Vanadium-based Prussian blue positive electrode of high-capacity ultralow-temperature hydrogen battery rich in vacancy and hydrogen bond network and preparation method of vanadium-based Prussian blue positive electrode
By designing vanadium-based Prussian blue analog cathode materials with vacancy-rich and hydrogen-bonded networks, the problem of insufficient battery capacity at extremely low temperatures in existing technologies has been solved, achieving high capacity and excellent rate performance, and ensuring normal operation of the battery in extremely low temperature environments.
Patent Information
- Application Number
- CN202511028087.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2025-06-23
- Filing Date
- 2025-07-24
- Publication Date
- 2025-11-14
AI Technical Summary
Existing Prussian blue analog cathode materials have insufficient specific capacity and discontinuous hydrogen bond networks at extremely low temperatures, resulting in low battery capacity retention and limiting the development of aqueous proton batteries.
By designing a vanadium-based Prussian blue analogue (VFeCN-VHCF) cathode material rich in vacancies and hydrogen bond networks, and combining it with a hydrogen anode, a full-cell system was constructed. The multi-vacancy and dense hydrogen bond network in the VFeCN-VHCF material was used to improve the proton storage sites and conductivity.
High capacity and excellent rate performance were achieved at extremely low temperatures. The battery can operate normally in an environment of -80℃ to -40℃ and has no significant capacity decay after 1000 cycles, thus improving the battery's low-temperature capacity retention rate.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of electrochemical energy storage technology, and in particular to a high-capacity ultra-low temperature hydrogen proton battery cathode with vacancy-rich and hydrogen bond network and its preparation method. Background Technology
[0002] As human activities expand into cross-regional fields such as high-altitude maritime transport, polar scientific research, and deep-sea exploration, there is an urgent need for electrochemical energy storage devices that can operate normally in extremely low-temperature environments. Although commercial lithium-ion batteries are widely used, their fast-charging and low-temperature performance still falls short of current requirements, especially with significant capacity degradation at -40°C. Aqueous proton batteries (APBs), due to the extremely small ionic radius and light mass of protons, and their ability to achieve the Grotthuss proton conduction mechanism through the breaking and recombination of covalent bonds in the hydrogen bond network of water molecules, exhibit excellent fast-charging and discharging capabilities and are considered a highly promising low-temperature energy storage technology.
[0003] Currently, cathode materials such as Prussian blue analogues (PBAs), as well as MXene, V₂O₅, MnO₂, and organic compounds, have been proven to achieve proton storage in acidic electrolytes. However, the cycle stability and rate performance of full-cell batteries are still inferior to high-performance aqueous batteries and lithium-ion batteries. In fact, NiFe-PBA, NaMn-PBA, and CuFe-PBA, due to the unique framework structure and zero-strain intercalation characteristics of PBAs, have been systematically studied, but the specific capacity is insufficient (<100 mAh g⁻¹) due to the inert metal elements in the framework. -1 The energy density is limited. Although breakthroughs have been made through strategies such as constructing V / Fe dual redox centers by replacing inert metal sites with active V and chemical reduction protonation, the specific capacity is still generally below 110 mAh g⁻¹ due to the limited number of metal sites in the PBA framework. -1 Furthermore, the discontinuous hydrogen bond network formed by interstitial water results in a capacity retention rate of less than 50% at -40°C. Currently, the lack of high-capacity cathodes and poor compatibility between cathode and anode materials are considered the main bottlenecks restricting the development of APBs.
[0004] Therefore, developing a high-capacity, low-temperature resistant Prussian blue cathode through innovative structural design and constructing a full battery system with a hydrogen anode is of great significance for low-temperature energy conversion. Summary of the Invention
[0005] The purpose of this invention is to provide a high-capacity ultra-low temperature hydrogen proton battery cathode with vacancy-rich and hydrogen-bonded networks, and a method for preparing the same. To achieve the above objective, the technical solution of this invention is as follows:
[0006] The first step is to prepare the vanadium precursor solution: vanadium pentoxide (V2O5) is added to hydrochloric acid solution and stirred. Then, glycerol is added to the mixture and stirring is continued to obtain the vanadium precursor solution.
[0007] The second step is to prepare vanadium-based Prussian blue analogues (V) with vacancy-rich and hydrogen-bonded networks. FeCN -VHCF):
[0008] (1) Take a certain amount of the vanadium precursor solution from the first step and name it solution A. Take a certain amount of potassium ferricyanide (K3Fe(CN)6) and add it to deionized water and stir evenly to name it solution B.
[0009] (2) After adding solution B dropwise to solution A and reacting for a period of time, V is obtained by co-precipitation. FeCN -VHCF.
[0010] Further, the dilute hydrochloric acid solution mentioned in the first step is preferably diluted with deionized water to 75 ml from 50 ml of concentrated hydrochloric acid; each 75 ml of dilute hydrochloric acid solution corresponds to 4 g of vanadium pentoxide (V2O5) and 700 μL of glycerol;
[0011] The next step is as follows: First, take 50 ml of concentrated hydrochloric acid and dilute it to 75 ml with deionized water; then, add 4 g of vanadium pentoxide (V2O5) to the diluted hydrochloric acid solution; stir the mixture at 60 °C for 30 minutes to form an orange suspension; then, carefully inject 700 μL of glycerol into the orange suspension and continue the reaction for 30 minutes to obtain a clear, deep blue solution, which should be stored away from air for later use; dilute each 9.4 mL of the clear solution to 50 mL with deionized water to obtain solution A.
[0012] Solution B: 0.6 g potassium ferricyanide (K3Fe(CN)6) per 50 mL of deionized water;
[0013] In further step (2), the molar ratio of vanadium to potassium ferrocyanide (K3Fe(CN)6) is (0.4-0.8):1, preferably 0.5:1.
[0014] Further step (2): Under continuous stirring, solution B is slowly added drop by drop to solution A, reacted at 60°C for 8 hours, and then allowed to stand for 8 hours; the mixture is repeatedly washed with deionized water and alcohol to obtain a dark green precipitate, which is then dried to obtain V. FeCN -VHCF sample.
[0015] A V FeCN -VHCF-H2 battery, with V FeCN- VHCF sample was used as the positive electrode active material to prepare the positive electrode, and Pt / C was used to prepare the negative electrode. The outer shell was a custom acrylic plate, which was filled and sealed with hydrogen gas. The positive and negative electrodes were isolated by an acrylic plate with an electrolyte, namely phosphoric acid.
[0016] A further V FeCN The preparation of a VHCF-H2 battery includes the following steps:
[0017] (1) Preparation of V FeCN -VHCF positive electrode plate:
[0018] To prepare the working electrode, the active material, acetylene black, and polyvinylidene fluoride (PVDF) were combined in a ratio of 7:2:1 to obtain a mixed powder. This powder was then dispersed in N-methylpyrrolidone (NMP) and stirred to produce a uniform slurry. The resulting slurry was then uniformly coated onto carbon fiber paper. Subsequently, the carbon paper with the slurry was placed under vacuum and dried overnight at 60°C to obtain V. FeCN -VHCF positive electrode preparation. The active material loading on each electrode is 1.5-2 mg / 4 cm⁻¹. 2 ;
[0019] (2) Preparation of Pt / C negative electrode:
[0020] Pt / C and PVDF were mixed in an 8:2 ratio to obtain a mixed powder; these powders were then dispersed in N-methylpyrrolidone (NMP) and stirred to produce a homogeneous slurry; the slurry was coated onto carbon paper with a gas diffusion layer; subsequently, the carbon paper with the slurry was placed under vacuum and dried overnight at 60°C to obtain a Pt / C negative electrode sheet; wherein the active material loading on each electrode was approximately 2-3 mg / 4 cm. 2 .
[0021] (3) Hydrogen battery assembly:
[0022] The outer shell is a custom acrylic sheet, which serves to fill and seal hydrogen gas; the inside contains positive and negative electrode materials that are isolated by an acrylic sheet with an electrolyte, wherein the electrolyte is phosphoric acid, preferably with a phosphoric acid concentration of 9.5M.
[0023] The above-mentioned V FeCN -VHCF-H2 batteries are used for energy storage in low-temperature environments (such as -80℃ to -40℃, and especially capable of operating at very low temperatures of -80℃); assembled V FeCN -VHCF-H2 battery due to V FeCNThe abundant vacancies and dense hydrogen bond network in VHCF cathode materials effectively increase proton storage sites, which is beneficial for improving capacity and rate performance. Furthermore, the dense hydrogen bond network enhances the VHCF's ability to store protons. FeCN -The low-temperature performance of VHCF cathode material makes V FeCN -VHCF-H2 batteries can operate normally in environments ranging from -80℃ to -40℃; they can cycle 1000 times at a low temperature of -40℃ without significant capacity decay.
[0024] The advantages of this invention are:
[0025] 1. This invention provides a high-capacity ultra-low temperature hydrogen proton battery cathode with vacancy-rich and hydrogen bond network and its preparation method, which is simple to prepare.
[0026] 2. The hydrogen battery assembled with this positive electrode material can complete the battery charging and discharging behavior.
[0027] 3. By designing vanadium-based Prussian blue analog cathodes with multi-vacancy, hydrogen-bonded networks, the capacity, rate performance, and capacity retention at low temperatures of cathode materials can be improved. Attached Figure Description
[0028] Figure 1 Embodiment 1 of the present invention is based on V FeCN XRD characterization of the VHCF cathode.
[0029] Figure 2 Embodiment 1 of the present invention is based on V FeCN -TGA characterization diagram of the VHCF cathode.
[0030] Figure 3 Embodiment 1 of the present invention is based on V FeCN XPS characterization of the VHCF cathode.
[0031] Figure 4 Embodiment 2 of the present invention is based on V FeCN - GCD curve of VHCF-H2 battery at room temperature.
[0032] Figure 5 Embodiment 2 of the present invention is based on V FeCN -VHCF-H2 battery rate retention performance at different currents.
[0033] Figure 6 Embodiment 2 of the present invention is based on V FeCN -Low-temperature GCD curve of VHCF-H2 battery.
[0034] Figure 7 Embodiment 2 of the present invention is based on V FeCN - Cyclic stability of VHCF-H2 batteries at room temperature and low temperature. Detailed Implementation
[0035] The present invention will be further described below with reference to the embodiments, but the present invention is not limited to the following embodiments.
[0036] Example 1
[0037] A high-capacity ultra-low temperature hydrogen proton battery cathode with vacancy-rich and hydrogen bond network (V FeCN -VHCF) and its preparation method are as follows:
[0038] The first step is to prepare the vanadium precursor solution: First, take 50 ml of concentrated hydrochloric acid and dilute it to 75 ml with deionized water. Then, add 4 g of vanadium pentoxide (V₂O₅) to the diluted hydrochloric acid solution. Stir the mixture at 60 °C for 30 minutes to form an orange suspension. Subsequently, carefully inject 700 μL of glycerol into the orange suspension and continue the reaction for 30 minutes to obtain a clear, deep blue solution, which should be stored in an airtight environment for later use.
[0039] The second step is to prepare V. FeCN -VHCF: Dilute 9.4 mL of the precursor solution to 50 mL with deionized water, stir well, and name this solution A. Add 0.6 g of potassium ferricyanide (K3Fe(CN)6) to 50 mL of deionized water and stir well. Record the resulting yellow solution as solution B. While stirring continuously, slowly add solution B drop by drop to solution A, react at 60 °C for 8 hours, and let stand for 8 hours. Wash repeatedly with deionized water and alcohol to obtain a dark green precipitate. After drying at 60 °C for 8 hours, obtain VHCF. FeCN -VHCF sample.
[0040] Example 2
[0041] V FeCN -VHCF-H2 battery:
[0042] The first step is to prepare V FeCN -VHCF positive electrode plate:
[0043] To prepare the working electrode, the active material, acetylene black, and polyvinylidene fluoride (PVDF) were combined in a ratio of 7:2:1 to obtain a total of 0.4 g of mixed powder. This powder was then dispersed in 1 mL of N-methylpyrrolidone (NMP) and stirred for 8 h to produce a homogeneous slurry. The resulting slurry was uniformly coated onto 2 × 1 cm carbon fiber paper. Subsequently, the carbon paper with the slurry was placed under vacuum and dried overnight at 60 °C to obtain V. FeCN -VHCF positive electrode sheet preparation. The loading of active material on each electrode is approximately 1.5-2 mg.
[0044] The second step is to prepare the Pt / C negative electrode sheet:
[0045] Pt / C and PVDF were mixed in an 8:2 ratio to obtain approximately 0.2 g of mixed powder. This powder was then dispersed in 1 mL of N-methylpyrrolidone (NMP) and stirred for 8 hours to produce a homogeneous slurry. This slurry was coated onto 2 × 2 cm carbon paper with a gas diffusion layer. Subsequently, the carbon paper with the slurry was placed under vacuum and dried overnight at 60 °C to obtain the Pt / C negative electrode sheet. The active material loading on each electrode was approximately 2-3 mg.
[0046] The third step is the assembly of the hydrogen battery: In this example, the outer shell is a custom-made acrylic sheet, which serves to fill and seal the hydrogen gas. Inside, the positive and negative electrode materials are separated by an acrylic sheet containing an electrolyte, namely 9.5M phosphoric acid.
[0047] Example 3
[0048] Select the V prepared in Example 1 above FeCN - X-ray diffraction, thermogravimetric analysis, and X-ray photoelectron spectroscopy were performed on the VHCF cathode material:
[0049] 1. V FeCN Structural characterization of the VHCF cathode:
[0050] VHCF and V FeCN X-ray diffraction (XRD) of VHCF Figure 1 ) pattern and typical compound V 1.5 Fe(CN)6 (JCPDS No. 42-1440) showed a good match, confirming V FeCN -VHCF is an analogue of VHCF. Thermogravimetric analysis (TGA) Figure 2 The weight loss below 200℃ in the curve corresponds to the loss of lattice water molecules. Wherein, V FeCN -VHCF loses 28.0% of its weight below 200℃, and its water of crystallization increases by 2.7% compared to VHCF, indicating that VHCF... FeCN -VHCF contains more [Fe(CN)6] vacancies, which can store more water of crystallization and are conducive to the formation of hydrogen bond networks.
[0051] In addition, VHCF and V were characterized using X-ray photoelectron spectroscopy (XPS). FeCN -The chemical composition of VHCF. It is noteworthy that, for example, the V 2p spectrum ( Figure 3 As shown in a), V FeCN -VHCF in V 5+ (524.4 eV and 517.1 eV) and V 3+ (522.6 eV and 515.5 eV), V4+ The ratio of (523.6 eV and 516.2 eV) is higher than that of VHCF, indicating that V FeCN In -VHCF, more V=O is generated, and the oxidation state of V is higher due to the [Fe(CN)6] vacancy-mediated VHCF structure. Furthermore, in the O1s XPS spectrum ( Figure 3 In (b), V FeCN The V=O bond content (530.7 eV) of -VHCF is increased compared to VHCF, further proving that the [Fe(CN)6] vacancy is conducive to the formation of V=O unit. V=O unit can serve as an active site for reversibly storing and releasing protons in electrochemically driven redox reactions, effectively promoting the increase of specific capacity.
[0052] Example 4
[0053] Select the V prepared in Example 1 above FeCN Electrochemical performance testing of VHCF cathode material:
[0054] Characterizing V through electrochemical performance testing FeCN - Improvements in VHCF-H2 battery capacity, rate performance, and low-temperature capability. For example... Figure 4 As shown, V FeCN -VHCF-H2 batteries exhibit excellent performance at room temperature, at 0.1Ag -1 It has a current of 165.16 mAh g -1 High specific capacity, even at 50Ag -1 It still has a capacity of 53.57mAh g under high current. -1 The capacity. Further tests on its capacity retention yielded the following results: Figure 5 As shown, when the current changes from 0.1Ag -1 Increase to 50Ag -1 It has returned to 0.1Ag -1 Even at that time, it can still maintain capacity, demonstrating excellent rate retention performance. Furthermore, such as... Figure 6 As shown, V FeCN -VHCF-H2 batteries can operate normally at low temperatures of -80°C and with a capacity of 0.1Ag -1 It still retains 52% of its specific capacity at room temperature under high current. Figure 7 This demonstrates V FeCN The cycle stability of the VHCF-H2 battery at different temperatures shows that, even at room temperature and 10Ag, it exhibits good cycle stability. -1 Even under high current, it retains 93.1% capacity after 1000 cycles; at -40℃, 1Ag -1 At the specified current density, it retains 78.9% capacity after 1000 cycles.
Claims
1. A method for preparing a vanadium-based Prussian blue cathode for high-capacity ultra-low temperature hydrogen batteries with vacancy-rich and hydrogen-bonded networks, characterized in that, Includes the following steps: The first step is to prepare the vanadium precursor solution: vanadium pentoxide (V2O5) is added to hydrochloric acid solution and stirred. Then, glycerol is added to the mixture and stirring is continued to obtain the vanadium precursor solution. The second step is to prepare vanadium-based Prussian blue analogues (V) with vacancy-rich and hydrogen-bonded networks. FeCN -VHCF): (1) Take a certain amount of the vanadium precursor solution from the first step and name it solution A. Take a certain amount of potassium ferricyanide (K3Fe(CN)6) and add it to deionized water and stir evenly to name it solution B. (2) After adding solution B dropwise to solution A and reacting for a period of time, V is obtained by co-precipitation. FeCN -VHCF.
2. The method according to claim 1, characterized in that, The dilute hydrochloric acid solution mentioned in the first step is preferably diluted to 75 ml with deionized water from 50 ml of concentrated hydrochloric acid; each 75 ml of dilute hydrochloric acid solution corresponds to 4 g of vanadium pentoxide (V2O5) and 700 μL of glycerol.
3. The method according to claim 1, characterized in that, Solution B: 0.6 g potassium ferricyanide (K3Fe(CN)6) per 50 mL of deionized water.
4. The method according to claim 1, characterized in that, In step (2), the molar ratio of vanadium to potassium ferrocyanide (K3Fe(CN)6) is (0.4-0.8):1, preferably 0.5:
1.
5. The method according to claim 1, characterized in that, Step (2): Under continuous stirring, solution B is slowly added drop by drop to solution A, and the reaction is carried out at 60°C for 8 hours, followed by standing for 8 hours. The solution is then repeatedly washed with deionized water and alcohol to obtain a dark green precipitate. After drying, V is obtained. FeCN -VHCF sample.
6. A vanadium-based Prussian blue cathode for high-capacity ultra-low temperature hydrogen batteries with vacancy-rich and hydrogen-bonded networks prepared according to any one of claims 1-5.
7. A V FeCN -VHCF-H2 battery, characterized in that With V FeCN - VHCF sample was used as the positive electrode active material to prepare the positive electrode, and Pt / C was used to prepare the negative electrode. The outer shell was a custom-made acrylic sheet, filled and sealed with hydrogen gas; the positive and negative electrodes were isolated by an acrylic sheet containing an electrolyte, wherein the electrolyte was phosphoric acid; the VHCF sample was used as the positive electrode active material to prepare the negative electrode. FeCN - The VHCF sample is a vanadium-based Prussian blue cathode for high-capacity ultra-low temperature hydrogen batteries with vacancy-rich and hydrogen-bonded networks, prepared according to the method described in any one of claims 1-5.
8. A V according to claim 7 FeCN The preparation of a VHCF-H2 battery includes the following steps: (1) Preparation of V FeCN -VHCF positive electrode plate: To prepare the working electrode, the active material, acetylene black, and polyvinylidene fluoride (PVDF) were combined in a ratio of 7:2:1 to obtain a mixed powder. This powder was then dispersed in N-methylpyrrolidone (NMP) and stirred to produce a uniform slurry. The resulting slurry was then uniformly coated onto carbon fiber paper. Subsequently, the carbon paper with the slurry was placed under vacuum and dried overnight at 60°C to obtain V. FeCN -VHCF positive electrode preparation. The active material loading on each electrode is 1.5-2 mg / 4 cm⁻¹. 2 ; (2) Preparation of Pt / C negative electrode: Pt / C and PVDF were mixed in an 8:2 ratio to obtain a mixed powder; these powders were then dispersed in N-methylpyrrolidone (NMP) and stirred to produce a homogeneous slurry; the slurry was coated onto carbon paper with a gas diffusion layer; subsequently, the carbon paper with the slurry was placed under vacuum and dried overnight at 60°C to obtain a Pt / C negative electrode sheet; wherein the active material loading on each electrode was approximately 2-3 mg / 4 cm. 2 . (3) Hydrogen battery assembly: The outer shell is a custom acrylic sheet, which serves to fill and seal hydrogen gas; the inside contains positive and negative electrode materials that are isolated by an acrylic sheet with an electrolyte, wherein the electrolyte is phosphoric acid, preferably with a phosphoric acid concentration of 9.5M.
9. A V according to claim 7 FeCN -VHCF-H2 batteries are used for energy storage in low-temperature environments (such as -80℃ to -40℃, especially at very low temperatures of -80℃); furthermore, they can cycle 1000 times at -40℃ without significant capacity decay.