A charging-free thermal regeneration electrochemical battery based on a double membrane structure and a method of use

Abstract

The present invention discloses a non-chargeable thermal regeneration electrochemical cell based on a double membrane structure and a method for using the same. 2+ / Fe 3 The negative electrode constitutes the primary battery, and the positive electrode potential and temperature coefficient are regulated by changing the ratio of Prussian blue analog metal materials, electrolyte concentration and embedded ions. The battery can be discharged at high and low temperatures through the conversion of positive and negative electrodes, that is, a rechargeable thermal regeneration electrochemical battery. The battery temperature coefficient can reach ‑2.5~‑3mV / K, which greatly improves the battery voltage, capacity, power density and thermoelectric conversion efficiency; and the double membrane structure effectively blocks the negative electrode Fe 2+ / Fe 3+ and ClO4 ‑ The influence on the embedding and extraction process of positive electrode ions can achieve long-term stable cycling.

Description

Technical Field

[0001] The present invention belongs to the field of thermo-electrochemical energy storage and conversion, and specifically relates to a charge-free thermal regeneration electrochemical battery based on a double-membrane structure and a use method thereof. Background Art

[0002] Low-temperature waste heat energy (<100℃) is widely present in various industrial production processes and nature. Due to its huge quantity, it is gradually considered as a "renewable energy source". The low-temperature waste heat energy generated by major energy-consuming sectors in my country accounts for about 10-20% of the total energy consumption. Therefore, the development of efficient low-temperature waste heat energy utilization technology is conducive to improving the overall energy efficiency and reducing carbon emissions. The temperature and temperature difference of low-temperature waste heat energy are relatively low, and traditional waste heat recovery technologies such as organic Rankine cycle and solid-state thermoelectric generator are difficult to achieve efficient utilization. In recent years, liquid thermoelectrochemical batteries or systems have attracted widespread attention due to their high efficiency and power density. Among them, the thermal regeneration electrochemical cycle based on the Seebeck effect of redox couples has achieved the highest thermoelectric conversion efficiency. However, the traditional thermal regeneration electrochemical cycle requires electrical assistance, and its practical application is limited. The charging-free thermal regeneration electrochemical cycle uses a couple with similar potentials. Based on the Seebeck effect, it can achieve simultaneous high and low temperature discharge without charging, but there is little research at present, and the electrochemical system only has PB / Fe(CN)6 3- / 4- and Fe(CN)6 3- / 4- / I - -I3 - , and the battery temperature coefficient is low (α cell <1.8), the overall performance needs to be improved. Summary of the invention

[0003] In view of the existing technical situation, the present invention proposes a non-chargeable thermal regeneration electrochemical cell based on a double membrane structure and a recycling method, that is, using the electrode pair Fe(ClO4)2 / Fe(ClO4)3 with a large positive temperature coefficient (1.5-1.8mV / K) as the negative electrode, and in order to match the electrode potential to construct a non-chargeable thermal regeneration electrochemical cell, a Prussian blue analog based on a transition metal (one or more of Cu, Co and Ni, etc.) is used as the positive electrode. The positive electrode has a relatively negative temperature coefficient (-0.4--1mV / K). The positive electrode potential and temperature coefficient can be regulated by changing the metal material ratio, electrolyte concentration and embedded ions. In addition, due to the negative electrode Fe 2+ / Fe 3+ It will affect the normal embedding and extraction process of the positive electrode Prussian blue analog material, and ClO4 - The strong oxidizing property of ClO4 will lead to the spontaneous release of embedded ions. Therefore, a double membrane structure is used to solve this problem, that is, a cation exchange membrane is used on the positive electrode electrolyte side to prevent ClO4 - Ion permeation, an anion exchange membrane is used on the cathode electrolyte side to prevent Fe2+ / Fe 3+ The ion penetration ensures that the battery can be stably cycled under the condition of large temperature coefficient and voltage. The present invention also develops a series of non-chargeable thermal regeneration electrochemical batteries, enriching the electrochemical system in this field.

[0004] In order to solve the above technical problems, the technical solution of the present invention is a non-chargeable thermal regeneration electrochemical cell based on a double membrane structure, the positive electrode material of the battery is a transition metal-based Prussian blue analog coated on a carbon material, the positive electrode electrolyte concentration is 0.5-4M, Na + Insert or remove to carry out positive electrode redox reaction; the negative electrode material of the battery is carbon material, the concentration of the negative electrode electrolyte is 0.1-1.5M, Fe 2+ and Fe 3+ Mutual conversion to carry out negative electrode redox reaction; an intermediate layer is set between the positive and negative electrolytes, the positive electrode electrolyte and the intermediate layer contain the same cations, the negative electrode electrolyte and the intermediate layer contain the same anions and the concentrations of the anions are equal, the intermediate layer is separated from the positive electrode electrolyte by a cation exchange membrane, which serves as a transmission channel for cations, and the intermediate layer is separated from the negative electrode electrolyte by an anion exchange membrane, which serves as an anion transmission channel.

[0005] like Figure 6 As shown in a, the positive electrode material of the battery is a Prussian blue analog based on a transition metal (one or more of Cu, Co and Ni) coated on a carbon material such as carbon felt, carbon cloth or carbon paper, and the positive electrode electrolyte is NaCl (concentration of 0.5-4M), Na + Embed or remove to carry out positive electrode redox reaction; the negative electrode material is carbon material such as carbon felt, carbon cloth or carbon paper, the negative electrode electrolyte is Fe(ClO4)2 and Fe(ClO4)3 (concentrations are 0.1-1.5M respectively), Fe 2+ and Fe 3+ The negative electrode redox reaction is carried out by mutual conversion; an intermediate layer is set between the positive and negative electrode electrolytes, and the intermediate layer electrolyte is NaClO4 (the concentration is the same as the ClO4 in the negative electrode electrolyte). - The middle layer and the positive electrode electrolyte are separated by a cation exchange membrane as Na + The transmission channel of ClO4 - transmission channel.

[0006] According to the non-chargeable thermal regeneration electrochemical cell based on the double membrane structure of the present invention, the Prussian blue analog positive electrode material can be selected from one or more of Cu, Co and Ni, and can also be selected from Cr, Mn, V, Fe, Zn and In. The anion in the positive electrode electrolyte can be Cl - 、SO42- 、NO3 - or ClO4 - One or more of .

[0007] The cations in the positive electrode electrolyte and the intermediate layer electrolyte may be Na + , K + NH4 + , Li + , Rb + , Cs + Mg 2 + , Ca 2+ , Sr 2+ , Ba 2+ , Fe 2+ 、Co 2+ 、Ni 2+ , Cu 2+ 、Zn 2+ 、Al 3+ One or more of .

[0008] The anions in the negative electrode and the intermediate layer electrolyte can be ClO4 - 、SO4 2- 、NO3 - or Cl - The positive electrode electrolyte, the intermediate layer and the negative electrode electrolyte are flowable.

[0009] The second technical solution of the present invention is a method for using a non-chargeable thermal regeneration electrochemical cell based on a double membrane structure, comprising:

[0010] Step 1: If Figure 6 As shown in b, the temperature coefficient of the battery is negative. For a specific heat source temperature range (T1-T2), by adjusting the charge state of the Prussian blue analog positive electrode material and the negative electrode Fe 2+ / Fe 3+ The concentration is such that at the intermediate temperature T0 = (T1 + T2) / 2, the battery voltage is zero;

[0011] Step 2: If Figure 6 As shown in b, c and d, process ① is to reduce the battery temperature from T0 to T1, thereby establishing a battery voltage of α cell (T0-T1), the positive electrode is a Prussian blue analogue, and the negative electrode is Fe 2+ / Fe 3+ ;

[0012] Step 3: If Figure 6 As shown in b, c and d, process ② is the battery discharge at low temperature T1, that is, the positive electrode ions are embedded in the Prussian blue analogue, and the negative electrode Fe 2+Oxidized to Fe 3+ , the discharge ends when the voltage drops to zero;

[0013] Step 4: If Figure 6 As shown in b, c and d, process ③ is to increase the battery temperature from T1 to T2, and the battery voltage becomes negative -α cell (T2-T0), by switching the positive and negative electrodes, that is, the positive electrode is Fe 2+ / Fe 3+ , the negative electrode is a Prussian blue analogue, the battery voltage can still be guaranteed to be positive α cell (T2-T0);

[0014] Step 5: If Figure 6 b, c and d, process ④ is the discharge of the battery at high temperature T2, that is, Fe 3+ Reduction to Fe 2+ , the negative electrode ions are released from the Prussian blue analogue, and the discharge ends when the voltage drops to zero;

[0015] Step 6: Repeat the operations from step 2 to step 5. A charging-free thermal regeneration electrochemical cycle consists of four processes. The electrode cycle undergoes oxidation and reduction reactions, continuously storing low-temperature thermal energy as chemical energy and converting it into electrical energy.

[0016] According to the method for using a non-chargeable thermal regeneration electrochemical battery based on a double membrane structure of the present invention, the four processes can be performed simultaneously by multiple battery modules. The battery cooling heat in step 2 can be used for the battery heating process in step 4 through one or more heat exchangers.

[0017] Compared with other thermal regeneration electrochemical cell technologies, the non-chargeable thermal regeneration electrochemical cell and its use method based on a double-membrane structure provided by the present invention have the following beneficial effects: the present invention achieves the regulation of the positive electrode potential and temperature coefficient by changing the ratio of Prussian blue analog metal materials, electrolyte concentration and embedded ions, so that the battery can be discharged at both high and low temperatures through positive and negative electrode conversion, i.e., a non-chargeable thermal regeneration electrochemical cell. The battery temperature coefficient can reach -2.5 to -3mV / K, which greatly improves the battery voltage, capacity, power density and thermoelectric conversion efficiency; and the double-membrane structure effectively blocks the negative electrode Fe 2+ / Fe 3+ and ClO4 - The influence of the positive electrode ion embedding and extraction process can achieve long-term stable cycling. By changing the positive electrode Prussian blue analog material and embedded ions, a series of non-chargeable thermal regeneration electrochemical cells with high temperature coefficients are proposed, and the double membrane structure ensures continuous and efficient operation of the battery.

[0018] First, by adopting a double-membrane structure, the electrode pair CuCoNiHCF and Fe(ClO4)2 / Fe(ClO4)3 with a larger temperature coefficient can be used to construct a charge-free thermal regeneration electrochemical cell. The theoretical temperature coefficient of the cell reaches -2.5mV / K, and the actual temperature coefficient can exceed -3mV / K.

[0019] Secondly, Fe(ClO4)2 / Fe(ClO4)3 has a high temperature coefficient (>1.5mV / K) in a large concentration range of 0.1-1.5M;

[0020] Then, the cathode material Prussian blue analogue can achieve a wide range of regulation of electrode potential (360-860 mV) and temperature coefficient (-0.4--1 mV / K) by changing the proportion of metal materials, electrolyte concentration and embedded ions, and a series of charge-free thermal regeneration electrochemical battery systems can be constructed;

[0021] Preliminary experiments show that when the heat source range is 20-60℃, the discharge capacity of the rechargeable thermal regeneration electrochemical cell composed of the electrode pair Cu3Ni1HCF / 3M NaCl / / 6MNaClO4 / / 1.2M Fe(ClO4)2 / Fe(ClO4)3 can reach 20mAh / g in one cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 (a) Diagram of the temperature coefficient measurement device of Prussian blue analogs CuCoNiHCF and Fe(ClO4)2 / Fe(ClO4)3; (b) Variation of electrode potential with temperature in negative electrode 0.1-1.5M Fe(ClO4)2 / Fe(ClO4)3 electrolyte; (c) Variation of electrode potential with temperature in positive electrode CuNiHCF at 50% SOC and 1-4M NaCl electrolyte; (d) Variation of electrode potential with temperature in positive electrode CuCoHCF at 50% SOC and 1MNaCl electrolyte; (e) Variation of electrode potential with temperature in positive electrode Cu3Ni1HCF at 50% SOC and 1M different embedded ions.

[0023] Figure 2 (a) Diagram of the experimental setup for the recharge-free thermal regeneration electrochemical cell Cu3Ni1HCF / 3M NaCl / / 6M NaClO4 / / 1.2MFe(ClO4)2 / Fe(ClO4)3 cycle; (b) Changes in the potential of the positive and negative electrodes of the battery with temperature; (c) Changes in the battery voltage with time within a cycle in the temperature range of 20-60°C; (d) Changes in the battery specific capacity within 50 consecutive cycles in the temperature range of 20-60°C.

[0024] Figure 3(a) Changes in the positive and negative electrode potentials of the rechargeable thermal regeneration electrochemical cell Cu1Co1HCF / 1M NaCl / / 6M NaClO4 / / 1.2MFe(ClO4)2 / Fe(ClO4)3 with temperature; (b) Changes in the battery voltage with time in a cycle in the temperature range of 20-60℃.

[0025] Figure 4 (a) Diagram of the experimental setup for the recharge-free thermal regeneration electrochemical cell Cu3Ni1HCF / 1M MgCl2 / / 5M NaClO4 / / 1MFe(ClO4)2 / Fe(ClO4)3 cycle; (b) Changes of the potential of the positive and negative electrodes of the battery with temperature; (c) Changes of the battery voltage with time in a cycle in the temperature range of 20-60°C.

[0026] Figure 5 (a) Exploded diagram of the components of the recharge-free thermal regeneration electrochemical flow battery Cu3Ni1HCF / 1M MgCl2 / / 5M NaClO4 / / 1MFe(ClO4)2 / Fe(ClO4)3; (b) Assembly diagram of the recharge-free thermal regeneration electrochemical flow battery; (c) Change of battery voltage over time in a cycle in the temperature range of 20-60°C.

[0027] Figure 6 (a) Schematic diagram of a double-membrane structured non-rechargeable thermal regeneration electrochemical cell based on a Prussian blue analog as the positive electrode and Fe(ClO4)2 / Fe(ClO4)3 as the negative electrode; (b) Schematic diagram of the four working processes (cooling, low-temperature discharge, heating, and high-temperature discharge) of the double-membrane non-rechargeable thermal regeneration electrochemical cell in one cycle; (c) Schematic diagram of the changes in battery voltage and capacity of the double-membrane non-rechargeable thermal regeneration electrochemical cell in one cycle; (d) Schematic diagram of the changes in battery temperature and entropy of the double-membrane non-rechargeable thermal regeneration electrochemical cell in one cycle DETAILED DESCRIPTION

[0028] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0029] In the description of the present invention, it is necessary to understand that the terms "one", "multiple", "first", "second", etc. merely indicate quantity or position relationship based on the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the devices or components referred to must have specific quantities and positions, operate in specific quantities and positions, and therefore cannot be understood as limitations on the present invention.

[0030] Example 1 Measurement of electrode potential and temperature coefficient of Prussian blue analogs CuCoNiHCF and Fe(ClO4)2 / Fe(ClO4)3 under different electrode materials, electrolyte concentrations and embedded ion conditions

[0031] Firstly, the electrode potential and temperature coefficient of Prussian blue analogs CuCoNiHCF and Fe(ClO4)2 / Fe(ClO4)3 were measured under different electrode materials, electrolyte concentrations and embedded ion conditions to obtain the optimal choice of temperature coefficient and the data basis for the construction of charge-free thermal regeneration electrochemical cells. Figure 1 (a) shows a constant temperature two-electrode test system, including a constant temperature circulating water bath, a water bath cup electrolytic cell (the working electrode is CuCoNiHCF or carbon felt, and the reference electrode is Ag / AgCl) and an electrochemical workstation. Figure 1 (b) It can be seen that the electrode potential of the Fe(ClO4)2 / Fe(ClO4)3 pair increases with increasing temperature, that is, the temperature coefficient is positive, and it does not change much with ion concentration. The maximum value of 1.79mV / K is obtained at 1.4M, and the electrode potential is between 530-650mV at 40℃. The experimental results based on different proportions of CuNiHCF and different concentrations of NaCl are shown in Figure 2. Figure 1 As shown in (c), the higher the proportion of Cu in the electrode material, the higher the electrode potential. The temperature coefficient of CuNiHCF is negative and the lower the electrolyte concentration, the larger the temperature coefficient, with a maximum of about -0.7mV / K. At 40°C, the electrode potential can be adjusted between 380-700mV, which can overlap with the Fe side to achieve the construction of a charge-free thermal regeneration electrochemical cell between 20-60°C, and can also meet other heat source ranges. Figure 1 As shown in (d), by changing the electrode material to CuCoHCF, the temperature coefficient can be increased to -0.92mV / K, and the electrode potential range is 490-650mV at 40°C, and a charge-free thermal regeneration electrochemical cell can also be constructed. Figure 1As shown in (e), based on Cu3Ni1HCF, in addition to NaCl, the use of 1M other ions (such as NH4Cl, RbCl, MgCl2, CaCl2, SrCl2, BaCl2, AlCl3) can also achieve optimization and regulation of electrode potential and temperature coefficient. In particular, RbCl has a temperature coefficient of -1mV / K, but the electrode potential is as high as 870mV (40°C). However, by reducing the Cu ratio, the electrode potential of NiHCF can be reduced to 640mV (40°C), and a high temperature coefficient (theoretically up to -2.8mV / K) non-chargeable thermal regeneration electrochemical cell can be constructed. In addition, the temperature coefficient of Cu3Ni1HCF under 1M MgCl2 is also as high as -0.92mV / K. In summary, Prussian blue analogs CuCoNiHCF and Fe(ClO4)2 / Fe(ClO4)3 can construct a series of non-chargeable thermal regeneration electrochemical cells suitable for different temperature heat source ranges and with large temperature coefficients.

[0032] Example 2 Cycle process of charging-free thermal regeneration electrochemical cell Cu3Ni1HCF / 3M NaCl / / 6M NaClO4 / / 1.2MFe(ClO4)2 / Fe(ClO4)3

[0033] The capacity of the battery is determined by the mass of the active material Cu3Ni1HCF. Figure 2 As shown in (a), the volume of electrolyte on both sides is about 12mL, the positive electrode Cu3Ni1HCF is coated on a 0.5cm square carbon cloth (the mass of active material is about 2-3mg), and the negative electrode is a 0.5cm square carbon felt (2.5mm thick). The positive and negative electrodes are fixed by platinum electrode clamps and connected to the external circuit. The middle layer is made of a 2mm thick silica gel plate, and the cation and anion membranes separate the positive and negative electrolytes respectively. The battery is a glass water bath cup sleeve, and the battery temperature is controlled by a constant temperature circulating water bath. In order to adapt to the heat source range of 20-60℃, the positive and negative electrodes are selected as Cu3Ni1HCF / 3M NaCl and 1.2M Fe(ClO4)2 / Fe(ClO4)3 electrode pairs, as shown in Figure 2 As shown in (b), the electrode potentials intersect at 40℃, which means that voltage balance can be achieved at 20℃ and 60℃. The middle layer electrolyte is 6M NaClO4, ensuring that ClO4 - The concentration is consistent with that of the negative electrode, and the battery theoretical temperature coefficient is -2.2mV / K. A battery cycle consists of four processes, such as Figure 2 As shown in (c), the battery is first cooled to 20°C, Cu3Ni1HCF is the positive electrode, Fe(ClO4)2 / Fe(ClO4)3 is the negative electrode, and a voltage of about 70mV can be established. Then, the battery is charged at 0.1mA (0.4mA / cm 2) for constant current discharge. After the discharge, the battery is heated to 60℃ and the voltage is reduced to about -65mV. At this time, the positive and negative electrodes are switched, and Fe(ClO4)2 / Fe(ClO4)3 is used as the positive electrode and Cu3Ni1HCF is used as the negative electrode. Constant current discharge can still be performed. The capacity change of the non-chargeable thermal regeneration electrochemical battery for 50 consecutive cycles is shown in the figure. Figure 2 As shown in (d), the initial capacity of a cycle battery is about 20mAh / g, which decays as the cycle progresses. The above experiments show that the non-chargeable thermal regeneration electrochemical cell Cu3Ni1HCF / 3MNaCl / / 6M NaClO4 / / 1.2MFe(ClO4)2 / Fe(ClO4)3 can be achieved by being non-charged under low-temperature and high-temperature heat sources, and by establishing a high voltage through a large temperature coefficient, and continuously outputting electrical energy.

[0034] Example 3 Cyclic process of non-charging thermal regeneration electrochemical cell Cu1Co3HCF / 1M NaCl / / 6M NaClO4 / / 1.2MFe(ClO4)2 / Fe(ClO4)3

[0035] In order to investigate the proposed method of constructing a series of non-chargeable thermal regeneration electrochemical cells by regulating electrode materials and electrolytes, based on Example 2, the negative electrode and the intermediate layer electrolyte remain unchanged, and the positive electrode material is introduced with metal Co, i.e., Cu1Co3HCF, where "1" and "3" indicate that the ratio of Cu to Co is 1:3, and the concentration of NaCl is correspondingly reduced to 1M, such as Figure 3 As shown in (a), the electrode potentials of Cu1Co3HCF / 1M NaCl and 1.2M Fe(ClO4)2 / Fe(ClO4)3 intersect at about 30°C. As shown in Example 1, increasing the intersection temperature can be achieved by increasing the NaCl concentration. In this embodiment, the battery voltage is adjusted to zero at 40°C, that is, the charge state SOC of the positive electrode Cu1Co3HCF will slightly deviate from 50%, as shown in Figure 3 As shown in (b), at 0.4 mA / cm 2 The current density can reach 100%, and after four cycles, it can still operate without charging and realize thermoelectric conversion.

[0036] Example 4 Cyclic process of the recharge-free thermal regeneration electrochemical cell Cu3Ni1HCF / 1M MgCl2 / / 5M NaClO4 / / 1MFe(ClO4)2 / Fe(ClO4)3

[0037] In order to further improve the temperature coefficient of the non-chargeable thermal regeneration electrochemical cell, according to the strategy of changing the embedded ions proposed in this application, on the basis of Example 2, Mg 2+ Replace Na + As the positive electrode, 1M MgCl2 electrolyte is used. Figure 4 (a) shows that the battery experimental device diagram is consistent with that in Example 2, but compared with the monovalent ion Na + , divalent ion Mg 2+ Insertion and extraction will affect the lattice stability, so in order to increase the capacity, 15mM CuCl2 and 5mM NiCl2 are added to the 1M MgCl2 electrolyte, so the solution appears light blue. In order to match the positive electrode potential, the negative electrode uses 1MFe(ClO4)2 / Fe(ClO4)3 electrolyte, such as Figure 4 As shown in (b), the battery temperature coefficient can theoretically reach -2.5mV / K, and the intermediate layer electrolyte adopts 5MNaClO4 accordingly. Figure 4 As shown in (b), at 0.4 mA / cm 2 The current density can be circulated in the heat source range of 20-60℃ through four cycles to achieve no charging and thermoelectric conversion.

[0038] Example 5: Cycle process of charging-free thermal regeneration electrochemical flow battery Cu3Ni1HCF / 1M MgCl2 / / 5M NaClO4 / / 1MFe(ClO4)2 / Fe(ClO4)3

[0039] Liquid flow batteries are one of the most promising energy storage devices currently, mainly due to their independent design that can achieve power and energy. The power depends on the size of the battery stack, while the capacity and energy depend on the volume of the electrolyte in the storage tank.

[0040] The electrolyte in the non-chargeable thermal regeneration electrochemical cell based on the double membrane structure proposed in this application can flow, and the corresponding liquid flow battery can be constructed. Therefore, based on the non-chargeable thermal regeneration electrochemical cell Cu3Ni1HCF / 1M MgCl2 / / 5M NaClO4 / / 1M Fe(ClO4)2 / Fe(ClO4)3 proposed in Example 4, a corresponding liquid flow battery was constructed, such as Figure 5 (b) is shown. The exploded diagram of the various parts of the flow battery is shown in Figure 5 As shown in (a), from outside to inside are organic glass end plate, silicone gasket, current collector, electrode and electrode frame, flow channel, cation / anion exchange membrane, silicone gasket and tetrafluoroethylene intermediate layer. The current collector is anti-corrosion titanium foil, the positive electrode Cu3Ni1HCF is 1cm square, and the negative electrode is still carbon felt. Figure 5 As shown in (c), a multi-channel peristaltic pump was used to drive the electrolyte circulation with a flow rate of 1.5 mL / min and a flow rate of 0.1 mA / cm 2 The current density can be circulated in the heat source range of 20-60℃ through four cycles to achieve no charging and thermoelectric conversion.

[0041] Table 1 lists the types of electrolytes in other embodiments except the above embodiment. Other working methods are similar to the above embodiment.

[0042] Table 1 Electrolyte combinations of other double membrane structure charge-free thermal regeneration electrochemical cells other than the embodiment

[0043]

[0044]

[0045]

[0046] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can make many modifications without departing from the purpose of the present invention, all of which are within the protection of the present invention.

Claims

1. A charge-free thermal regeneration electrochemical cell based on a double membrane structure, characterized in that: The positive electrode material of the battery is a transition metal-based Prussian blue analog coated on a carbon material, the positive electrode electrolyte concentration is 0.5-4M, and the positive electrode electrolyte cations are embedded or extracted to perform positive electrode redox reactions; the negative electrode material of the battery is a carbon material, the negative electrode electrolyte concentration is 0.1-1.5M, Fe 2+ and Fe 3+ Mutual conversion to negative electrode redox reaction; an intermediate layer is set between the positive and negative electrolytes, the positive electrolyte and the intermediate layer contain the same cations, the negative electrolyte and the intermediate layer contain the same anions and the concentration of the anions is equal, the intermediate layer and the positive electrolyte are separated by a cation exchange membrane as a cation transmission channel, and the intermediate layer and the negative electrolyte are separated by an anion exchange membrane as an anion transmission channel; The Prussian blue analogue positive electrode material is selected from Cu, Co, Ni or one or more composites; The anion in the positive electrode electrolyte is Cl - 、SO4 2- 、NO3 - or ClO4 - One or more of; The positive electrode electrolyte cation is Na + , K + NH4 + , Li + , Rb + , Cs + Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , Fe 2+ 、Co 2+ 、Ni 2 + , Cu 2+ 、Zn 2+ 、Al 3+ One or more of; The negative electrode electrolyte anion is ClO4 - .

2. The non-chargeable thermal regeneration electrochemical cell based on a double membrane structure according to claim 1, characterized in that: So right The cathode electrolyte, the intermediate layer electrolyte and the cathode electrolyte are flowing.

3. The method for using the non-chargeable thermal regeneration electrochemical cell based on the double membrane structure according to claim 1 or 2 comprises: Step 1: The temperature coefficient of the battery is negative. For a specific heat source temperature range T1-T2, by adjusting the charge state of the Prussian blue analog positive electrode material and the negative electrode Fe 2+ / Fe 3+ The concentration is such that at the intermediate temperature T0 = (T1 + T2) / 2, the battery voltage is zero; Step 2: Process ① is to reduce the battery temperature from T0 to T1, thereby establishing a battery voltage of α cell (T0-T1), α cell is the battery temperature coefficient, the positive electrode is a Prussian blue analogue, and the negative electrode is Fe 2+ / Fe 3+ ; Step 3: Process ② is to discharge the battery at low temperature T1, that is, the positive electrode ions are embedded in the Prussian blue analogue, and the negative electrode Fe 2 + Oxidized to Fe 3+ , the discharge ends when the voltage drops to zero; Step 4: Process ③ is to increase the battery temperature from T1 to T2, and the battery voltage becomes negative -α cell (T2-T0), by switching the positive and negative electrodes, that is, the positive electrode is Fe 2+ / Fe 3+ , the negative electrode is a Prussian blue analogue, the battery voltage can still be guaranteed to be positive α cell (T2-T0); Step 5: Process ④ is to discharge the battery at high temperature T2, that is, Fe 3+ Reduction to Fe 2+ , the negative electrode ions are released from the Prussian blue analogue, and the discharge ends when the voltage drops to zero; Step 6: Repeat the operations from step 2 to step 5. A charging-free thermal regeneration electrochemical cycle consists of four processes. The electrode cycle undergoes oxidation and reduction reactions, continuously storing low-temperature thermal energy as chemical energy and converting it into electrical energy.

4. The method according to claim 3, characterized in that The above processes ① to ④ are respectively performed simultaneously by multiple battery modules.

5. The method according to claim 3, characterized in that: The battery cooling heat in step 2 is used for the battery heating process in step 4 through one or more heat exchangers.

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