room temperature, with linear sweep voltammetry curves ranging from 0 to 0.6 V at scan rates of 10–100 mV / s. Constant current charge-discharge curves were performed in the range of 0.2–2 mA cm⁻¹. -2 The current density was measured.

[0077] Figure 3 This is an electrochemical performance test of the micro supercapacitor prepared in the embodiments of the present invention. Figure 3 Cyclic voltammetry yielded approximately rectangular cyclic voltammetry curves, exhibiting optimal capacitive behavior at scan rates ranging from 10 mV / s to 100 mV / s. Figure 3 The constant current charge-discharge curve exhibits an isosceles triangle shape, demonstrating high coulombic efficiency.

[0078] Example 3

[0079] This embodiment provides a method for preparing an MXene / CC / PEDOT:PSS highly conductive ink. First, MXene, CC, and PEDOT:PSS are homogeneously mixed using a physical mixing method. Then, 3D printing technology is used to obtain an MXene / CC / PEDOT:PSS electrode material with a high mass loading. In the MXene / CC / PEDOT:PSS highly conductive ink, the mass ratio of MXene to CC is 8:1, and the amount of PEDOT:PSS added is 75% of the mass of CC.

[0080] The preparation method of the MXene / CC / PEDOT:PSS high conductivity ink is as follows:

[0081] S1. Preparation of conductive cellulose; specifically including the following steps:

[0082] X1. Conductive cellulose materials were prepared by confined carbonization using bamboo powder as raw material.

[0083] X2. Place 1g of bamboo powder in a three-necked flask and dissolve it in 80mL of 64wt% sulfuric acid. Note that the temperature should not exceed 25℃. Seal the flask completely with a rubber stopper and purge with nitrogen for 30 minutes.

[0084] X3. Heat the reaction to 40°C and stir for 30 minutes. Ensure the entire process is sealed and protected with high-throughput N2.

[0085] X4. Next, perform self-confined carbonization of the nano-surface by raising the temperature to 90°C and stirring rapidly for 1 hour. Note that the entire process should be sealed and protected with high-throughput N2.

[0086] X5. After the reaction is complete, the mixture is rapidly cooled to room temperature in a cold water bath, then dialyzed to neutral, and freeze-dried to obtain conductive cellulose.

[0087] S2. Preparation of MXene nanosheet dispersion; specifically including the following steps:

[0088] W1. Etch 1g Ti3AlC2 with 9mol / L hydrochloric acid and 1.2g lithium fluoride for 48h;

[0089] W2. After the reaction in step W1 is completed, centrifuge and wash the mixture until the pH value is 6-7.

[0090] W3. Collect the precipitate and sonicate it at 100-400W power for 20-60 minutes. Note that this process requires the introduction of inert gas for protection and an ice-water bath for protection.

[0091] W4. After sonication, centrifuge at 3500 r / min for 60 min, collect the supernatant to obtain a 10 mg / mL MXene nanosheet dispersion.

[0092] The preparation of the MXene / CC / PEDOT:PSS highly conductive ink in step S3 includes the following steps:

[0093] S3-1. Mix the conductive cellulose from step S1 and the MXene nanosheet dispersion from step S2 evenly, and add PEDOT:PSS dropwise while stirring to obtain a homogeneous dispersion of MXene / CC / PEDOT:PSS, with a mass ratio of MXene, CC and PEDOT:PSS of 8:1:0.75.

[0094] S3-2. The homogeneous dispersion in step S3-1 is concentrated using a superabsorbent polymer to obtain MXene / CC / PEDOT:PSS ink suitable for 3D printing.

[0095] 1 g of polyvinyl alcohol (PVA) was added to 10 mL of 1 M H2SO4 solution and stirred at 95 °C for 2 h to dissolve, thus obtaining PVA / H2SO4 electrolyte.

[0096] Using PET as a substrate, ink was loaded onto the substrate by 3D printing and freeze-dried for 24 hours to obtain a microelectrode; then, PVA / H2SO4 electrolyte was coated onto the microelectrode to obtain a flexible micro supercapacitor, denoted as MCP-3.

[0097] Electrochemical performance tests were performed on a CHI660E electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd.). All tests were conducted at room temperature, with linear sweep voltammetry curves ranging from 0 to 0.6 V at scan rates of 10–100 mV / s. Constant current charge-discharge curves were performed in the range of 0.2–2 mA cm⁻¹. -2 The current density was measured.

[0098] Figure 4 This is an electrochemical performance test of the micro supercapacitor prepared in the embodiments of the present invention. Figure 4 Cyclic voltammetry yielded an approximately rectangular cyclic voltammetry curve, exhibiting good capacitive behavior at scan rates from 10 mV / s to 100 mV / s. Figure 4 The constant current charge-discharge curve exhibits an isosceles triangle shape, demonstrating good coulombic efficiency.

[0099] like Figure 5 As shown: The area capacitance comparison diagram of the miniature flexible supercapacitors (Example 1, Example 2, Example 3) prepared in this invention exceeds that of most current miniature supercapacitors.

[0100] In summary, this patent prepared an MXene / CC / PEDOT:PSS highly conductive ink and further fabricated a high-performance micro supercapacitor using 3D printing technology. This invention uses the conductive polymer PEDOT:PSS as an interlayer spacer, preventing the stacking of MXene nanosheets through interaction forces, providing more conductive pathways, and facilitating the transport of electrolyte ions. Importantly, this invention utilizes the hydrogen and ionic interactions between CC and MXene to promote interfacial bonding, resulting in high yield stress and unique shear-thinning behavior. Furthermore, the "flexible on the outside, rigid on the inside" structure of CC improves the ink's mechanical properties and contributes to its capacitance. The micro supercapacitor fabricated using 3D printing technology exhibits excellent electrochemical performance due to the unique structure of the microelectrodes, possessing high areal capacitance, energy density, and power density, demonstrating significant application potential in the energy storage field.

[0101] The preferred embodiments of the present invention have been described in detail above. However, those skilled in the art will understand that various substitutions, variations, and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the content disclosed in the embodiments.

Claims

1. A method for preparing a highly conductive ink based on MXene / conductive cellulose / conductive polymer, characterized in that, The specific preparation method includes the following steps: (1) Conductive cellulose material was prepared by confined carbonization using bamboo powder as raw material. 0.5~1.25 g of bamboo powder was placed in a three-necked flask and dissolved in 80 mL of 64wt% sulfuric acid. The temperature was controlled at 10~25 ℃, and the flask was completely sealed with a rubber stopper. Nitrogen gas was introduced for 30~60 min. The reaction temperature was raised to 40~50 ℃ and hydrolyzed under N2 protection for 30 min. Then, self-confined carbonization of the nano-surface was carried out. The temperature was raised to 90~100 ℃ and the mixture was stirred rapidly for 1~4 h. After the reaction was completed, the mixture was rapidly cooled to room temperature in a cold water bath and then dialyzed to neutral. The mixture was then freeze-dried to obtain conductive cellulose. (2) To prepare an MXene nanosheet dispersion, 1 g of Ti3AlC2 was etched with 9-12 mol / L hydrochloric acid and 1-1.2 g of lithium fluoride for 24-48 h. After the reaction was complete, the mixture was centrifuged and washed until the pH value was 5-7. The precipitate was collected and sonicated at 100-400 W for 20-60 min. Note that this process requires the introduction of inert gas protection and an ice-water bath protection. After sonication, the mixture was centrifuged at 3500 r / min for 20-60 min. The supernatant was collected to obtain an MXene dispersion of 5-15 mg / mL. (3) Mix conductive cellulose and MXene nanosheet dispersion evenly, and add PEDOT:PSS dropwise while stirring to obtain a homogeneous dispersion of MXene / conductive cellulose / PEDOT:PSS, wherein the mass ratio of MXene, conductive cellulose and PEDOT:PSS is 8:1:0.25~1; concentrate using a super absorbent polymer to obtain a highly conductive ink of MXene / conductive cellulose / conductive polymer suitable for 3D printing.

2. The method for preparing the MXene / conductive cellulose / conductive polymer high conductivity ink according to claim 1, characterized in that, In step (2), 1 g Ti3AlC2 was etched for 36 h using 12 mol / L hydrochloric acid and 1.2 g lithium fluoride; after centrifugation and washing to neutrality, it was ultrasonically peeled off by ice-water bath, centrifuged for 30 min, and the supernatant was collected to obtain a 10 mg / mL MXene nanosheet dispersion.

3. The method for preparing the MXene / conductive cellulose / conductive polymer highly conductive ink according to claim 1, characterized in that, In step (3), MXene, conductive cellulose and PEDOT:PSS are homogeneously mixed at a mass ratio of 8:1:0.

5.

4. A highly conductive ink for 3D printing, prepared by the method according to claims 1-3, consisting of MXene / conductive cellulose / conductive polymer.

5. An application of the MXene / conductive cellulose / conductive polymer highly conductive ink according to claim 4 in the field of flexible micro supercapacitors.

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