High-stability low-temperature proton battery as well as preparation method and application thereof

Abstract

The invention provides a high-stability low-temperature proton battery as well as a preparation method and application thereof, and belongs to the technical field of proton batteries. According to the invention, vanadium hexacyanoferrate is used as a positive electrode material, a PTCDA / MXene composite material is used as a negative electrode material, and an acetic acid-phosphoric acid solution is used as an electrolyte to prepare the proton battery, so that the interface stability of the electrode material and the electrolyte is good, and meanwhile, active substances cannot fall off in a circulating process; the acetic acid-phosphoric acid electrolyte has relatively high decomposition voltage and excellent electrochemical stability, can stably work in a relatively wide voltage range, and reduces the problems of electrolyte decomposition and water evaporation, so that the safety and cycle performance of the battery are improved; the acetic acid-phosphoric acid electrolyte has relatively good conductivity under a low temperature condition, can maintain relatively stable battery performance in a cold environment, and improves the problem of battery capacity fading at a low temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of proton batteries, and in particular to a high-stability low-temperature proton battery and a preparation method and application thereof. Background Art

[0002] As global energy demand continues to increase, the application of battery technology in energy storage, mobile electronic devices, electric vehicles, and renewable energy storage has gradually expanded. In order to meet the needs of high power, high energy density, and long cycle life, battery technology is constantly being optimized in terms of materials, design, and processes. However, in the face of higher operating voltages, larger capacities, and long cycle performance requirements, existing battery technology still faces many challenges. In particular, in terms of high-voltage stability, cycle life, safety, and low-temperature performance of batteries, traditional battery materials and electrolyte systems often find it difficult to meet new application requirements.

[0003] Traditional water-based battery electrolytes have been widely used in capacitor energy storage systems due to their good conductivity and low cost. However, as the battery voltage continues to increase, the decomposition voltage of water-based electrolytes is low, and electrolyte decomposition and water evaporation are prone to occur, resulting in battery performance degradation and safety hazards. In addition, the conductivity of water-based electrolytes is also significantly affected by temperature changes. Especially in low temperature environments, the ionic conductivity of the electrolyte drops sharply, resulting in a significant attenuation of the battery's capacity and power output. This problem is particularly prominent in devices using batteries in cold climates. Therefore, the limitations of water-based electrolytes under high voltage and low temperature conditions have become an important factor limiting the scope of battery applications.

[0004] However, the improvement of battery performance does not only rely on the optimization of electrolytes, the selection of electrode materials is also crucial. The energy density and power density of batteries are largely limited by the specific capacity, conductivity and compatibility of electrode materials with electrolytes. For example, transition metal oxides or phosphate materials are widely used in the positive and negative electrodes of batteries due to their high theoretical capacity and stability, but in practical applications they also face problems such as poor interface stability between electrolytes and electrodes and shedding of active substances during the cycle.

[0005] Therefore, how to dual optimize the electrolyte and electrode materials to improve the stability, safety and cycle performance of the battery under high voltage, low temperature and long-term use has become a technical problem that needs to be urgently solved in this field. Summary of the invention

[0006] The purpose of the present invention is to provide a high-stability low-temperature proton battery and a preparation method and application thereof. The high-stability low-temperature proton battery provided by the present invention has a high operating voltage and excellent performance in a low-temperature environment. At the same time, the battery has good cycle performance and high stability.

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

[0008] The present invention provides a high-stability low-temperature proton battery, wherein the positive electrode material of the high-stability low-temperature proton battery is vanadium hexacyanoferrate, the negative electrode material is a PTCDA / MXene composite material, and the electrolyte is an acetic acid-phosphoric acid electrolyte.

[0009] Preferably, the preparation method of vanadium hexacyanoferrate (H-VHCF) comprises the following steps:

[0010] (1) mixing vanadium pentoxide and hydrochloric acid to obtain a suspension, and then adding glycerol to the suspension to obtain a mixed solution;

[0011] (2) mixing the mixed solution obtained in step (1) with water, and then adding potassium ferrocyanide solution to carry out a complex reaction to obtain VHCF;

[0012] (3) Mixing the VHCF obtained in step (2) with water, and then adding a hydrazine hydrate solution for chemical reduction to obtain vanadium hexacyanoferrate.

[0013] Preferably, in step (1), the ratio of the amount of vanadium pentoxide, the volume of hydrochloric acid and the amount of glycerol is (20-30) mmol: (70-80) mL: (9-10) mmol.

[0014] Preferably, the temperature of the complexation reaction in step (2) is 50 to 80° C., and the time of the complexation reaction is 8 to 10 hours.

[0015] Preferably, in step (3), the ratio of the mass of VHCF to the volume of the hydrazine hydrate solution is 1 g: (5-15) mL.

[0016] Preferably, the method for preparing the PTCDA / MXene composite material comprises the following steps:

[0017] 1) mixing lithium fluoride, hydrochloric acid and Ti3AlC2 and performing an etching reaction, followed by centrifugation, washing and ultrasonic dispersion in sequence to obtain a MXene dispersion;

[0018] 2) The MXene dispersion obtained in step (1) and the tribenzoic anhydride suspension are mixed, subjected to ultrasonic treatment, and then dried to obtain a PTCDA / MXene composite material.

[0019] Preferably, in step 1), the ratio of the mass of lithium fluoride, the volume of hydrochloric acid and the mass of Ti3AlC2 is (1-3) g:20 mL:(0.5-1.5) g.

[0020] Preferably, the volume ratio of phosphoric acid to acetic acid in the acetic acid-phosphoric acid electrolyte is (5-6):(4-5).

[0021] The present invention provides a method for preparing the high-stability low-temperature proton battery described in the above technical solution, comprising assembling a positive electrode material, a negative electrode material and an electrolyte to obtain a high-stability low-temperature proton battery.

[0022] The present invention provides the application of the high-stability low-temperature proton battery described in the above technical solution or the high-stability low-temperature proton battery prepared by the preparation method described in the above technical solution in energy storage, electric transportation and low-temperature environment.

[0023] The present invention provides a high-stability low-temperature proton battery, wherein the positive electrode material of the high-stability low-temperature proton battery is vanadium hexacyanoferrate, the negative electrode material is a PTCDA / MXene composite material, and the electrolyte is an acetic acid-phosphoric acid electrolyte. The present invention adopts vanadium hexacyanoferrate as a positive electrode material, a PTCDA / MXene composite material as a negative electrode material, and an acetic acid-phosphoric acid electrolyte as an electrolyte to prepare a proton battery. The structure of vanadium hexacyanoferrate is a defective face-centered cubic structure, which belongs to a high-performance pre-proton Prussian blue positive electrode. The PTCDA / MXene composite material is an organic / inorganic hybrid material, which has good interface stability with the electrolyte, and can ensure that the active material will not fall off during the cycle process; the acetic acid-phosphoric acid electrolyte has a high decomposition voltage and excellent electrochemical stability, can work stably in a wide voltage range, reduce the problems of electrolyte decomposition and water evaporation, thereby improving the safety and cycle performance of the battery; at the same time, the acetic acid-phosphoric acid electrolyte has relatively good conductivity under low temperature conditions, can maintain relatively stable battery performance in a cold environment, and improve the problem of battery capacity attenuation at low temperature; by optimizing the electrochemical properties of the electrolyte, the structure of the electrode material and the interface design, the stability problem of the existing battery in high voltage, low temperature and long-cycle use is solved, thereby obtaining a battery with high energy density, long life and high rate performance. The results of the examples show that the high-stability low-temperature proton battery provided by the present invention achieves an operating voltage range of 2V, and the proton battery can be stably cycled 10,000 times at room temperature without obvious capacity decay, while achieving a capacity of 32.6kWkg -1 Maximum power density at 50A g -1 Under the high current density, it only takes 9 seconds to be fully charged, showing the characteristics of fast response and low cost. It is suitable for large-scale energy storage applications such as peak shaving and valley filling and frequency regulation. In addition, the proton battery performs well in an environment of -40℃, which is very suitable for large-scale power grid applications in extreme climates. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a SEM image of the positive electrode material vanadium hexacyanoferrate prepared in Example 1;

[0025] Figure 2 This is a SEM image of the negative electrode material PTCDA / MXene composite material prepared in Example 1;

[0026] Figure 3 Physical pictures of the acetic acid-phosphoric acid electrolyte prepared in Example 1 (left) and the water-phosphoric acid electrolyte prepared in Comparative Example 1 (right);

[0027] Figure 4 The constant current polarization curves of the batteries for the application example and the comparative application example;

[0028] Figure 5 The battery self-discharge for the application example and the comparative application example;

[0029] Figure 6 The battery rate performance of the application examples and comparative application examples;

[0030] Figure 7 The long cycle performance of batteries for application examples and comparative application examples;

[0031] Figure 8 The battery performance at different temperatures for application examples and comparative application examples;

[0032] Fig. 9 Battery energy density and power density performance for application examples. DETAILED DESCRIPTION

[0033] The present invention provides a high-stability low-temperature proton battery, wherein the positive electrode material of the high-stability low-temperature proton battery is vanadium hexacyanoferrate, the negative electrode material is a PTCDA / MXene composite material, and the electrolyte is an acetic acid-phosphoric acid electrolyte.

[0034] In the present invention, the vanadium hexacyanoferrate is preferably protonated vanadium hexacyanoferrate.

[0035] In the present invention, the preparation method of vanadium hexacyanoferrate (H-VHCF) preferably comprises the following steps:

[0036] (1) mixing vanadium pentoxide and hydrochloric acid to obtain a suspension, and then adding glycerol to the suspension to obtain a mixed solution;

[0037] (2) mixing the mixed solution obtained in step (1) with water, and then adding potassium ferrocyanide solution to carry out a complex reaction to obtain VHCF;

[0038] (3) Mixing the VHCF obtained in step (2) with water, and then adding a hydrazine hydrate solution for chemical reduction to obtain vanadium hexacyanoferrate.

[0039] In the present invention, vanadium pentoxide and hydrochloric acid are preferably mixed to obtain a suspension, and then glycerol is added to the suspension to obtain a mixed solution.

[0040] In the present invention, the concentration of the hydrochloric acid is preferably 8 mol / L. In the present invention, the preparation method of the hydrochloric acid is preferably to dilute concentrated hydrochloric acid (12 mol / L) to 1.5 times the volume to obtain hydrochloric acid. The present invention has no particular limitation on the specific operation of the dilution, which can be determined according to the technical common sense of those skilled in the art. The present invention is beneficial to the subsequent reaction with vanadium pentoxide by controlling the concentration of hydrochloric acid.

[0041] In the present invention, the ratio of the amount of the vanadium pentoxide to the volume of hydrochloric acid is preferably (20-30) mmol: (70-80) mL: (9-10) mmol. The present invention can promote the oxidation reaction of vanadium pentoxide and hydrochloric acid by controlling the dosage relationship between the two, thereby forming a yellow suspension. As an embodiment of the present invention, the ratio of the amount of the vanadium pentoxide to the volume of hydrochloric acid can be (21-25) mmol: (72-78) mL: (9-10) mmol, and can also be (22.1-23) mmol: 75 mL: (9-10) mmol.

[0042] In the present invention, when glycerol is added to the suspension, the temperature of the suspension is preferably 50 to 80° C.; the suspension is preferably continuously stirred. As an embodiment of the present invention, the temperature of the suspension may be 60 to 70° C. The present invention has no particular limitation on the stirring rate, which may be determined according to the technical common sense of those skilled in the art to avoid splashing of the solution.

[0043] The present invention has no particular limitation on the speed of adding the glycerol, which can be determined according to the technical common sense of those skilled in the art.

[0044] After obtaining the mixed solution, the present invention mixes the mixed solution with water, then adds potassium ferrocyanide solution to carry out complex reaction to obtain VHCF.

[0045] In the present invention, the volume ratio of the suspension to water is preferably (8-12): (38-42). The present invention can play a dilution role and reduce the concentration by adding a certain amount of water, thereby facilitating subsequent complexation. As an embodiment of the present invention, the volume ratio of the suspension to water can be (9-10): (40-41), and can also be 9.375: 40.625.

[0046] In the present invention, the concentration of the potassium ferrocyanide solution is preferably 0.06 to 0.1 mmol / mL; the volume ratio of the total volume of the suspension and water to the potassium ferrocyanide solution is preferably 1:(0.8 to 1.2). The present invention can achieve better complexation by controlling the dosage relationship of potassium ferrocyanide, thereby obtaining VHCF. As an embodiment of the present invention, the concentration of the potassium ferrocyanide solution can be 0.06 to 0.1 mmol / mL, and can also be 0.072 to 0.08 mmol / mL; the volume ratio of the total volume of the suspension and water to the potassium ferrocyanide solution can be 1:1.

[0047] In the present invention, the potassium ferrocyanide solution is preferably added slowly. The present invention has no particular limitation on the specific rate of the slow addition, which can be determined according to the technical common sense of those skilled in the art.

[0048] In the present invention, the potassium ferrocyanide solution is preferably added under the condition of magnetic stirring. In the present invention, the temperature of the magnetic stirring is preferably 50 to 80° C. The present invention has no special limitation on the rate of the magnetic stirring, and according to the technical common sense of those skilled in the art, there is no special limitation, as long as the potassium ferrocyanide can be mixed evenly. As an embodiment of the present invention, the temperature of the magnetic stirring can be 60 to 70° C.

[0049] In the present invention, the temperature of the complex reaction is preferably 50-80°C; the time of the complex reaction is preferably 8-10h; the complex reaction is preferably carried out under the condition of magnetic stirring. The present invention has no special limitation on the rate of the magnetic stirring, and there is no special limitation according to the technical common sense of those skilled in the art, as long as the components can be mixed evenly. As an embodiment of the present invention, the temperature of the complex reaction can be 60-70°C; the time of the complex reaction can be 9h. The present invention can react potassium ferrocyanide into VHCF through complex reaction.

[0050] In the present invention, after the complex reaction is completed, the product of the complex reaction is preferably cooled, centrifuged and dried in sequence to obtain VHCF. The present invention has no particular limitation on the specific operations of cooling, centrifuging and drying, and it is determined according to the technical common sense of those skilled in the art that the liquid can be removed to obtain dry VHCF. As an embodiment of the present invention, the drying is preferably dried in air at 80°C overnight.

[0051] After obtaining VHCF, the present invention mixes the VHCF with water, and then adds a hydrazine hydrate solution for chemical reduction to obtain vanadium hexacyanoferrate H-VHCF.

[0052] In the present invention, the water is preferably deionized water, more preferably deionized water from which oxygen is removed by nitrogen. In the present invention, the ratio of the mass of the VHCF to the volume of water is preferably 1 g: (10-30) mL. The present invention facilitates subsequent chemical reduction by mixing VHCF and water. As an embodiment of the present invention, the ratio of the mass of the VHCF to the volume of water can be 1 g: (15-25) mL, or 1 g: 20 mL.

[0053] In the present invention, the concentration of the hydrazine hydrate (N2H4·H2O) solution is preferably 0.01-0.1 mol / L; the ratio of the mass of the VHCF to the volume of the hydrazine hydrate solution is preferably 1 g: (5-15) mL. The present invention is conducive to sufficient chemical reduction by controlling the concentration and dosage of the hydrazine hydrate solution. As an embodiment of the present invention, the concentration of the hydrazine hydrate solution can be 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L or 0.09 mol / L; the ratio of the mass of the VHCF to the volume of the hydrazine hydrate solution can be 1 g: 10 mL.

[0054] In the present invention, the temperature of the chemical reduction is preferably room temperature; the time of the chemical reduction is preferably 5 to 20 minutes; and the chemical reduction is preferably carried out under stirring conditions. The present invention has no special limitation on the stirring rate, which can be determined according to the technical common sense of those skilled in the art, so that the components can be mixed evenly and the solution can be avoided from splashing. The present invention can achieve complete reaction by controlling the conditions of chemical reduction. As an embodiment of the present invention, the time of the chemical reduction can be 10 to 15 minutes.

[0055] The present invention preferably centrifuges and dries the chemically reduced product in sequence after chemical reduction to obtain vanadium hexacyanoferrate. The present invention has no special limitation on the specific operation of the centrifugation and drying, which can be determined according to the technical common sense of those skilled in the art as long as the impurities can be removed. As an embodiment of the present invention, the drying can be carried out in a vacuum oven; the drying temperature can be 40 to 50°C.

[0056] In the present invention, the preparation method of the PTCDA / MXene composite material preferably comprises the following steps:

[0057] 1) mixing lithium fluoride, hydrochloric acid and Ti3AlC2 and performing an etching reaction, followed by centrifugation, washing and ultrasonic dispersion in sequence to obtain a MXene dispersion;

[0058] 2) The MXene dispersion obtained in step (1) and the tribenzoic anhydride suspension are mixed, subjected to ultrasonic treatment, and then dried to obtain a PTCDA / MXene composite material.

[0059] The present invention preferably mixes lithium fluoride, hydrochloric acid and Ti3AlC2 and then performs an etching reaction, followed by centrifugation, washing and ultrasonic dispersion in sequence to obtain a MXene dispersion.

[0060] In the present invention, the lithium fluoride (LiF), hydrochloric acid and Ti3AlC2 are preferably mixed in the following manner: first, lithium fluoride is slowly added to hydrochloric acid, and then Ti3AlC2 is added. The present invention can improve safety by mixing in the above manner.

[0061] In the present invention, the hydrochloric acid is preferably concentrated hydrochloric acid; the concentration of the hydrochloric acid is preferably 12 mol / L; the ratio of the mass of the lithium fluoride, the volume of the hydrochloric acid and the mass of Ti3AlC2 is preferably (1-3) g:20 mL:(0.5-1.5) g, more preferably 2 g:20 mL:1 g.

[0062] In the present invention, the temperature of the etching reaction is preferably 40 to 70°C; the time of the etching reaction is preferably 36 to 72 hours. In the present invention, lithium fluoride reacts with hydrochloric acid to generate HF through an etching reaction, and HF can etch away the Al layer in Ti3AlC2, so that the Ti3C2 layers are separated, thereby forming a two-dimensional structure of Ti3C2Tx MXene. As an embodiment of the present invention, the temperature of the etching reaction can be 50 to 60°C; the time of the etching reaction can be 42 to 60 hours, and can also be 48 to 54 hours.

[0063] The present invention has no particular limitation on the specific operations of centrifugation and washing, which can be determined according to the technical common sense of those skilled in the art as long as the pH value of the detergent can reach neutrality.

[0064] In the present invention, the ultrasonic dispersion time is preferably 0.5 to 2 hours, more preferably 1 to 1.5 hours. The present invention has no particular limitation on the power of the ultrasonic dispersion, and it can be determined according to the technical common sense of those skilled in the art as long as the two-dimensional Ti3C2Tx MXene can be converted into a few-layer Ti3C2Tx MXene.

[0065] The present invention preferably collects a dark supernatant after the ultrasonic dispersion is completed to obtain a MXene dispersion. The present invention has no special limitation on the specific operation of collecting the dark supernatant, and it can be collected according to the technical common sense of those skilled in the art. The supernatant collected by the present invention contains a few layers of Ti3C2Tx MXene.

[0066] After obtaining the MXene dispersion, the present invention preferably mixes the MXene dispersion and the tribenzoic anhydride suspension, performs ultrasonic treatment, and then dries to obtain a PTCDA / MXene composite material.

[0067] In the present invention, the preparation method of the tribenzoic anhydride suspension is preferably to mix tribenzoic anhydride (PTCDA) and deionized water and then perform ultrasonic treatment. The present invention has no special restrictions on the dosage relationship of the tribenzoic anhydride and deionized water, as long as the concentration of the tribenzoic anhydride suspension meets the requirements. In the present invention, the time of the ultrasonic treatment is preferably 15 to 30 minutes, more preferably 20 to 25 minutes. The present invention has no special restrictions on the power of the ultrasonic treatment, which can be determined according to the technology of those skilled in the art, as long as the tribenzoic anhydride can be fully dispersed in deionized water.

[0068] In the present invention, the concentration of the MXene dispersion is preferably 0.5-2 mg / mL, more preferably 1 mg / mL; the concentration of the tribenzoic anhydride suspension is preferably 1.5-3 mg / mL, more preferably 2-2.5 mg / mL; the volume ratio of the MXene dispersion to the tribenzoic anhydride suspension is preferably 1:(6-10), more preferably 1:8. The present invention can control the amount of PTCDA and MXene in the PTCDA / MXene composite material by controlling the concentration and amount relationship of each component, thereby further improving the electrochemical performance of the PTCDA / MXene composite material.

[0069] In the present invention, the ultrasonic treatment time is preferably 15 to 30 minutes, more preferably 20 to 25 minutes. The present invention has no special limitation on the power of the ultrasonic treatment, which can be determined according to the technology of those skilled in the art, as long as the components can be fully mixed. The present invention can fully compound PTCDA and MXene through ultrasonic treatment.

[0070] In the present invention, the drying method is preferably freeze drying overnight. The freeze drying of the present invention does not affect the structure of the PTCDA / MXene composite material.

[0071] In the present invention, the concentration of acetic acid in the acetic acid-phosphoric acid electrolyte is preferably 8-9 mol / L, more preferably 8.5 mol / L. In the present invention, the volume ratio of phosphoric acid to acetic acid in the acetic acid-phosphoric acid electrolyte is preferably (5-6):(4-5), more preferably 5.6:4.4; the purity of the phosphoric acid is preferably ≥98%. The present invention can further improve the decomposition voltage and electrochemical stability of the acetic acid-phosphoric acid electrolyte by controlling the composition of the acetic acid-phosphoric acid electrolyte.

[0072] In the present invention, the method for preparing the acetic acid-phosphoric acid electrolyte preferably comprises: mixing phosphoric acid and acetic acid to obtain the acetic acid-phosphoric acid electrolyte.

[0073] The present invention adopts vanadium hexacyanoferrate as a positive electrode material, a PTCDA / MXene composite material as a negative electrode material, and an acetic acid-phosphoric acid solution as an electrolyte to prepare a proton battery. The structure of vanadium hexacyanoferrate is a defective face-centered cubic structure, which belongs to a high-performance pre-proton Prussian blue positive electrode. The PTCDA / MXene composite material is an organic / inorganic hybrid material, which has good interface stability with the electrolyte, and can ensure that the active material will not fall off during the cycle process; the acetic acid-phosphoric acid electrolyte has a high decomposition voltage and excellent electrochemical stability, can work stably in a wide voltage range, reduce the problems of electrolyte decomposition and water evaporation, thereby improving the safety and cycle performance of the battery; at the same time, the acetic acid-phosphoric acid electrolyte has relatively good conductivity under low temperature conditions, can maintain relatively stable battery performance in a cold environment, and improve the problem of battery capacity attenuation at low temperature; by optimizing the electrochemical properties of the electrolyte, the structure of the electrode material and the interface design, the stability problem of the existing battery in high voltage, low temperature and long-cycle use is solved, thereby obtaining a battery with high energy density, long life and high rate performance.

[0074] The present invention also provides a method for preparing the high-stability low-temperature proton battery described in the above technical solution, comprising assembling a positive electrode material, a negative electrode material and an electrolyte to obtain a high-stability low-temperature proton battery.

[0075] The present invention has no particular limitation on the specific operation of the assembly, and the operation of assembling a positive electrode material, a negative electrode material and an electrolyte into a battery, which is well known to those skilled in the art, can be adopted.

[0076] The present invention also provides the application of the high-stability low-temperature proton battery described in the above technical solution or the high-stability low-temperature proton battery prepared by the preparation method described in the above technical solution in energy storage, electric transportation and low-temperature environment.

[0077] The present invention has no particular limitation on the specific manner of the application, and the application can be carried out in a manner well known to those skilled in the art.

[0078] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0079] Example 1

[0080] A high-stability low-temperature proton battery, wherein the positive electrode material of the high-stability low-temperature proton battery is vanadium hexacyanoferrate, the negative electrode material is a PTCDA / MXene composite material, and the electrolyte is an acetic acid-phosphoric acid electrolyte;

[0081] The preparation method of the vanadium hexacyanoferrate is:

[0082] (1) diluting 12 mol / L concentrated hydrochloric acid to 1.5 times its volume to obtain 8 mol / L hydrochloric acid, adding 22.1 mmol of vanadium pentoxide to 75 mL of hydrochloric acid to obtain a yellow suspension, and then adding 9.6 mmol of glycerol to the suspension under stirring at 60° C. to obtain a blue mixed solution;

[0083] (2) 9.375 mL of the mixed solution obtained in step (1) was mixed with water to obtain 50 mL of a mixed solution, and then 50 mL of a potassium ferrocyanide solution with a concentration of 0.072 mmol / mL was slowly added to the mixed solution under magnetic stirring, and the complexation reaction was continued under magnetic stirring, and finally, the mixture was cooled, centrifuged, and dried in air at 80° C. overnight to obtain VHCF; the temperature of the complexation reaction was 60° C., and the time of the complexation reaction was 9 hours;

[0084] (3) mixing the VHCF obtained in step (2) with deionized water (using nitrogen to remove oxygen), then adding a hydrazine hydrate solution and stirring at room temperature for 10 minutes for chemical reduction, and finally centrifuging and drying in a vacuum oven at 40° C. to obtain vanadium hexacyanoferrate; the ratio of the mass of the VHCF to the volume of water is 1 g:20 mL; the concentration of the hydrazine hydrate solution is 0.05 mol / L, and the ratio of the mass of the VHCF to the volume of the hydrazine hydrate solution is 1 g:10 mL;

[0085] The preparation method of the PTCDA / MXene composite material is:

[0086] 1) First, lithium fluoride is slowly added to 12 mol / L concentrated hydrochloric acid, and then Ti3AlC2 is added for etching reaction, followed by centrifugation, washing until the pH value reaches neutrality and ultrasonic dispersion for 1 hour, and finally the dark supernatant is collected to obtain a MXene dispersion; the mass ratio of the lithium fluoride, the volume of hydrochloric acid and the mass of Ti3AlC2 is 2g:20mL:1g; the temperature of the etching reaction is 50°C, and the etching reaction time is 48h;

[0087] 2) 190 mg of tribenzoic anhydride and 80 mL of deionized water were mixed and subjected to ultrasonic treatment for 20 min to obtain a tribenzoic anhydride suspension, and then 10 mL of the MXene dispersion obtained in step (1) was added to the tribenzoic anhydride suspension and ultrasonically treated for 20 min, wherein the concentration of the MXene dispersion was 1 mg / mL, and finally freeze-dried overnight to obtain a PTCDA / MXene composite material;

[0088] The preparation method of the acetic acid-phosphoric acid electrolyte is as follows: 5.6 mL of phosphoric acid with a purity of 98% and 4.4 mL of acetic acid are mixed to obtain the acetic acid-phosphoric acid electrolyte.

[0089] Example 2

[0090] The preparation method of the acetic acid-phosphoric acid electrolyte is as follows: 5.2 mL of phosphoric acid with a purity of 98% and 4.8 mL of acetic acid are mixed to obtain the acetic acid-phosphoric acid electrolyte;

[0091] Other conditions are the same as in Example 1.

[0092] Example 3

[0093] The preparation method of the acetic acid-phosphoric acid electrolyte is as follows: 5.4 mL of phosphoric acid with a purity of 98% and 4.6 mL of acetic acid are mixed to obtain the acetic acid-phosphoric acid electrolyte;

[0094] Other conditions are the same as in Example 1.

[0095] Comparative Example 1

[0096] The electrolyte is a water-phosphoric acid electrolyte, and the preparation method of the water-phosphoric acid electrolyte is as follows: 5.6 mL of phosphoric acid with a purity of 98% and 4.4 mL of water are mixed to obtain the water-phosphoric acid electrolyte;

[0097] Other conditions are the same as in Example 1.

[0098] The SEM image of the positive electrode material vanadium hexacyanoferrate prepared in Example 1 is as follows: Figure 1 As shown. Figure 1 It can be seen that the positive electrode material (H-VHCF) prepared by the present invention presents an irregular nanosphere morphology in the range of 20 to 30 nm, and these nanospheres have a certain aggregation, indicating that the positive electrode material has self-assembly characteristics during the synthesis process. This morphology helps to increase the specific surface area of ​​the positive electrode, thereby improving its electrochemical performance, especially during the charge and discharge process, which may help to improve the transmission efficiency of ions and electrons.

[0099] The SEM image of the negative electrode material PTCDA / MXene composite material prepared in Example 1 is as follows: Figure 2 As shown. Figure 2It can be seen that the negative electrode material (PTCDA / MXene composite material) is composed of short rod-like structures of about 500 nm in length, which are uniformly attached to the surface of the MXene thin layer. This unique structural feature helps to improve the mechanical stability of the negative electrode, while promoting effective contact between the electrolyte and the negative electrode, which may enhance the ion transfer efficiency and improve the electrochemical performance. In addition, the combination of short rods and thin sheets can provide more reaction sites for the electrode, further improving its electrochemical performance.

[0100] The actual pictures of the acetic acid-phosphoric acid electrolyte prepared in Example 1 (left) and the water-phosphoric acid electrolyte prepared in Comparative Example 1 (right) are as follows: Figure 3 As shown. Figure 3 It can be seen that both the acetic acid-phosphoric acid electrolyte and the water-phosphoric acid electrolyte are transparent solutions, which indicates that both electrolytes visually exhibit good solubility and stability, and no obvious precipitation or stratification is observed.

[0101] Application Examples

[0102] A high-stability, low-temperature proton battery is assembled from the positive electrode material, negative electrode material and electrolyte in Example 1.

[0103] Comparative Application Examples

[0104] A proton battery is assembled from the positive electrode material, negative electrode material and electrolyte in Comparative Example 1.

[0105] The comparison of the battery constant current polarization curves of the application example and the comparative application example is shown in the figure below: Figure 4 As shown. Figure 4 It can be seen that the decomposition voltage of the acetic acid-phosphoric acid electrolyte is increased to 1.62 V compared with the decomposition voltage of the traditional water-phosphoric acid electrolyte of 1.48 V, indicating that the acetic acid-phosphoric acid electrolyte has higher stability and stronger resistance to electrolysis.

[0106] The comparison of battery self-discharge between the application example and the comparative application example is shown in the figure below: Figure 5 As shown. Figure 5 It can be seen that after 2 hours of standing, the self-discharge rate of the battery with acetic acid-phosphoric acid electrolyte is only 30%, while the self-discharge rate of the battery using traditional water-phosphoric acid electrolyte reaches 75%. This result shows that the acetic acid-phosphoric acid electrolyte has a significantly lower self-discharge rate, indicating that it has obvious advantages in battery stability and energy retention.

[0107] The battery rate performance comparison chart of the application example and the comparative application example is as follows: Figure 6 As shown. Figure 6 It can be seen that at different current densities, the battery using acetic acid-phosphoric acid electrolyte has a high current density at 1, 2, 5, 10, 20 and 50Ag. -1At a current density of 1.54 mAh g -1 , 141mAh g -1 , 125mAh g -1 , 108mAh g -1 、99.5mAh g -1 and 69.3mAh g -1 , which are higher than the corresponding values ​​in water-phosphoric acid electrolyte (150 mAh g -1 , 131mAh g -1 , 113mAh g -1 , 99mAh g -1 , 87mAh g -1 and 63mAh g -1 ). This result shows that the acetic acid-phosphoric acid electrolyte used in the present invention exhibits a higher specific capacity in a wide current density range and has a more excellent rate performance.

[0108] The comparison of battery long cycle performance between application examples and comparative application examples is shown in the figure below: Figure 7 As shown. Figure 7 It can be seen that the battery using acetic acid-phosphoric acid electrolyte has a capacity retention rate of 82.4% after 10,000 cycles, showing excellent cycle stability and low decay rate. In contrast, the battery using water-phosphoric acid electrolyte has almost completely decayed in capacity after only 2,000 cycles, indicating that its stability in long-term use is poor, which may be due to performance degradation caused by electrolyte decomposition or internal battery reactions.

[0109] The battery performance of the application examples and comparative application examples at different temperatures is as follows Figure 8 As shown. Figure 8 It can be seen that the battery based on acetic acid-phosphoric acid electrolyte shows good capacity retention under low temperature conditions. At -40℃, the battery has a capacity retention rate of 0.2Ag. -1 At a current density of 5Ag, the capacity retention rate is 45% of that at room temperature; -1 At a higher current density, the capacity retention rate at -40°C is 32% of that at room temperature. This result shows that the acetate-phosphoric acid electrolyte can maintain the electrochemical properties of the battery well under low temperature conditions, although low temperature will affect the migration rate of ions and the conductivity of the electrolyte. The battery can still maintain a relatively stable capacity at -40°C, indicating that it still has strong application potential in extreme low temperature environments, especially in fields that require low temperature operation, such as energy storage systems and electric vehicles in cold climates, which has significant advantages.

[0110] Battery energy density and power density performance of application examples such as Fig. 9 As shown. Fig. 9It can be seen that the battery based on acetate-phosphoric acid electrolyte has high power density and fast charging speed, showing the characteristics of fast response and low cost, and is suitable for large-scale energy storage applications such as peak shaving and valley filling and frequency regulation.

[0111] From the above analysis, it can be seen that the proton battery provided by the present invention has the following advantages:

[0112] 1. High voltage window: Unlike most proton batteries with voltages below 1.5V, the proton battery provided by the present invention achieves an operating voltage range of 2V, surpassing all existing non-metallic proton batteries (without metal materials or carriers) and much higher than the electrochemical window of commonly used zinc / manganese dioxide batteries (~0.9V).

[0113] 2. Excellent cycle stability: The proton battery provided by the present invention can be stably cycled 10,000 times at room temperature without obvious capacity decay. Its cycle life is 10 times that of commercial lithium-ion batteries and 20 times that of zinc-ion batteries.

[0114] 3. High power density and fast charging: The proton battery provided by the present invention achieves 32.6kWkg -1 The maximum power density is 30 times higher than that of commercial lithium-ion batteries; at 50Ag -1 Under a high current density, the proton battery provided by the present invention can be fully charged in only 9 seconds, showing the characteristics of fast response and low cost, and is suitable for large-scale energy storage applications such as peak shaving and valley filling and frequency regulation.

[0115] 4. Wide temperature adaptability: The proton battery provided by the present invention performs excellently in an environment of -40°C and is very suitable for large-scale power grid applications in extreme climates.

[0116] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high-stability low-temperature proton battery, wherein the positive electrode material of the high-stability low-temperature proton battery is vanadium hexacyanoferrate, the negative electrode material is a PTCDA / MXene composite material, and the electrolyte is an acetic acid-phosphoric acid electrolyte.

2. The high stability low temperature proton battery according to claim 1, characterized in that: The preparation method of vanadium hexacyanoferrate comprises the following steps: (1) mixing vanadium pentoxide and hydrochloric acid to obtain a suspension, and then adding glycerol to the suspension to obtain a mixed solution; (2) mixing the mixed solution obtained in step (1) with water, and then adding potassium ferrocyanide solution to carry out a complex reaction to obtain VHCF; (3) Mixing the VHCF obtained in step (2) with water, and then adding a hydrazine hydrate solution for chemical reduction to obtain vanadium hexacyanoferrate.

3. The high stability low temperature proton battery according to claim 2, characterized in that: In the step (1), the ratio of the amount of vanadium pentoxide, the volume of hydrochloric acid and the amount of glycerol is (20-30) mmol: (70-80) mL: (9-10) mmol.

4. The high stability low temperature proton battery according to claim 2, characterized in that: The temperature of the complexation reaction in step (2) is 50-80° C., and the time of the complexation reaction is 8-10 hours.

5. The high stability low temperature proton battery according to claim 2, characterized in that: In the step (3), the ratio of the mass of VHCF to the volume of the hydrazine hydrate solution is 1 g: (5-15) mL.

6. The high stability low temperature proton battery according to claim 1, characterized in that: The preparation method of the PTCDA / MXene composite material comprises the following steps: 1) mixing lithium fluoride, hydrochloric acid and Ti3AlC2 and performing an etching reaction, followed by centrifugation, washing and ultrasonic dispersion in sequence to obtain a MXene dispersion; 2) The MXene dispersion obtained in step (1) and the tribenzoic anhydride suspension are mixed, subjected to ultrasonic treatment, and then dried to obtain a PTCDA / MXene composite material.

7. The high stability low temperature proton battery according to claim 6, characterized in that: In the step 1), the ratio of the mass of lithium fluoride, the volume of hydrochloric acid and the mass of Ti3AlC2 is (1-3) g: 20 mL: (0.5-1.5) g.

8. The high stability low temperature proton battery according to claim 1, characterized in that: The volume ratio of phosphoric acid to acetic acid in the acetic acid-phosphoric acid electrolyte is (5-6):(4-5).

9. The method for preparing the high-stability low-temperature proton battery according to any one of claims 1 to 8, comprising assembling a positive electrode material, a negative electrode material and an electrolyte to obtain a high-stability low-temperature proton battery.

10. Application of the high-stability low-temperature proton battery according to any one of claims 1 to 8 or the high-stability low-temperature proton battery prepared by the preparation method according to claim 9 in energy storage, electric transportation and low-temperature environments.

Images