Thermal rechargeable battery based on anion exchange membrane and preparation method thereof

Abstract

The invention provides a thermal rechargeable battery based on an anion exchange membrane and a preparation method of the thermal rechargeable battery, and belongs to the technical field of thermoelectric batteries. The thermal rechargeable battery comprises an anion exchange membrane, an n-type aqueous electrolyte and a P-type aqueous electrolyte, an n-type aqueous electrolyte is arranged on one side of the anion exchange membrane, and a P-type aqueous electrolyte is arranged on the other side of the anion exchange membrane; the electrolyte of the n-type aqueous electrolyte is FeCl3; the electrolyte of the P-type aqueous electrolyte is K4Fe (CN) 6; the obtained heat rechargeable battery is high in heat energy utilization rate, and energy is saved; battery replacement and manual maintenance are not needed in the using process, the situation that equipment fails to work due to the fact that the electric quantity of the battery is exhausted is avoided, and high voltage, high output power density, high energy density and high thermoelectric conversion efficiency are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of sensor devices, and in particular relates to a thermally rechargeable battery based on an anion exchange membrane and a preparation method thereof. Background Art

[0002] Low-grade heat (<100°C) is a thermal energy resource that is difficult to use directly. It is widely present in industrial waste gas, wastewater and other emissions. Due to its low energy density, the traditional recycling efficiency is not high. How to effectively convert thermal energy into electrical energy is a key issue. Through advanced thermoelectric materials and technologies, this waste heat can be converted into electrical energy to achieve energy reuse.

[0003] For typical e-TE materials, the Seebeck coefficient (α) is only ~100 μV K. Therefore, it is very challenging to generate a sufficient voltage of 1 to 5 V by integrating a large amount of e-TE. Therefore, a new type of thermally rechargeable battery with higher performance needs to be further designed and considered.

[0004] Ionic thermoelectric devices (i-TEs), which are used for direct energy harvesting, provide two different mechanisms, including thermoelectric effect and thermal diffusion effect. Low-grade heat can be continuously converted into electrical energy because the temperature difference causes a voltage difference. At present, a thermal charging supercapacitor based on the thermal diffusion effect has emerged, using 1.0 mol / L KNO3 electrolyte and porous carbon (PC) electrodes, with an α value of 1.21 mV / K at a temperature difference of 52K. However, the thermal current performance of this thermal charging supercapacitor is still limited by the adsorption / desorption and diffusion of electrolyte ions; another alternative strategy is to introduce iron / ferrocyanide [Fe(CN)6 4- / Fe(CN)6 3- ] and other redox pairs to design the electrolyte. The above methods are all limited by the problems of low open circuit voltage and low thermoelectric conversion efficiency.

[0005] Therefore, there is an urgent need to provide a thermally rechargeable battery that does not require external power, increases the open circuit voltage of the battery, and improves the thermoelectric conversion efficiency. Summary of the invention

[0006] In view of this, the object of the present invention is to provide a thermal rechargeable battery based on anion exchange membrane and a preparation method thereof. The obtained thermal rechargeable battery can be used continuously for a long time and has a high utilization rate of low-grade thermal energy.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] In a first aspect, the present invention provides a thermal rechargeable battery based on an anion exchange membrane, the thermal rechargeable battery comprising an anion exchange membrane, an n-type aqueous electrolyte, and a p-type aqueous electrolyte;

[0009] One side of the anion exchange membrane is an n-type aqueous electrolyte, and the other side is a p-type aqueous electrolyte;

[0010] The electrolyte of the n-type aqueous electrolyte is FeCl3;

[0011] The electrolyte of the P-type aqueous electrolyte is K4Fe(CN)6.

[0012] By adopting the above technical solution, the AEM-DTCC (thermal rechargeable battery with anion exchange membrane) of the present invention is a three-layer DTCC battery, one side of which is an n-type aqueous electrolyte, the middle of which is an anion exchange membrane, and the other side is a p-type aqueous electrolyte. The anion exchange membrane maintains the electrochemical potential between the asymmetric electrolytes, forms a concentration difference between cations and anions, and generates a thermal diffusion voltage. In addition, due to the pore structure and ion conduction of the ion exchange membrane, two asymmetric Fe(CN)6 4- / 3- and Fe 3+ / 2+ During high temperature discharge, the anion exchange membrane allows OH - By balancing the ionic charge in the system, a p-type Fe(CN)6 with a negative electrode temperature coefficient in the liquid phase system is used. 4- / 3- and n-type Fe with positive electrode temperature coefficient 3+ / 2+ As a redox couple, the battery has a higher open circuit voltage and output power density through the synergistic effect of temperature-sensitive redox ion pairs and electrochemical energy.

[0013] Preferably, the thermally rechargeable battery further comprises a cathode electrode and an anode electrode; the cathode electrode is graphene oxide or carbon nanotubes, and the anode electrode is carbon nanotubes or carbon nanotubes.

[0014] Preferably, the anion exchange membrane has a hydrophilic film that allows hydroxide to pass through, and specifically can be made of gel polystyrene cross-linked with divinylbenzene.

[0015] Preferably, the electrolyte content of the n-type aqueous electrolyte is 0.5 mol / L; the electrolyte content of the p-type aqueous electrolyte is 0.5 mol / L.

[0016] In a second aspect, the present invention provides a method for preparing the above-mentioned thermal rechargeable battery, comprising the following steps:

[0017] First, prepare P-type water system and N-type water system electrolytes of corresponding concentrations, then place the anion exchange membrane in the middle of the mold, and finally inject the two electrolytes into both sides of the mold respectively.

[0018] Contains at least the following beneficial technical effects:

[0019] 1) The thermal rechargeable battery prepared by the present invention has high thermal energy utilization and saves energy; during use, there is no need to replace batteries or perform manual maintenance, and the device will not fail due to battery exhaustion.

[0020] 2) The thermal rechargeable battery prepared by the present invention has higher voltage, output power density, energy density and thermoelectric conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a physical picture of the battery prepared by the present invention.

[0022] Figure 2 This is a schematic diagram of the battery structure and principle.

[0023] Figure 3 The figure shows the battery output power detection at different temperatures.

[0024] Figure 4 The open circuit voltage detection diagram of batteries with different electrolyte concentrations.

[0025] Figure 5 The voltage variation diagram at different temperatures. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0027] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0028] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the main idea or essential features of the present invention. Therefore, from all points of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0029] In addition, it should be understood that although this specification is described according to the implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. These other implementation modes are also covered within the protection scope of the present invention.

[0030] It should also be understood that the specific embodiments described above are only used to explain the present invention, and the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, which should be covered by the protection scope of the present invention / invention.

[0031] Example

[0032] Prepare electrolyte: prepare 0.5 mol / L FeCl3 aqueous solution and 0.5 mol / L K4Fe(CN)6 aqueous solution.

[0033] Place an anion exchange membrane in the middle of the mold, and finally inject the two electrolytes into both sides of the mold and connect the circuits.

[0034] Actual picture Figure 1 shown.

[0035] The structure and principle diagram are as follows Figure 2 shown.

[0036] In Fe(CN)6 4- / 3- and Fe 3+ / 2+ In the aqueous redox electrolyte, AEM-DTCC (thermal rechargeable battery with anion exchange membrane) is configured with an anion exchange membrane, the cathode of the battery is graphene oxide, and the battery-type anode is carbon nanotubes. The electrode is inserted in the middle of the electrolyte, which greatly improves the ion conductivity. AEM-DTCC undergoes three stages of thermal charging, discharging and self-generation in one cycle.

[0037] Due to the difference in electrochemical potentials (ΔV0) between electrodes with different electrolytes at low temperatures, and then further increase after heating, a built-in open circuit voltage (V OC ).

[0038] When DTCC is heated from low temperature to high temperature under open circuit condition (stage 1), the temperature-induced Fe(CN)6 4- / 3- and Fe 3 + / 2+ The thermoelectric effect of the asymmetric electrolyte forms the thermovoltage in two parts. First, heating enhances the difference in electrochemical potential of the asymmetric electrolyte, causing the open circuit voltage to increase with temperature. In addition, the electrochemical voltage is introduced into the battery by coupling the asymmetric aqueous electrolyte.

[0039] Secondly, due to Fe 3+ / 2+ The temperature coefficient of Fe(CN)6 is positive. 4- / 3- The temperature coefficient is negative. At high temperatures, Fe 3+ / 2+ Reduction reaction occurs, Fe(CN)6 4- / 3- Oxidation reaction occurs, further enhancing VOC When an external load is connected (stage 2), the DTCC is discharged continuously under high temperature conditions, where the discharge capacity is mainly attributed to the anode Fe(CN)6 4- / 3- Oxidation and Fe on the cathode 3+ Battery V OC The anode Fe(CN)6 is driven by an external circuit 4- Oxidation of Fe(CN)6 3- Produce electrons; most of the electrons are used for Fe 3+ Reduction to Fe 2+ , protecting the functional groups of GO from reduction, significantly improving the discharge capacity of the thermally rechargeable battery. The discharge process stops until the battery voltage drops to ΔV0, because Fe(CN)6 4- and Fe 3+ is depleted, resulting in a voltage drop and eventually stopping discharge. In the third stage, the oxidized Fe(CN)6 3- and reduced Fe 2+ A reversible reaction will occur under low temperature conditions. At this time, the positive and negative electrodes are short-circuited to chemically regenerate Fe 3+ and Fe(CN)6 4- ; This synergistic self-regeneration mechanism allows the cyclability of thermally renewable batteries.

[0040] During thermal charging, entropy increases as the battery is heated from low temperature to high temperature. During high temperature discharge, entropy increases as redox reactions occur, and finally, entropy decreases and discharge stops, and finally, reversibility is achieved during the temperature reduction process.

[0041] The battery output power at different temperatures is tested. Figure 3 , where the solid line represents the current density and the dotted line represents the power density. The discharge power at different temperatures is shown in Figure 3 As shown. The power P is calculated by the formula P=U·I, where U is the voltage and I is the output current. As the temperature increases, the open circuit voltage of the battery increases, and the current density also increases accordingly, causing the power density to rise. At 30℃, 50℃, 70℃ and 90℃, the maximum current density is 0.057A / g, 0.062A / g, 0.99A / g and 0.125A / g, respectively, and the power density changes parabolically. The corresponding power densities are 3768W / m3, 4987W / m3, 7689W / m3 and 12330W / m 2 .

[0042] The open circuit voltage of batteries with electrolyte concentrations of 0.05M, 0.01M, and 0.1M were tested at different temperatures. Figure 4 shown.

[0043] Figure 5This is the voltage variation diagram at 50 and 70℃.

[0044] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A thermal rechargeable battery based on anion exchange membrane, characterized in that: The thermal rechargeable battery comprises an anion exchange membrane, an n-type aqueous electrolyte, and a p-type aqueous electrolyte; One side of the anion exchange membrane is an n-type aqueous electrolyte, and the other side is a p-type aqueous electrolyte; The electrolyte of the n-type aqueous electrolyte is FeCl3; The electrolyte of the P-type aqueous electrolyte is K4Fe(CN)6.

2. The thermal rechargeable battery according to claim 1, characterized in that The thermal rechargeable battery further comprises a cathode electrode and an anode electrode; the cathode electrode is graphene oxide or carbon nanotubes, and the anode electrode is graphene oxide or carbon nanotubes.

3. The thermal rechargeable battery according to claim 1, characterized in that The anion exchange membrane is a hydrophilic membrane that allows hydroxide to pass through.

4. The thermally rechargeable battery according to claim 3, characterized in that The material of the anion exchange membrane is: gel polystyrene material cross-linked with divinylbenzene.

5. The thermally rechargeable battery according to claim 1, characterized in that The electrolyte content of the n-type aqueous electrolyte is 0.5 mol / L; the electrolyte content of the p-type aqueous electrolyte is 0.5 mol / L.

6. The method for preparing the thermally rechargeable battery according to claim 5, characterized in that: The following steps are involved: First, prepare P-type water system and N-type water system electrolytes of corresponding concentrations, then place the anion exchange membrane in the middle of the mold, and finally inject the two electrolytes into both sides of the mold respectively.

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