TWI750909B - Hydrogel, method for fabricating the same, hydrogel electrolyte, supercapacitor, and battery - Google Patents

Abstract

The invention relates to a hydrogel including a polymer scaffold and water which is composes of hydrated bound water instead of free water. The polymer scaffold is in-situco-crosslinked and polymerized by zwitterionic polymers and zwitterionic-functionalized inorganic nanoparticles to form a hierarchical foam-like porous structure including a cross-linked heterocenter and a main chain. The water is composed of a hydrated bound water layer on the surface of the polymer scaffold. The hydrogel transforms the state of water in it, and has remarkable mechanical properties with high toughness and strength. The hydrogel can be further added with electrolytic salt as a hydrogel electrolyte. The resulting hydrogel electrolyte exhibits an extended electrochemical window, respectable ionic conductivity, and a subdued self-discharge. Therefore, the hydrogel electrolyte can be applied in supercapacitors and electrochemical batteries.

Description

Hydrogel, preparation method thereof, hydrogel electrolyte, supercapacitor and battery

The present invention relates to a hydrogel, its preparation method, hydrogel electrolyte and application thereof, in particular to a hydrogel without free water, its preparation method, hydrogel electrolyte and application thereof.

The world's demand for energy is increasing day by day. Facing the advent of the era of portable electronics, all-solid-state flexible energy storage devices have been further optimized to bring more functions and experiences to flexible electronic devices. To realize flexible batteries, the most critical technology is to replace liquid electrolytes with solid electrolytes. Conventional solid-state electrolytes include inorganic solid-state electrolytes and organic solid-state electrolytes, wherein inorganic solid-state electrolytes include sulfides, oxides or glass electrolytes, and organic solid-state electrolytes include pure solid-state polymers and colloidal electrolytes.

Colloidal electrolytes are the most promising materials for the fabrication of flexible batteries because of their easy flexibility and excellent ionic conductivity. In order to provide an electrochemical window for the redox of battery active materials, colloidal electrolyte materials today need to use flammable organic solvents as plasticizers. However, if the battery is short-circuited, it will lead to a high risk of explosion. On the other hand, the battery active material and the disintegrating plasticizer will generate an irreversible solid electrolyte interface (SEI), resulting in a significant drop in Coulomb efficiency, and the continuously growing unstable solid electrolyte interface will evolve into lithium dendrites. In turn, the colloidal electrolyte and the isolation layer are broken through, resulting in battery damage. Furthermore, conventional colloidal electrolytes require the introduction of large amounts of organic solvents as plasticizers to ensure usable ionic conductivity. However, the introduction of a large amount of organic solvents will lead to low integrated mechanical strength of the colloidal electrolyte, which is difficult to be practically applied in the process of wearing sports, and is more likely to cause battery leakage, thereby causing physiological damage to the user. The use of water-based solvents instead of organic solvents as plasticizers can meet the safety requirements, but due to the limitation of water electrolysis voltage, it cannot provide a wide electrochemical window for redox charging and discharging of active substances.

Another promising energy storage method is supercapacitors, which are electrochemical capacitors with high power density that utilize the high specific surface area on the electrodes to physically adsorb charges. At present, supercapacitors are mostly used in backup energy, energy storage of chips in the fields of smart home appliances and communications, or electric vehicles. However, compared with other energy storage devices, supercapacitors have the problem of high self-discharge rate, which limits the ability of supercapacitors to store energy stably for a long time like traditional batteries. Therefore, it is particularly important to develop supercapacitors that can supply energy stably. At present, the common technology is to chemically modify carbon-based electrodes with high specific surface area, so that the charges tend to stay on the electrode surface instead of diffusing into the electrolyte. However, modified carbon-based electrodes do not maintain their characteristics for a long time, and are not practical in the long run.

One aspect of the present invention is to provide a hydrogel comprising a polymer scaffold and water. The aforesaid polymer scaffold is formed by in-situ cross-linking and gelation reaction of zwitterionic polymers and zwitterion-surfaced inorganic nanoparticles to form a multi-layered reticulated foam cell structure with cross-linked heterocenters and main chains, wherein the cross-linked heterocenters The zwitterion-surfaced inorganic nanoparticles are polymerized to form the main chain, and the zwitterionic polymers are polybetaines. The zwitterion-surfaced inorganic nanoparticles have vinyl functional groups and zwitterionic functional groups. Water forms a bound water film on the surface of the polymer scaffold. Wherein the aforementioned hydrogel does not contain free water.

Thereby, the hydrogel of the present invention changes the type of water therein, does not contain free water, has a fluffy multi-layered reticulated foam cell structure, and has mechanical properties of high toughness and strength.

According to the aforementioned hydrogel, the cationic group of the zwitterionic polymer can be -R ¹ -N ⁺ -R ² , R ¹ and R ^{2 are the} same or different, and are alkyl groups with 1 to 7 carbon atoms. The anion group of the zwitterionic polymer can be -COO ^- , (R ³ O) ₂ -P(=O)O ^- , -SO ₃ ^- or -O-SO ₃ ^- , and R ³ is carbon number 1 to 7 alkyl.

According to the aforementioned hydrogel, the average particle size of the zwitterion-surfaced inorganic nanoparticles may be 50 nm to 200 nm. Further, the zwitterion-surfaced inorganic nanoparticles may be zwitterion-surfaced silicon (Si) nanoparticles, zwitterion-surfaced iron oxide (Fe ₃ O ₄ ) nanoparticles, zwitterion-surfaced gold (Au) nanoparticles, or amphoteric Ionized silver (Ag) nanoparticles.

Another aspect of the present invention provides a method for preparing a hydrogel, comprising the following steps. The zwitterion-surfaced inorganic nanoparticles are provided, an aqueous solution is provided, a mixing step is performed, and an in-situ cross-linking gelation reaction is performed. The aforementioned zwitterion-surfaced inorganic nanoparticles have vinyl functional groups and zwitterionic functional groups, and the aqueous solution contains zwitterionic macromolecules, and the zwitterionic macromolecules are polybetaines. In the reaction to carry out the mixing step, the zwitterion-surfaced inorganic nanoparticles are added to the aqueous phase solution to obtain a mixture. The step of performing crosslinking in situ gelling reaction, the catalyst system was added to the mixture, and at 40 ^o C to 50 ^o C 20 hours to 30 hours, to obtain the hydrogel.

According to the aforementioned preparation method of the hydrogel, the addition concentration of the zwitterion-surfaced inorganic nanoparticles may be 0.2 wt % to 2 wt %.

According to the aforementioned preparation method of the hydrogel, the average particle size of the zwitterion-surfaced inorganic nanoparticles may be 50 nm to 200 nm.

Another aspect of the present invention is to provide a hydrogel electrolyte, comprising the aforementioned hydrogel and electrolytic salts, the electrolytic salts having a solubility of 6 m to 11 m ^{at 25 o C at 1 atm,} And the electrolytic salts are dissociated into cations and anions in the hydrogel, and the cations and the anions are distributed on the surface of the binding water film.

According to the aforementioned hydrogel electrolyte, the monomer polymerization concentration of the zwitterionic macromolecule of the hydrogel can be 13 wt % to 31 wt %.

According to the aforementioned hydrogel electrolyte, the electrolytic salts may be lithium salts, sodium salts or ammonium salts.

According to the aforementioned hydrogel electrolyte, the water content of the hydrogel electrolyte may be 10 wt % to 37 wt %.

Yet another aspect of the present invention is to provide a supercapacitor comprising an electrode and the hydrogel electrolyte described in the preceding paragraph.

According to the aforementioned supercapacitor, wherein the electrode can be activated carbon . Further, the activated carbon can be selected from the group consisting of high-porosity carbon materials, high-conductivity carbon materials, and combinations thereof.

Yet another aspect of the present invention is to provide a battery including a positive electrode , a negative electrode and an ion-conducting layer, the ion-conducting layer is disposed between the positive electrode and the negative electrode, and the ion-conducting layer comprises the hydrogel electrolyte described in the preceding paragraph.

Thereby, the hydrogel of the present invention changes the form of internal water, contains only bound water but not free water, and has mechanical properties of high toughness and strength, so that the integrated mechanical properties can be optimized. In addition, the hydrogel of the present invention can further add electrolytic salts as the hydrogel electrolyte, so that it has an enlarged electrochemical window, maintains the available ionic conductivity, and can suppress the self-discharge rate and increase the lithium ion migration rate. . Therefore, the hydrogel electrolyte of the present invention can be further applied to supercapacitors and batteries, so that the prepared supercapacitors and batteries have good electrochemical properties such as safety, low self-discharge and wide electrochemical window.

The disclosure of this specification proposes a novel hydrogel, which is a polymer scaffold with a multi-layered reticulated foam cell structure formed by in-situ cross-linking and gelation of zwitterionic polymers and zwitterion-surfaced inorganic nanoparticles. The water contained therein forms a bound water film on the surface of the polymer scaffold, so that the prepared hydrogel does not contain free water and has mechanical properties of high toughness and strength. The present specification also discloses a novel hydrogel electrolyte, which comprises the hydrogel of the present invention and electrolytic salts, has an enlarged electrochemical window, maintains usable ionic conductivity, and can suppress self-discharge rate. In addition, this specification further discloses a supercapacitor containing the hydrogel electrolyte of the present invention and a battery containing the hydrogel electrolyte of the present invention, which have good electrochemical performances such as safety, low self-discharge and wide electrochemical window.

The following are descriptions of specific terms used in this manual:

The aforementioned "zwitterionic polymer" in the specification is a polymer with both anionic and cationic groups, which can be highly hydrated, has excellent hydrophilic properties, excellent thermal and chemical stability, biocompatibility, resistance to Biofouling properties (such as anti-protein contamination, anti-bacterial adhesion, and anti-coagulation) and special anti-polyelectrolyte effects make them more and more applications in related fields such as biomedicine.

Specification of the "free water", also known as free water, bound by non-aqueous means the material is not water chemistry, the general nature of the water, frozen at the time of 0 ^o C, it will be evaporated by heat loss, and can serve as a good The solvent is the medium for all biochemical reactions.

The aforementioned "bound water" in the specification refers to the equilibrium water content under saturated air, and usually refers to the part of water that exists in the vicinity of the solute or other non-aqueous components and binds with the solute molecules through chemical bonds. The content of bound water has a considerable relationship with the water content of the external environment. Generally, substances containing bound water are called hygroscrpic substances. The bound water has ^{properties such as no freezing or no solvent effect even at 0 o} C, unless the temperature of the object drops to about -20 ^o C, the freezing phenomenon occurs.

Please refer to FIG. 1 , which shows a schematic diagram of the structure of the hydrogel 100 of the present invention. The hydrogel 100 contains a polymeric scaffold 110 and water (not numbered). The polymer scaffold 110 is made of zwitterionic polymers and zwitterion-surfaced inorganic nanoparticles through an in-situ cross-linking gelation reaction to form a multi-layered reticulated foam cell structure with cross-linked heterocenters 113 and main chains 111, wherein the cross-linked The linked heterocenter 113 is a zwitterion-surfaced inorganic nanoparticle, and the zwitterion-surfaced inorganic nanoparticle has a vinyl functional group and a zwitterionic functional group. As shown in FIG. 1 , the crosslinked heterocenter 113 has a cationic group 112 and anionic group 114. The main chain 111 is formed by polymerizing the zwitterionic polymer, and the zwitterionic polymer is polybetaine. As shown in FIG. 1 , the formed main chain 111 has a cationic group 112 and an anionic group 114 .

Further, the cationic group of the zwitterionic polymer can be -R ¹ -N ⁺ -R ² , where R ¹ and R ^{2 are the} same or different, and are alkyl groups with 1 to 7 carbon atoms. The anion group of the zwitterionic polymer can be -COO ^- , (R ³ O) ₂ -P(=O)O ^- , -SO ₃ ^- or -O-SO ₃ ^- , and R ³ is carbon number 1 to 7 alkyl. For example, the zwitterionic polymer can be sulfobetaine methacrylate ([2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, SBMA), N-(2-methacryloyloxy)ethyl -N,N-dimethylammonio propanesulfonate [N-(2-methacryloyloxy)ethyl-N,N-dimethylammonio propanesulfonate], N-(3-methacrylamido)propyl-N,N- N-(3-methacryloylimino)propyl-N,N-dimethylammonio propanesulfonate, 2-(methacryloyloxy)ethyl-phosphatidylcholine, or 2-(methacryloyloxy)ethyl-phosphatidylcholine Carboxybetaine (carboxybetaine).

The average particle size of the zwitterion-surfaced inorganic nanoparticles may be 50 nm to 200 nm. In addition, the zwitterion-surfaced inorganic nanoparticles may be zwitterion-surfaced silicon (Si) nanoparticles, zwitterion-surfaced iron oxide (Fe ₃ O ₄ ) nanoparticles, zwitterion-surfaced gold (Au) nanoparticles, or zwitterion-surfaced nanoparticles Surfaced silver (Ag) nanoparticles, the aforementioned zwitterion-surfaced inorganic nanoparticles have biocompatibility, and are easy to obtain, cheap and easy to modify. The so-called "easy to modify" refers to the surface of the nanoparticle Easily modified into vinyl (C=C) functional groups and zwitterionic functional groups.

Water forms a binding water film 120 on the surface of the polymer scaffold 110 , wherein the aforementioned hydrogel 110 does not contain free water.

Please refer to FIG. 2 , which shows a flow chart of the steps of the hydrogel preparation method 300 of the present invention. In FIG. 2 , the hydrogel preparation method 300 includes step 310 , step 320 , step 330 and step 340 .

Step 310 is to provide zwitterion-surfaced inorganic nanoparticles having vinyl functional groups and zwitterionic functional groups. Preferably, the average particle size of the zwitterion-surfaced inorganic nanoparticles may be 50 nm to 200 nm. Further, the zwitterion-surfaced inorganic nanoparticles may be zwitterion-surfaced silicon (Si) nanoparticles, zwitterion-surfaced iron oxide (Fe ₃ O ₄ ) nanoparticles, zwitterion-surfaced gold (Au) nanoparticles, or amphoteric Ionized silver (Ag) nanoparticles.

Step 320 is to provide an aqueous phase solution, wherein the aqueous phase solution includes zwitterionic polymers, wherein the zwitterionic polymers are polybetaines. Preferably, the cationic group of the zwitterionic polymer is -R ¹ -N ⁺ -R ² , R ¹ and R ^{2 are the} same or different, and are alkyl groups with 1 to 7 carbon atoms. The anion group of the zwitterionic polymer is -COO ^- , (R ³ O) ₂ -P(=O)O ^- , -SO ₃ ^- or -O-SO ₃ ^- , and R ³ is carbon number 1 to 7 the alkyl group.

Step 330 is a mixing step of adding zwitterion-surfaced inorganic nanoparticles to the aqueous solution to obtain a mixture. The addition concentration of the zwitterion-surfaced inorganic nanoparticles may be 0.2 wt% to 2 wt%. In addition, the monomer polymerization concentration of the zwitterionic polymer may be 13 wt % to 31 wt %.

Step 340 is crosslinking in situ gelling reaction system a catalyst is added in the mixture, and at 40 ^o C to 50 ^o C 20 hours to 30 hours, to obtain the hydrogel according to the present invention. Accordingly, the hydrogel prepared by the aforementioned method can be used in supercapacitors or batteries by adding electrolytic salts subsequently.

Please refer to FIG. 3 again, which shows a schematic structural diagram of the hydrogel electrolyte 200 of the present invention. The hydrogel electrolyte 200 comprises the aforementioned hydrogel (not numbered) and electrolytic salts 230 .

The hydrogel contains the polymeric scaffold 210 and water (not numbered). The polymer scaffold 210 is composed of zwitterionic polymers and zwitterion-surfaced inorganic nanoparticles through in-situ cross-linking and gelation reaction to form a multi-layered reticulated foam cell structure with cross-linked heterocenters 213 and main chains 211, wherein the cross-linked The heterocenter 213 is a zwitterion-surfaced inorganic nanoparticle, and the zwitterion-surfaced inorganic nanoparticle has a vinyl functional group and a zwitterionic functional group. As shown in FIG. 3, the cross-linked heterocenter 213 has a cationic group 212 and Anionic group 214. The zwitterionic polymer is polymerized to form the main chain 211 , and the zwitterionic polymer is polybetaines. As shown in FIG. 3 , the formed main chain 211 has a cationic group 212 and an anionic group 214 . Water forms a bound water film 220 on the surface of the polymer scaffold 210, wherein the hydrogel does not contain free water.

The electrolytic salts 230 will dissociate into cations 231 and anions 232 in the hydrogel. The cations 231 and anions 232 are distributed on the surface of the bound water film 220 and can move freely. The anion 232 moves toward the positive electrode, and the moving cation 231 and the anion 232 form an ionic current in the hydrogel, so that the hydrogel electrolyte can conduct electricity. The hydrogel electrolyte of the present invention is subsequently applied to flexible energy devices, such as biomedical chips and wearable electronic devices. Therefore, the electrolytic salts are biocompatible electrolytic salts, and considering that the hydrogel of the present invention only retains bound water and does not contain free water, the solubility of the ^{added electrolytic salts at 25 o C at 1 atm is:} 6 m to 11 m to avoid supersaturated precipitation. And it can be selected according to different ion batteries for subsequent applications, such as lithium salts, sodium salts or ammonium salts, so that the hydrogel electrolyte of the present invention can be applied to lithium ion batteries, sodium ion batteries or air batteries (such as zinc-air batteries) . Specifically, electrolytic salts such as lithium chloride (LiCl, saturated solubility of 19.6 m), sodium chloride (NaCl, saturated solubility of 6.1 m) can be used.

The present invention further provides a supercapacitor comprising an electrode and the aforementioned hydrogel electrolyte. The electrode can be activated carbon, and further, the activated carbon is one selected from the group consisting of high-porosity carbon materials, high-conductivity carbon materials, and combinations thereof.

In addition, the present invention further provides a battery comprising a positive electrode, a negative electrode and the aforementioned hydrogel electrolyte. The battery can be a lithium-ion battery, a sodium-ion battery or an air battery, and the materials of the positive electrode and the negative electrode can be selected according to the type of battery used. For example, if the battery is a lithium ion battery, the material of the positive electrode can be lithium manganate (LiMn ₂ O ₄ ), lithium iron phosphate (LiFePO ₄ ), lithium manganese oxide (LiMnO ₂ ), lithium cobalt oxide (LiCoO ₂ ), lithium Nickel cobalt oxide (LiNi _p Co1- _p O ₂ , 0<p<1). The material of the negative electrode can be graphite, lithium titanium oxide (Li ₄ Ti ₅ O ₁₂ ) or lithium. However, the present invention is not limited to this.

The following specific test examples are hereby used to further demonstrate the present invention, in order to facilitate those skilled in the art to which the present invention pertains, to fully utilize and practice the present invention without excessive interpretation, and these test examples should not be regarded as It is intended to limit the scope of the invention, but to illustrate how the materials and methods of the invention may be practiced.

1. Hydrogel of the present invention and preparation method thereof

1.1 Preparation of zwitterion-surfaced inorganic nanoparticles

The zwitterion-surfaced inorganic nanoparticles used in this test example are silicon nanoparticles, and further, vinyl silicon nanoparticles. In the experiment, vinyl silicon nanoparticles were prepared first to test the best preparation conditions. The tetraethoxysilane (TEOS) and vinyltriethoxysilane (VTEOS) in the molar ratio of 1:1 to 6:1 (the total weight in this test example is 3.9 g, then The present invention is not limited to this) is dissolved in 30 ml of deionized water, 0.1 ml of ammonia water is added after uniform shaking, TEOS and VTEOS are hydrolyzed and condensed in an alkaline environment, and the reaction is carried out under the stirring of a magnet for 20 hours to 30 hours. Hour. After the reaction is completed, it is washed with isopropanol and centrifuged at high speed to obtain vinyl silicon nanoparticles. Separately, under an argon atmosphere, 4.5 g of propane sultone was dissolved in 37 mL of acetone, and 7.5 g of (N,N-dimethyl-3-aminopropyl)trimethoxysilane was added. The reaction was vigorously stirred for 6 hours. The white precipitate was collected by vacuum filtration and washed twice with acetone. The white solid was dried and stored under argon. Next, an appropriate amount of zwitterionic siloxane dissolved in water was added to the vinylsilicon nanoparticles at a final concentration of 10 wt%. After stirring at room temperature for 6 hours at a pH of about 9, the solution was centrifuged at 13000 rpm for 15 minutes. The centrifuge was collected, redispersed in deionized water and washed several times. The final centrifuge (hereafter referred to as SiNS) was collected to test the optimal preparation conditions.

The prepared SiNS was then analyzed by nanoparticle size and interface potential analyzer to analyze the average particle size. Please refer to Table 1 below for the effect of different reaction conditions on the change of the average particle size of SiNS.

Table I Response time: 20 hours TEOS : VTEOS (Morby) 1:1 2:1 3:1 4:1 5:1 6:1 Average particle size (nm) 48 ± 8 72 ± 11 98 ± 18 113 ±21 104 ± 16 102 ± 24 Response time: 25 hours TEOS : VTEOS (Morby) 1:1 2:1 3:1 4:1 5:1 6:1 Average particle size (nm) 76 ± 9 96 ± 13 153 ± 13 166 ± 19 148 ± 16 157 ± 31 Response time: 30 hours TEOS : VTEOS (Morby) 1:1 2:1 3:1 4:1 5:1 6:1 Average particle size (nm) 114 ± 14 143 ± 14 202 ± 18 197 ± 22 208 ± 28 205 ± 37

It can be seen from the results in Table 1 that SiNS with different average particle sizes can be obtained by adjusting the molar ratio of TEOS and VTEOS and the reaction time. And analyzed by nanoparticle size and interface potential analyzer, the average particle size of the prepared SiNS is about 50 nm to 200 nm. Among them, when the reaction time is 30 hours, and the molar ratio of TEOS to VTEOS is 3:1 to 6:1, SiNS of about 200 nm can be obtained.

In the experiment, the morphology of the prepared SiNS was observed with a scanning electron microscope. Please refer to Figure 4, which is a scanning electron microscope photo of SiNS. The preparation conditions of SiNS in Figure 4 are that the reaction time is 30 hours, and the TEOS The molar ratio to VTEOS is 3:1, it can be seen that the prepared SiNS is uniform in size and the average particle size is about 200 nm.

1.2 The effect of the average particle size of zwitterion-surfaced inorganic nanoparticles on the properties of hydrogels

In this experiment, the absorption spectra of SiNS and zwitterionic polymer were firstly analyzed by Fourier transform infrared spectrometer. )ammonium hydroxide, SBMA). Please refer to Figure 5A, which is the far-infrared Fourier spectrum of SiNS and SBMA. The results show that the spectrum of SBMA and SiNS ^{can see vinyl groups (C=C) at 1640 cm -1} , so SiNS and SBMA can be copolymerized by the vinyl groups they have. The characteristic absorption spectrum of NH can be seen at 2970 cm ^-1 for SBMA, and the characteristic absorption spectrum for NH is visible at 2962 cm ^{-1 for} SiNS, indicating that zwitterionic functional groups are grafted on the surface of SiNS.

Further, this experiment tested whether the in-situ cross-linking gelation reaction of SiNS with different average particle diameters and zwitterionic polymers would affect the properties of the obtained hydrogels. The zwitterionic polymers used were methyl groups. Acrylic sulfobetaine ([2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, SBMA). In the experiment, SiNS with an average particle size of about 50 nm to 200 nm and SBMA were used for in-situ cross-linking gelation reaction, and the viscosity of the prepared hydrogel was analyzed by rheometer. Please refer to Table 2 below for the relationship between the average particle size of SiNS and the viscosity of the hydrogel.

Table II The average particle size ~50 nm ~100 nm ~150 nm ~200 nm Viscosity (Pa s) 0.017 0.16 2.06 606.8

It can be seen from the results in Table 2 that if SiNS with an average particle size of less than 200 nm (including 200 nm) is used for in-situ cross-linking and gelation reaction with SBMA, the viscosity of the prepared hydrogel will vary with the average size of SiNS. increases with the increase in particle size. In addition, when the reaction time in preparing SiNS exceeds 30 hours, SiNS having an average particle diameter of 450 nm to more than 500 nm is formed. If the subsequent in-situ crosslinking and gelation reaction is performed with SiNS with an average particle size of more than 500 nm and SBMA, a solid gel will be formed, which cannot be processed and prepared. In order to have processability and high viscosity at the same time, so that it can increase the contact between the electrodes, the subsequent experiments used SiNS with an average particle size of 200 nm (the molar ratio of TEOS and VTEOS used was 3:1, and the reaction time was 30 Hour).

In the experiment, the obtained hydrogel was analyzed by scanning electron microscope. Please refer to Figure 5B, which is a scanning electron microscope photograph of the hydrogel of the present invention. It can be clearly seen from the scanning electron microscope pictures that the hydrogel of the present invention has a polymer scaffold with a multi-layered reticulated foam cell structure.

1.3 Effect of the addition amount of zwitterion-surfaced inorganic nanoparticles on the properties of hydrogels

This experiment also tested whether different addition amounts of SiNS would affect the properties of the prepared hydrogels. In the experiment, SiNS with different weight concentrations was added to SBMA for in-situ cross-linking and gelation reaction. 0.2 wt% to 2 wt% SiNS was dissolved in 3.1 g of SBMA monomer deionized aqueous solution, and ultrasonically oscillated for 30 after minutes, then add ammonium sulfate (ammonium sulfate, AMS) as a catalyst, and then injecting nitrogen to remove oxygen in the solution, and finally placed in 45 ± 5 ^o C oil bath for 30 hours, to obtain the hydrogel according to the present invention, It is a viscous colloid.

Please refer to Figure 6A and Figure 6B, which are photographs of the hydrogel of the present invention, which is an example of a hydrogel prepared by adding 0.2 wt% of SiNS. Figure 6A shows the liquid hydrogel prepared by adding 0.2 wt% SiNS. The liquid hydrogel was placed under ^{the conditions of room temperature 25 o} C and humidity of 50%, and left standing for 24 hours to form Figure 6B of solid hydrogels. However, according to the addition of different weight concentrations of SiNS, the microscopic behavior of the prepared hydrogels will be completely different, and finally hydrogels with different mechanical strengths will be obtained. Tensile mechanical properties are used to test the tensile strength of the hydrogel of the present invention under load under static state, and the ultimate tensile strength can be obtained.

Please refer to Figure 6C, which is an analysis diagram of the tensile mechanical properties of hydrogels prepared by adding SiNS with different weight percentages, wherein SBMA-co-SiNS represents the hydrogel prepared by cross-linking SBMA and SiNS , and the weight concentration of SiNS added is indicated in parentheses. The results in Figure 6C show that as the weight concentration of SiNS added increases, the tensile strength of SBMA-co-SiNS also increases, ranging from 85 KPa to 4461 KPa. However, when the weight concentration of SiNS was added at 2 wt%, the mechanical behavior of SBMA-co-SiNS (2 wt%) changed to brittle plastic behavior, and the amount of tensile strain was shortened to 730%.

The linear viscoelastic evolution of SBMA-co-SiNS (2 wt%) was further analyzed by a rheometer. Please refer to Fig. 6D, which is a rheological analysis of SBMA-co-SiNS (2 wt%), which shows that SBMA-co-SiNS (2 wt%) is not reversible at shear strains ranging from 0.1% to 5.5%. The dynamic chain behavior, that is, the storage modulus (G') and the destruction modulus (G'') are stable and parallel without intersection, show that the internal molecular chains of SBMA-co-SiNS (2 wt%) are not easy to move, which is very important for the ionic conduction efficiency. not good. The addition amount of SiNS in the hydrogels prepared in subsequent experiments is taken as an example with 1 wt%.

2. The hydrogel electrolyte of the present invention

2.1 Preparation of the hydrogel electrolyte of the present invention

The hydrogel electrolyte of the present invention is further prepared under the above optimal conditions for preparing hydrogel. The electrolytic salts used in this test example are lithium salts, and further, are lithium bis(tri-fluoromethanesulfonyl)imide (LiTFSI). First, 12.7 mL of a mixed solution of TEOS and VTEOS (3:1 v/v TEOS:VTEOS) was mixed with 100 mL of ethanol, followed by 5 mL of NH ₄ OH (33 wt%) to initiate base-catalyzed hydrolysis, The vinyl nanoparticles were recovered by centrifugation at 3,000 rpm for 20 minutes after the condensation reaction was carried out under stirring at 25 ^{o C for 30 hours, and washed several times with deionized water and isopropanol.} Separately, under an argon atmosphere, 4.45 g of propane sultone was dissolved in 37 mL of acetone, and 7.5 g of (N,N-dimethyl-3-aminopropyl)trimethoxysilane was added. The reaction was vigorously stirred for 6 hours. The white precipitate was collected by vacuum filtration and washed twice with acetone. The white solid was dried and stored under argon. Next, an appropriate amount of zwitterionic siloxane dissolved in water was added to the vinyl nanoparticles at a final concentration of 10 wt%. After stirring at room temperature for 6 hours at a pH of about 9, the solution was centrifuged at 13000 rpm for 15 minutes to obtain the SiNS product. Then 2.34 g of SBMA monomer was dissolved in 9 mL of deionized water, and 0.16 g of SiNS prepared above and 2.6 g of LiTFSI were added, where the final concentration of LiTFSI was 1 M. The mixture was sonicated for an additional 10 minutes and stirred for 30 minutes. The solution was flushed with nitrogen for an additional 10 minutes. Then, 0.024 g of ammonium persulfate was dissolved to ^{react in an oil bath at 45±2 o} C for 30 hours to gel (hereinafter referred to as PSBMA). In the drying step, the residual bulk water is ^{evaporated at 80 o} C for 24 hours, and then stored in the surrounding environment (25 ^o C, 50% humidity) until it reaches a practical equilibrium with the surrounding environment, that is, the invention is obtained. Hydrogel electrolyte.

In the experiment, polyvinyl alcohol (PVA) hydrogel electrolyte and polythiobetaine [Poly (sulfobetaine methacrylate), PSBMA] hydrogel electrolyte were prepared as comparative examples. The PVA hydrogel electrolyte was prepared as follows: 2.34 g of PVA powder (33 K MW) and 2.6 g of LiTFSI were dissolved in 9 mL of deionized water for 4 h under stirring ^{at 60 o C to form a transparent wet gel, which was then dried} . The difference between the PSBMA hydrogel electrolyte and the hydrogel electrolyte of the present invention is that no SiNS is added in the preparation process, and the rest of the preparation process is the same. In addition, the hydrogel electrolytes of the present invention with LiTFSI concentrations of 1.5, 2, and 3 m were prepared experimentally to explore their effects on ionic conductivity.

2.2 Analysis of the properties of the hydrogel electrolyte of the present invention

The properties of the prepared hydrogel electrolyte of the present invention were further analyzed experimentally. Please refer to Figure 7A and Figure 7B, Figure 7A is the far-infrared Fourier spectrum of the hydrogel electrolyte of the present invention and PSBMA hydrogel electrolyte, Figure 7B is the hydrogel electrolyte of the present invention, PSBMA hydrogel electrolyte Differential scanning calorimetry analysis results of gel electrolyte and PVA hydrogel electrolyte, wherein SBMA-co-SiNS represents the hydrogel electrolyte of the present invention, PSBMA represents PSBMA hydrogel electrolyte, and PVA represents PVA hydrogel electrolyte.

Because the hydrogel electrolyte has abundant positive and negative groups, it can effectively attract LiTFSI to help dissociation. The results in Figure 7A show that in the presence of the zwitterionic polymer SBMA, the bonding peak of LiTFSI decreases, indicating that LiTFSI has a forced dissociation phenomenon. The positive group (NH ₂ ⁺ ) and the negative group (SO ₃ ^- ) of the zwitterionic polymer have their peaks rising and moving to high wavenumbers (blue-shift phenomenon), which means that molecules with strong electronegativity attract each other and change the molecular vibration. energy, namely attracting ^{with TFSI -} and Li ^{+ respectively.} On the other hand, by differential scanning calorimetry, it can be observed from the results in Figure 7B that SBMA-co-SiNS does ^{not have any endothermic or exothermic peaks near 0 o} C, which proves that there is no free water inside and all are Bound water, while PVA hydrogel electrolytes (i.e. general commercial gel electrolytes) have a large amount of free water present. In addition, the PSBMA hydrogel electrolyte of the comparative example still has some free water.

2.3 Influence of electrolytic salt concentration and polymer polymerization concentration on the properties of the hydrogel electrolyte of the present invention

In the test, the hydrogel electrolyte (solid state) of the present invention was formed on two pieces of 316L stainless steel plates, and electrochemical AC impedance test was carried out with an electrochemical workstation. Due to the small cation radius of LiTFSI lithium salt, it is a strong water-absorbing salt, which will absorb water in the atmosphere until it is saturated. The bound water content of the hydrogel electrolyte also affects the performance of ionic conductivity. In the experiment, the concentration of LiTFSI was adjusted to 1 m to 3 m, and the water content in the hydrogel electrolyte prepared with the monomer polymerization concentration of zwitterionic polymer (hereinafter referred to as the polymer polymerization concentration) was detected by freeze-drying. Please refer to Table 3 below, which is the relationship between the lithium salt concentration, the polymer polymerization concentration and the water content of the hydrogel electrolyte.

Table 3 Lithium salt concentration Polymer polymerization concentration 1 m 1.5 m 2 m 3 m 13 wt% Moisture content 9.3 wt% Moisture content 15.1 wt% Moisture content 30.5 wt% Moisture content 37.2 wt% 17 wt% Moisture content 10.5 wt% Moisture content 14.8 wt% Moisture content 29.6 wt% Moisture content 37.1 wt% 21 wt% Moisture content 11.3 wt% Moisture content 15.6 wt% Moisture content 31.1 wt% Moisture content 37.4 wt% 28 wt% Moisture content 9.1 wt% Moisture content 14.8 wt% Moisture content 32.3 wt% Moisture content 37.1 wt% 31 wt% Moisture content 8.7 wt% Moisture content 15.1 wt% Moisture content 29.4 wt% Moisture content 36.5 wt% 34 wt% Forms unprocessable solid gels

The results in Table 3 show that when the polymer polymerization concentration is greater than 31 wt%, the solution will form a solid gel, which cannot be processed or prepared in the next step. When the polymer polymerization concentration is lower than 13 wt%, the solution is too dilute to form a solid film after air-drying. When the concentration of polymer polymerization is about 13-31 wt% and the concentration of electrolytic salt is 1-3 m, the water content measured by freeze-drying method is 8.7-37.4 wt%, and it is found that the water content of the hydrogel electrolyte will vary with the added amount. The electrolytic salt concentration is determined, and has nothing to do with the polymer polymerization concentration. When the lithium salt concentration was added to 2 m or 3 m and air-dried, the surface was too wet, and all materials turned into a glue-like rather than a complete solid film. When these liquid colloids are cast on the substrate and tested ^{to be air-dried when the ambient humidity is 20-60% and the temperature is 15-35 o} C, the water content of the material is roughly kept constant. The reason is the tight cross-linking inside the hydrogel electrolyte of the present invention. The structure and the addition of zwitterions have strong water retention capacity, which can not be affected by too much environmental humidity.

For further analysis of the electrochemical impedance and ionic conductivity of the hydrogel electrolyte of the present invention, please refer to Figure 8A and Figure 8B. Figure 8A shows the electrochemical performance of the hydrogel electrolyte of the present invention prepared with different polymer polymerization concentrations The impedance analysis diagram is a Nyquist diagram, wherein SBMA-co-SiNS represents the hydrogel electrolyte of the present invention, and the numbers in the subscripts represent the polymer polymerization concentration. Figure 8B shows the ionic conductivity of the hydrogel electrolyte of the present invention prepared with different polymer polymerization concentrations. The results in Figures 8A and 8B show that when the polymer polymerization concentrations are 13, 17 and 21 wt% and the electrolytic salt concentration is 1.5 m, the ionic conductivities that can be obtained are 13.6, 4.2 and 0.2 mS/cm, respectively. This is similar to the electrolyte used in most literatures and patents, and is sufficient for practical applications in supercapacitors or lithium-ion batteries.

In the experiment, the effect of different polymer polymerization concentrations on the tensile properties of the hydrogel electrolyte of the present invention was further tested. tested for salt concentration. Please refer to Figure 9A, which is a tensile stress-strain diagram of the hydrogel electrolyte of the present invention prepared with different polymer concentrations . The results show that the tensile strength and strain of the hydrogel electrolyte of the present invention are higher than the values reported in the general literature and patents known so far. When the polymer polymerization concentration is 13 wt%, 17 wt% and 21 wt% were 0.26 MPa, 0.42 MPa and 1.1 MPa, respectively. At the same time, the tensile strain exhibited by it can reach more than 4000%, even when the polymer concentration is 13 wt% and 17 wt%, it can reach more than 6000%.

In the experiment, the hydrogel electrolyte of the present invention with a polymer polymerization concentration of 17 wt% was used as an example to test its ionic conductivity performance under different bending (simulating wearable sports). Please refer to Figure 9B, which is the Plot of ionic conductivity versus bending strain for hydrogel electrolytes. The results in Figure 9B show that the ionic conductivity of this hydrogel electrolyte remains unchanged under different strains. It shows the stability of its material structure and is suitable as an all-solid-state flexible energy storage device.

2.4 Usable electrochemical window of the hydrogel electrolyte of the present invention

In the experiment, linear sweep voltammetry of oxidation potential and reduction potential was performed on the hydrogel electrolyte of the present invention with a polymer polymerization concentration of 17 wt% using a three-electrode system of 316L stainless steel electrode and Ag/AgCl reference electrode. , the purpose is to verify the usable electrochemical window of the hydrogel electrolyte of the present invention.

Please refer to Fig. 10A to Fig. 10C, Fig. 10A and Fig. 10B are linear scan voltammograms of the hydrogel electrolyte and aqueous LiTFSI liquid electrolyte of the present invention, wherein Fig. 10A is the result of forward scanning, and Fig. Figure 10B is the result of the reverse scan. Figure 10C is a schematic diagram of the available electrochemical window of the hydrogel electrolyte of the present invention, which is converted to lithium (Li/Li ⁺ ) potential. Since both SiNS and SBMA are highly hydrated materials and cross-linked to each other into a three-dimensional network structure, this synergistic effect reduces the activity of water, thus maximizing the available electrochemical window. From the results of Figure 10A and Figure 10B, it is shown that the usable electrochemical window of the hydrogel electrolyte of the present invention can reach 2.8 V. Please also refer to Figure 10C, the hydrogel electrolyte of the present invention has a higher usable electrochemical window than the current water-based pure liquid LiTFSI (1.2-1.5 V) and conventional hydrogel electrolyte (1.4-1.8 V), This can be said to be a great breakthrough and innovation for the application of energy storage of aqueous electrolytes.

3. Supercapacitors

In order to evaluate the feasibility of using the hydrogel electrolyte of the present invention for supercapacitors (Electrical Double Layer Capacitor, EDLC), supercapacitors were experimentally assembled in a symmetrical configuration, in which the same electrodes were used to sandwich the hydrogel electrolyte of the present invention between middle. The electrode contains 91 wt% activated carbon (AC), 2.5 wt% conductive carbon black, and 5 wt% styrene butadiene rubber (SBR)/1.5 wt% carboxymethyl cellulose (carbonxymethyl cellulose, CMC) as the adhesive and aluminum foil as the substrate. Dry the electrodes in ^{an oven at 120 o} C for 1 hour before use. The resulting mass loading was 2.15 mg cm ⁻² and the thickness was 32 μm. Both electrodes were coated with the liquid hydrogel electrolyte of the present invention (before the drying step), and subjected to vacuum treatment to make the hydrogel electrolyte of the present invention (liquid) in close physical contact with the electrodes, After drying at 80 ^o C for 24 hours to remove the residual lumpy water, and then ^{storing in air at 25 o} C for 24 hours, the aforementioned two electrodes were sealed by a hydraulic press to prepare a supercapacitor. The supercapacitors were subjected to multiple cyclic voltammetry (CV) tests, where the voltage was swept between 0-1.5 V, 0-2 V, and 0-2.5 V, respectively. In addition, a galvanostatic charge/discharge (GCD) curve was obtained experimentally by applying a current density of 0.5 to 10 A g ^{−1 .}

Please refer to Figures 11A to 11E, Figure 11A is a cyclic voltammogram of the supercapacitor of the present invention, Figure 11B is an electrochemical impedance analysis diagram of the supercapacitor of the present invention, and Figure 11C is a supercapacitor of the present invention Figure 11D is a photograph of the supercapacitor of the present invention under different bending angles, and Figure 11E is a cyclic voltammogram of the supercapacitor of the present invention under different bending angles.

It can be seen from the results in Figure 11A that the supercapacitor assembled with activated carbon and a hydrogel electrolyte with a polymer concentration of 17 wt% has an available electrochemical window of 2.5 V without electrolysis of water. It can be seen from the results in Fig. 11B that, compared with the pure liquid LiTFSI electrolyte, the hydrogel electrolyte of the present invention has lower interfacial impedance because the viscous colloid has good contact with the carbon electrode. Therefore, at a current density of 0.5 A/g and an electrochemical window of 1.5 V, the capacitance performance (144 F/g) of the supercapacitor of the present invention is better than that of the liquid electrolyte (110 F/g). Under the current density of 0.5 A/g and the electrochemical window of 2.5 V, the supercapacitor of the present invention has a capacitance performance of 183 F/g. In addition, the results of Fig. 11C show that the energy density of the supercapacitor of the present invention can reach an energy density of 39.1 Wh/Kg at a power density of 390 W/Kg, and still retains an energy density of 6.7 Wh/Kg at a power density of 10,000 W/Kg. Energy density in Wh/Kg. In addition, the results of Fig. 11D and Fig. 11E show that the supercapacitor of the present invention can also maintain nearly the same capacitance performance under the high tensile test (0-180°).

In the experiment, the self-discharge test of the supercapacitor of the present invention was also carried out, and the supercapacitor of the present invention and the supercapacitor of the comparative example ^{were charged to 1.5 V at 1 A g-1} and stayed for 2 hours to ensure that the capacitor was fully charged to the greatest extent. to minimize any self-discharge caused by spontaneous charge redistribution. The self-discharge was then tested under open circuit conditions for 6 hours and the voltage decay curve was recorded. All electrochemical analyzes were carried out at 25 ^o C, the aqueous PVA in Comparative Example is a gel electrolyte, PSBMA LiTFSI aqueous liquid electrolyte and gel electrolyte as an electrolyte of a supercapacitor.

Please refer to Fig. 12A and Fig. 12B, Fig. 12A is the current-time relationship diagram of the supercapacitor of the present invention and the supercapacitor of the comparative example under the open-circuit voltage, which is self-discharge from 1.5 V; Fig. 12B is the present invention. Plot of drop voltage vs. diffusion mechanism and activation mechanism for supercapacitors and comparative supercapacitors. SBMA-co-SiNS represents the supercapacitor of the present invention, PSBMA represents the supercapacitor containing PSBMA hydrogel electrolyte, PVA represents the supercapacitor containing PVA hydrogel electrolyte, and LiTFSI represents the supercapacitor containing LiTFSI liquid electrolyte.

The results of Figure 12A and Figure 12B show that the self-discharge of the supercapacitor of the present invention is only 0.37 V, while the self-discharge of the supercapacitor containing PVA hydrogel electrolyte and the supercapacitor containing LiTFSI liquid electrolyte are 1.03 V and 1.03 V, respectively. 1.43 V, the above results show that the hydrogel electrolyte of the present invention has a good self-discharge inhibition effect. One of the reasons is that the charges of the zwitterionic groups on the zwitterionic polymer and the zwitterionic surface-surfaced inorganic nanoparticles are properly distributed in the porous structure of the multi-layered reticulated foam, and the electrolytic salt is fixed by electrostatic adsorption. The second is that the internal water form of the hydrogel electrolyte of the present invention is bound water, which means that the water activity is reduced, thus reducing the decomposition of the electrolyte solvent.

Accordingly, the multi-layered reticulated foam cell structure formed by the in-situ cross-linking and gelation reaction of zwitterionic macromolecules and zwitterion-surfaced inorganic nanoparticles in the hydrogel electrolyte of the present invention can effectively utilize the electrostatic effect to maximize adsorption and adsorption. Charged ions and suppresses self-discharge. Therefore, it can be used as a colloidal electrolyte for supercapacitors and improve the self-discharge phenomenon of supercapacitors.

Fourth, the battery

In order to evaluate the feasibility of using the hydrogel electrolyte of the present invention in batteries, the lithium iron phosphate/activated carbon battery and the lithium iron phosphate/lithium titanate battery were assembled in a symmetrical configuration as examples, in which the lithium iron phosphate/activated carbon battery was used as an example. _{A lithium iron phosphate battery (LiFePO 4} ) with a weight of 1.67 mg cm ^-2 and a thickness of 60 μm was used as the positive electrode, and ^{an activated carbon with a weight of 2.12 mg cm -2} and a thickness of 32 μm was used as the negative electrode . The lithium iron phosphate/lithium titanate battery used lithium iron phosphate with a weight of 1.67 mg cm ^-2 and a thickness of 60 μm as the positive electrode, and ^{lithium titanate with a weight of 2.12 mg cm -2} and a thickness of 15 μm (lithium- titanate battery, LTO) as the negative pole. The hydrogel electrolyte of the present invention is sandwiched between the positive electrode and the negative electrode. The lithium iron phosphate electrode and lithium titanate electrode contained 70 wt% active material, 21 wt% conductive carbon black, and 7.5 wt% styrene butadiene rubber (SBR)/1.5 wt% carbon methylol Cellulose (carbonxymethyl cellulose, CMC) is used as a binder, and aluminum foil and copper foil are used as the base material. Dry the electrodes in ^{an oven at 120 o} C for 1 hour before use. Both electrodes were coated with the liquid hydrogel electrolyte of the present invention (ie, before the drying step) with an electrolytic salt concentration of 1.5 m, and vacuum treatment was performed to make the hydrogel electrolyte of the present invention (liquid) and the electrode They were in close physical contact with each other, ^{dried at 80 o} C for 24 hours to remove the residual lumpy water, and then ^{stored in air at 25 o} C for 24 hours, and the aforementioned two electrodes were sealed by a hydraulic press to make A solid-state lithium iron phosphate battery was obtained. Before the full cell test, the lithium iron phosphate half cell and the lithium titanate half cell were tested by cyclic voltammetry to find the best working voltage of the full cell. The fabricated flexible solid-state battery was tested by cyclic voltammetry.

Please refer to Figures 13A to 13D. Figure 13A is a graph showing the analysis results of the available electrochemical window of the hydrogel electrolyte of the present invention. Figure 13B is the cyclic voltammogram of the lithium iron phosphate/activated carbon battery of the present invention, the working voltage is 0.3-2.5V, the scanning frequency is 0.5 mVs ^-1 , and the number of cycles is 100 cycles. Fig. 13C is the cyclic voltammogram of the lithium iron phosphate/lithium titanate battery of the present invention, the working voltage is 0.9-2.4V, and the scanning frequency is 2 mVs ^-1 . Figure 13D is an analysis result of the lithium iron phosphate/lithium titanate battery of the present invention.

The results from Figure 13A to Figure 13C show that the available electrochemical window of the hydrogel electrolyte of the present invention is 1.4-4.2 V (vs. Li/Li ⁺ ), while the iron phosphate containing the hydrogel electrolyte of the present invention Lithium/activated carbon batteries and lithium iron phosphate/lithium titanate contain complete electrochemical reactions of lithium iron phosphate and lithium titanate at operating voltages of 0.3-2.5 V and 0.9-2.4 V, respectively, and stable cycle characteristics. The results in Figure 13D show that the lithium iron phosphate/lithium titanate battery containing the hydrogel electrolyte of the present invention has an energy density of 68 Wh/Kg at a 1C charge-discharge rate.

In summary, the hydrogel of the present invention uses zwitterionic polymers and zwitterion-surfaced inorganic nanoparticles to undergo in-situ cross-linking and gelation reaction to form a polymer scaffold with cross-linked heterocenters and main chains, and has multiple layers Reticulated foam cell structure. The water contained therein forms a bound water film on the surface of the polymer scaffold, so that the prepared hydrogel does not contain free water, is light in weight and has high integrated mechanical strength. In addition, the hydrogel of the present invention can further add electrolytic salts as the hydrogel electrolyte, the raw materials used are easy to obtain, and the amount of electrolytic salts used is very low (electrolytic salts have the highest cost ratio in the electrolyte) raw materials), and because the hydrogel electrolyte of the present invention has a low water content, it can effectively reduce the quality of the overall energy storage element, and has an expanded electrochemical window, maintains the available ionic conductivity, and can suppress the self-discharge rate and increase. Lithium ion migration number and other properties, so it has broad application potential. The hydrogel electrolyte of the present invention can be further applied to supercapacitors and batteries, so that the prepared supercapacitors and batteries have good electrochemical properties such as safety, low self-discharge and wide electrochemical window, so it can solve the problem of conventional flexibility. In electronic equipment, liquid electrolytes are insufficient in safety and high-voltage operation, and solid-state electrolytes have low ionic conductivity.

However, the present invention has been disclosed as above in an embodiment, but it is not intended to limit the present invention. Anyone who is familiar with the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection of the present invention The scope shall be determined by the scope of the appended patent application.

100: Hydrogel 110,210: Polymer scaffolds 111,211: Main chain 112,212: cationic groups 113,213: Cross-linked heterocenters 114,214: Anionic groups 120, 220: bound water film 200: Hydrogel Electrolyte 230: Electrolytic salts 231: cation 232: Anion 300: Preparation method of hydrogel 310, 320, 330, 340: Steps

In order to make the above and other objects, features, advantages and embodiments of the present invention more clearly understood, the accompanying drawings are described as follows: Figure 1 shows a schematic structural diagram of the hydrogel of the present invention; Figure 2 shows a flow chart of the steps of the preparation method of the hydrogel of the present invention; Figure 3 is a schematic diagram of the structure of the hydrogel electrolyte of the present invention; Figure 4 is a scanning electron microscope photograph of SiNS; Figure 5A shows the far-infrared Fourier spectra of SiNS and SBMA; Figure 5B is a scanning electron microscope photograph of the hydrogel of the present invention; Figure 6A and Figure 6B are photographs of the hydrogel of the present invention; Figure 6C is an analysis diagram of tensile mechanical properties of SBMA-co-SiNS added with different weight percentage concentrations of SiNS; Figure 6D shows the rheological analysis of SBMA-co-SiNS (2 wt%); Figure 7A is a far-infrared Fourier spectrum diagram of the hydrogel electrolyte of the present invention and the PSBMA hydrogel electrolyte; Fig. 7B is the differential scanning calorimetry analysis result of the hydrogel electrolyte of the present invention, PSBMA hydrogel electrolyte and PVA hydrogel electrolyte; Figure 8A is an electrochemical impedance analysis diagram of the hydrogel electrolyte of the present invention prepared with different polymer polymerization concentrations; Figure 8B shows the ionic conductivity of the hydrogel electrolyte of the present invention prepared with different polymer polymerization concentrations; Figure 9A is a tensile stress-strain diagram of the hydrogel electrolyte of the present invention prepared with different polymer concentrations; Fig. 9B is a graph showing the relationship between ionic conductivity and bending strain of the hydrogel electrolyte of the present invention; Figure 10A and Figure 10B are linear scan voltammograms of the hydrogel electrolyte and the aqueous LiTFSI liquid electrolyte of the present invention; Figure 10C is a schematic diagram of the available electrochemical window of the hydrogel electrolyte of the present invention; Figure 11A is a cyclic voltammogram of the supercapacitor of the present invention; Figure 11B is an electrochemical impedance analysis diagram of the supercapacitor of the present invention; Figure 11C is a distribution diagram of energy density and power density of the supercapacitor of the present invention; Figure 11D is a photograph of the supercapacitor of the present invention under different bending angles; Fig. 11E is a cyclic voltammogram of the supercapacitor of the present invention under different bending angles; Fig. 12A is a current-time relationship diagram under the open circuit voltage of the supercapacitor of the present invention and the supercapacitor of the comparative example; Figure 12B is a graph showing the relationship between the drop voltage vs. diffusion mechanism and activation mechanism of the supercapacitor of the present invention and the supercapacitor of the comparative example; Fig. 13A is the analysis result of the available electrochemical window of the hydrogel electrolyte of the present invention; Figure 13B is a cyclic voltammogram of the lithium iron phosphate/activated carbon battery of the present invention; Figure 13C is a cyclic voltammogram of the lithium iron phosphate/lithium titanate battery of the present invention; and Figure 13D is an analysis result of the lithium iron phosphate/lithium titanate battery of the present invention.

100: Hydrogel

110: Polymer scaffold

111: Main chain

112: cationic group

113: Cross-linked heterocenters

114: Anionic group

120: Combined water film

Claims (15)

A hydrogel comprising: a polymer scaffold, which is formed by a zwitterionic polymer and a zwitterion-surfaced inorganic nanoparticle through an in-situ cross-linking gelation reaction to form a multi-layered reticulated foam cell structure with a cross-linked heterocenter and a main chain, The cross-linked heterocenter is the zwitterion-surfaced inorganic nanoparticle, the zwitterion polymer forms the main chain, and the zwitterion polymer is polybetaine, and the zwitterion-surfaced inorganic nanoparticle has a vinyl functional group and a zwitterionic functional group; and a water, the water forms a bound water film on the surface of the polymer scaffold; wherein the hydrogel contains no free water. The hydrogel according to claim 1, wherein the cationic group of the zwitterionic polymer is -R ¹ -N ⁺ -R ² , R ¹ and R ^{2 are the} same or different, and are alkanes with 1 to 7 carbon atoms and the anion group of the zwitterionic macromolecule is -COO ^- , (R ³ O) ₂ -P(=O)O ^- , -SO ₃ ^- or -O-SO ₃ ^- , R ³ is carbon number 1 to 7 alkyl groups. The hydrogel of claim 1, wherein the average particle size of the zwitterion-surfaced inorganic nanoparticles is 50 nm to 200 nm. The hydrogel of claim 1, wherein the zwitterion-surfaced inorganic nanoparticles are a zwitterion-surfaced silicon (Si) nanoparticle, a zwitterion-surfaced iron oxide (Fe ₃ O ₄ ) nanoparticle, a zwitterion-surfaced iron oxide (Fe 3 O 4 ) nano-particle, a Zwitterion-surfaced gold (Au) nanoparticles or a zwitterion-surfaced silver (Ag) nanoparticle. A method for preparing a hydrogel, comprising: providing a zwitterion-surfaced inorganic nanoparticle, the zwitterion-surfaced inorganic nanoparticle has a vinyl functional group and a zwitterionic functional group; providing an aqueous phase solution, the aqueous phase The solution includes a zwitterionic polymer, wherein the zwitterionic polymer is polybetaine; performing a mixing step of adding the zwitterion-surfaced inorganic nanoparticles to the aqueous solution to obtain a mixture; and performing a crosslinking in situ gelling reaction system in a catalyst is added to the mixture, and at 40 ^o C to 50 ^o C 20 hours to 30 hours, to give the hydrogel. The preparation method of the hydrogel according to claim 5, wherein in the mixing step, the addition concentration of the zwitterion-surfaced inorganic nanoparticles is 0.2 wt% to 2 wt%. The preparation method of a hydrogel according to claim 5, wherein the average particle size of the zwitterion-surfaced inorganic nanoparticles is 50 nm to 200 nm. A hydrogel electrolyte, comprising: the hydrogel of any one of claim 1 to claim 4; and an electrolytic salt having a solubility of 6 m to ^{25 o C at 1 atm} 11 m, and the electrolytic salts dissociated into a cation and an anion in the hydrogel, and the cation and the anion were distributed on the surface of the bound water film. The hydrogel electrolyte according to claim 8, wherein the polymerization concentration of one monomer of the zwitterionic polymer in the hydrogel is 13 wt% to 31 wt%. The hydrogel electrolyte according to claim 8, wherein the electrolytic salts are lithium salts, sodium salts or ammonium salts. The hydrogel electrolyte according to claim 8, wherein the water content of the hydrogel electrolyte is 10 wt% to 37 wt%. A supercapacitor comprising: an electrode; and The hydrogel electrolyte according to any one of claim 8 to claim 11. The supercapacitor of claim 12, wherein the electrode is an activated carbon. The supercapacitor of claim 13, wherein the activated carbon is one selected from the group consisting of a highly porous carbon material, a highly conductive carbon material, and combinations thereof. A battery containing: a positive electrode; a negative electrode; and An ion-conducting layer is disposed between the positive electrode and the negative electrode, wherein the ion-conducting layer comprises the hydrogel electrolyte according to any one of claim 8 to claim 11.

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