Wide-temperature-range flexible ion thermoelectric battery and preparation method thereof

Abstract

The invention discloses a wide-temperature-range flexible ion thermoelectric battery and a preparation method thereof. The wide-temperature-range flexible ion thermoelectric battery comprises thermoelectric hydrogel and an electrode, the thermoelectric hydrogel is obtained by placing a dual-network gel matrix in a binary redox electrolyte for solvent exchange, and binary redox ions in the binary redox electrolyte comprise a redox pair K3 / 4Fe (CN) 6 and a redox pair (NH4) 3 / 4 [Fe (CN) 6]. According to the wide-temperature-range flexible ion thermoelectric battery provided by the invention, the thermal stability of the flexible ion thermoelectric battery in a high-temperature region is improved, and the wide-temperature-range flexible ion thermoelectric battery has excellent thermoelectric performance, so that a feasible path is provided for realizing conversion and collection of relatively high-temperature heat energy by using the flexible ion thermoelectric battery; wide application prospects are realized in the fields of sensing monitoring, flexible wearable equipment, refrigeration and cooling, heat preservation and heat insulation and the like.

Description

Technical Field

[0001] This invention belongs to the field of thermoelectric energy conversion technology, and specifically relates to a wide-temperature-range flexible ion thermoelectric battery and its preparation method. Background Technology

[0002] Abundant low-grade thermal energy is widely distributed in social production and human activities. Developing efficient harvesting strategies is key to advancing sustainable energy technologies and powering wearable or distributed electronic systems. Thermoelectric technology, capable of directly converting thermal energy into electrical energy, has broad application prospects due to its compact structure, lack of moving parts, and long lifespan. Among existing thermoelectric technologies, quasi-solid-state thermochemical cells (QSTs) have emerged as a promising solution due to their low cost, mechanical flexibility, and high Seebeck coefficient generated by entropy-driven redox reactions. The core of high-performance QSTs lies in redox couples (such as [Fe(CN)6)). 3- / 4- Ion pairs have a large entropy change (Δ) S r c). To enhance this effect, recent research breakthroughs have utilized liquid-ionized cations (such as guanidinium ions, Gdm). + Induced [Fe(CN)6] 4- Thermosensitive crystals are formed, and a steep concentration gradient is constructed through a dynamic crystallization-precipitation-dissolution equilibrium, which increases the Seebeck coefficient of the thermochemical cell. S i From approximately 1.4 mVK -1 Increased to 3.7 mVK -1 That's all. However, these supramolecular assemblies, which result in a huge increase in entropy, rely on fragile non-covalent interactions for maintenance, leading to their thermal instability. The thermodynamic dissociation of the formed thermosensitive crystals at high temperatures (>55 °C) disrupts the construction of the concentration gradient, thereby weakening the thermoelectric performance. Therefore, achieving thermodynamic ion regulation is a key but unsolved problem in improving the thermoelectric performance of flexible ion thermoelectric batteries at high temperatures. Summary of the Invention

[0003] The purpose of this invention is to provide a wide-temperature-range flexible ion thermoelectric battery and its preparation method to address the shortcomings of existing technologies, thereby expanding the operating temperature range for thermochemical batteries to achieve continuous, stable and efficient thermoelectric conversion.

[0004] The technical solution adopted in this invention is as follows: A wide-temperature-range flexible ion thermoelectric battery includes a thermoelectric hydrogel and a platinum wire electrode, wherein the thermoelectric hydrogel includes a dual-network gel matrix and a binary redox electrolyte. The dual-network gel matrix was prepared by a sequential network method. The binary redox electrolyte comprises binary redox ion pairs, water, organic small molecule additives, and water-soluble metal salts. The thermoelectric hydrogel is obtained by immersing a dual-network gel matrix in a binary redox electrolyte.

[0005] The present invention provides a wide-temperature-range flexible ion thermoelectric battery based on a dual-network gel and binary redox pairs, utilizing ammonium cations (NH4+). + To reconfigure [Fe(CN)6] 4- The solvated shell enhances lattice energy by strengthening ion association, effectively raising the upper limit of the temperature tolerance of the crystalline structure. This system is then synergistically integrated with a dual-network hydrogel. Ultimately, the fabricated flexible ion thermoelectric battery achieves decoupling of thermal responsiveness and structural stability, realizing efficient and stable thermoelectric performance output over a wide temperature range of 25–90℃.

[0006] In a binary redox ion pair, the redox pair K 3 / 4 Fe(CN)6 and its redox pair (NH4) 3 / 4 The total concentration of [Fe(CN)6] was fixed at 0.2-0.12 M.

[0007] Redox pairs K 3 / 4 The concentration of Fe(CN)6 was 0.1–0.6 M, and the redox pair (NH4) 3 / 4 The concentration of [Fe(CN)6] was 0.1~0.6 M.

[0008] 4. The wide-temperature-range flexible ion thermoelectric battery according to claim 1, characterized in that the binary redox electrolyte further comprises water, organic small molecule additives, and water-soluble metal salts; the organic small molecule additives and water-soluble metal salts are dispersed together in an aqueous solution of redox pairs composed of binary redox ion pairs and water; the concentration of the organic small molecule additives in the binary redox electrolyte is 0.5 ~ 4 M; the concentration of the water-soluble metal salts in the binary redox electrolyte is 0.5 ~ 4 M.

[0009] The method for preparing thermoelectric hydrogel provided by the present invention is as follows: a dual-network gel matrix is ​​placed in a binary redox electrolyte for solvent exchange to obtain thermoelectric hydrogel.

[0010] In the above-mentioned method for preparing thermoelectric hydrogels, the method for preparing the dual-network gel is as follows: (1) Mix monomers, crosslinking agents and photoinitiators, and then cure the reaction under ultraviolet light to obtain a single-network gel matrix; (2) The single-network gel matrix was immersed in a mixed solution composed of monomer, crosslinking agent and photoinitiator for 24 hours and then cured by ultraviolet light to obtain a double-network gel matrix.

[0011] Furthermore, in step (1), the monomers include 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and acrylamide (AM), the crosslinking agent is N,N'-methylenebisacrylamide (BIS), and the photoinitiator is 2-hydroxy-2-methylphenylacetone (HMPP). The concentration of BIS is 0.002 ~ 0.02 M; the mass ratio of HMPP to deionized water is 1:200 ~ 1:50; the mass ratio of AM to AMPS is 1:2 ~ 1:0.2; and the mass ratio of total monomers to deionized water is 1:10 ~ 1:3.

[0012] Furthermore, in step (2), the monomer is acrylamide (AM), the crosslinking agent is polyethylene glycol diacrylate (PEGDA), and the photoinitiator is 2-hydroxy-2-methylphenylacetone (HMPP). The mass ratio of AM to deionized water is 1:10 to 1:6; the concentration of PEGDA is 0.002 to 0.02 M; and the mass fraction of HMPP is 0.1 to 1 wt%.

[0013] Furthermore, the two UV curing reactions were both 0.4 to 1 hour, and the UV wavelengths were 365 nm or 395 nm.

[0014] In the above-mentioned method for preparing thermoelectric hydrogels, the binary redox ion pairs in the binary redox electrolyte are composed of K... 3 / 4 Fe(CN)6 and (NH4) 3 / 4 [Fe(CN)6] integration, wherein the organic small molecules and water-soluble metal salts are co-dispersed in the aqueous solution of the redox pair; Furthermore, the organic small molecule additive is guanidine hydrochloride, wherein guanidine hydrochloride can be replaced by one or more guanidine salt derivatives, including but not limited to guanidine carbonate, guanidine phosphate, guanidine sulfate, or guanidine aminosulfonate.

[0015] Furthermore, the water-soluble metal salt is sodium chloride.

[0016] In the above-mentioned method for preparing thermoelectric hydrogel, the method for preparing the binary redox electrolyte is as follows: mixing binary redox ion pairs with water, adding guanidine hydrochloride, and then adding sodium chloride to obtain the electrolyte.

[0017] Furthermore, in binary redox ion pairs, the redox pair K 3 / 4 Fe(CN)6 and its redox pair (NH4) 3 / 4 The total concentration of [Fe(CN)6] is fixed at 0.4 M, and the molar ratios of the two are 4:0, 3:1, 2:2, 1:3, and 0:4, respectively.

[0018] Furthermore, the concentration of guanidine hydrochloride in the binary redox electrolyte is 0.5 ~ 4 M. Furthermore, the concentration of sodium chloride in the binary redox electrolyte is 0.5 ~ 4 M. In the above-mentioned method for preparing thermoelectric hydrogels, the reaction conditions for solvent exchange are: soaking at an ambient temperature of 85-95°C for 1-3 hours, then removing and cooling at room temperature.

[0019] The method for preparing a wide-temperature-range flexible ion thermoelectric battery provided by the present invention is as follows: platinum wire is used as an electrode, the electrode is integrated on the left and right sides of the thermoelectric hydrogel, the electrodes on both sides are in contact with a cold source and a heat source respectively, and a flexible encapsulation material is used to encapsulate the wide-temperature-range flexible ion thermoelectric battery.

[0020] Furthermore, the electrode spacing of the platinum wire electrode is 5~30 mm; Furthermore, the thickness of the gel electrolyte is 0.5 ~ 5 mm; Compared with the prior art, the present invention has the following beneficial effects: 1. Traditional K 3 / 4 Fe(CN)6 quasi-solid-state thermochemical batteries typically utilize the addition of ionized cations (such as guanidine cations Gdm). + [Fe(CN)6] induces 4- Thermosensitive crystals are formed, and a steep concentration gradient is constructed through dynamic precipitation-dissolution equilibrium, thereby increasing the Seebeck coefficient of the thermochemical cell. S i From approximately 1.4 mVK -1 Increased to 3.7 mVK -1 That's all. However, these supramolecular assemblies, which result in a huge increase in entropy, rely on fragile non-covalent interactions for maintenance, leading to their thermal instability. The thermodynamic dissociation of the resulting thermosensitive crystals at high temperatures (>55 °C) disrupts the construction of the concentration gradient, thereby weakening the thermoelectric properties. Unlike previous methods, we employ a method at K... 3 / 4 (NH4) is introduced into the Fe(CN)6 system. 3 / 4 [Fe(CN)6] is integrated into a binary redox pair system by introducing ammonium cations (NH4+). + To reconfigure [Fe(CN)6] 4- The solvated shell essentially reconstructs its energy state, enhances lattice energy by strengthening ion association, and effectively increases the upper limit of the temperature tolerance of the crystal structure from 55℃ to 90℃.

[0021] 2. The flexible ion thermoelectric battery utilizes a robust, chemically cross-linked dual-network hydrogel as its gel substrate, exhibiting excellent thermal stability. The dual-network hydrogel is synergistically integrated with a binary redox pair system. Ultimately, the fabricated flexible ion thermoelectric battery achieves decoupling of thermal responsiveness and structural stability, reaching 3.02 mVK over a wide temperature range of 25–90 °C. -1 It has an extremely large and stable Seebeck coefficient and an electrical conductivity as high as 15.6 Sm. -1 And the maximum output power density can reach 7.16Wm -2 . Attached Figure Description

[0022] Figure 1 This is the flexible thermochemical battery body of the thermoelectric hydrogel of the present invention.

[0023] Figure 2 K is prepared in different mixing ratios as described in Example 1. 3 / 4 Fe(CN)6 and (NH4) 3 / 4 Temperature difference-open circuit voltage curve of Fe(CN)6 (guanidine hydrochloride concentration of 3 M).

[0024] Figure 3 Add 0.4 MK to Example 1 3 / 4 The temperature difference-open circuit voltage curve of Fe(CN)6 (guanidine hydrochloride concentration of 3 M) is shown. The slope of the fitted curve represents the thermoelectric potential of the hydrogel.

[0025] Figure 4 Different concentrations (K) of guanidine hydrochloride prepared in Example 2 3 / 4 The Fe(CN)6 concentration is 0.1 M, (NH4) 3 / 4 Conductivity and Seebeck coefficient of Fe(CN)6 thermoelectric hydrogel with a concentration of 0.3M.

[0026] Figure 5 Different sodium chloride concentrations (K) prepared in Example 3 3 / 4 The Fe(CN)6 concentration is 0.1 M, (NH4) 3 / 4 Conductivity and Seebeck coefficient of Fe(CN)6 thermoelectric hydrogel with a concentration of 0.3M.

[0027] Figure 6 The optimized thermoelectric hydrogel (0.1 MK) in Example 3 3 / 4 Fe(CN)6-0.3 M (NH4) 3 / 4 Temperature difference-open circuit voltage curve of Fe(CN)6-3 M guanidine hydrochloride-3 M sodium chloride.

[0028] Figure 7The maximum power density and corresponding normalized power density of the optimized thermoelectric hydrogel under different temperature differences in Example 3 are shown. Detailed Implementation

[0029] This invention provides a wide-temperature-range thermochemical battery and its preparation method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. The invention is further described in detail below through examples, which are merely illustrative and not intended to limit the invention: The testing methods involved in this embodiment are as follows: The thermoelectric performance was measured using a self-made testing experimental device. The temperature difference between the hot and cold ends was generated by a commercially available Peltier chip controlled by a temperature controller, and the temperature of the hot and cold end semiconductor cooling chip was monitored using a thermometer (YET-640X) paired with a T-type thermocouple. The Seebeck coefficient of the thermochemical cell was determined using the steady-state method, with the open-circuit voltage change rate ≤ 0.4 mV min. -1 The steady-state state was defined as the initial state. Open-circuit voltage-time was measured using a Keithley 2450 instrument, while a thermometer simultaneously collected temperature difference-time data. The heating process continued until the open-circuit voltage reached a steady state. At least six consecutive steady-state open-circuit voltage and temperature difference values ​​were selected in the experiment, and open-circuit voltage-temperature difference curves were plotted. The slope of these curves represents the Seebeck coefficient at steady state. To determine the ionic conductivity and normalized power density of the thermochemical cell, a linear sweep voltammetry method was used to obtain current-voltage curves from 0 V to the open-circuit voltage. The conductivity was calculated from the slope of the current-voltage curves. The Seebeck coefficient and conductivity of each sample were measured at least three times to ensure data reliability. The cold-end temperature was fixed at 25°C when testing the thermoelectric hydrogel's thermoelectric properties.

[0030] Example 1: The preparation method of the thermoelectric hydrogel of the present invention is as follows: (1) An aqueous solution of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), acrylamide (AM) and N,N'-methylenebisacrylamide (BIS) (0.02 M) was mixed, wherein the mass ratio of AMPS:AM was 2:1, the total monomer concentration was fixed at 16.5 wt%, and the mixture was initiated by photoinitiator 2-hydroxy-2-methylphenylacetone (HMPP) (1.4 wt%) under ultraviolet light for 30 minutes (25 °C).

[0031] (2) The single-network gel prepared in step (1) was then immersed in an aqueous solution containing AM (12.5 wt%), polyethylene glycol diacrylate (PEGDA) (2 mol%) and 2-hydroxy-2-methylphenylacetone (HMPP) (0.3 wt%) for 24 hours until equilibrium was reached, and then polymerized under ultraviolet light for 30 minutes (25 °C).

[0032] (3) Immerse the double-network gel prepared in step (2) in K 3 / 4 Fe(CN)6 / (NH4) 3 / 4 In a mixed solution of [Fe(CN)6] and guanidine hydrochloride, wherein the concentration of guanidine hydrochloride is 3 M, K 3 / 4 Fe(CN)6 / (NH4) 3 / 4 The concentrations of [Fe(CN)6] were 0.4 M / 0 M (K) 0.4 N0), 0.1M / 0.3M (K) 0.1 N 0.3 ), 0.2M / 0.2M (K 0.2 N 0.2 ), 0.3M / 0.1M (K 0.3 N 0.1 ), 0M / 0.4M (K0N 0.4 ), and heated in an oil bath at 92 ℃ at 300 r / min -1 After stirring, heating, and soaking for 2 hours, the samples were removed and obtained containing different amounts of potassium. 3 / 4 Fe(CN)6 / (NH4) 3 / 4 Thermoelectric hydrogels with [Fe(CN)6] concentration ratios, such as Figure 1 As shown.

[0033] (4) Cut the thermoelectric hydrogel obtained in step (3) into strips of 30 mm × 5 mm. Use platinum wire as an electrode to connect the left and right ends of the thermoelectric hydrogel to obtain a thermoelectric hydrogel thermoelectric device with an effective length of 20 mm in the middle.

[0034] Figure 2 As shown, K is prepared using different mixing ratios as described in Example 1. 3 / 4 Fe(CN)6 and (NH4) 3 / 4 Temperature difference-open circuit voltage curve of Fe(CN)6 (guanidine hydrochloride concentration of 3M) thermoelectric hydrogel. Figure 2 It can be seen that when K 3 / 4 Fe(CN)6 and (NH4) 3 / 4 When the Fe(CN)6 concentration is 0.1 M and 0.3 M respectively (K 0.1 N 0.3 Thermoelectric hydrogels can simultaneously possess excellent thermal stability and thermoelectric properties within the temperature range of 25 ~ 90 ℃. Figure 3 It is 0.4 MK added in Example 1 3 / 4 The temperature difference-open circuit voltage curve of Fe(CN)6 (guanidine hydrochloride concentration of 3 M) shows that when (NH4) is not added... 3 / 4When the temperature difference between the hot and cold ends is approximately 30 K, the open-circuit voltage of the thermoelectric hydrogel decreases rapidly. When the temperature difference is between 0 and 30 K, the open-circuit voltage of the K0NN decreases rapidly. 0.4 of S i Approximately 3.55 mVK -1 When the temperature difference is 30 ~ 65 K, K0N 0.4 of S i Reduced to approximately 1.18 mV K -1 .

[0035] Example 2: The preparation method of the thermoelectric hydrogel of the present invention is as follows: the soaking solution in step (3) of Example 1 is changed to a 0.5 ~ 4M guanidine hydrochloride solution (K 3 / 4 The Fe(CN)6 concentration is 0.1 M, (NH4) 3 / 4 Five groups of thermoelectric hydrogels were prepared using the Fe(CN)6 concentration of 0.3 M and the remaining steps were the same as in Example 1.

[0036] Figure 4 The image shows the conductivity and Seebeck coefficient of the thermoelectric hydrogels prepared in Example 2 with different concentrations of guanidine hydrochloride. It can be seen that as the guanidine hydrochloride concentration increases from 0.5 M to 4 M, both the Seebeck coefficient and conductivity show a trend of first increasing and then decreasing. When 3 M guanidine hydrochloride is added, the Seebeck coefficient and conductivity reach their optimal values ​​of 2.2 mVK. -1 and 12.9 S m -1 .

[0037] Example 3: The preparation method of the thermoelectric hydrogel of the present invention is as follows: the soaking solution in step (3) of Example 1 is changed to a 0.5 ~ 4M sodium chloride solution (guanidine hydrochloride concentration is 3 M, K 3 / 4 The Fe(CN)6 concentration is 0.1 M, (NH4) 3 / 4 Five groups of thermoelectric hydrogels were prepared using the same Fe(CN)6 concentration of 0.3M as in Example 1, with the remaining steps being the same.

[0038] Figure 5 The image shows the conductivity and Seebeck coefficient of the thermoelectric hydrogels prepared in Example 3 with different sodium chloride concentrations. As the sodium chloride concentration increases from 0.5 M to 4 M, the conductivity increases from 13.1 S / m. -1 (Sodium chloride concentration increased from 0.5M to 15.6 S m) -1 (Sodium chloride concentration is 3 M), but further increasing sodium chloride concentration will cause a slight decrease in conductivity. S i From 2.04 mV K-1 (Sodium chloride concentration of 0.5 M) increased to 3.07 mV K -1 (Sodium chloride concentration is 4M).

[0039] Figure 6 As shown, this is the optimized thermoelectric hydrogel (0.1MK) in Example 3. 3 / 4 Fe(CN)6-0.3M (NH4) 3 / 4 The temperature difference-open circuit voltage curve of Fe(CN)6-3M guanidine hydrochloride-3M sodium chloride. Figure 5 It can be seen that the optimized thermoelectric hydrogel maintains a relatively stable thermoelectric potential of 3.02 mV K in the temperature range of 25~90℃. -1 . Figure 7 To optimize the thermoelectric properties of the thermoelectric hydrogel under different temperature differences, the low-temperature end of the thermoelectric hydrogel was controlled at 25 °C, with temperature differences of 25 K, 45 K, and 65 K. It can be seen that as the temperature difference increases, the maximum output power density decreases from 0.44 W / m³. -2 Increased to 7.16 W m -2 This is superior to most thermoelectric hydrogels reported in the literature, with a normalized maximum output power density of approximately 1.70 mW / m³ at a temperature difference of 65 K. -2 K -2 .

Claims

1. A wide-temperature-range flexible ion thermoelectric battery, comprising a thermoelectric hydrogel and electrodes, wherein the thermoelectric hydrogel is obtained by solvent exchange in a binary redox electrolyte on a dual-network gel matrix, characterized in that... The binary redox electrolyte contains binary redox ions including a first redox and a second redox, wherein the first redox is K. 3 / 4Fe(CN)6, the second redox pair is (NH4). 3 / 4 [Fe(CN)6], Li 3 / 4 Fe(CN)6 and Na 3 / 4 One of Fe(CN)6.

2. The wide-temperature-range flexible ion thermoelectric battery according to claim 1, characterized in that, In a binary redox ion pair, the redox pair K 3 / 4 Fe(CN)6 and its redox pair (NH4) 3 / 4 The total concentration of [Fe(CN)6] was fixed at 0.2-0.12 M.

3. The wide-temperature-range flexible ion thermoelectric battery according to claim 2, characterized in that, Redox pairs K 3 / 4 The concentration of Fe(CN)6 was 0.1–0.6 M, and the redox pair (NH4) 3 / 4 The concentration of [Fe(CN)6] was 0.1~0.6 M.

4. The wide-temperature-range flexible ion thermoelectric battery according to claim 1, characterized in that, The binary redox electrolyte further includes water, organic small molecule additives, and water-soluble metal salts; the organic small molecule additives and water-soluble metal salts are dispersed together in an aqueous solution of redox pairs composed of binary redox ion pairs and water; the concentration of the organic small molecule additives in the binary redox electrolyte is 0.5 ~ 4 M; the concentration of the water-soluble metal salts in the binary redox electrolyte is 0.5 ~ 4 M.

5. The wide-temperature-range flexible ion thermoelectric battery according to claim 4, characterized in that, The organic small molecule additive is one or more of the guanidine salt derivatives; the guanidine salt derivatives include guanidine hydrochloride, guanidine carbonate, guanidine phosphate, guanidine sulfate, and guanidine aminosulfonate.

6. The wide-temperature-range flexible ion thermoelectric battery according to claim 4, characterized in that, The water-soluble metal salt is sodium chloride.

7. The wide-temperature-range flexible ion thermoelectric battery according to claim 1, characterized in that, The reaction conditions for solvent exchange in a binary redox electrolyte on a dual-network gel matrix are as follows: soaking at an ambient temperature of 85 ~ 95 ℃ for 1 ~ 3 h, then removing and cooling.

8. The method for preparing a wide-temperature-range flexible ion thermoelectric battery according to any one of claims 1-7, characterized in that, include: Preparation of dual-network gel matrix: (1) Mix the first monomer, the first crosslinking agent and the photoinitiator, and then cure the reaction under ultraviolet light to obtain a single-network gel matrix; (2) The single-network gel matrix is ​​immersed in a mixed solution composed of the second monomer, the second crosslinking agent and the photoinitiator, and then subjected to ultraviolet light curing reaction to obtain a double-network gel matrix; Preparation of thermoelectric hydrogel: The thermoelectric hydrogel is obtained by solvent exchange in a binary redox electrolyte on a double network gel matrix; Encapsulated electrodes: The electrodes are integrated on the left and right sides of the thermoelectric hydrogel, with the electrodes on both sides in contact with the cold source and the heat source, respectively, and encapsulated with a flexible encapsulation material to obtain a wide temperature range flexible ion thermoelectric battery.

9. The wide-temperature-range flexible ion thermoelectric battery according to claim 8, characterized in that, In step (1), the first monomer includes 2-acrylamido-2-methyl-1-propanesulfonic acid and acrylamide, the first crosslinking agent is N,N'-methylenebisacrylamide, and the photoinitiator is 2-hydroxy-2-methylphenylacetone; The concentration of N,N'-methylenebisacrylamide was 0.002 ~ 0.02 M; the mass ratio of 2-hydroxy-2-methylphenylacetone to deionized water was 1:200 ~ 1:50; the mass ratio of acrylamide to 2-acrylamide-2-methyl-1-propanesulfonic acid was 1:2 ~ 1:0.2; and the mass ratio of total monomers to deionized water was 1:10 ~ 1:

3. In step (2), the second monomer is acrylamide, the second crosslinking agent is polyethylene glycol diacrylate, and the photoinitiator is 2-hydroxy-2-methylphenylacetone; the mass ratio of acrylamide to deionized water is 1:10 to 1:6; the concentration of polyethylene glycol diacrylate is 0.002 to 0.02 M; and the mass fraction of 2-hydroxy-2-methylphenylacetone is 0.1 to 1 wt%.

10. The wide-temperature-range flexible ion thermoelectric battery according to claim 8, characterized in that, The two UV curing reactions took 0.4 to 1 hour each, with UV wavelengths of 365 nm or 395 nm.

Images