N-p type hydrogel thermal battery module and preparation and application thereof

Abstract

The present application relates to a kind of n-p type hydrogel thermal battery module and its preparation and application, including n-type hydrogel thermal battery and p-type hydrogel thermal battery;Wherein n-type hydrogel thermal battery in hydrogel is network skeleton, by Fe 3+ / Fe 2+ Redox ion pair constructs n-type hydrogel thermal battery, and the hydrogel in p-type hydrogel thermal battery is network skeleton, Fe 3+ / Fe 2+ And carboxylate complex constructs p-type hydrogel thermal battery.The n-p hydrogel thermal battery module provided in the application has high thermoelectric performance, and can be applied to information encryption field.

Description

Technical Field

[0001] This invention belongs to the field of thermoelectrics, and specifically relates to an np-type hydrogel thermoelectric cell module and its preparation and application. Background Technology

[0002] Thermoelectric cells (TGCs), an emerging thermoelectric material based on redox reactions occurring under temperature gradients, exhibit high Seebeck coefficients (mV / K) and show significant advantages in the field of recovering low-level heat energy. Generally, a positive Seebeck coefficient defines a p-type thermoelectric cell, where an oxidation reaction (electron loss) occurs at the hot-end electrode interface, and a reduction reaction (electron gain) occurs at the cold-end electrode interface, such as Fe(CN)6. 4- / Fe(CN)6 3- Conversely, a negative Seebeck coefficient defines an n-type thermoelectric cell, where a reduction reaction (gaining electrons) occurs at the hot-end electrode interface, and an oxidation reaction (losing electrons) occurs at the cold-end electrode interface, such as Fe. 3+ / Fe 2+ and I - / I3 - To generate a practically applicable voltage under temperature differences, multiple p-type and n-type thermoelectric cells are typically connected in series. Common pn thermoelectric cell arrays generally consist of p-type Fe(CN)6... 4- / Fe(CN)6 3- and n-type Fe 3+ / Fe 2+ Composition. Most research focuses on improving Fe(CN)6. 4- / Fe(CN)6 3- The Seebeck coefficient, for example, was increased from 1.4 to 3.7 mV / K by Duan Jiangjiang et al. from Huazhong University of Science and Technology using the thermosensitive crystallization effect; other studies have also shown that adding organic solvents to Fe(CN)6... 4- / Fe(CN)6 3- The system increased the Seebeck coefficient from 1.4 to 2.9 mV / K. Although Fe(CN)6 4- / Fe(CN)6 3- The system has been well-developed, but it still has a safety defect: it produces toxic HCN gas when exposed to acidic solutions. It is often associated with Fe(CN)6. 4- / Fe(CN)6 3- Fe used in series in the system 3+ / Fe 2+ The system is acidic, therefore the combination of pn in series poses a safety hazard.

[0003] In summary, developing a substitute for Fe(CN)6 is crucial. 4- / Fe(CN)63- Furthermore, the new p-type redox ion pair with a high safety factor is used for Fe 3+ / Fe 2+ Implementing NP-chaining in the system is valuable and necessary. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an np-type hydrogel thermoelectric cell module and its preparation and application.

[0005] This invention provides a method for preparing an np-type hydrogel thermoelectric cell module, comprising:

[0006] Step (1) Soaking Fe in hydrogel 3+ / Fe 2+ An aqueous solution was used to obtain an n-type hydrogel thermoelectric cell;

[0007] Step (2) involves adding carboxylates and Fe... 3+ / Fe 2+ The aqueous solution is mixed and the pH is adjusted to 7-7.8 to obtain a mixed solution. Then, the hydrogel is soaked in the mixed aqueous solution to obtain a p-type hydrogel thermal galvanic cell. The carboxylate is at least one of sodium pyrrolidone carboxylate and sodium lactate.

[0008] Step (3) Assemble the n-type hydrogel thermoelectric cell and the p-type hydrogel thermoelectric cell.

[0009] Preferably, the hydrogel in steps (1) and (2) includes one or more of polyacrylamide hydrogel and bacterial cellulose hydrogel. The hydrogel serves as the network framework.

[0010] The polyacrylamide hydrogel is formed by thermally initiating copolymerization in water of monomer acrylamide, crosslinking agent N,N-methylenebisacrylamide, and initiator ammonium persulfate.

[0011] The polyacrylamide hydrogel has a solid content of 20 wt%, which means the weight ratio of acrylamide monomer to water is 1:4. The crosslinking agent N,N-methylenebisacrylamide and the initiator ammonium persulfate are both used in amounts of 1% of the mass of the acrylamide monomer.

[0012] Preferably, in steps (1) and (2) Fe 3+ / Fe 2+ Fe in aqueous solution 3+ with Fe 2+ The molar concentration ratio is 1:1; of which Fe 3+ / Fe 2+ Fe in aqueous solution 3+ The concentration was 0.05-0.25 mol / L; Fe 2+ The concentration is 0.05-0.25 mol / L.

[0013] The steps (1) and (2) Fe 3+ / Fe 2+ The anion in the aqueous solution is ClO4. - Cl - and SO4 2- One or more of them.

[0014] Preferably, Fe in steps (1) and (2) 3+ / Fe 2+ The corresponding ferric and ferrous salts include one or more of ferric perchlorate / ferrous perchlorate, ferric sulfate / ferrous sulfate, and ferric chloride / ferrous chloride.

[0015] The soaking time in steps (1) and (2) is 8-15 hours.

[0016] Preferably, in step (2) Fe 3+ / Fe 2+ The total molar amount to carboxylate molar ratio is 1:3 to 1:12; the pH is 7.4.

[0017] In step (2), K2CO3 solution is used to adjust the pH value.

[0018] Preferably, the Seebeck coefficient of the n-type hydrogel thermoelectric cell in step (1) is -1.3 ~ -1.5 mV / K.

[0019] Preferably, the Seebeck coefficient of the p-type hydrogel thermoelectric cell in step (2) is +2.8 ~ +3.8 mV / K.

[0020] In step (3), the assembly includes an n-type hydrogel thermoelectric cell and a p-type hydrogel thermoelectric cell connected in series.

[0021] This invention provides an np-type hydrogel thermoelectric cell module prepared by any of the methods described above, comprising an n-type hydrogel thermoelectric cell and a p-type hydrogel thermoelectric cell; wherein in the n-type hydrogel thermoelectric cell, the hydrogel forms a network framework and is composed of Fe... 3+ / Fe 2 + Redox ion pairs are used to construct n-type hydrogel thermoelectric cells. In p-type hydrogel thermoelectric cells, the hydrogel forms the network framework, and Fe... 3+ / Fe 2+ Construct p-type hydrogel thermoelectric cells by complexing with carboxylates.

[0022] The present invention provides an np thermoelectric response encoder, which includes an n-type hydrogel thermoelectric cell and a p-type hydrogel thermoelectric cell.

[0023] Furthermore, the np thermoelectric response encoder also includes platinum electrodes.

[0024] Furthermore, a platinum electrode is connected in series between the n-type hydrogel thermoelectric cell and the p-type hydrogel thermoelectric cell.

[0025] This invention provides an application of the NP-type hydrogel thermoelectric battery module or the NP thermoelectric response encoder in the fields of thermoelectric signal conversion and information encryption.

[0026] This invention discloses an np-type hydrogel thermoelectric cell module, comprising an n-type hydrogel thermoelectric cell and a p-type hydrogel thermoelectric cell. The p-type hydrogel thermoelectric cell is fabricated by converting the redox potential of a conventional n-type thermoelectric redox pair. The conventional n-type thermoelectric redox pair is Fe. 3+ / Fe 2+ Its pair ion is ClO4. - Cl - and SO4 2- One or more of them.

[0027] This invention converts the redox potential of a traditional n-type thermoelectric redox pair by altering the redox entropy difference of an n-type thermoelectric cell through ion complexation, thereby producing a p-type thermoelectric effect. The ion complexation is achieved using Fe... 3+ / Fe 2+ Complexation with carboxylate ions, wherein the carboxylate is one or more of the moisturizing factors sodium pyrrolidone carboxylate and sodium lactate. Fe 3+ / Fe 2+ It exhibits n-type thermoelectric behavior, meaning that a reduction reaction of Fe occurs at the thermoelectrode interface. 3+ +e - →Fe 2 + An oxidation reaction occurs at the cold-end electrode interface, involving Fe. 2+ →Fe 3+ +e - When carboxylate ions react with Fe... 3+ / Fe 2+ After complexation, Fe(RCOO)6 is produced. 4- / Fe(RCOO)6 3- It then exhibits p-type thermoelectric behavior, that is, an oxidation reaction Fe(RCOO)6 occurs at the thermoelectrode interface. 4- →Fe(RCOO)6 3- +e - A reduction reaction, Fe(RCOO)6, occurs at the cold-end electrode interface. 3- +e - →Fe(RCOO)6 4- (likeFigure 1 (As shown).

[0028] Beneficial effects: The np-type hydrogel thermoelectric cell module prepared by this invention, wherein the p-type hydrogel thermoelectric cell utilizes carboxylate, Fe... 3+ / Fe 2+ The aqueous solution was mixed thoroughly, and the pH was controlled at 7-7.8 to obtain a p-type hydrogel thermoelectric cell, whose Seebeck coefficient was higher than that of the traditional Fe(CN)6. 4- / Fe(CN)6 3- Thermoelectric cells are more efficient.

[0029] The np-type hydrogel thermoelectric cell module prepared in this invention is derived from an improved n-type thermoelectric cell, and its p-type hydrogel thermoelectric cell is prepared based on the traditional Fe(CN)6. 4- / Fe(CN)6 3- Thermoelectric batteries are safer, and the carboxylates used are all components of natural moisturizing factors, making them more environmentally friendly.

[0030] The NP-type hydrogel thermoelectric cell module prepared by this invention can not only recover waste heat and convert it into electrical energy, but also realize its application in the field of information encryption by utilizing thermoelectric response signals. Attached Figure Description

[0031] Figure 1 This is a schematic diagram illustrating the working principle of the n-type and p-type thermoelectric cells of the present invention;

[0032] Figure 2 Diagram of the Seebeck coefficient testing setup;

[0033] Figure 3 The Seebeck coefficient of the n-type and p-type hydrogel thermoelectric cells prepared for Comparative Examples 1 and 2 is shown as a graph relating the carboxylate concentration.

[0034] Figure 4 The Seebeck coefficient of the p-type hydrogel thermoelectric cell prepared in Comparative Example 3 and Fe 3+ / Fe 2+ Concentration relationship graph;

[0035] Figure 5 The voltage versus temperature difference curves and Seebeck coefficient fitting curves of the n-type and p-type hydrogel thermoelectric cells prepared in Comparative Example 3 are shown.

[0036] Figure 6 The graph shows the Seebeck coefficient versus pH value for the p-type hydrogel thermoelectric cell prepared in Example 1.

[0037] Figure 7 The Seebeck coefficients of the n-type and p-type hydrogel thermoelectric cells prepared in Example 2;

[0038] Figure 8 The Seebeck coefficient is the np-tandem hydrogel thermoelectric cell module prepared in Example 3;

[0039] Figure 9 The diagram and test diagram show the np-series hydrogel thermal cell module prepared in Example 3 used for binary and quaternary-to-decimal conversion. Detailed Implementation

[0040] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0041] I. Preparation of PAAm hydrogel used in the examples and comparative examples: m1 g of monomer acrylamide (AAm), m2 g of crosslinking agent N,N-methylenebisacrylamide and m3 g of initiator ammonium persulfate were dissolved in m4 g of deionized water and shaken to obtain a mixed solution, wherein m1:m4=1:4, m1:m2=1:0.01, m1:m3=1:0.01; then the mixed solution was poured into a glass mold and thermally initiated polymerization at 60°C for 8 hours to obtain polyacrylamide hydrogel (i.e., PAAm hydrogel).

[0042] Bacterial cellulose was commercially purchased (Hainan Yide Food Co., Ltd.). Before use, it was soaked in a 10g / L sodium hydroxide aqueous solution for 12 hours to remove impurities. Then, it was soaked in deionized water to remove the alkaline solution from the bacterial cellulose. This process was repeated until neutral, and then bacterial cellulose hydrogel was obtained.

[0043] II. Related Tests

[0044] Seebeck coefficient testing: The Seebeck coefficient was tested using a self-built apparatus (e.g., Figure 2 (As shown). The open-circuit voltage was recorded using a DMM6500 digital multimeter, and the temperature difference was acquired by a type-T thermocouple and recorded using a DMM6500 digital multimeter. The temperature difference was generated by a commercially available cooling chip; the temperature difference was changed by adjusting the hot junction temperature, and the corresponding open-circuit voltage was recorded. The Seebeck coefficient can be obtained by linearly fitting the open-circuit voltage difference and the temperature difference.

[0045] Example 1

[0046] An np-series hydrogel thermoelectric cell module is provided, and its preparation method is as follows:

[0047] Step (1): Dissolve ferric perchlorate hydrate and ferrous perchlorate hydrate in deionized water to control Fe3+ / Fe 2+ The molar concentration ratio is 1:1, and the Fe in the solution is... 3+ The concentration is 0.2 mol / L, Fe 2+ At a concentration of 0.2 mol / L, Fe was obtained. 3+ / Fe 2 + Aqueous solution. Then, the PAAm hydrogel was soaked in Fe... 3+ / Fe 2+ The cells were immersed in an aqueous solution for 12 hours to ensure sufficient solvent exchange, ultimately yielding an n-type hydrogel thermoelectric cell.

[0048] Step (2), sodium pyrrolidone carboxylate and Fe 3+ / Fe 2+ Mix the aqueous solution thoroughly, and control the reaction of sodium pyrrolidone carboxylate with Fe. 3 + / Fe 2+ The molar ratio of Fe was 9:1. 0.4 mol / L K₂CO₃ was added to adjust the pH of the solution to 7.4, resulting in a mixed aqueous solution. PAAm hydrogel was immersed in this mixed aqueous solution for 12 hours to ensure sufficient solvent exchange, ultimately yielding a p-type hydrogel thermoelectric cell. Fe 3+ / Fe 2+ The aqueous solution is prepared in the same way as step (1).

[0049] The Seebeck coefficient of the n-type hydrogel thermoelectric cell prepared in this embodiment is -1.42 mV / K, and the Seebeck coefficient of the p-type hydrogel thermoelectric cell is +3.27 mV / K (e.g., ...). Figure 6 (As shown).

[0050] Example 2

[0051] An np-series hydrogel thermoelectric cell module is provided, and its preparation method is as follows:

[0052] Step (1): Dissolve ferric perchlorate hydrate and ferrous perchlorate hydrate in deionized water to control Fe 3+ / Fe 2+ The molar concentration ratio is 1:1, and the Fe in the solution is... 3+ The concentration is 0.2 mol / L, Fe 2+ At a concentration of 0.2 mol / L, Fe was obtained. 3+ / Fe 2 + Aqueous solution.

[0053] Bacterial cellulose hydrogel was soaked in Fe 3+ / Fe 2+ The cells were immersed in an aqueous solution for 12 hours to ensure sufficient solvent exchange, ultimately yielding an n-type hydrogel thermoelectric cell.

[0054] Step (2), sodium pyrrolidone carboxylate and Fe 3+ / Fe 2+ Mix the aqueous solution thoroughly, and control the reaction of sodium pyrrolidone carboxylate with Fe. 3 + / Fe 2+ The molar ratio of Fe was 9:1. 0.4 mol / L K₂CO₃ was added to adjust the pH of the solution to 7.4, resulting in a mixed solution. The bacterial cellulose hydrogel was immersed in the mixed solution for 12 hours to ensure sufficient solvent exchange, ultimately yielding a p-type hydrogel thermoelectric cell. Fe... 3+ / Fe 2+ The aqueous solution is prepared in the same way as step (1).

[0055] The Seebeck coefficient of the n-type hydrogel thermoelectric cell prepared in this embodiment is -1.6 mV / K, and the Seebeck coefficient of the p-type hydrogel thermoelectric cell is +2.98 mV / K (see [reference]). Figure 7 (As shown).

[0056] Example 3

[0057] An np-series hydrogel thermoelectric cell module is provided, and its preparation method is as follows:

[0058] The n-type hydrogel thermoelectric cell and the p-type hydrogel thermoelectric cell prepared in Example 1 are connected in series with a platinum electrode (specifically, one n-type and one p-type hydrogel thermoelectric cell are connected in series) to obtain an np series hydrogel thermoelectric cell module.

[0059] The Seebeck coefficient of this np-series hydrogel thermoelectric cell module is 5.11 mV / K (e.g., Figure 8 (As shown). This indicates that the np cascade structure can effectively improve the Seebeck coefficient.

[0060] The rapid and differentiated thermoelectric response of an NP-series hydrogel thermoelectric cell module can be used for digital encryption simulation. For example, touching each of the four corners of the module with a finger generates four different electrical signals to represent the numbers 0, 1, 2, and 3, enabling binary or quaternary-to-decimal conversion (e.g., ...). Figure 9 (As shown).

[0061] Comparative Example 1

[0062] An np-series hydrogel thermoelectric cell module is provided, and its preparation method is as follows:

[0063] Step (1): Dissolve ferric perchlorate hydrate and ferrous perchlorate hydrate in deionized water to control Fe 3+ / Fe 2+ The molar concentration ratio is 1:1, and the Fe in the solution is...3+ The concentration is 0.1 mol / L, Fe 2+ At a concentration of 0.1 mol / L, Fe was obtained. 3+ / Fe 2 + Aqueous solution. The PAAm hydrogel was immersed in the above aqueous solution for 12 hours to ensure sufficient solvent exchange, and finally an n-type hydrogel thermal galvanic cell was obtained.

[0064] Step (2), sodium lactate and Fe 3+ / Fe 2+ Mix the aqueous solution thoroughly, and control the concentration of sodium lactate and Fe. 3+ / Fe 2+ A mixed solution (pH 4.5-5.5) was obtained by setting the molar concentration ratio to 9:1. The PAAm hydrogel was then immersed in the mixed solution for 12 hours to ensure sufficient solvent exchange, ultimately yielding a p-type hydrogel thermoelectric cell.

[0065] The Seebeck coefficient of the n-type hydrogel thermoelectric cell prepared in this comparative example is -1.38 mV / K, and the Seebeck coefficient of the p-type hydrogel thermoelectric cell is +0.36 mV / K (e.g., ...). Figure 3 (As shown).

[0066] Comparative Example 2

[0067] An np-series hydrogel thermoelectric cell module is provided, and its preparation method is as follows:

[0068] Step (1): Dissolve ferric perchlorate hydrate and ferrous perchlorate hydrate in deionized water to control Fe 3+ / Fe 2+ The molar concentration ratio is 1:1, and the Fe in the solution is... 3+ The concentration is 0.1 mol / L, Fe 2+ At a concentration of 0.1 mol / L, Fe was obtained. 3+ / Fe 2 + Aqueous solution. The PAAm hydrogel was immersed in the above aqueous solution for 12 hours to ensure sufficient solvent exchange, and finally an n-type hydrogel thermal galvanic cell was obtained.

[0069] Step (2), sodium pyrrolidone carboxylate and Fe 3+ / Fe 2+ Mix the aqueous solution thoroughly, and control the reaction of sodium pyrrolidone carboxylate with Fe. 3 + / Fe 2+ A mixed solution (pH 4.5-5.5) was obtained by setting the molar concentration ratio to 9:1. The PAAm hydrogel was then immersed in the mixed solution for 12 hours to ensure sufficient solvent exchange, ultimately yielding a p-type hydrogel thermoelectric cell.

[0070] The Seebeck coefficient of the n-type hydrogel thermoelectric cell prepared in this comparative example is -1.38 mV / K, and the Seebeck coefficient of the p-type hydrogel thermoelectric cell is +0.51 mV / K (e.g., ...). Figure 3 (As shown).

[0071] Comparative Example 3

[0072] An np-series hydrogel thermoelectric cell module is provided, and its preparation method is as follows:

[0073] Step (1): Dissolve ferric perchlorate hydrate and ferrous perchlorate hydrate in deionized water to control Fe 3+ / Fe 2+ The molar concentration ratio is 1:1, and the Fe in the solution is... 3+ The concentration is 0.2 mol / L, Fe 2+ At a concentration of 0.2 mol / L, Fe was obtained. 3+ / Fe 2 + Aqueous solution. The PAAm hydrogel was immersed in the above aqueous solution for 12 hours to ensure sufficient solvent exchange, and finally an n-type hydrogel thermal galvanic cell was obtained.

[0074] Step (2), sodium pyrrolidone carboxylate and Fe 3+ / Fe 2+ Mix the aqueous solution thoroughly, and control the reaction of sodium pyrrolidone carboxylate with Fe. 3 + / Fe 2+ The molar ratio of the solvents was 9:1, resulting in a mixed solution (pH 4.5-5.5). The PAAm hydrogel was then immersed in the above aqueous solution for 12 hours to ensure sufficient solvent exchange, ultimately yielding a p-type hydrogel thermoelectric cell.

[0075] The Seebeck coefficient of the n-type hydrogel thermoelectric cell prepared in this comparative example is -1.42 mV / K, and the Seebeck coefficient of the p-type hydrogel thermoelectric cell is +0.65 mV / K (e.g., ...). Figure 4 (As shown). Figure 5 The voltage curves and corresponding voltage difference and temperature difference fitting curves of the n-type and p-type hydrogel thermoelectric cells prepared above are shown.

Claims

1. A method for preparing an np-type hydrogel thermoelectric cell module, characterized in that, include: Step (1) Hydrogel soaked Fe 3+ / Fe 2+ Aqueous solution, n-type hydrogel thermal battery is obtained; Step (2) mixing the carboxylate, Fe 3+ / Fe 2+ aqueous solution, adjusting the pH to 7-7.8 to obtain a mixed solution, and then immersing the hydrogel in the mixed aqueous solution to obtain a p-type hydrogel thermal battery; wherein the carboxylate is at least one of sodium pyrrolidone carboxylate and sodium lactate; Step (3) Assemble the n-type hydrogel thermoelectric cell and the p-type hydrogel thermoelectric cell.

2. The preparation method according to claim 1, characterized in that, The hydrogels in steps (1) and (2) include one or more of polyacrylamide hydrogels and bacterial cellulose hydrogels.

3. The preparation method according to claim 1, characterized in that, The steps (1), (2) Fe 3+ / Fe 2+ Fe 3+ with Fe 2+ molar concentration ratio of 1:

1.

4. The preparation method according to claim 1, characterized in that, The steps (1), (2) Fe 3+ / Fe 2+ Anions in the aqueous solution are one or several of ClO4 - , Cl - and SO4 2- .

5. The preparation method according to claim 1, characterized in that, The soaking time in steps (1) and (2) is 8-15 hours.

6. The preparation method according to claim 1, characterized in that, In step (2), Fe 3+ / Fe 2+ The total molar amount to carboxylate molar ratio is 1:3 to 1:12; the pH is 7.

4.

7. The preparation method according to claim 1, characterized in that, The Seebeck coefficient of the n-type hydrogel thermoelectric cell in step (1) is -1.3 ~ -1.5 mV / K, and the Seebeck coefficient of the p-type hydrogel thermoelectric cell in step (2) is +2.8 ~ +3.8 mV / K.

8. An np-type hydrogel thermoelectric cell module prepared by the method of any one of claims 1-7.

9. An NP thermoelectric response encoder, characterized in that, The np thermoelectric response encoder includes the n-type hydrogel thermoelectric cell and the p-type hydrogel thermoelectric cell as described in claim 1.

10. The application of the NP-type hydrogel thermoelectric cell module of claim 8 or the NP thermoelectric response encoder of claim 9 in the field of thermoelectric signal conversion and information encryption.

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