Preparation method for n-p type ionic thermoelectric hydrogel based on bi-crosslinked network structure

Abstract

Provided in the present invention is a preparation method for an n-p type ionic thermoelectric hydrogel based on a bi-crosslinked network structure. The preparation method comprises the following steps: (1) dissolving a binary hydrogel substrate in water according to a certain proportion; (2) adding a cross-linking agent thereto; (3) adding the stirred solution dropwise into a mold, and subjecting same to curing molding and drying at a certain temperature; and (4) respectively soaking the cured hydrogel in an n-type ion solution and a p-type ion solution with a certain concentration, and after a period of time, assembling same, so as to obtain an n-p type ionic thermoelectric hydrogel based on a bi-crosslinked network structure. In contrast to a thermoelectric hydrogel which only has a single network structure and only uses one thermoelectric type, the present technical solution designs a thermoelectric hydrogel initiated by n-p type ions based on a double-crosslinked network structure, and can achieve more efficient and more stable energy conversion and utilization, thereby providing a new solution for the fields of flexible electronic devices, low-grade heat energy recovery, etc.

Description

A method for preparing np-type ion thermoelectric hydrogels based on a double cross-linked network structure Technical Field

[0001] This invention belongs to the field of functional polymer materials, specifically relating to a method for preparing an np-type ionic thermoelectric hydrogel based on a dual-network cross-linked structure. Background Technology

[0002] Thermoelectric materials have become a research hotspot in the energy field because they can directly convert heat energy into electrical energy, and they have significant application potential, especially in the fields of low-grade heat energy recovery and power supply for flexible electronic devices.

[0003] Thermoelectric hydrogels combine the energy conversion capabilities of traditional thermoelectric materials with the flexibility, biocompatibility, and ionic conductivity of hydrogels, making them an ideal flexible thermoelectric material. The thermoelectric effect of ionized hydrogels is primarily based on ion migration and redox reactions. However, single-type thermoelectric ionized hydrogels exhibit limited performance in thermoelectric properties, stability, and energy conversion efficiency, making it difficult to meet the demands for efficient energy recovery and long-term stable applications.

[0004] To overcome the aforementioned limitations, this technology proposes a method for preparing thermoelectric hydrogels using two thermoelectric types. By integrating n-type ions (such as FeCl2 / FeCl3) and p-type ions (such as K3[Fe(CN)6] / K4[Fe(CN)6]) into a single hydrogel system, the synergistic effect of the two thermoelectric types significantly improves the thermoelectric performance and output power of the hydrogel. Furthermore, the use of a dynamic cross-linking network and ion thermal migration mechanism further enhances the mechanical strength, self-healing ability, and electrochemical stability of the hydrogel, thereby meeting the practical needs of flexible electronic devices and low-grade heat energy recovery.

[0005] This technology not only provides new research ideas for the development of novel flexible thermoelectric materials, but also lays the foundation for realizing efficient and stable energy conversion devices. Technical issues

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing thermoelectric hydrogels that is simple to prepare, has a hydrogel cross-linking network, uses thermoelectric types initiated by two ions, and is capable of assembling small thermoelectric devices. Technical solutions

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] A method for preparing an np-type ionic thermoelectric hydrogel based on a double cross-linked network structure includes the following steps:

[0009] (1) Preparation of hydrogel precursor solution: A certain amount of binary hydrogel substrate is added to deionized water and stirred at a certain temperature and speed until the material is dissolved;

[0010] (2) Preparation of cross-linked hydrogel: After the solution is cooled to room temperature, add the cross-linking agent and stir until the material is dissolved;

[0011] (3) Preparation of hydrogel precursor: The stirred solution is dropped into the mold, and the mold is placed in a forced-air drying oven for curing and heat drying;

[0012] (4) Take out the solidified hydrogel from step (3) and soak it in an ionic solution of a certain concentration;

[0013] (5) The thermoelectric hydrogel obtained in step (4) is then assembled and connected in series using copper foil to obtain an np-type thermoelectric hydrogel.

[0014] Furthermore, the hydrogel substrate of the present invention can be acrylamide, sodium alginate, sodium carboxymethyl cellulose, polyvinyl alcohol, polyacrylic acid, sodium acrylate, chitosan, gelatin, etc.

[0015] Furthermore, the crosslinking agent of the present invention is N'N'-methylenebisacrylamide and ammonium persulfate or potassium persulfate.

[0016] Furthermore, the ionic solution in which the n-type thermoelectric hydrogel is immersed is either ferric chloride / ferrous chloride or sulfate / sulfite.

[0017] Furthermore, the ionic solution in which the p-type thermoelectric hydrogel is immersed is a potassium ferricyanide / potassium ferrocyanide or a triiodide / iodide ion pair.

[0018] Furthermore, the two thermoelectric types of thermoelectric hydrogels of the present invention are assembled using copper foil to obtain an np-type thermoelectric hydrogel. Beneficial effects

[0019] The present invention utilizes a binary hydrogel substrate, which forms a three-dimensional double cross-linked network structure under the action of a cross-linking agent. This structure enhances the mechanical properties of the hydrogel while maintaining its original flexibility and toughness. The hydrogel precursor, fabricated using a custom mold, can meet the assembly requirements of various types of flexible thermoelectric devices. Two different types of thermoelectric hydrogels of different thermoelectric types were obtained by immersion in two different types of ions. The present invention's np-type thermoelectric hydrogels, which absorb different types of ions, can significantly improve electrical power when connected in series under temperature difference driving and can achieve large-scale production. Attached Figure Description

[0020] Figure 1 is an electron microscope image of the thermoelectric hydrogel precursor of the present invention;

[0021] Figure 2 illustrates the assembly principle of the np-type thermoelectric hydrogel prepared in Example 4 of this invention;

[0022] Figure 3 shows the np-type thermoelectric hydrogel miniature thermoelectric device prepared in Example 4 of the present invention.

[0023] Figure 4 shows the power density of the NP-type thermoelectric hydrogel condensed assembly. Embodiments of the present invention

[0024] The invention will be described in more detail by way of examples and comparative examples, but the invention is not limited to these examples without departing from its spirit.

[0025] Example 1

[0026] A method for preparing a thermoelectric hydrogel using two thermoelectric types includes the following steps:

[0027] (1) Preparation of hydrogel precursor solution: Add 0.5~1g of polyvinyl alcohol (PVA) and 2.1~3.5g of acrylamide to 10~30mL of deionized water and stir at 90℃ and 400rpm for 1h until the material is dissolved;

[0028] (2) Preparation of cross-linked hydrogel: After the solution is cooled to room temperature, add 0.01~0.04g of N'N-methylenebisacrylamide and 0.01~0.04g of ammonium persulfate, and stir at 400rpm for 10min until the material is dissolved;

[0029] (3) Preparation of hydrogel precursor: The stirred solution was dropped into a 10*10*3mm mold, the mold was placed in a forced-air drying oven and dried at 80℃ for 12h;

[0030] (4) Take out the dried hydrogel precursor from step (3) and soak it in a 0.05~0.15mol / L potassium ferrocyanide / potassium ferrocyanide solution to obtain a p-type thermoelectric hydrogel.

[0031] (5) Take out the dried hydrogel precursor from step (3) and soak it in a 0.01~0.1mol / L ferric chloride / ferrous chloride solution to obtain an n-type thermoelectric hydrogel.

[0032] (6) Then, the thermoelectric hydrogels obtained in steps (4) and (5) are assembled and connected in series using copper foil to obtain an np-type thermoelectric hydrogel.

[0033] Test Example 1

[0034] The surface structure of the thermoelectric hydrogel obtained in Example 1 was characterized using scanning electron microscopy, as shown in Figure 1; and a temperature gradient was applied to the assembled thermoelectric hydrogel using a digital source table for testing, as shown in Figure 4.

[0035] As shown in Figure 1, the surface of the hydrogel precursor has a porous structure, indicating that the hydrogel can fully absorb ions during immersion and provide numerous pathways for ions under thermal stimulation. This invention utilizes a polyvinyl alcohol-filled acrylamide hydrogel with a filled three-dimensional network structure, exhibiting a certain degree of mechanical strength.

[0036] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an np-type ionic thermoelectric hydrogel based on a double cross-linked network structure, characterized in that, Includes the following steps: a. Preparation of hydrogel precursor solution: A certain amount of binary hydrogel substrate is added to deionized water and stirred until the material dissolves under certain temperature and rotation speed conditions; b. Preparation of cross-linked hydrogel: After cooling the above solution to room temperature, add the cross-linking agent and stir under a certain number of revolutions until the material dissolves; c. Preparation of hydrogel precursor: The stirred solution is dropped into a custom mold, the mold is placed in a forced-air drying oven, and cured and dried under certain temperature conditions; d. Take out the dried hydrogel precursor from step c and soak it in different ionic solutions to obtain n-type or p-type thermoelectric hydrogels respectively. e. The two types of thermoelectric hydrogels from step d were assembled into an NP-type thermoelectric hydrogel.

2. The method for preparing a thermoelectric hydrogel using two thermoelectric types according to claim 1, characterized in that, The hydrogel substrate mentioned in step a can be acrylamide, sodium alginate, sodium carboxymethyl cellulose, polyvinyl alcohol, polyacrylic acid, sodium acrylate, chitosan, gelatin, etc.

3. The method for preparing a thermoelectric hydrogel using two thermoelectric types according to claim 1, characterized in that, The crosslinking agent mentioned in step b is N'N'-methylenebisacrylamide and ammonium persulfate or potassium persulfate.

4. The method for preparing a thermoelectric hydrogel using two thermoelectric types according to claim 1, characterized in that, The ionic solution in which the n-type thermoelectric hydrogel is immersed in step d is either ferric chloride / ferrous chloride or sulfate / sulfite.

5. The method for preparing a thermoelectric hydrogel using two thermoelectric types according to claim 1, characterized in that, The ionic solution in which the p-type thermoelectric hydrogel is immersed in step d is potassium ferricyanide / potassium ferrocyanide or triiodide / iodide ion pair.

6. A method for preparing a thermoelectric hydrogel using two thermoelectric types according to any one of claims 1 to 5, characterized in that, The thermoelectric hydrogel obtained in step d is assembled and connected in series using copper foil to obtain an np-type thermoelectric hydrogel.

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