Spiral core-sheath carbon-based yarns, methods of making and moisture power generation applications thereof

Abstract

The present application relates to a spiral core structure carbon-based yarn and its preparation method and moisture power generation application, the spiral core structure carbon-based yarn includes first conductive carbon-based fiber and second conductive carbon-based fiber, the first conductive carbon-based fiber is divided into first processing section and first untreated section along its axial direction, and the first processing section is coated with ion transmission channel layer outside;Second conductive carbon-based fiber is divided into second processing section and second untreated section along its axial direction, and the second processing section is coated with moisture absorption layer outside;The first processing section of the first conductive carbon-based fiber and the second processing section of the second conductive carbon-based fiber are twisted to form a spiral core structure.The present application is based on the spiral core structure, and there is hydrophilicity difference in the radial direction of fiber, which can produce moisture concentration difference, and provides the path of proton migration;The moisture absorption layer absorbs water to drive electrolyte diffusion, so that conductive ions are reoriented and dislocated, and the potential across the bridge is induced;It also cooperates with the flow potential mechanism based on the double-layer effect formed in the pore of carbon-based fiber to generate electricity.

Description

Technical Field

[0001] This invention belongs to the field of functional fiber technology, specifically relating to a spiral core-sheath structure carbon-based yarn, its preparation method, and its application in moisture power generation. Background Technology

[0002] With the popularization of smart lifestyles, flexible and multifunctional wearable electronic products, such as electronic textiles, electronic skin, bracelets, and implantable devices, have attracted great attention. To this end, various types of green and simple energy generators have been continuously developed to power these electronic devices, such as piezoelectric generators, triboelectric generators, thermoelectric generators, and moisture induction generators. Among them, moisture induction generators (MEGs) can convert the chemical energy of water molecules in the atmosphere into electrical energy through the interaction of hygroscopic materials or electrodes with moisture, providing a new option for meeting the energy needs of the wearable electronics field.

[0003] Most current wet gas power generation materials are in bulk or membrane form. Fibers, as wet gas power generation materials, have a large aspect ratio, which helps increase the contact area with moisture, thereby improving wet gas power generation efficiency. Their high mechanical strength and flexibility make them easier to adapt to different shapes and surfaces, facilitating integration into various devices and systems. Furthermore, fiber preparation is relatively simple and can be achieved through textile processing technology. However, existing fibrous MEGs can only produce intermittent electrical output, and effective integration strategies remain lacking.

[0004] Therefore, there is an urgent need in this field to develop fiber / yarn-type MEGs with continuous output, high power density, and effective integration with wearable devices. Summary of the Invention

[0005] Based on the aforementioned shortcomings and deficiencies in the prior art, one of the objectives of this invention is to at least solve one or more of the aforementioned problems in the prior art. In other words, one of the objectives of this invention is to provide a spiral core-sheath structure carbon-based yarn, its preparation method, and its application in moisture power generation that meets one or more of the aforementioned requirements.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] A spiral core-sheath structure carbon-based yarn includes a first conductive carbon-based fiber and a second conductive carbon-based fiber. The first conductive carbon-based fiber is divided into a first treated section and a first untreated section along its axial direction, and the first treated section is covered with an ion transport channel layer. The second conductive carbon-based fiber is divided into a second treated section and a second untreated section along its axial direction, and the second treated section is covered with a moisture-absorbing layer.

[0008] The first processed section of the first conductive carbon fiber and the second processed section of the second conductive carbon fiber are twisted together to form a spiral core-sheath structure.

[0009] The first untreated segment of the first conductive carbon-based fiber and the second untreated segment of the second conductive carbon-based fiber are located at the two ends of the spiral core structure, respectively.

[0010] As a preferred embodiment, the ion transport channel layer is a polymer electrolyte gel.

[0011] As a preferred embodiment, the polymer electrolyte gel is one or more of the following: phosphate polyvinyl alcohol gel, hydrochloric acid polyvinyl alcohol gel, and polyethylene glycol-modified chitosan gel.

[0012] As a preferred embodiment, the moisture-absorbing layer is one or more of silicon dioxide, magnesium sulfate, and calcium chloride.

[0013] As a preferred embodiment, the first conductive carbon-based fiber is selected from carbon nanotube fibers or graphene fibers.

[0014] The second conductive carbon-based fiber is selected from carbon nanotube fibers or graphene fibers.

[0015] As a preferred embodiment, the first conductive carbon-based fiber and the second conductive carbon-based fiber are respectively formed by twisting multiple strands of carbon-based fiber filaments.

[0016] As a preferred option, the twist of the multi-strand carbon-based fiber precursor is 75–500 T / m.

[0017] As a preferred embodiment, the length ratio of the first treated segment to the first untreated segment of the first conductive carbon-based fiber is 1:(0.2~0.5);

[0018] The length ratio of the second treated segment to the second untreated segment of the second conductive carbon-based fiber is 1:(0.2 to 0.5).

[0019] This invention also provides a method for preparing a helical core-sheath structure carbon-based yarn as described in any of the preceding embodiments, comprising the following steps:

[0020] (1) An ion transport channel layer is attached to the outside of the first processed section of the first conductive carbon fiber by dip-coating method.

[0021] A moisture-absorbing layer is attached to the outside of the second processed section of the second conductive carbon-based fiber using an impregnation-coating method.

[0022] (2) Using a yarn twister, the first treated section of the first conductive carbon fiber and the second treated section of the second conductive carbon fiber are twisted together to obtain a spiral core structure carbon yarn.

[0023] The present invention also provides the application of the spiral core-sheath structure carbon-based yarn as described in any of the above embodiments or the spiral core-sheath structure carbon-based yarn prepared by the preparation method described in the above embodiments, for use in wet gas power generation.

[0024] Compared with the prior art, the beneficial effects of this invention are:

[0025] (1) The carbon-based yarn of the present invention is based on its helical core-sheath structure. The radial direction of the fiber has a difference in hydrophilicity, which can spontaneously generate a water concentration difference and provide a path for proton migration. By introducing a water concentration gradient structure, it can generate electricity in synergy with the flow potential mechanism based on the double electric layer effect formed in the carbon-based fiber channel.

[0026] (2) The carbon-based yarn of the present invention has good moisture power generation performance and can generate electricity continuously, with a maximum instantaneous output power density of 8.79*10 -5 W / m 2 ;

[0027] (3) The carbon-based yarn of the present invention can be woven into fabrics to generate more energy to power commercial electronic devices. This flexible, portable, and multifunctional spiral core structure carbon-based yarn has good application prospects and development potential in the field of wearable electronics and is expected to be continuously produced. Attached Figure Description

[0028] Figure 1 This is a microscopic magnified structural diagram of the carbon-based yarn of Embodiment 1 of the present invention;

[0029] Figure 2 This is a digital photograph of the carbon-based yarn of Embodiment 1 of the present invention;

[0030] Figure 3 These are scanning electron microscope images of the surfaces of the spiral core-sheath structure carbon-based yarn, CNT-HCl / PVA fiber, and CNT-CaCl2 fiber of Embodiment 1 of the present invention;

[0031] Figure 4 This is the open-circuit voltage curve of FEMG in Embodiment 1 of the present invention at approximately RH = 80%;

[0032] Figure 5 This is a short-circuit current curve of FEMG in Embodiment 1 of the present invention at approximately RH = 80%. Detailed Implementation

[0033] To more clearly illustrate the embodiments of the present invention, specific implementation methods will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0034] The spiral core-sheath structure carbon-based yarn of the present invention comprises a conductive electrode material, a polymer electrolyte gel, and a hygroscopic agent. The conductive electrode material is prepared by high-strength carbon nanotube fiber precursors using high-temperature vapor phase spinning, and then spirally twisted carbon nanotube fibers are prepared by twisting multiple carbon nanotube fiber precursors using a yarn twister. Alternatively, the conductive electrode material may also be graphene fiber or silver nanowire, but is preferably carbon nanotube fiber.

[0035] The aforementioned polymer electrolyte gels play an important role in wet power generation, providing ion conduction pathways while maintaining a humid environment, which helps stabilize the operation of wet power generation materials. Examples include polyvinyl alcohol hydrochloride gel, polyvinyl alcohol phosphate gel, and polyethylene glycol-modified chitosan gel.

[0036] The aforementioned hygroscopic agents (also known as desiccants) have strong hygroscopic properties and can absorb moisture from the air. They are selected from materials such as silicon dioxide, magnesium sulfate, and calcium chloride. When combined with carbon nanotube fibers, their hydrophilicity can be greatly improved.

[0037] The preferred polymer electrolyte gel and desiccant are polyvinyl alcohol hydrochloride gel and calcium chloride, respectively.

[0038] Specifically, the spiral core-sheath structure carbon-based yarn is described in detail using carbon nanotube fibers as the electrode material, polyvinyl alcohol hydrochloride gel as the polymer electrolyte gel, and calcium chloride as the hygroscopic agent. The spiral core-sheath structure carbon-based yarn is prepared using high-temperature vapor phase spinning, twisting with a yarn twist meter, and an impregnation-lifting method. The specific preparation process includes the following steps:

[0039] S1. Preparation of carbon nanotube fibers

[0040] Ferrocene and thiophene were added to an ethanol solution to prepare a reaction precursor, which was then prepared by floating catalytic chemical vapor deposition. Carbon nanotube fiber precursors were catalytically grown at a high temperature of 1200℃ using a vertical furnace of a carbon nanotube growth apparatus. The preparation process of the above carbon nanotube fiber precursors can refer to existing technologies and will not be elaborated here.

[0041] S2, carbon nanotube fiber twisting

[0042] Take 4-10 strands of carbon nanotube fiber precursor from the same batch and twist them at four different twist rates (75T / m, 200T / m, 325T / m, and 500T / m) using a yarn twister. After twisting, fix both ends to prevent loosening. The optimal method for this step is to take 4 strands of carbon nanotube fiber precursor from the same batch, twist them at a twist rate of 200T / m using a yarn twister, and fix both ends to prevent loosening to obtain CNT fibers.

[0043] S3. Preparation of CNT-HCl / PVA fibers by impregnation and lifting method:

[0044] An HCl / PVA gel electrolyte was prepared by dissolving 10g of PVA in 100mL of 1M HCl solution at 85℃ and stirring at a stirring speed of 200-700r / min. The lower section (7cm) of the twisted CNT fiber (total length 10cm) was repeatedly immersed and pulled in 1-4mL of HCl / PVA gel electrolyte. This process was repeated 3-8 times. The fiber was then dried in a fume hood to obtain the first CNT fiber.

[0045] In a preferred embodiment, 10g of PVA is dissolved in 100mL of 1M HCl solution at 85°C and stirred at 300r / min for 2 hours to prepare HCl / PVA gel electrolyte; one end (7cm) of the twisted CNT fiber is repeatedly immersed and pulled in 2mL of HCl / PVA gel electrolyte 4 times, and then dried in a fume hood at 30°C for 3 hours.

[0046] S4. Preparation of CNT-CaCl2 fibers by impregnation and lifting method

[0047] The lower section (7cm) of another twisted CNT fiber (total length 10cm) was immersed in CaCl2 with a volume of 1-10ul and a mass fraction of 10-30wt%. After absorption, it was dried in a vacuum oven at 30℃ for 3h to obtain the second CNT fiber.

[0048] In a preferred embodiment, one end (7cm) of the twisted CNT fiber is immersed in 3uL of CaCl2 with a mass fraction of 20wt%, and after absorption, it is dried in a vacuum oven at 30°C for 3h.

[0049] S5, Assembled spiral core structure carbon-based yarn

[0050] Carbon nanotube yarn is obtained by spiral twisting a portion of the first and second CNT fibers (i.e., the lower section).

[0051] The application of the aforementioned carbon-based yarns in moisture power generation is as follows: CNT-HCl / PVA fibers and CNT-CaCl2 fibers are used as electrodes, HCl / PVA serves as an ion transport channel, and CNT-CaCl2 fibers are a hydrophilic material. The untreated end (3cm) of the CNT-HCl / PVA fiber and the untreated end (3cm) of the CNT-CaCl2 fiber are directly connected to the test circuit to obtain a fiber-based moisture generator (FMEG) for moisture power performance testing.

[0052] Power density is an important indicator for measuring wet electrical performance. The maximum instantaneous output power density P can be calculated using the following formula. mi :

[0053]

[0054] Among them, V max I represents the maximum open-circuit voltage. max The maximum short-circuit current is represented by S, which represents the effective area of ​​FMEG, i.e., the surface area of ​​the carbon-based yarn.

[0055] Example 1:

[0056] The method for preparing CNT yarn in this embodiment includes the following steps:

[0057] Four strands of carbon nanotube fiber filaments were taken and twisted to a twist of 200T / m using a yarn twister, and the ends were fixed to prevent loosening to obtain CNT fibers.

[0058] A 7cm segment of a twisted CNT fiber was repeatedly immersed and pulled in 2mL of HCl / PVA gel electrolyte 4 times, and dried in a fume hood at 30℃ for 3h to obtain CNT-HCl / PVA fiber.

[0059] A 7cm segment of another twisted CNT fiber was immersed in 2ul of CaCl2 with a mass fraction of 20wt% and dried in a vacuum oven at 30°C for 3 hours to obtain CNT-CaCl2 fiber.

[0060] A portion (7cm) of dried CNT-HCl / PVA fiber and CNT-CaCl2 fiber was twisted into a spiral to obtain carbon-based yarn. The untreated end (3cm) of the CNT-HCl / PVA fiber and the untreated end (3cm) of the CNT-CaCl2 fiber were directly connected to the test circuit for wet electrical performance testing.

[0061] like Figure 1 As shown, two helical twisted carbon-based yarn electrodes, bridged by HCl / polyvinyl alcohol (PVA) gel, form a helical core-sheath structure.

[0062] like Figure 2 As shown, a portion (7cm) of CNT-HCl / PVA fiber and CNT-CaCl2 fiber is twisted into a carbon-based yarn. The untreated segments (3cm) of CNT-HCl / PVA fiber and CNT-CaCl2 fiber are located at both ends of the spiral core structure, respectively. The free ends of the untreated segments of CNT-HCl / PVA fiber and CNT-CaCl2 fiber are directly connected to the test circuit.

[0063] like Figure 3As shown, a is a scanning electron microscope image of a spiral core-sheath structure carbon-based yarn, which is obtained by spiral twisting CNT-HCl / PVA fibers and CNT-CaCl2 fibers; b is a scanning electron microscope image of CNT-HCl / PVA fibers, in which HCl / PVA gel electrolyte is uniformly coated on the twisted CNT fibers; c and d are SEM images of CNT-CaCl2 fibers and the microporous structure of CNT-CaCl2 fibers, respectively, in which CaCl2 particles can be observed on the CNT fibers.

[0064] like Figure 4 As shown, when the spiral core-shell structure carbon-based yarn was placed in a humidity chamber (RH = 80%) as a humidifier FMEG and connected to the test circuit, the open-circuit voltage VOC initially rose slowly and then fell slowly, reaching a maximum value of 0.023V after 760s; Figure 5 As shown, the short-circuit current also increases slowly, with a maximum value of 84nA.

[0065] In addition, the helical core structure carbon-based yarn with a diameter of only 50nm in this embodiment can generate an open-circuit voltage of 23mV, proving that it has excellent wet gas power generation capability.

[0066] The power generation mechanism of the spiral core-sheath structure carbon-based yarn in this embodiment is as follows: When the spiral core-sheath structure carbon-based yarn, acting as a moisture-absorbing generator (FMEG), is in a humid environment, CaCl2 absorbs moisture from the environment, activating the formation of the CaCl2 solution. Due to the radial differences in hydrophilicity of the fibers, a moisture concentration gradient can be spontaneously generated. The CaCl2 solution then drives the diffusion of electrolytes, and the anions and cations (CaCl2, Ca ... + H + Cl - The separation of the double layer leads to a voltage potential across the device; and the double layer will be introduced at the surface of the CNT film, and the flow potential formed in the CNT film channels based on the double layer effect also plays a role in enhancing its power generation performance.

[0067] Example 2:

[0068] The preparation process of the carbon-based yarn in this embodiment differs from that in Example 1 in that the process includes:

[0069] Two twisted CNT fibers (7 cm each) were repeatedly immersed and pulled four times in 2 ml of HCl / PVA gel electrolyte and dried in a fume hood at 30°C for 3 hours. They were then immersed in 2 μL of 20 wt% CaCl2 and dried in a vacuum oven at 30°C for 3 hours. The CNT-HCl / PVA and CNT-CaCl2 fibers were twisted together with copper wire, which served as the internal electrode connected to the test circuit. Another copper wire was introduced onto the surface of the spiral core wet-electric fiber and connected to the test circuit for wet-electric performance testing.

[0070] Example 3:

[0071] The difference between the preparation process of the carbon-based yarn in this embodiment and that in embodiment 1 is that 10 strands of fiber filament are twisted to form CNT fibers.

[0072] The specific preparation process includes:

[0073] Ten strands of fiber precursor were twisted to obtain CNT fibers. Two twisted CNT fibers (7cm) were repeatedly immersed and pulled four times in 2mL of HCl / PVA gel electrolyte and dried in a fume hood at 30℃ for 3h to obtain CNT-HCl / PVA fibers. They were then immersed in 2ul of CaCl2 with a mass fraction of 20wt% and dried in a vacuum oven at 30℃ for 3h to obtain CNT-CaCl2 fibers.

[0074] The untreated end (3cm) of CNT-HCl / PVA fiber and the untreated end of CNT-CaCl2 fiber were directly connected to the test circuit to obtain the fiber moisture generator FMEG for wet electrical performance testing.

[0075] Example 4:

[0076] The preparation process of the carbon-based yarn in this embodiment differs from that in Example 1 in that the process includes:

[0077] Four strands of CNT fiber were twisted together. Two twisted CNT fibers (7cm each) were repeatedly immersed and pulled four times in 2ml of polyvinyl alcohol / phosphate (PVA-HP) gel electrolyte and dried in a fume hood at 30°C for 3 hours. Then, they were immersed in 2ul of 20wt% CaCl2 and dried in a vacuum oven at 30°C for 3 hours. The untreated end (3cm) of the CNT-PVA-HP fiber and the untreated end of the CNT-CaCl2 fiber were directly connected to the test circuit to obtain the fiber moisture generator (FMEG) for wet electrical performance testing.

[0078] Table 1. Maximum output power of the fiber moisture-absorbing generator FMEG in Examples 1-4

[0079] serial number Maximum output power Example 1 <![CDATA[8.79*10 -5 W / m 2 ]]> Example 2 <![CDATA[7.24*10 -5 W / m 2 ]]> Example 3 <![CDATA[8.16*10 -5 W / m 2 ]]> Example 4 <![CDATA[8.21*10 -5 W / m 2 ]]>

[0080] Given that there are numerous embodiments of the present invention, and the raw materials and quantities involved can be selected within a limited range according to actual needs, and that the experimental data for each embodiment are extensive and numerous, it is not suitable to list and describe them one by one here. However, the content to be verified and the final conclusions obtained in each embodiment are similar. Therefore, the verification content of each embodiment will not be described one by one here.

[0081] The above description is merely a detailed explanation of preferred embodiments and principles of the present invention. For those skilled in the art, there may be changes in specific implementation methods based on the ideas provided by the present invention, and these changes should also be considered within the scope of protection of the present invention.

Claims

1. A carbon-based yarn with a spiral core-sheath structure, characterized in that, It includes a first conductive carbon fiber and a second conductive carbon fiber. The first conductive carbon fiber is divided into a first treated segment and a first untreated segment along its axial direction. An ion transport channel layer is wrapped around the first treated segment. The second conductive carbon fiber is divided into a second treated segment and a second untreated segment along its axial direction. A moisture-absorbing layer is wrapped around the second treated segment. The first processed section of the first conductive carbon fiber and the second processed section of the second conductive carbon fiber are twisted together to form a spiral core-sheath structure. The first untreated segment of the first conductive carbon fiber and the second untreated segment of the second conductive carbon fiber are located at the two ends of the spiral core structure, respectively. The first conductive carbon-based fiber and the second conductive carbon-based fiber are respectively formed by twisting multiple strands of carbon-based fiber filaments; The length ratio of the first treated segment to the first untreated segment of the first conductive carbon-based fiber is 1:(0.2~0.5). The length ratio of the second treated segment to the second untreated segment of the second conductive carbon-based fiber is 1:(0.2 to 0.5).

2. The helical core-sheath structure carbon-based yarn according to claim 1, characterized in that, The ion transport channel layer is a polymer electrolyte gel.

3. The helical core-sheath structure carbon-based yarn according to claim 2, characterized in that, The polymer electrolyte gel is one or more of the following: polyvinyl phosphate gel, polyvinyl hydrochloride gel, and polyethylene glycol-modified chitosan gel.

4. The helical core-sheath structure carbon-based yarn according to claim 1, characterized in that, The moisture-absorbing layer is one or more of silicon dioxide, magnesium sulfate, and calcium chloride.

5. The helical core-sheath structure carbon-based yarn according to claim 1, characterized in that, The first conductive carbon-based fiber is selected from carbon nanotube fibers or graphene fibers. The second conductive carbon-based fiber is selected from carbon nanotube fibers or graphene fibers.

6. The helical core-sheath structure carbon-based yarn according to claim 1, characterized in that, The twist of the multi-strand carbon-based fiber precursor is 75–500 T / m.

7. The method for preparing the helical core-sheath structure carbon-based yarn according to any one of claims 1-6, characterized in that, Includes the following steps: (1) An ion transport channel layer is attached to the outside of the first processed section of the first conductive carbon-based fiber using the dip-coating method. A moisture-absorbing layer is attached to the outside of the second processed section of the second conductive carbon-based fiber using an impregnation-coating method. (2) Using a yarn twister, the first treated section of the first conductive carbon fiber and the second treated section of the second conductive carbon fiber are twisted together to obtain a spiral core structure carbon yarn.

8. The application of the helical core-sheath structure carbon-based yarn as described in any one of claims 1-6 or the helical core-sheath structure carbon-based yarn prepared by the preparation method as described in claim 7, characterized in that, Used for wet gas power generation.

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