A diazene-based organic negative electrode material for aqueous alkaline batteries and its application

Abstract

The present invention discloses a diazine-based organic negative electrode material for aqueous alkaline batteries and its application, relating to the field of battery technology. This type of organic negative electrode has an electrochemical redox active center with a nitrogen-nitrogen double bond (N=N), including but not limited to azobenzene; azobenzene modified with at least one of halogen, methyl, and nitro functional groups; benzo[c]cinnoline; and benzo[c]cinnoline modified with at least one of halogen, methyl, and nitro functional groups. The organic negative electrode material provided by the present invention can operate stably under various alkaline conditions and is compatible with nickel hydroxide positive electrodes and air positive electrodes. The material has excellent rate performance and long-term cycle stability, and its wide source makes it suitable for large-scale application.

Description

Technical Field

[0001] The present invention relates to the technical field of battery materials and energy storage, and in particular to a neutral aqueous all-quinone liquid flow battery. Background Art

[0002] Aqueous batteries are a suitable choice for large-scale electrochemical energy storage due to their inherently safe, pollution-free, and low-cost electrolytes. Alkaline batteries, in particular, have garnered widespread attention. However, common alkaline battery anode materials (iron, cadmium, zinc, and hydrogen storage alloys) often present safety risks due to hydrogen evolution and dendrite growth, environmental risks posed by high toxicity, and short cycle life due to poor cycling. Therefore, the development of novel aqueous alkaline battery anode materials is crucial.

[0003] In recent years, the application of organic electrode materials in large-scale energy storage has attracted widespread attention. As electrode materials, they are not only environmentally friendly but also widely available and low-cost. Furthermore, the structural diversity of organic materials allows for a high degree of molecular designability, enabling adjustable electrochemical performance. However, many organic electrode materials suffer from severe dissolution issues in alkaline electrolytes during charge and discharge. In recent years, significant efforts have been made to incorporate electrochemically redox-active polymers into aqueous alkaline batteries. The Marcilla group (R. Grieco, A. Molina, JS Sanchez, N. Patil, M. Liras, R. Marcilla, A significantly improved polymer||Ni(OH)2alkaline rechargeable battery using anthraquinone-based conjugated microporous polymer anode. Materials Today Energy 2022, 27, 101014.) used anthraquinone as a small molecule active unit to polymerize, successfully suppressing the dissolution of the organic electrode material and achieving a discharge capacity of 150 mAh / g.

[0004] Polymerizing redox-active small molecules can effectively address the dissolution problem of electrode materials, but the introduction of inactive units reduces the material's specific capacity. However, the current selection of insoluble small-molecule organic anodes for alkaline batteries is very limited. Therefore, the development of small-molecule organic anode materials for aqueous alkaline batteries is needed. Summary of the Invention

[0005] To address the shortcomings of existing technologies or the need for improvement, the present invention provides a diazenium-based organic electrode material and its application in aqueous alkaline batteries. This material is widely available, environmentally friendly, and exhibits excellent electrochemical performance when applied to aqueous alkaline batteries.

[0006] Specifically, the present invention is achieved through the following technical solutions:

[0007] The first aspect of the present invention provides a diazine organic electrode material for aqueous alkaline batteries, which is characterized by having a redox active center with a nitrogen-nitrogen double bond, including but not limited to azobenzene; azobenzene modified with at least one of halogen, methyl, and nitro functional groups; benzo[c]cinnoline; and benzo[c]cinnoline modified with at least one of halogen, methyl, and nitro functional groups.

[0008] A second aspect of the present invention provides an aqueous alkaline battery. It is characterized by comprising the aforementioned diazenium-based organic negative electrode material, and is a button cell or a multi-layer soft-pack battery. The battery form is not limited and can be cylindrical, square, or soft-pack.

[0009] Preferably, the cathode material is a porous air cathode or nickel hydroxide cathode loaded with ruthenium dioxide and platinum-carbon catalyst. The current collector is carbon felt or carbon paper; the binder is Nafion; and the conductive additive is one or a mixture of Ketjen black, carbon nanotubes, or graphene in any proportion.

[0010] Preferably, the electrolyte is an aqueous solution of one or more of potassium hydroxide, sodium hydroxide or lithium hydroxide in any proportion.

[0011] Preferably, the electrolyte concentration is 1 mol / L-10 mol / L.

[0012] The present invention has the following beneficial effects through one or more embodiments:

[0013] The present invention uses diazene organic electrode materials as the negative electrode of the aqueous alkaline battery. The redox active center of this type of material is a nitrogen-nitrogen double bond (N=N), which has low production cost, is simple and easy to obtain, and is convenient for scaled-up production.

[0014] The organic electrode material provided by the present invention can achieve stable operation in an alkaline environment without special treatment through molecular design, without dissolution of the electrode material, and can provide a high cycle specific capacity and good cycle stability and rate performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments.

[0016] Figure 1is the charge and discharge curve of the battery in Example 1 of the present invention;

[0017] Figure 2A is the charge and discharge curve of the battery in Example 2 of the present invention, Figure 2B is its cycle performance diagram;

[0018] Figure 3 is a cycle performance diagram of the battery in Example 3 of the present invention;

[0019] Figure 4 1 is the charge and discharge curve of the first two cycles of the battery in Example 4 of the present invention;

[0020] Figure 5A is the charge and discharge curve of the first two cycles of the battery in Example 5 of the present invention, Figure 5B is its cycle performance diagram;

[0021] Figure 6 This is the charge and discharge curve of the battery in Example 6 of the present invention. DETAILED DESCRIPTION

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] Unless otherwise specified, the technical means used in the embodiments of the present invention are conventional means well known to those skilled in the art.

[0024] Example 1

[0025] This embodiment provides a button-type battery. Specifically, azobenzene as the negative electrode active material, Ketjen black as the conductive additive, and PTFE as the binder were uniformly mixed in a mass ratio of 5:4:1 and rolled onto a titanium mesh current collector to produce the negative electrode. Glass fiber as the separator, a 6 mol / L potassium hydroxide aqueous solution as the electrolyte, nickel hydroxide as the positive electrode active material, SP as the conductive additive, and PVDF as the binder were uniformly mixed in a mass ratio of 8:1:1 and loaded onto a nickel foam current collector to produce the positive electrode. The battery was then assembled into a CR2032 button-type battery under atmospheric conditions. Figure 1 As shown, the battery exhibits minimal polarization, can provide a specific capacity of 286.6 mAh / g and has a stable discharge platform.

[0026] Example 2

[0027] This embodiment provides a button-type battery. Specifically, azobenzene as the negative electrode active material, Ketjen black as the conductive additive, and PTFE as the binder are uniformly mixed in a mass ratio of 8:1:1 and rolled onto a titanium mesh current collector to produce the negative electrode. Glass fiber as the separator, a 6 mol / L potassium hydroxide aqueous solution as the electrolyte, nickel hydroxide as the positive electrode active material, CNTs as the conductive additive, and PVDF as the binder are uniformly mixed in a mass ratio of 8:1:1 and loaded onto a carbon paper current collector to produce the positive electrode. The battery is then assembled into a CR2032 button-type battery in an atmospheric environment. Figure 2A As shown, the battery exhibits small polarization and can still provide a specific capacity of 238.2 mAh / g even at a high current density. Figure 2B As shown, the battery exhibits good rate performance.

[0028] Example 3

[0029] This embodiment provides a button-type battery. Specifically, 3,3-dimethylazobenzene is used as the negative electrode active material, Ketjen black is used as the conductive additive, and PTFE is used as the binder. The mixture is uniformly mixed at a mass ratio of 5:4:1 and then rolled onto a titanium mesh current collector to produce the negative electrode. Glass fiber is used as the separator, a 6 mol / L potassium hydroxide aqueous solution is used as the electrolyte, activated carbon is used as the positive electrode material, SP is used as the conductive additive, and PTFE is used as the binder. The mixture is uniformly mixed at a mass ratio of 8:1:1 and then loaded onto a titanium mesh current collector to produce the positive electrode. The battery is then assembled into a CR2032 button-type battery in an atmospheric environment. Figure 3 The battery exhibits good cycle performance.

[0030] Example 4

[0031] This embodiment provides a button-type battery. Specifically, benzo[c]cinnoline as the negative electrode active material, Ketjen black as the conductive additive, and PTFE as the binder were uniformly mixed in a mass ratio of 5:4:1 and then roll-pressed onto a titanium mesh current collector to produce the negative electrode. Glass fiber as the separator, a 10 mol / L potassium hydroxide aqueous solution as the electrolyte, nickel hydroxide as the positive electrode active material, SP as the conductive additive, and PTFE as the binder were uniformly mixed in a mass ratio of 8:1:1 and loaded onto a nickel foam current collector to produce the positive electrode. The battery was then assembled into a CR2032 button-type battery under atmospheric conditions. Figure 4 As shown, the battery exhibits smaller polarization, higher operating voltage and stable discharge platform.

[0032] Example 5

[0033] This embodiment provides a button-type battery. Specifically, benzo[c]cinnoline as the negative electrode active material, Ketjen black as the conductive additive, and PTFE as the binder are uniformly mixed in a mass ratio of 5:4:1 and then rolled onto a titanium mesh current collector to produce the negative electrode. Glass fiber as the separator, a 10 mol / L potassium hydroxide aqueous solution as the electrolyte, activated carbon as the positive electrode active material, SP as the conductive additive, and PTFE as the binder are uniformly mixed in a mass ratio of 7:2:1 and loaded onto a titanium mesh current collector to produce the positive electrode. The battery is then assembled into a CR2032 button-type battery under atmospheric conditions. Figure 5A and Figure 5B As shown, the battery exhibits small polarization and good cycling stability.

[0034] Example 6

[0035] This embodiment provides a molded air-positive battery. Specifically, azobenzene is used as the negative electrode active material, Ketjen black is used as the conductive additive, and PTFE is used as the binder. A uniform mixture of materials at a mass ratio of 8:1:1 is then rolled onto a titanium mesh current collector to produce the negative electrode sheet. Glass fiber is used as the separator, a 6 mol / L potassium hydroxide aqueous solution is used as the electrolyte, a 1:1 mixture of ruthenium dioxide and platinum-carbon (by mass) is used as the positive electrode catalyst, Ketjen black is used as the conductive additive, and Nafion is used as the binder. A uniform mixture of materials at a mass ratio of 5:4:1 is then loaded onto a carbon paper current collector to produce the positive electrode sheet. The molded air battery is then assembled in an atmospheric environment. Figure 6 As shown in Figure 3, its discharge platform is smooth and has a specific capacity of 276.1 mAh / g.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention. To further facilitate understanding of the present invention, the present invention is described below with reference to the following embodiments, but is not intended to limit the scope of the present invention.

Claims

1. A diazine-based organic negative electrode material for aqueous alkaline batteries, characterized by: The nitrogen-nitrogen double bond is an electrochemical redox active unit; it includes azobenzene modified with at least one of halogen, methyl, and nitro functional groups, benzo[c]cinnoline, or benzo[c]cinnoline modified with at least one of halogen, methyl, and nitro functional groups.

2. A use of the diazene organic negative electrode material for aqueous alkaline batteries according to claim 1, characterized in that: Used to prepare aqueous alkaline batteries.

3. The use according to claim 2, characterized in that: The material described in claim 1 is used as the negative electrode active material; the conductive agent is one or a mixture of two or more of conductive graphite, conductive carbon black, carbon nanotubes, graphene and Ketjen black; the binder is one or a mixture of two or more of polytetrafluoroethylene, polyvinylidene fluoride and sodium methyl cellulose; the mass ratio of the negative electrode active material, the conductive agent and the binder is 30-90:10-70:10-40; the current collector is nickel foam, stainless steel mesh, carbon paper or titanium mesh; the diaphragm is glass fiber, PP / PE non-woven fabric or cellulose non-woven fabric; the electrolyte is an aqueous solution of one or more of potassium hydroxide, sodium hydroxide or lithium hydroxide.

4. The use according to claim 3, characterized in that: The electrolyte concentration is 1 mol / L-10 mol / L.

5. The use according to claim 2 or 3, characterized in that: The positive electrode is a porous air positive electrode loaded with ruthenium dioxide and platinum carbon catalyst; the current collector is carbon felt or carbon paper; the binder is Nafion; and the conductive additive is one or a mixture of Ketjen black, carbon nanotubes or graphene.

6. The use according to claim 2 or 3, characterized in that: The positive electrode active material is nickel hydroxide or cobalt-doped nickel hydroxide; the current collector is foamed nickel; the binder is PTFE; and the conductive additive is one or a mixture of Ketjen black, carbon nanotubes or graphene.

7. The use according to claim 2, characterized in that: The battery is a button cell or a multi-layer soft pack cell.

Images