CN115207362A - An elastic current collector printing ink and its preparation method and its application in 3D inkjet printing of multidirectional stretchable batteries - Google Patents

Abstract

The invention relates to an elastic current collector printing ink, a preparation method thereof and application thereof in 3D ink-jet printing of a multidirectional stretching battery, and belongs to the technical field of wearable electronic devices. The invention discloses an elastic current collector printing ink which is prepared by mixing a carbon nano tube grafted graphene conductive composite material, a polymer emulsion, a surfactant and deionized water, wherein the carbon nano tube grafted graphene conductive composite material is of a three-dimensional net structure, and Ni metal nano particles are used as nodes to connect graphene and carbon nano tubes. The invention also discloses positive/negative electrode printing ink. The invention further discloses a 3D ink-jet printing multidirectional stretching battery.

Description

A kind of elastic current collector printing ink and its preparation method and its application in 3D inkjet printing Applications in Multidirectional Stretched Batteries

technical field

The invention belongs to the technical field of wearable electronic devices, and relates to an elastic current collector printing ink, a preparation method thereof, and its application in a 3D inkjet printing multidirectional stretchable battery.

Background technique

In recent years, the rapid development of the consumer electronics industry has directly penetrated into important fields such as medical and health care, sports health, and infotainment that are related to people's quality of life, such as flexible displays, flexible electronic skins, smart electronic clothing, and microelectronic mechanical systems. In order to ensure that the wearable device can be applied to different deformation scenarios, the flexibility and stretchability of the battery are very important. Traditional energy storage devices such as lithium-ion batteries, alkaline zinc-manganese batteries, lead-acid batteries, etc. may have high energy density, but their inherent shortcomings such as large volume, heavy weight, and fixed shape make them unable to match the storage capacity of flexible wearable devices. To meet the energy demand, new flexible stretchable batteries and their related materials have become a hotspot for development.

At present, the research on flexible electrodes is mainly realized through the design of extrinsic flexible structures of rigid materials and the improvement of intrinsically flexible materials. The flexible design of rigid materials is mainly inspired by bionics and origami art, and adopts the micro-element/flexible design of rigid materials, through ingenious structural designs such as Kirigami, origami, island bridge, wave, and coil spring. , to obtain an extrinsic flexible electrode with macroscopic flexibility, which improves the degree of freedom of flexible battery deformation to a certain extent. The preparation of intrinsically flexible electrodes mainly relies on solvothermal, chemical deposition, vacuum filtration and other methods. The active material is loaded on the intrinsically flexible substrate, showing an integrated design, which can not only ensure the integrity of the electrode structure under complex deformation, but also It can maintain the stability of battery performance, mainly including the direct compounding of metal materials with elastic substrates, the compounding of rigid materials with excellent electrical conductivity and polymers with stretchability, and the compounding of carbon materials with excellent electrical conductivity and flexibility. The base material is processed and used as a current collector for stretchable electrodes.

The current collector is the core component of the battery. In order to maintain the stability of the electrochemical performance of the electrode in the tensile state, it is very important to ensure that the current collector still has excellent electrical conductivity under synchronous deformation. Traditional current collectors (aluminum foil, copper foil, etc.) are no longer suitable for stretchable battery systems. The introduction of new elastic materials has fundamentally changed the structure of electrodes and current collectors in conventional batteries. A stretchable conductive elastomer is prepared by compounding conductive fillers and elastic materials. Among them, the most widely used fillers are still graphite, graphene, carbon nanotubes, etc. The ultra-high aspect ratio and specific surface area of carbon nanotubes and graphene lead to extremely strong van der Waals forces between single carbon nanotubes and between single-layer and few-layer graphene, which are prone to agglomeration and entanglement, affecting polymerization. The formation of the conductive network inside the material and the stability in the stretched state.

In order to achieve the goal that the electrode can still maintain stable performance under multi-directional stretching, bending and stretching, it is impossible to rely solely on the design of extrinsic flexible structures or the use of intrinsically flexible materials, because the use of extrinsic flexible materials alone cannot be achieved. The structural design cannot cope with any stretching of the electrode body, and the use of intrinsically flexible materials alone, especially the intrinsically flexible electrodes with a single structure configuration, is difficult to effectively deal with multi-directional stretching conditions, and its microstructure and conductive network will still be If it is damaged, the active material will fall off, the electrode and the current collector will be peeled off, and the battery performance will drop sharply. Combining the design of the extrinsic flexible structure and the improvement of the performance of the intrinsic flexible material, the combination of rigidity and flexibility can realize the electrode more effectively. It maintains stable energy output under multi-directional stretching and various deformation states.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the above problems existing in the prior art, and proposes an elastic current collector printing ink, which can be prepared together with the positive/negative electrode printing ink prepared from positive/negative electrode active materials in multi-directional stretching (deformation) The electrodes can still maintain a stable 3D inkjet-printed multidirectional stretchable battery in the state.

The object of the present invention can be realized through the following technical solutions:

An elastic current collector printing ink, the elastic current collector printing ink is made by mixing a carbon nanotube-grafted graphene conductive composite material, a polymer emulsion, a surfactant, and deionized water, wherein the carbon nanotube-grafted graphene conductive composite material The material is a three-dimensional network structure, with Ni metal nanoparticles as nodes connecting graphene and carbon nanotubes.

Preferably, the solid content of the carbon nanotube-grafted graphene conductive composite material in the elastic current collector printing ink is 2-20 wt %.

Preferably, the viscosity of the elastic current collector printing ink is 13-35 Pa·s.

Preferably, the mass ratio of the carbon nanotube-grafted graphene conductive composite material, the polymer emulsion, and the surfactant is (1-10):(0.5-20):(1-20).

In the present invention, graphene and carbon nanotubes, which themselves have ultra-high electrical conductivity, are connected with Ni metal nanoparticles with ultra-high electrical conductivity as nodes. Printing inks also have excellent electrical conductivity and expand application fields.

Preferably, the preparation method of the carbon nanotube-grafted graphene conductive composite material comprises: mixing glucose monohydrate, ammonium chloride, divalent nickel inorganic acid salt with deionized water, drying and grinding to obtain mixed powder, adding to It is preheated in a binary salt system composed of sodium chloride and potassium chloride, and the preheated material is transferred to a tube furnace for heat preservation in an argon atmosphere. The gas and gas passages are cooled to normal temperature, cleaned and dried to obtain a carbon nanotube-grafted graphene conductive composite material.

The present invention adopts the molten salt method which is simple, easy, low cost and environment-friendly. In the ionic flux of the high temperature KCl/ ^NaCl eutectic salt, the strong polar ionic liquid environment is favorable for the sp hybridized CC or CX direction. CC conversion of ^sp hybridization, which directly converts glucose into graphene materials. During the conversion of glucose to graphene in the molten salt method, the lone pair of electrons on the N atom doped on the small aromatic ring fragment can form a conjugated structure with the π bond in the carbon ring, which is beneficial to the presence of a large number of sp The aromatic ring fragments of the ² -hybridized carbon undergo recombination to form graphene. At the same time, in the high-temperature strong polar ionic liquid environment, when glucose is converted into graphene, a reducing cracking gas will be generated, which can reduce the divalent nickel ions in the precursor to metallic nickel, which is generated in situ on the surface of graphene. Ni nanoparticles (Ni@Gr). On the basis of Ni@Gr, it is directly maintained in a high-temperature polar ionic liquid environment to promote the Ni@Gr graphene sheet in a stretched state, and acetylene gas is introduced to grow carbon nanoparticles more efficiently with Ni nanoparticles as catalytic sites. The resulting carbon nanotubes act as a scaffold to effectively stretch the graphene sheets (Gr), thereby producing a CNT-g-Gr conductive composite with an integrated three-dimensional network structure with ultra-high specific surface area.

Preferably, the mass ratio of the monohydrate glucose, ammonium chloride, and divalent nickel inorganic acid salt is 100:(30-100):(2-15).

Further preferably, the mass ratio of the mixed powder of glucose monohydrate, ammonium chloride and divalent nickel inorganic acid salt to deionized water is 1:(0.5-1.5).

More preferably, the divalent nickel inorganic acid salt is one or more of nickel chloride and nickel nitrate.

Preferably, the mass ratio of sodium chloride and potassium chloride in the binary salt system is 1:(0.5-1.5).

Preferably, the mass ratio of glucose monohydrate and binary salt system is 1:(10-100).

Further preferably, the mass ratio of the mixed powder and the binary salt system is 1:(20-100).

Preferably, the preheating temperature is 100-200°C, and the time is 5-24h.

In the preheating treatment stage, the Maillard reaction of glucose monohydrate and ammonium chloride occurs to generate the precursor of graphene.

Preferably, the temperature kept in the argon atmosphere is the first temperature, and the keeping time is the first keeping time; the temperature kept in the acetylene gas is the second temperature, and the keeping time is the second keeping time.

Further preferably, the first temperature is higher than the second temperature; wherein the first temperature is 800-1300°C, and the second temperature is 750-1000°C.

Further preferably, the first holding time is 30-120min, and the second holding time is 5-60min.

Preferably, the heating rate in the tube furnace is 5-30°C/min.

The invention also discloses a preparation method of an elastic current collector printing ink. The preparation method comprises: dropwise adding a polymer emulsion to a conductive composite material consisting of carbon nanotube grafted graphene, surfactant and deionized water In the dispersion liquid, the viscosity is adjusted to obtain the elastic current collector printing ink.

Further preferably, the polymer includes polystyrene-ethylene-butylene-styrene, polystyrene-polymethyl acrylate-polystyrene, polystyrene-poly-n-butyl acrylate-polystyrene, polyimide One or more of amine, polyvinylidene fluoride, polytetrafluoroethylene, polydimethylsiloxane.

Polymer emulsions can be prepared from polymers by conventional methods.

Preferably, the surfactant is sodium dodecyl sulfonate.

Preferably, the carbon nanotube-grafted graphene conductive composite material is first prepared with deionized water to prepare a solution with a concentration of 5-15 mg/mL.

Preferably, the mass ratio of the carbon nanotube-grafted graphene conductive composite material and the surfactant in the dispersion is 1:(1-10).

Preferably, the dispersion liquid is prepared by magnetic stirring and ultrasonication in sequence.

The invention also discloses a positive/negative electrode printing ink, the positive/negative electrode printing ink is made of positive/negative electrode active materials, a conductive agent, a binder and a dispersing agent.

Preferably, the mass ratio of positive/negative electrode active material, conductive agent, and binder is (70-80): (10-20): (10-20).

Preferably, the mass ratio of the positive electrode and the negative electrode in the positive/negative electrode active material is (1:10):1.

Further preferably, the positive electrode and the negative electrode in the positive/negative electrode active material are any two materials that can be assembled into a battery.

The changes of the conductivity of the batteries assembled with conventional different positive and negative electrode materials in the present invention conform to the rules described in the present invention, and after being stretched at different angles, the changes of the surface conductivity are basically the same.

Preferably, the area of the stretchable battery is 0.4-16 cm ² ;

Preferably, the printing thickness of the current collector is 50 μm-150 μm, and the printing thickness of the positive electrode and the negative electrode is 50 μm-200 μm;

Preferably, the conductive agent is SuperP.

Preferably, the binder is the above-mentioned polymer emulsion.

Further preferably, the binder is the same as the polymer emulsion in the elastic current collector printing ink.

Preferably, the dispersion medium is deionized water.

The present invention further discloses a 3D inkjet printing multidirectional stretchable battery, comprising:

flexible substrate;

an elastic current collector printing ink layer, which is printed on the surface of the flexible substrate;

Positive/negative electrode printing ink layer, which is printed on the surface of the elastic current collector printing ink layer;

and a gel electrolyte fill layer, which fills between the positive/negative lines.

Preferably, the 3D inkjet printable multi-directional stretchable battery is formed by controlling the movement of the printing nozzle through software to form the elastic current collector printing ink on the surface of the flexible substrate, and then covering and printing the positive/negative printing ink to obtain the positive/negative electrode, and the Gel electrolyte is used to fill between the positive/negative lines, and it is made after encapsulation.

The 3D printing technology adopted in the present invention is based on the digital model file, and the morphology is precisely controlled by layer-by-layer printing. The biggest advantage lies in the design and manufacture of the electrode microstructure; wherein the electrode prepared by the 3D printing technology can ensure the content of energy storage active materials, Effectively shorten the distance between positive and negative electrodes and improve the energy density per unit area. In terms of electrode structure configuration, the shorter the ion transmission distance is, the lower the resistance and the faster the ion diffusion kinetics are; in the periodic configuration design, the fractal curve continuously stretches, compresses, and twists the spatial objects, and the dimension remains unchanged. . Among them, the regular fractal in the fractal curve has strict self-similarity and tight space filling, and has the characteristics of high clustering and strong continuity, which can achieve the goal of optimizing the energy density of the electrode in a given area. The electrode provides a solid structural guarantee, giving the electrode multi-directional stretchability.

Preferably, the gel electrolyte includes one or more of PMMA-based polymer gel electrolyte and PVDF-HFP/NPGDA polymer gel electrolyte.

Further preferably, the proportion of the initiator in the raw material of the gel electrolyte is 0.1-1.0 wt %.

Preferably, the flexible substrate is polydimethylsiloxane (PDMS).

Preferably, the battery system suitable for the 3D inkjet printing multidirectional stretchable battery includes one or more of lithium-ion batteries, sodium-ion batteries, zinc-ion batteries, and lithium-sulfur batteries.

Preferably, the printed circuit configuration in the 3D inkjet-printable multi-directional stretchable battery includes one or more of concentric circle type, Piano curve type, Hilbert curve type, square type, and spiral type.

Compared with the prior art, the present invention has the following beneficial effects:

1. In the elastic current collector printing ink of the present invention, a carbon nanotube-grafted graphene conductive composite material with a three-dimensional network structure of graphene and carbon nanotubes is used as a node to connect graphene and carbon nanotubes as a raw material. It also imparts good deformability and stretchability to the material while conducting electricity.

2. The elastic current collector printing ink of the present invention needs to adjust the viscosity so that it can meet the conditions of 3D printing.

3. The elastic current collector printing ink of the present invention can be mixed with positive/negative electrode active materials to obtain positive/negative electrode printing ink, which together form a battery.

4. The preparation method adopted in the present invention is simple, strong in operability and low in cost, avoids the generation of strong acid waste liquid in the process of preparing graphene by traditional redox method, and is beneficial to large-scale production.

5. The present invention adopts 3D printing technology and reasonably plans the path configuration of the positive and negative electrodes based on the fractal curve with high clustering and strong continuity, so as to achieve the goal of optimizing the energy density of the electrode in a given area, and at the same time provide a stable electrode for the electrode. The structure guarantees that the electrode can be stretched in multiple directions.

Description of drawings

Fig. 1 is the TEM electron microscope picture of the carbon nanotube-grafted graphene conductive composite material obtained in the embodiment of the present invention 1.

2 is a schematic diagram of the integrated carbon nanotube-grafted graphene conductive composite material prepared in Example 1 of the present invention.

3 is a schematic diagram of the configuration of the printing structure of the Hilbert fractal curve structure adopted in Embodiment 1 of the present invention.

Description of the drawings: 1. Carbon nanotubes, 2. Metal nickel nanoparticles, 3. Graphene.

Detailed ways

The following are specific embodiments of the present invention to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

Example 1

Weigh 1.98g of glucose, 0.35g of nickel nitrate, and 1.51g of ammonium chloride and grind them evenly in a mortar, add equal mass of deionized water, stir well, dry in the shade, and then place it in a vacuum drying box at 60°C for 12 hours. The obtained mixed powder was transferred to a mortar and ground to obtain a mixed powder. Then weigh 53.6g of potassium chloride and 46.5g of sodium chloride, add them together in the agate ball mill tank, the ball milling speed is 300rpm, and grind 1h to obtain a binary salt system. After the ball milling, the materials from the first two steps were mechanically stirred in a mortar, mixed evenly, and then transferred to a square quartz boat, and preheated at a constant temperature of 100°C in a blast dryer for 8h. Then transferred to a tube furnace, rapidly heated to a first temperature of 1000°C at 5°C/min in an argon atmosphere, kept for 60 minutes, then stopped heating, cooled to 950°C naturally, switched to the acetylene gas channel, restarted the heating, After 30 min of constant temperature treatment at the second temperature of 950°C, the heating was stopped, and then it was switched to the argon gas path again until it dropped to normal temperature, and the whole process of cooling was protected by an argon gas atmosphere. The product was taken out, washed with deionized water for 5 times to remove salt, and vacuum annealed at 80 °C for 24 h to obtain a carbon nanotube-grafted graphene conductive composite (CNT-g-Gr). Its TEM image is shown in Figure 1; its schematic diagram as shown in picture 2. Then, 16.5 mg of carbon nanotube-grafted graphene conductive composite material (CNT-g-Gr), 50 mg of sodium dodecylbenzenesulfonate were taken, 10 mL of deionized water was measured, and after magnetic stirring, ultrasonicated for 30 min at 300 W power to prepare CNT-g-Gr dispersion, then the polystyrene-polymethyl acrylate-polystyrene emulsion was slowly added dropwise to the CNT-g-Gr dispersion, so that the solid content of CNT-g-Gr in the conductive elastomer was 5 wt %, magnetic stirring for 15 min, and adjusting the viscosity to 30 Pa·s to obtain an elastic current collector printing ink.

Weigh the positive and negative active materials in a mass ratio of 7:1, SuperP is a conductive additive, polystyrene-polymethyl acrylate-polystyrene emulsion is used as a binder, deionized water is used as a dispersion medium, and magnetic stirring is performed for a period of time. Time, by adjusting the amount of the binder and the dispersion medium, the viscosity of the printing ink is 30 Pa·s, and the positive/negative printing ink is prepared.

The Hilbert fractal curve structure model was established using SolidWorks software and imported into the printer assistant software Repetier-Host. The current collector printing ink is loaded into the syringe, and the printing nozzle movement is controlled by the software to control the formation of the ink on the surface of the polydimethylsiloxane (PDMS) flexible substrate. Then the syringe is replaced, and the positive and negative printing inks are added respectively. The positive/negative electrode of the battery with the Hilbert fractal curve configuration structure is overlaid on the printed current collector. The area of the printed electrode area is 2cm × 2cm, the printing thickness of the current collector is 100 μm, the printing thickness of the positive and negative electrodes is 100 μm and 110 μm respectively, and the methyl methacrylate (MMA) monomer, Methyl acrylate (MA) soft monomer and initiator azobisisoheptanenitrile (ABVN) were placed in a beaker, and the initiator accounted for 0.4wt% of the total mass, sealed with plastic wrap, and polymerized in an oven at 55°C for 5h, After the reaction was completed, it was dried in a vacuum drying oven at 110° C. to remove unreacted monomers. The material was cut into small pieces for volume-adapted circuits, and 1 mol/L of LiPF ₆ in EC+DMC+EMC (1:1:1) electrolyte was added for immersion for 10 min to obtain a PMMA-based polymer gel electrolyte. The gel electrolyte is filled between the positive and negative electrodes, and finally encapsulated with PDMS film, a multidirectional stretchable battery with a Hilbert fractal curve structure is prepared. Among them, according to the Hilbert fractal curve structure, the current collector, and the positive/negative electrode printing circuit configuration schematic diagram is shown in FIG. 3 .

The performance of the prepared multi-directional stretchable battery was tested. After being stretched at different angles, the change of its surface conductivity remained basically the same. When not stretched, the initial capacity of the battery is 3.57mAh. When the tensile deformation is 30%, the battery retains 95.6% of the capacity; when the tensile deformation is 100%, it still maintains 60.7% of the capacity.

Example 2

Compared with Example 1, the difference is that the polymer emulsions in the elastic current collector printing ink and the positive/negative electrode printing ink are all polystyrene-ethylene-butylene-styrene emulsions. The performance of the prepared multi-directional stretchable battery was tested. After being stretched at different angles, the change of its surface conductivity remained basically the same. When not stretched, the initial capacity of the battery is 3.42mAh, when the tensile deformation is 30%, the battery maintains 92.1% of the capacity; when the tensile deformation is 100%, it still maintains 55.6% of the capacity.

Example 3

Compared with Example 1, the difference is that the elastic current collector printed electrode structure is configured as a Peano fractal curve. The performance of the prepared multi-directional stretchable battery was tested. After being stretched at different angles, the change of its surface conductivity remained basically the same. When not stretched, the initial capacity of the battery is 3.35mAh, and when the tensile deformation is 30%, the battery retains 93.3% of the capacity; when the tensile deformation is 100%, it still maintains 59.4% of the capacity.

Example 4

Compared with Example 1, the difference is that the CNT-g-Gr solid content is 2 wt%. The performance of the prepared multi-directional stretchable battery was tested. After being stretched at different angles, the change of its surface conductivity remained basically the same. When not stretched, the initial capacity of the battery is 3.52mAh, when the stretching deformation is 30%, the battery maintains 80.4% of the capacity; when the deformation is 100%, it still maintains 50.1% of the capacity.

Example 5

Compared with Example 1, the difference is that the CNT-g-Gr solid content is 10 wt%. The performance of the prepared multi-directional stretchable battery was tested. After being stretched at different angles, the change of its surface conductivity remained basically the same. When unstretched, the initial capacity of the battery is 3.55mAh, and when the stretching deformation is 30%, the battery maintains 88.7% of the capacity; when the deformation is 100%, it still maintains 56.4% of the capacity.

Example 6

Compared with Example 1, the difference is that the CNT-g-Gr solid content is 20 wt%. The performance of the prepared multi-directional stretchable battery was tested. After being stretched at different angles, the change of its surface conductivity remained basically the same. When unstretched, the initial capacity of the battery is 3.59mAh, and when the stretching deformation is 30%, the battery maintains 72.8% of the capacity; when the deformation is 100%, it still maintains 51.2% of the capacity.

Example 7

Compared with Example 1, the difference is that the CNT-g-Gr solid content is 25 wt%. The performance of the prepared multi-directional stretchable battery was tested. After being stretched at different angles, the change of its surface conductivity remained basically the same. When the deformation amount is 30%, the battery maintains 50.7% capacity; when the deformation amount is 100%, the battery cannot work normally.

Comparative Example 1

Compared with Example 1, the difference is that the nanotube-grafted graphene conductive composite material (CNT-g-Gr) is replaced with a graphene and metal nickel nanoparticle composite material, and the preparation method of the graphene and metal nickel nanoparticle composite material includes: : Weigh 1.98g glucose, 0.22g nickel chloride, 1.51g ammonium chloride and grind them evenly in a mortar, add equal quality deionized water, stir well, dry in the shade, and then place them in a vacuum drying box to continue drying at 60°C After 12 h, the obtained solidified product was transferred to a mortar, ground evenly, and set aside. Then weigh 53.6 g of potassium chloride and 44.6 g of sodium chloride, and add them together into the agate ball milling jar. After the ball milling, the materials of the first two steps were mechanically stirred in a mortar, mixed uniformly, and then transferred to a square quartz boat. Transferred to a tube furnace, rapidly heated to 900°C at 5°C/min, treated for 60min, then stopped heating, cooled naturally, and protected by an argon atmosphere throughout the process. The product was taken out, washed repeatedly with deionized water to remove salt, and vacuum-dried at 80 °C for 24 h to obtain a composite material of graphene and metal nickel nanoparticles. Then the multi-directional stretchable battery was prepared according to the method of Example 1, and the performance test was carried out. When unstretched, the initial capacity of the battery is 3.54mAh. When the stretching deformation is 30%, the battery maintains 70.3% of the capacity; when the deformation is 100%, it still maintains 29.8% of the capacity.

Comparative Example 2

Compared with Example 1, the difference is that the nanotube-grafted graphene conductive composite material (CNT-g-Gr) is replaced with a nitrogen-doped graphene material. The preparation method of the nitrogen-doped graphene material includes: weighing 1.98g of glucose, 1.51 Grind 1 g ammonium chloride in a mortar evenly, add equal mass of deionized water, stir well, dry in the shade, and then place it in a vacuum drying oven at 60°C for 12 hours, transfer the obtained solidified product to a mortar, and grind uniformly ,stand-by. Then weigh 53.6 g of potassium chloride and 45.6 g of sodium chloride, add them into the agate ball milling jar, and the ball milling speed is 300 rpm for 2 hours. After the ball milling, the materials of the first two steps were mechanically stirred in a mortar, mixed uniformly, and then transferred to a square quartz boat. Transferred to a tube furnace, rapidly heated to 800°C at 5°C/min, treated for 60min, then stopped heating, cooled naturally, and protected by an argon atmosphere throughout the process. The product was taken out, washed repeatedly with deionized water to remove salt, filtered with suction, and vacuum-dried at 80 °C for 24 h to obtain nitrogen-doped graphene material. Then, the multi-directional stretchable battery was prepared according to the method of Example 1, and the performance test was carried out. When not stretched, the initial capacity of the battery is 3.53mAh, when the stretching deformation is 30%, the battery maintains 60.8% of the capacity; when the deformation is 100%, it still maintains 26.4% of the capacity.

To sum up, the elastic current collector printing ink of the present invention contains carbon nanotube-grafted graphene conductive composite material (CNT-g-Gr), so that the multidirectional stretchable battery obtained after subsequent 3D printing has excellent scalability. Tensile properties, and can still maintain good electrical conductivity under tensile (deformed) conditions.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which the present invention pertains can make various modifications or additions to the described specific embodiments or substitute in similar manners, but will not deviate from the spirit of the present invention or go beyond the definitions of the appended claims range.

Claims (10)

1. The printing ink for the elastic current collector is characterized by being prepared by mixing a carbon nano tube grafted graphene conductive composite material, a polymer emulsion, a surfactant and deionized water, wherein the carbon nano tube grafted graphene conductive composite material is of a three-dimensional net structure, and Ni metal nano particles are used as nodes to connect graphene and carbon nano tubes.

2. The elastic current collector printing ink according to claim 1, wherein the carbon nanotube-grafted graphene conductive composite material in the elastic current collector printing ink has a solid content of 2 to 20wt%; the viscosity of the printing ink of the elastic current collector is 13-35 Pa.s.

3. The elastic current collector printing ink according to claim 1 or 2, wherein the preparation method of the carbon nanotube-grafted graphene conductive composite material comprises: mixing monohydrate dextrose, ammonium chloride, divalent nickel inorganic acid salt and deionized water, drying and grinding to obtain mixed powder, adding the mixed powder into a binary salt system consisting of sodium chloride and potassium chloride, preheating, transferring the preheated material into a tubular furnace, preserving heat in an argon atmosphere, switching to an acetylene gas channel, continuing preserving heat, then switching to an argon gas channel, cooling to normal temperature, cleaning and drying to obtain the carbon nanotube grafted graphene conductive composite material.

4. The method according to claim 3, wherein the preheating temperature is 100-200 ℃ and the time is 5-24 hours.

5. The production method according to claim 3, wherein the temperature of the incubation in the argon atmosphere is a first temperature, and the incubation time is a first incubation time; the temperature of the acetylene gas is kept at the second temperature, and the heat preservation time is the second heat preservation time; the first temperature is higher than the second temperature; wherein the first temperature is 800-1300 deg.C, and the second temperature is 750-1000 deg.C.

6. A preparation method of elastic current collector printing ink is characterized by comprising the following steps: and dropwise adding the polymer emulsion into a dispersion liquid consisting of the carbon nano tube grafted graphene conductive composite material, a surfactant and deionized water, and adjusting the viscosity to obtain the printing ink of the elastic current collector.

7. The preparation method according to claim 6, wherein the mass ratio of the carbon nanotube-grafted graphene conductive composite material to the surfactant in the dispersion liquid is 1: (1-10).

8. A positive/negative electrode printing ink, characterized in that it is made of the elastic current collector printing ink of claim 1, positive/negative electrode active material, conductive agent, binder, dispersant.

9. The positive and negative electrode printing ink according to claim 8, wherein the elastic current collector printing ink, the positive electrode active material and the negative electrode active material are mixed in a mass ratio of (70-80): (10-20): (10-20).

10. A3D inkjet-printed multi-direction stretchable battery, comprising:

a flexible substrate;

the elastic current collector printing ink layer is printed on the surface of the flexible substrate;

the positive/negative printing ink layer is printed on the surface of the printing ink layer of the elastic current collector;

and a gel electrolyte filling layer filled between the positive/negative electrode lines.

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