Polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel as well as preparation method and application thereof

Abstract

The invention discloses polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel as well as a preparation method and application thereof. The preparation method comprises the following steps: firstly, dispersing polyvinyl alcohol into water, stirring into sol, and freezing and thawing for three times; the preparation method comprises the following steps: adding sodium alginate into deionized water, and sequentially adding acrylic acid, silicon dioxide, N, N '-methylene bisacrylamide and an initiator to obtain a mixture A; uniformly mixing A with polyvinyl alcohol sol to obtain a mixture B, and performing thermal polymerization to form solid gel; soaking the solid gel in a calcium chloride solution, and soaking the solid gel in a potassium hydroxide and zinc acetate solution to prepare the conductive hydrogel. According to the method, a physical cross-linked network formed by freezing and thawing polyvinyl alcohol is combined with a network formed by cross-linking sodium alginate and calcium chloride, so that an efficient ion migration channel is constructed, and the conductivity is improved; the uniform and continuous network structure can be in good contact with electrodes, charge transfer is increased, internal resistance is reduced, loss is reduced, and the open-circuit voltage and power density of the battery are effectively improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of high polymers and energy storage, and relates to a polyvinyl alcohol-acrylic acid-sodium alginate double-network conductive hydrogel as well as a preparation method and application thereof. BACKGROUND

[0002] Ion-conducting hydrogels are a kind of polymer materials with high water content, stretchability and good conductivity, which show great potential in wearable sensing devices, energy storage devices and biomedical applications.

[0003] In recent years, the research focus in the field of ion-conducting hydrogels is to solve the inherent defects of traditional single-network structure hydrogels. Single-network hydrogels are often weak in mechanical properties and have disordered ion channels, resulting in generally low ion conductivity and power density. Increasing the crosslinking density to improve the strength will hinder ion migration, making it difficult to achieve high conductivity and high mechanical strength at the same time.

[0004] Ion-conducting hydrogels, as a kind of polymer material with unique properties, show great potential in wearable sensing devices, energy storage devices and biomedical applications. With the increasing demand for health monitoring, smart wear and efficient energy storage, wearable sensing devices need to have more accurate sensing performance and comfortable wearing experience; energy storage devices pursue higher energy density and power density; and the biomedical field expects materials to have better compatibility and functionality with biological bodies. Ion-conducting hydrogels, with their high water content, stretchability and good conductivity, exactly meet the development needs of these fields. High water content enables better fusion with biological tissues and reduces rejection reactions; stretchability ensures normal operation in various complex deformation environments; and good conductivity provides a basis for signal transmission and energy storage.

[0005] However, the field of ion-conducting hydrogels still faces many challenges. In recent years, the research focus has mainly been on solving the inherent defects of traditional single-network structure hydrogels. Single-network hydrogels have obvious shortcomings in performance, with weak mechanical properties and difficulty in withstanding large external forces, which easily leads to damage in practical applications. At the same time, the disordered distribution of ion channels leads to chaotic ion migration paths, resulting in generally low ion conductivity and power density, limiting their application in energy storage and efficient sensing. More problematic is that when the crosslinking density is increased to improve the strength of the hydrogel, although the mechanical properties can be enhanced to some extent, a tighter network structure is formed, which severely hinders ion migration. This creates a dilemma: to achieve high conductivity, a more loose network structure is needed to facilitate ion migration; while to achieve high mechanical strength, a tight crosslinking structure is needed, and the two are difficult to reconcile. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel, its preparation method, and its application, thereby solving the technical problems of insufficient power density and energy conversion efficiency of conductive hydrogels in the prior art.

[0007] This invention is achieved through the following technical solution: A method for preparing a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel includes the following steps: S1: Silica and crosslinking agent N,N' Methylenebisacrylamide and the initiator ammonium persulfate were added to a mixed solution of sodium alginate and acrylic acid to obtain mixture A; S2: Polyvinyl alcohol sol is added to mixture A, and after polymerization, a solid gel is obtained; S3: The solid gel is first soaked in calcium chloride solution, and then soaked in a mixed solution of potassium hydroxide and zinc acetate to obtain the polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel.

[0008] Preferably, in step S1, the mass ratio of silica, N,N'-methylenebisacrylamide and initiator ammonium persulfate is (0.1-0.2):(0.05-0.1):(0.1-0.15).

[0009] Preferably, in step S1, the ratio of sodium alginate to acrylic acid is (0.3-0.5) g:(2-4) mL.

[0010] Preferably, in step S2, the preparation of the polyvinyl alcohol sol is specifically as follows: polyvinyl alcohol particles are added to water and stirred at 95-100 °C for 30-40 min. After the PVA particles are completely dissolved, they are placed at -15-20 °C for repeated freeze-thaw cycles to obtain the polyvinyl alcohol sol.

[0011] Preferably, in step S2, the volume ratio of the polyvinyl alcohol sol to mixture A is 1:(8-10).

[0012] Preferably, in step S2, the polymerization reaction temperature is 60-65 °C and the time is 40-60 min.

[0013] Preferably, in step S3, the concentration of the calcium chloride solution is 0.04-0.06 mol / L, and the solid gel is soaked in the calcium chloride solution for 12-24 h.

[0014] Preferably, in step S3, the concentration of potassium hydroxide in the mixed solution of potassium hydroxide and zinc acetate is 5-7 mol / L, and the concentration of zinc acetate is 0.1-0.3 mol / L.

[0015] A polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel is prepared by the method; the ion conductivity of the polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel is 620-680 mS / cm; the open-circuit voltage is 1.20-1.40 V; and the power density is 160-220 mW / cm 2 .

[0016] The polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel is applied in the field of high polymers and energy storage technology.

[0017] Compared with the prior art, the present application has the following beneficial technical effects: The application discloses a preparation method of a polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel. First, the method constructs a double network structure, and through the division of labor of the rigid and flexible network, a more efficient transmission path is provided for ions while the mechanical properties are ensured. In the preparation process, silica, a crosslinking agent N,N'-methylenebisacrylamide and an initiator ammonium persulfate are added into a mixed solution of sodium alginate and acrylic acid to form a mixture A, and then polyvinyl alcohol sol is added to perform a polymerization reaction to obtain a solid gel. The double network structure is not simply superimposed, but is combined with the network formed by physical and chemical crosslinking, and the synergistic effect is significant. The physical crosslinking and the chemical crosslinking cooperate with each other to form an efficient ion migration channel, so that the ions can be quickly conducted therein, and the ion conductivity is greatly improved, and the low power density bottleneck caused by the slow ion migration rate is fundamentally broken. Secondly, the preparation method is also helpful for the uniform deposition of zinc ions. The solid gel is first soaked in a calcium chloride solution and then soaked in a mixed solution of potassium hydroxide and zinc acetate, and in this process, the double network structure can guide the uniform deposition of zinc ions and inhibit the formation of zinc dendrites. The reduction of zinc dendrites avoids the problems of battery short circuit caused by the penetration of dendrites into the separator and the like, improves the stability and energy conversion efficiency of the battery, and further effectively improves the power density of the battery, thereby providing a more optimal solution for the application of the conductive hydrogel in the field of energy storage.

[0018] Further, in step S1, the mass ratio of the silica, N,N'-methylenebisacrylamide and initiator ammonium persulfate is (0.1-0.2):(0.05-0.1):(0.1-0.15). This mass ratio range can ensure that each component fully plays a role in the reaction system. Silica serves as a filling or reinforcing component, and a suitable amount can improve the mechanical properties of the hydrogel; N,N'-methylenebisacrylamide serves as a crosslinking agent, and this ratio can form a moderately crosslinked network structure, which can ensure that the hydrogel has certain strength and elasticity, and also will not hinder ion transmission due to excessive crosslinking; ammonium persulfate serves as an initiator, and this amount can effectively initiate the polymerization reaction, so that the reaction proceeds smoothly, thereby preparing a conductive hydrogel precursor with stable performance and reasonable structure, laying a foundation for ultimately obtaining a hydrogel with high power density and energy conversion efficiency.

[0019] Further, in step S1, the mass ratio of the silica, N,N'-methylenebisacrylamide and initiator ammonium persulfate is (0.1-0.2):(0.05-0.1):(0.1-0.15). This mass ratio range can ensure that each component fully plays a role in the reaction system. Silica serves as a filling or reinforcing component, and a suitable amount can improve the mechanical properties of the hydrogel; N,N'-methylenebisacrylamide serves as a crosslinking agent, and this ratio can form a moderately crosslinked network structure, which can ensure that the hydrogel has certain strength and elasticity, and also will not hinder ion transmission due to excessive crosslinking; ammonium persulfate serves as an initiator, and this amount can effectively initiate the polymerization reaction, so that the reaction proceeds smoothly, thereby preparing a conductive hydrogel precursor with stable performance and reasonable structure, laying a foundation for ultimately obtaining a hydrogel with high power density and energy conversion efficiency.

[0020] Further, in step S2, the preparation of the polyvinyl alcohol sol is as follows: polyvinyl alcohol particles are added to water, stirred at 95-100 ℃ for 30-40 min, and then the PVA particles are completely dissolved. After the PVA particles are completely dissolved, they are placed at minus 15-20 ℃ for repeated freezing and thawing to obtain the polyvinyl alcohol sol. Stirring at 95-100 ℃ can make the polyvinyl alcohol particles quickly and fully dissolve in water to form a uniform solution. Repeated freezing and thawing at minus 15-20 ℃ can form physical crosslinking points between polyvinyl alcohol molecular chains, and a sol with a three-dimensional network structure is formed. This special sol structure provides a good reaction environment for the subsequent polymerization reaction with mixture A, which helps to form a stable double network structure and improve the mechanical properties and ion transport capacity of the hydrogel.

[0021] Further, in step S2, the volume ratio of the polyvinyl alcohol sol to mixture A is 1:(8-10), which can ensure that the polyvinyl alcohol sol and mixture A are fully mixed, so that the two can be uniformly combined in the polymerization reaction. The physical network formed by the polyvinyl alcohol sol and the network formed by the chemical reaction of mixture A interpenetrate each other to form a stable double network structure. A suitable ratio can avoid uneven network structure due to excessive or insufficient amount of a certain component, thereby ensuring that the hydrogel has good mechanical properties and ion conductivity and improving the power density and energy conversion efficiency.

[0022] Further, in step S2, the temperature of the polymerization reaction is 60-65 DEG C, and the time is 40-60 min. The temperature range of 60-65 DEG C is a suitable condition for initiating and stabilizing the polymerization reaction. At this temperature, the initiator can effectively initiate the polymerization of monomers, and the reaction rate is moderate, which is conducive to the formation of a uniform polymer network. The reaction time of 40-60 min can ensure that the polymerization reaction proceeds sufficiently, so that the polymer chain reaches a suitable length and crosslinking degree, forming a double-network hydrogel with stable structure and good performance, providing an efficient transport channel for ions and improving the power density of the hydrogel.

[0023] Further, in step S3, the concentration of the calcium chloride solution is 0.04-0.06 mol / L, and the solid gel is soaked in the calcium chloride solution for 12-24 h. The calcium chloride solution with a concentration of 0.04-0.06 mol / L can interact with the components in the hydrogel, such as sodium alginate, to form a stable crosslinked structure, further enhancing the mechanical properties of the hydrogel. The soaking time of 12-24 h can allow the interaction to proceed sufficiently, making the structure of the hydrogel more stable, and creating good conditions for the subsequent introduction of other ions, which helps to improve the overall performance and ion conduction ability of the hydrogel.

[0024] Further, in step S3, the concentration of the calcium chloride solution is 0.04-0.06 mol / L, and the solid gel is soaked in the calcium chloride solution for 12-24 h. The calcium chloride solution with a concentration of 0.04-0.06 mol / L can interact with the components in the hydrogel, such as sodium alginate, to form a stable crosslinked structure, further enhancing the mechanical properties of the hydrogel. The soaking time of 12-24 h can allow the interaction to proceed sufficiently, making the structure of the hydrogel more stable, and creating good conditions for the subsequent introduction of other ions, which helps to improve the overall performance and ion conduction ability of the hydrogel. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0026] Figure 1 The conductivity column chart of the sample prepared in Example 2 of the present application; Figure 2 The open-circuit voltage diagram of the sample obtained in Example 2 of this invention; Figure 3 The power density curve of the sample obtained in Example 2 of this invention is shown. Detailed Implementation

[0027] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0028] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0029] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0030] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0031] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0032] This invention provides a method for preparing a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel, comprising the following steps: S1: Silica and crosslinking agent N,N' Methylenebisacrylamide and the initiator ammonium persulfate were added to a mixed solution of sodium alginate and acrylic acid to obtain mixture A; The mass ratio of silica, N,N'-methylenebisacrylamide and initiator ammonium persulfate is (0.1-0.2):(0.05-0.1):(0.1-0.15).

[0033] The preparation of the mixed solution of sodium alginate and acrylic acid is specifically as follows: a certain mass of sodium alginate is added into a beaker containing deionized water, stirred uniformly, and a certain volume of acrylic acid is added dropwise into the beaker and stirred for 20-30 min to prepare the mixed solution of sodium alginate and acrylic acid. The dosage ratio of the sodium alginate to the acrylic acid is (0.3-0.5) g:(2-4) mL.

[0034] S2: The polyvinyl alcohol sol is added into the mixture A, and after polymerization, a solid gel is obtained. The preparation of the polyvinyl alcohol sol is specifically as follows: a certain mass of polyvinyl alcohol (PVA) particles is added into a beaker containing water, stirred at 95-100 ℃ for 30-40 min, and then the PVA particles are placed at minus 15-20 ℃ for repeated freezing and thawing three times to obtain the PVA sol. The volume ratio of the polyvinyl alcohol sol to the mixture A is 1:(8-10).

[0035] The polymerization temperature is 60-65 ℃, and the polymerization time is 40-60 min.

[0036] S3: The solid gel is first immersed in a calcium chloride solution and then immersed in a mixed solution of potassium hydroxide and zinc acetate to prepare the polyvinyl alcohol-acrylic acid-sodium alginate double-network conductive hydrogel.

[0037] The concentration of the calcium chloride solution is 0.04-0.06 M (i.e. mol / L), and the solid gel is first immersed in the calcium chloride solution for 12-24 h.

[0038] In the mixed solution of potassium hydroxide and zinc acetate, the concentration of potassium hydroxide is 5-7 M, and the concentration of zinc acetate is 0.1-0.3 M. The immersion time in the mixed solution of potassium hydroxide and zinc acetate is 2-4 days.

[0039] The method provides more efficient transmission paths for ions while guaranteeing mechanical properties through the network division of the rigid-flexible network structure, and realizes the rapid conduction and uniform deposition of ions in cooperation, so that the output power is improved; and the method provides a new idea for fundamentally breaking through the low power density bottleneck caused by the slow ion migration rate. The method takes polyvinyl alcohol (PVA), sodium alginate (SA), acrylic acid (AA) and silicon dioxide as raw materials, obtains a mixture in stages, and stirs to cause cross-linking, polymerizes to form a stable transparent colloid, and finally introduces conductive ions to prepare a conductive hydrogel. The efficient ion migration channel formed by the combination of the physical and chemical cross-linked networks significantly improves the ion conductivity, and also helps the uniform deposition of zinc ions and inhibits the formation of zinc dendrites, so that the power density of the battery is effectively improved. The preparation process of the method in the application is simple, and does not depend on complex equipment or conditions, so the preparation can be realized in various production environments. Only a simple container is needed, and the conductive hydrogel can be prepared through simple operation, which is convenient to use. The method is not only efficient, but also has strong flexibility, so that the preparation becomes more convenient and economical.

[0040] That is, the application discloses a preparation method of polyvinyl alcohol-acrylic acid-sodium alginate double-network conductive hydrogel. The preparation method disperses polyvinyl alcohol in water, stirs the polyvinyl alcohol at a certain temperature until the polyvinyl alcohol is in sol, and then freezes and thaws the polyvinyl alcohol three times at a certain temperature; a certain mass of sodium alginate is added to deionized water, and then a certain mass of acrylic acid, silicon dioxide, N,N'-methylenebisacrylamide and an initiator are added to the deionized water in sequence to obtain a mixture A; the mixture A is stirred with polyvinyl alcohol sol to obtain a mixture B; and the mixture B is heat-polymerized to form a solid gel. The physical cross-linked network formed by freezing and thawing of the polyvinyl alcohol and the network formed by cross-linking of the sodium alginate and calcium chloride are combined to form an efficient ion migration channel, so that the conductivity is improved; the uniform and continuous network structure of the hydrogel can form good interface contact with zinc electrodes and air electrodes, increase the charge transfer at the interface, reduce the internal resistance of the battery, reduce the energy loss, and effectively improve the open-circuit voltage and the power density of the battery.

[0041] The application will be further described in combination with specific examples. It should be understood that the examples are only used to illustrate the application but not to limit the scope of the application. In addition, it should be understood that those skilled in the art can make various modifications or changes to the application after reading the content of the application, and these equivalent forms also fall within the scope defined by the appended claims of the application.

[0042] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0043] Example 1 A method for preparing a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel includes the following steps: Preparation of polyvinyl alcohol sol: First, add 2.5g of PVA particles to a beaker containing 50mL of deionized water, stir at 95℃ for 30min, and after the PVA particles are completely dissolved, place it at -15℃ and freeze and thaw three times to obtain PVA sol.

[0044] Preparation of sodium alginate-acrylic acid solution: Add 0.3g of sodium alginate to a beaker containing 50mL of deionized water and stir for 30min. Then add 3mL of acrylic acid dropwise to the beaker and stir until the mixture is homogeneous.

[0045] Add 0.1 g of silica and 0.05 g of crosslinking agent N,N' to the above solution sequentially. Mixture A was obtained by adding methylenebisacrylamide and 0.15 g of initiator. 5 mL of the PVA sol prepared above was added to mixture A and stirred for 30 min to obtain mixture B. Mixture B was polymerized at 95 °C for 40 min to obtain a solid gel. This gel was then removed and soaked in 0.04 M calcium chloride solution for 15 h, followed by soaking in 6 M KOH + 0.2 M Zn(Ac)₂ solution for 2 days to obtain a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel.

[0046] Example 2 A method for preparing a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel includes the following steps: Preparation of polyvinyl alcohol sol: First, add 2.5 g of PVA particles to a beaker containing 50 mL of deionized water, stir at 95 ℃ for 30 min, and after the PVA particles are completely dissolved, place it at -15 ℃ and freeze and thaw three times to obtain PVA sol.

[0047] Preparation of sodium alginate-acrylic acid solution: Add 0.4 g of sodium alginate to a beaker containing 50 mL of deionized water and stir for 30 min. Add 3 mL of acrylic acid dropwise to the beaker and stir until the mixture is homogeneous.

[0048] Add 0.1 g of silica and 0.05 g of crosslinking agent N,N' to the above solution sequentially. Mixture A was obtained by adding methylenebisacrylamide and 0.15 g of initiator. 5 mL of the PVA sol prepared above was added to mixture A and stirred for 30 min to obtain mixture B. Mixture B was polymerized at 95 °C for 40 min to obtain a solid gel. This gel was then removed and soaked in 0.04 M calcium chloride solution for 15 h, followed by soaking in 6 M KOH + 0.2 M Zn(Ac)₂ solution for 2 days to obtain a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel.

[0049] The polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel prepared in this embodiment has an ionic conductivity of 673 mS / cm, an open-circuit voltage of 1.33 V, and a power density of 213 mW / cm. 2 .

[0050] Example 3 A method for preparing a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel includes the following steps: Preparation of polyvinyl alcohol sol: First, add 2.5 g of PVA particles to a beaker containing 50 mL of deionized water, stir at 95 ℃ for 30 min, and after the PVA particles are completely dissolved, place it at -15 ℃ and freeze and thaw three times to obtain PVA sol.

[0051] Preparation of sodium alginate-acrylic acid solution: Add 0.5 g of sodium alginate to a beaker containing 50 mL of deionized water and stir for 30 min. Add 3 mL of acrylic acid dropwise to the beaker and stir until the mixture is homogeneous.

[0052] Add 0.15 g of silica and 0.05 g of crosslinking agent N,N' to the above solution sequentially. Mixture A was obtained by adding methylenebisacrylamide and 0.1 g initiator. 5 mL of the prepared PVA sol was added to mixture A and stirred for 20 min to obtain mixture B. Mixture B was polymerized at 95 °C for 40 min to obtain a solid gel. This gel was then removed and soaked in 0.05 M calcium chloride solution for 15 h, followed by soaking in 6 M KOH + 0.2 M Zn(Ac)₂ solution for 2 days to obtain a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel.

[0053] The polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel prepared in this embodiment has an ionic conductivity of 621.2 mS / cm, an open-circuit voltage of 1.23 V, and a power density of 165 mW / cm. 2 .

[0054] Example 4 A method for preparing a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel includes the following steps: Preparation of polyvinyl alcohol sol: First, add 2.5 g of PVA particles to a beaker containing 50 mL of deionized water, stir at 95 ℃ for 30 min, and after the PVA particles are completely dissolved, place it at -15 ℃ and freeze and thaw three times to obtain PVA sol.

[0055] Preparation of sodium alginate-acrylic acid solution: Add 0.6 g of sodium alginate to a beaker containing 50 mL of deionized water and stir for 30 min. Then add 3 mL of acrylic acid dropwise to the beaker and stir until the mixture is homogeneous.

[0056] Add 0.15 g of silica and 0.05 g of crosslinking agent N,N' to the above solution sequentially. Mixture A was obtained by adding methylenebisacrylamide and 0.1 g initiator. 5 mL of the prepared PVA sol was added to mixture A and stirred for 20 min to obtain mixture B. Mixture B was polymerized at 95 °C for 40 min to obtain a solid gel. This gel was then removed and soaked in 0.05 M calcium chloride solution for 15 h, followed by soaking in 6 M KOH + 0.2 M Zn(Ac)₂ solution for 2 days to obtain a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel.

[0057] The polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel prepared in this embodiment has an ionic conductivity of 622 mS / cm, an open-circuit voltage of 1.33 V, and a power density of 165.2 mW / cm². 2 .

[0058] Example 5 A method for preparing a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel includes the following steps: Preparation of polyvinyl alcohol sol: First, add 2.5 g of PVA particles to a beaker containing 50 mL of deionized water, stir at 95 ℃ for 30 min, and after the PVA particles are completely dissolved, place it at -15 ℃ and freeze and thaw three times to obtain PVA sol.

[0059] Preparation of sodium alginate-acrylic acid solution: Add 0.7 g of sodium alginate to a beaker containing 50 mL of deionized water and stir for 30 min. Add 3 mL of acrylic acid dropwise to the beaker and stir until the mixture is homogeneous.

[0060] Add 0.15 g of silica and 0.05 g of crosslinking agent N,N' to the above solution sequentially. Methylene bisacrylamide and 0.1 g initiator to obtain mixture A. 5 mL of the above prepared PVA sol was added into mixture A and stirred for 20 min to obtain mixture B. Mixture B was polymerized at 95 ℃ for 40 min to obtain a solid gel, which was taken out and soaked in a 0.06 M calcium chloride solution for 15 h, and then soaked in a 6 M KOH + 0.2 M Zn(Ac)2 solution for 2 days to obtain a polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel.

[0061] The ion conductivity of the polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel prepared in this example was 657 mS / cm; the open circuit voltage was 1.38 V; and the power density was 157 mW / cm 2 .

[0062] Example 6 A method for preparing a polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel, comprising the following steps: S1: A certain amount of sodium alginate was added into a beaker containing deionized water, stirred uniformly, and a certain volume of acrylic acid was added dropwise into the beaker and stirred for 20 min to prepare a mixed solution of sodium alginate and acrylic acid; the amount ratio of sodium alginate to acrylic acid was 0.3 g:2 mL; silica, crosslinking agent N,N’ Methylene bisacrylamide and initiator ammonium persulfate were added into the mixed solution of sodium alginate and acrylic acid to obtain mixture A; the mass ratio of silica, N,N’ methylene bisacrylamide and initiator ammonium persulfate was 0.1:0.05:0.1.

[0063] S2: A certain amount of polyvinyl alcohol (PVA) particles were added into a beaker containing water, stirred at 95 ℃ for 40 min, and then placed at minus 15 ℃ for repeated freeze-thawing three times to obtain a polyvinyl alcohol sol; the polyvinyl alcohol sol was added into mixture A according to a volume ratio of 1:8, and a solid gel was obtained after polymerization reaction at 60 ℃ for 60 min; S3: The solid gel was first soaked in a 0.04 M calcium chloride solution for 24 h, and then soaked in a mixed solution of potassium hydroxide and zinc acetate for 2 days, wherein the concentration of potassium hydroxide in the mixed solution was 5 M and the concentration of zinc acetate was 0.1 M, to obtain the polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel.

[0064] The ion conductivity of the polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel prepared in this example was 625 mS / cm; the open circuit voltage was 1.28 V; and the power density was 163 mW / cm 2.

[0065] Example 7 A method for preparing a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel includes the following steps: S1: A certain mass of sodium alginate is added to a beaker containing deionized water and stirred until homogeneous. A certain volume of acrylic acid is then added dropwise to the beaker and stirred for 30 minutes to obtain a mixed solution of sodium alginate and acrylic acid. The ratio of sodium alginate to acrylic acid is 0.5 g: 4 mL. Silica and crosslinking agent N,N' are also added. Methylenebisacrylamide and initiator ammonium persulfate were added to a mixed solution of sodium alginate and acrylic acid to obtain mixture A; the mass ratio of silica, N,N'-methylenebisacrylamide and initiator ammonium persulfate was 0.2:0.1:0.15.

[0066] S2: A certain mass of polyvinyl alcohol (PVA) particles is added to a beaker containing water and stirred at 100 °C for 30 min. After the PVA particles are completely dissolved, the mixture is placed at -20 °C and repeatedly frozen and thawed three times to obtain polyvinyl alcohol sol. The volume ratio of polyvinyl alcohol sol to mixture A is 1:10. The polyvinyl alcohol sol is added to mixture A and polymerized at 65 °C for 40 min to obtain a solid gel. S3: The solid gel is first soaked in a 0.06 M calcium chloride solution for 24 h, and then soaked in a mixed solution of potassium hydroxide and zinc acetate for 4 days. The concentration of potassium hydroxide in the mixed solution is 7 M and the concentration of zinc acetate is 0.3 M, thus obtaining the polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel.

[0067] The polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel prepared in this embodiment has an ionic conductivity of 667 mS / cm, an open-circuit voltage of 1.35 V, and a power density of 198 mW / cm. 2 .

[0068] Example 8 A method for preparing a polyvinyl alcohol-acrylic acid-sodium alginate dual-network conductive hydrogel includes the following steps: S1: A certain mass of sodium alginate is added to a beaker containing deionized water and stirred until homogeneous. A certain volume of acrylic acid is then added dropwise to the beaker and stirred for 25 minutes to obtain a mixed solution of sodium alginate and acrylic acid. The ratio of sodium alginate to acrylic acid is 0.4 g:3 mL. Silicon dioxide and crosslinking agent N,N' are also added. The methylene bisacrylamide and initiator ammonium persulfate are added into a mixed solution of sodium alginate and acrylic acid to obtain a mixture A; the mass ratio of the silica, N,N'-methylene bisacrylamide and initiator ammonium persulfate is 0.15:0.08:0.12.

[0069] S2: a certain mass of polyvinyl alcohol (PVA) particles are added into a beaker containing water, stirred at 98 ℃ for 35 min, and after the PVA particles are completely dissolved, the PVA sol is obtained by repeatedly freezing and thawing three times at minus 18 ℃; according to the volume ratio of the PVA sol to the mixture A being 1:9, the PVA sol is added into the mixture A, and after the polymerization reaction is carried out at 63 ℃ for 50 min, a solid gel is obtained; S3: the solid gel is first immersed in a 0.05 M calcium chloride solution for 20 h, and then immersed in a mixed solution of potassium hydroxide and zinc acetate for 3 days, wherein the concentration of potassium hydroxide in the mixed solution of potassium hydroxide and zinc acetate is 6 M, and the concentration of zinc acetate is 0.2 M, so as to prepare the polyvinyl alcohol-acrylic acid-sodium alginate double-network conductive hydrogel.

[0070] The ion conductivity of the polyvinyl alcohol-acrylic acid-sodium alginate double-network conductive hydrogel prepared in the example is 679 mS / cm; the open-circuit voltage is 1.38 V; and the power density is 218 mW / cm 2 .

[0071] Figure 1 The conductivity column chart of the sample prepared in the example 2 is shown in the figure, and it can be known from the figure that the conductivity is 673 mS / cm under the experimental scheme.

[0072] Figure 2 The open-circuit voltage chart of the sample prepared in the example 2 is shown in the figure, and it can be known from the figure that the open-circuit voltage is 1.33 V under the experimental scheme. Figure 3 The power density curve chart of the sample prepared in the example 2 is shown in the figure, and it can be known from the figure that the power density is 213 mW / cm 2 .

[0073] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A process for the preparation of polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel, characterized by, The method comprises the following steps: S1: Silica and crosslinking agent N,N' Methylenebisacrylamide and the initiator ammonium persulfate were added to a mixed solution of sodium alginate and acrylic acid to obtain mixture A; S2: adding polyvinyl alcohol sol into the mixture A, and obtaining a solid gel after polymerization; S3: immersing the solid gel in a calcium chloride solution, and then immersing the solid gel in a mixed solution of potassium hydroxide and zinc acetate, thereby obtaining the polyvinyl alcohol-acrylic acid-sodium alginate double-network conductive hydrogel.

2. A process for the preparation of a polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel according to claim 1, characterized in that, In step S1, the mass ratio of the silica, N,N'-methylenebisacrylamide and initiator ammonium persulfate is (0.1-0.2):(0.05-0.1):(0.1-0.15).

3. A process for the preparation of a polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel according to claim 1, characterized in that, In step S1, the amount ratio of the sodium alginate and acrylic acid is (0.3-0.5) g:(2-4) mL.

4. A process for the preparation of a polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel according to claim 1, characterized in that, In step S2, the preparation of the polyvinyl alcohol sol is as follows: polyvinyl alcohol particles are added into water, and stirring is performed at 95-100 ℃ for 30-40 min; after the PVA particles are completely dissolved, the solution is repeatedly frozen and thawed at minus 15-20 ℃, thereby obtaining the polyvinyl alcohol sol.

5. A process for the preparation of a polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel according to claim 1, characterized by, In step S2, the volume ratio of the polyvinyl alcohol sol and the mixture A is 1:(8-10).

6. A process for the preparation of a polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel according to claim 1, characterized in that, In step S2, the polymerization temperature is 60-65 ℃, and the polymerization time is 40-60 min.

7. A process for the preparation of a polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel according to claim 1, characterized in that, In step S3, the concentration of the calcium chloride solution is 0.04-0.06 mol / L, and the solid gel is immersed in the calcium chloride solution for 12-24 h.

8. A process for the preparation of a polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel according to claim 1, characterized by, In step S3, in the mixed solution of potassium hydroxide and zinc acetate, the concentration of potassium hydroxide is 5-7 mol / L, and the concentration of zinc acetate is 0.1-0.3 mol / L; the immersion time in the mixed solution of potassium hydroxide and zinc acetate is 2-4 days.

9. A polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel, characterized in that, made by the method of any one of claims 1-8; the polyvinyl alcohol-acrylic acid-sodium alginate double network conductive hydrogel has an ionic conductivity of 620-680 mS / cm; an open circuit voltage of 1.20-1.40 V; a power density of 160-220 mW / cm 2 .

10. The polyvinyl alcohol-acrylic acid-sodium alginate double-network conductive hydrogel in claim 9 is applied in the field of high polymers and energy storage technology.

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