Hydrogen solid-state secondary battery with vanadium-based positive electrode

Abstract

The invention relates to the technical field of secondary batteries, in particular to a hydrogen solid-state secondary battery with a vanadium-based positive electrode, which comprises a VHCF positive electrode, a Pt / C negative electrode and a solid-state electrolyte, the solid electrolyte comprises an acidic electrolyte and clay, and the basic structure and characteristics of the VHCF positive electrode are formed by the following chemical formula: VHCF = # imgabs0 # 1-y. N # imgabs1 # O, the positive electrode material has relatively high specific capacity, the overall capacity performance of the battery is remarkably improved, and the VHCF positive electrode is successfully introduced into a novel hydrogen solid-state secondary battery system, so that the excellent electrochemical performance of the VHCF positive electrode is fully exerted; and the whole battery system shows excellent cycling stability, good rate capability and excellent low-temperature adaptability, the application range of the VHCF positive electrode under different environmental conditions is greatly widened, and in addition, the preparation process of the VHCF positive electrode is simple, efficient, low in energy consumption and low in cost.

Description

Technical Field

[0003] The present invention relates to the technical field of secondary batteries, and particularly to a hydrogen solid-state secondary battery with a vanadium-based positive electrode. Background Art

[0005] Vanadium-based positive electrodes generally refer to positive electrode materials mainly composed of vanadium elements, which are widely used in energy storage systems such as vanadium redox flow batteries (VRFB). Vanadium redox flow batteries have advantages such as high energy efficiency, long cycle life, and good safety, and are very suitable for large-scale energy storage scenarios. The hydrogen solid-state secondary battery with a vanadium-based positive electrode is a relatively cutting-edge research direction, combining the multivalent characteristics of vanadium materials with the potential of hydrogen storage, aiming to develop a safe, efficient, and long-life energy storage system.

[0006] Since 2018, a series of new aqueous secondary batteries - hydrogen batteries have been reported. Due to using H + as a carrier (with the smallest ionic radius), it has the fastest conduction rate in the electrolyte, which in turn enables the battery to have excellent rate performance. The hydrogen negative electrode can match different positive electrodes. For example, the hydrogen negative electrode can match insertion / extraction type positive electrodes. In the prior art, nickel-metal hydride (Ni-H2) batteries, Prussian blue (PBA)-H2 batteries, and lithium manganese oxide-hydrogen (LMO-H2) batteries have been developed in alkaline, acidic, and neutral electrolytes respectively. Among them, nickel hydroxide in the positive electrode of the Ni-H2 battery has a low abundance in the earth's crust, and both the positive electrode material PBA in the PBA-H2 battery and lithium manganese oxide in the LMO-H2 battery have low specific capacities, thus limiting the large-scale application of the above batteries. Summary of the Invention

[0008] The present invention aims at the technical problems existing in the prior art and provides a hydrogen solid-state secondary battery with a vanadium-based positive electrode.

[0009] The technical solution of the present invention to solve the above technical problems is as follows: A hydrogen solid-state secondary battery with a vanadium-based positive electrode includes a VHCF positive electrode, a Pt / C negative electrode, and a solid electrolyte; the solid electrolyte includes an acidic electrolyte and clay, and the basic structure and characteristics of the VHCF positive electrode are constituted by the following chemical formula: VHCF = 1-y.n O.

[0010] In a preferred embodiment, the preparation method of the VHCF positive electrode includes the following steps: Dissolve in HCl to obtain a vanadium source solution, and dissolve [Fe Dissolve it in water to obtain a potassium ferricyanide solution. Drop the potassium ferricyanide solution into the vanadium source solution and react at 60 °C for 9 h. After washing and drying, the VHCF positive electrode material is obtained.

[0011] In a preferred embodiment, the mass-volume ratio of the vanadium source, potassium ferricyanide and water is 80~120 mg : 100~200 mg : 30~60 mL. The following chemical formula can be obtained from the mixing reaction of the vanadium source solution and the potassium ferricyanide solution: VO 2+ +K3[Fe(CN)6]→KVO[Fe(CN)6].

[0012] In a preferred embodiment, the vanadium source includes VOS and VC . The vanadium source includes vanadium oxides, vanadates and nitrido vanadium salt solutions. After the vanadium source reacts, it appears in two forms: blue and purple. The VOS is suitable for redox reactions, and the pH needs to be controlled at 2~3 to prevent hydrolysis.

[0013] In a preferred embodiment, when the vanadium oxides, vanadates and nitrido vanadium salt solutions react, the reaction temperature is 25~80 °C and the reaction time is 7~12 h.

[0014] In a preferred embodiment, the mass ratio of the acidic electrolyte to the clay in the solid electrolyte is 0.5~1.5:1~5, and the volume concentration of the acidic electrolyte is 10%~85%.

[0015] In a preferred embodiment, the acidic electrolyte includes and / or . The clay includes M ·3.0 O, A Si·1.19 O and A S ·0.32 O, any one of them.

[0016] In a preferred embodiment, the Pt in the Pt / C negative electrode accounts for 15%~50% of the total mass of the Pt / C negative electrode, and the diameter of the Pt / C negative electrode sheet is 19 mm.

[0017] The beneficial effects of the present invention are as follows: The positive electrode material has a high specific capacity, which is beneficial to significantly improving the overall capacity performance of the battery. By successfully introducing the VHCF positive electrode into the new hydrogen solid-state secondary battery system, not only its excellent electrochemical performance is fully exerted, but also the entire battery system exhibits excellent cycle stability, good rate performance, and excellent low-temperature adaptability, greatly broadening its application scope under different environmental conditions. In addition, the VHCF positive electrode preparation process adopted in the present invention is simple and efficient, with low energy consumption, low cost, and does not rely on scarce resources, having good scalability and environmental friendliness, meeting the requirements of green and sustainable development. Therefore, it is very conducive to realizing large-scale industrial production and practical application promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the battery structure of the present invention;

[0020] Figure 2 It is a schematic diagram of the charge and discharge principle of the present invention;

[0021] Figure 3 It is a diagram for evaluating the cycle performance of the battery of the present invention;

[0022] Figure 4 It is a process flow diagram of the present invention;

[0023] Figure 5 It is a process flow diagram of the working process of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0026] In the description of the present application, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present application, "a plurality" means two or more, unless otherwise specifically defined.

[0027] In the description of the present application, the term "for example" is used to mean "serving as an example, illustration, or explanation". Any embodiment described as "for example" in the present application is not necessarily construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to implement and use the present invention. In the following description, details are set forth for purposes of explanation. It should be understood that those of ordinary skill in the art can recognize that the present invention can be implemented without the use of these specific details. In other instances, well-known structures and processes are not elaborated in detail to avoid obscuring the description of the present invention with unnecessary details. Therefore, the present invention is not intended to be limited to the embodiments shown, but rather to be in line with the broadest scope consistent with the principles and features disclosed in the present application.

[0028] Embodiment 1:

[0029] As Figures 1-5 , this embodiment provides: A hydrogen solid-state secondary battery with a vanadium-based positive electrode, including a VHCF positive electrode, a Pt / C negative electrode, and a solid electrolyte; the solid electrolyte includes an acidic electrolyte and clay, and the basic structure and characteristics of the VHCF positive electrode are constituted by the following chemical formula: VHCF = 1-y.n O, where x represents the mixing valence state ratio of vanadium ions (V), y represents the cyanide iron vacancy ratio, and n represents the number of water molecules bound in each VHCF lattice unit.

[0030] Figure 1 Meanings of each letter in : Specific capacity / mAh represents the specific capacity; Coulombicefficiency / % represents the reversibility of the battery; 0.5A represents the current density; Cycle number represents the number of cycles;

[0031] Figure 2 Meanings of each letter in : Voltage / V represents the voltage value represented by the vertical coordinate (Y-axis), with the unit of volt (V); Specific capacity / mAh represents the specific capacity represented by the horizontal coordinate (X-axis), that is, the amount of electricity stored or released per unit mass of the active material, with the unit of milliampere-hour per gram (mAh / g); A represents the current density per unit mass, that is, the "charge and discharge rate", indicating the current load capacity of the battery active material;

[0032] Figure 3 Meanings of each letter in : mAh Specific capacity; Cycle number represents the number of cycles; Coulombic efficiency / % represents the percentage ratio of discharge capacity to charge capacity, reflecting the reversibility of the battery.

[0033] Example 2:

[0034] The preparation method of the VHCF positive electrode includes the following steps: Dissolve in HCl to obtain a vanadium source solution. Dissolve [Fe in water to obtain a potassium ferricyanide solution. Drop the potassium ferricyanide solution into the vanadium source solution and react at 60 °C for 9 h. After washing and drying, the VHCF positive electrode material is obtained. The specific capacity of the VHCF positive electrode reaches 146.52 mAh / g, far exceeding that of traditional positive electrode materials. The VHCF positive electrode is a vanadium-based Prussian blue analogue, with reversible deintercalation .

[0035] The mass-volume ratio of the vanadium source, potassium ferricyanide and water is 80~120 mg : 100~200 mg : 30~60 mL. Mixing and reacting the vanadium source solution and the potassium ferricyanide solution can obtain the following chemical formula: VO 2+ +K3[Fe(CN)6]→KVO[Fe(CN)6]. The vanadium source solution and the potassium ferricyanide solution are mixed and reacted at 40~80 °C for 9~12 hours. In the above chemical formula, where VOS acts as the vanadium source to provide ions, [Fe provides ligands, and the generated V[Fe (vanadium-based Prussian blue analogue, VHCF) is the final positive electrode active material. The reaction conditions are mild, the product has high crystallinity, is suitable for large-scale production, and the generated VHCF has an open framework structure, which is conducive to rapid deintercalation and improvement of the battery rate performance.

[0036] The vanadium source includes VOS and VC . The vanadium source includes vanadium oxides, vanadates and nitrovandate solutions. The vanadium source shows two forms of blue and purple after reaction. VOS is suitable for redox reactions, and the pH needs to be controlled at 2~3 to prevent hydrolysis. The vanadium source forms two forms of vanadium-based Prussian blue analogues in blue and purple after reaction, where the blue form corresponds to the stable state, and the purple form corresponds to the reduced state. When using VOS as the vanadium source, the pH of the reaction system needs to be controlled at 2~3 to prevent vanadium ion hydrolysis. Specifically, it can be achieved by adding dilute sulfuric acid ( S ) or phosphoric acid ( P ) is used to adjust the acidity. The blue ( ) and purple ( ) forms of VHCF can broaden the battery operating voltage window. Precise pH control ensures product purity, making it suitable for industrial production. The acidic conditions inhibit side reactions and improve the cycle life of the positive electrode.

[0037] When vanadium oxides, vanadates, and nitrido-vanadate solutions react, the reaction temperature is 25 - 80 °C and the reaction time is 7 - 12 h. This temperature and time range can ensure that vanadium ions fully participate in the reaction, while avoiding product decomposition or a decrease in crystallinity due to excessive temperature. During the reaction process, continuous stirring is required to promote uniform mixing of the reactants, and an inert gas (such as nitrogen or argon) is introduced for protection to prevent the oxidation of vanadium ions. After the reaction is completed, the product needs to be centrifuged, washed, and dried to obtain high-purity vanadium-based Prussian blue analog (VHCF). The importance of continuous stirring and inert gas protection is emphasized to avoid vanadium ion oxidation or uneven local concentration. The temperature control range ensures efficient reaction progress and avoids the generation of by-products. The optimized conditions ensure high crystallinity and stable specific capacity of VHCF, which is applicable to various vanadium sources and provides parameter basis for industrial production.

[0038] The mass ratio of the acidic electrolyte to the clay in the solid electrolyte is 0.5 - 1.5:1 - 5, and the volume concentration of the acidic electrolyte is 10% - 85%. The solid electrolyte inhibits side reactions and improves cycle stability. The hydrogen battery ( battery) uses as the carrier and has ultra-high rate performance. It has a fast conduction rate and can adapt to low-temperature environments. By fixing the acidic electrolyte, side reactions at the electrode / electrolyte interface (such as vanadium dissolution and an increase in the overpotential of hydrogen evolution) are reduced, and the capacity retention rate of the battery remains > 90% after 500 cycles. It can inhibit side reactions. Using as the carrier, it conducts through the Grotthuss mechanism in the solid electrolyte, and the room-temperature proton conductivity reaches S / cm, supporting 20C (12 minutes) rapid charge and discharge, which is convenient for improving the rate performance.

[0039] The acidic electrolyte includes and / or , and the clay includes M ·3.0 O, A Si·1.19 O and A S ·0.32 One of the following in O, for optimizing the solid electrolyte, 63% can be used P Mix with bentonite ( Si·19 O) in a mass ratio of 1:1, the formed gel electrolyte membrane has high proton conductivity ( S / cm) and flexibility, is suitable for low-temperature environments, and the formed gel has the following characteristics: high proton conductivity: up to S / cm at room temperature, superior to traditional liquid electrolytes; excellent flexibility: can be bent to 180° without breaking, adapting to the stress of battery assembly; low-temperature adaptability: still maintains S / cm conductivity at -20°C; interface stability: compatible with VHCF positive electrode and Pt / C negative electrode, without side reactions; the preparation method of the solid electrolyte includes: adding P solution slowly into the bentonite powder, stirring until a homogeneous gel is formed, degassing under vacuum at 60°C and then pressing into a film (thickness 0.2 - 0.5 mm). The solid gel eliminates the risk of liquid leakage, the conductivity in a wide temperature range meets the application in extreme environments, the raw materials are easily available, and the film-forming process is simple.

[0040] Pt in the Pt / C negative electrode accounts for 15% - 50% of the total mass of the Pt / C negative electrode. The diameter of the Pt / C negative electrode sheet is 19 mm, and the thickness is 0.1 - 0.3 mm, and the loading amount of Pt is 0.8 - 1.2 mg / c , the Pt / C negative electrode catalyzes oxidation / reduction reaction. During the charging process, Pt catalyzes the reduction of protons ( ) to generate hydrogen gas ( ); during the discharging process, Pt catalyzes the oxidation of hydrogen gas ( ) to regenerate protons ( ). The Pt / C negative electrode has high catalytic activity, excellent electrical conductivity and stable electrochemical performance, can effectively improve the rate performance and cycle stability of the battery. The catalytic role of the Pt / C negative electrode during charge and discharge: Charging: + →1 / 2 (Pt catalyzes proton reduction); Discharging: 1 / 2 → + (Pt catalyzes hydrogen oxidation). Pt nanoparticles provide abundant active sites, significantly reduce the reaction energy barrier, and the optimized Pt content and loading amount ensure the long-term stability of the electrode. The slurry coating method is easy for large-scale production and is compatible with existing battery manufacturing processes.

[0041] Example 3:

[0042] First, prepare the VHCF positive electrode. Add 4 g of V2O5 to 75 ml of HCl and stir. Take 9.4 ml of the solution and dilute it to 50 ml, denoted as A. Then, add 36 mol of K3[Fe(CN)6] to 50 mL of deionized water to form a green solution, denoted as B. Then, slowly add B dropwise to solution A under continuous stirring, react at 60 °C for 9 h, wash, centrifuge, and dry to obtain the positive electrode VHCF.

[0043] Then, prepare the positive electrode plate, Pt / C negative electrode plate, and solid electrolyte membrane.

[0044] The preparation method of the positive electrode plate is as follows: Roll the slurry of the positive electrode active material VHCF, conductive agent acetylene black, and binder PTFE into an electrode in a ratio of 7:2:1. Among them, the current collector is a titanium mesh, the loading of the active substance is 1.285 mg·cm-2, and the diameter of the positive electrode plate is 19 mm.

[0045] The preparation method of the Pt / C negative electrode plate is as follows: Roll the slurry of the Pt / C negative electrode catalyst powder and binder PTFE into an electrode in a ratio of 8:2. Among them, the current collector is a titanium mesh, the loading of Pt is 1 mg·cm-2, and the diameter of the Pt / C negative electrode plate is 19 mm; Pt accounts for 40% of the total mass of the Pt / C negative electrode.

[0046] The production method of the solid electrolyte membrane is as follows: Mix bentonite A Si·1.19 O and acidic electrolyte P in a mass ratio of 1:1 to make a gel-like solid electrolyte membrane. Among them, the concentration of the acidic electrolyte P is 63%.

[0047] Finally, assemble the battery. The assembly order of the battery is: positive electrode plate, solid electrolyte membrane, and Pt / C negative electrode plate.

[0048] During the first charging process, the positive electrode material VHCF embeds H + . Protons in the solid electrolyte membrane react to generate hydrogen under the catalysis of the negative electrode catalyst Pt. During the discharging process, hydrogen reacts on the negative electrode catalyst Pt to generate protons, which are transferred to the solid electrolyte and conduct out through the Grotthuss mechanism to generate H-VHCF in the positive electrode material. During the second and subsequent charge-discharge processes, protons are embedded in VHCF (discharging process) and removed from H-VHCF (charging process) at the positive electrode, and oxidation and reduction reactions of protons occur at the negative electrode.

[0049] It should be noted that in the above embodiments, the descriptions of each embodiment have their own emphases. For parts not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0050] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0051] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded computer, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for realizing the functions specified in Figure 1 one or more of the flows Figure 1 or a plurality of flows and / or blocks

[0052] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device realizes the functions specified in Figure 1 one or more of the flows Figure 1 or a plurality of flows and / or blocks

[0053] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for realizing the functions specified in Figure 1 one or more of the flows Figure 1 or a plurality of flows and / or blocks

[0054] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn the basic inventive concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present invention.

[0055] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A hydrogen solid-state secondary battery with a vanadium-based positive electrode, characterized in that, It includes a VHCF positive electrode, a Pt / C negative electrode, and a solid electrolyte; the solid electrolyte includes an acidic electrolyte and clay, and the basic structure and characteristics of the VHCF positive electrode are constituted by the following chemical formula: VHCF = 1-y.n O.

2. The hydrogen solid-state secondary battery with a vanadium-based positive electrode according to claim 1, characterized in that, The preparation method of the VHCF positive electrode includes the following steps: Dissolve in HCl to obtain a vanadium source solution, and dissolve [Fe in water to obtain a potassium ferricyanide solution. Drop the potassium ferricyanide solution into the vanadium source solution, react at 60 °C for 9 h, wash and dry to obtain the VHCF positive electrode material.

3. The hydrogen solid-state secondary battery with a vanadium-based positive electrode according to claim 2, characterized in that, wherein the mass-volume ratio of the vanadium source, potassium ferricyanide and water is 80-120 mg: 100-200 mg: 30-60 mL, and the following chemical formula can be obtained by mixing and reacting the vanadium source solution and the potassium ferricyanide solution: VO 2+ + K3[Fe(CN)6] → KVO[Fe(CN)6].

4. A hydrogen solid-state secondary battery with a vanadium-based positive electrode according to claim 1, characterized in that, Among them, the vanadium source includes VOS and VC , the vanadium source includes vanadium oxides, vanadates and nitrato-vanadium salt solutions. After the reaction of the vanadium source, it appears in two forms: blue and purple. The VOS is applicable to redox reactions, and the pH needs to be controlled at 2-3 to prevent hydrolysis.

5. A hydrogen solid-state secondary battery with a vanadium-based positive electrode according to claim 1, characterized in that, When the vanadium oxide, vanadate, and nitrovandate solution react, the reaction temperature is 25 to 80 °C, and the reaction time is 7 to 12 h.

6. The hydrogen solid-state secondary battery with a vanadium-based positive electrode according to claim 1, characterized in that, The mass ratio of the acidic electrolyte to the clay in the solid electrolyte is 0.5 to 1.5: 1 to 5, and the volume concentration of the acidic electrolyte is 10% to 85%.

7. The hydrogen solid-state secondary battery with a vanadium-based positive electrode according to claim 1, characterized in that, The acidic electrolyte includes and / or , and the clay includes M ·3.0 O,[[]] A Si·1.19 O and A S ·0.32 O, any one of them.

8. The hydrogen solid-state secondary battery with a vanadium-based positive electrode according to claim 1, wherein The Pt in the Pt / C negative electrode accounts for 15% to 50% of the total mass of the Pt / C negative electrode, and the diameter of the Pt / C negative electrode sheet is 19 mm.

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