Composite zinc-based negative electrode, preparation method and nickel-zinc battery

Abstract

The invention discloses a composite zinc-based negative electrode, a preparation method and a nickel-zinc battery, the composite zinc-based negative electrode comprises a substrate pole piece and a functional material, the functional material is coated on the substrate pole piece, a coating layer is formed on the substrate pole piece, and the functional material comprises poly (3, 3, 4-trimethyl-1, 3-pentanediol). The preparation method comprises the following steps: preparing poly (3, 4-ethylenedioxythiophene), dodecylbenzene sulfonic acid and 3-glycidyl ether oxypropyl trimethoxy silane, enabling poly (3, 4-ethylenedioxythiophene) and dodecylbenzene sulfonic acid to form a PEDOT: DBSA (poly (3, 4-ethylenedioxythiophene)) material, and adding 3-glycidyl ether oxypropyl trimethoxy silane into the PEDOT: DBSA material to form the functional material. The functional material is combined with the substrate pole piece, so that the problem that the cycle life of the battery is reduced due to zinc dendrite growth, corrosion hydrogen evolution and surface passivation of the negative electrode of the alkaline nickel-zinc battery is effectively solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a composite zinc-based negative electrode, a preparation method and a nickel-zinc battery. BACKGROUND

[0002] The aqueous nickel-zinc battery is an alkaline secondary battery, uses nickel hydroxide as a positive active material, uses metal zinc as a negative active material, uses a potassium hydroxide solution as an electrolyte, and has a nominal voltage of 1.6 V. The energy density of the nickel-zinc battery is close to that of a lithium ion battery, the material is recyclable nickel-zinc metal, the recycling cost is lower than that of a lead-acid battery / lithium battery, compared with a nickel-cadmium battery, the nickel-zinc battery eliminates the problem of cadmium pollution, and compared with a lithium ion battery, the nickel-zinc battery has safety and cost advantages and no risk of combustion and explosion. However, the dendrite growth and hydrogen evolution side reaction generated by the zinc negative electrode during the cycle process lead to a decrease in the cycle stability of the nickel-zinc battery, which becomes a core problem restricting the commercial application thereof.

[0003] At present, the improvement of the nickel-zinc battery negative electrode in the industry mainly focuses on the following two schemes: ZnO powder modification and tab structure optimization. The ZnO powder modification refers to improving the negative electrode by coating or doping the surface of ZnO powder, so as to improve the cycle life of the battery, but this scheme needs a complex precursor treatment process. The tab structure optimization refers to using a polyvinyl alcohol coating layer to isolate the negative electrode from the electrolyte, so as to inhibit hydrogen evolution and dendrite growth, but due to the insulating property of the polyvinyl alcohol, a carbon layer needs to be coated on the tab to maintain the conductivity, leading to the complication of the negative electrode structure. As can be seen, the existing scheme for solving the problems of hydrogen evolution and dendrite growth of the nickel-zinc battery negative electrode still has defects. Based on this, the application provides a composite zinc-based negative electrode coated with a conductive polymer, a preparation method and a nickel-zinc battery. SUMMARY

[0004] To solve the above technical problems, the purpose of the application is to provide a composite zinc-based negative electrode, a preparation method and a nickel-zinc battery, which effectively solve the problems of zinc dendrite growth, corrosion hydrogen evolution and surface passivation of the alkaline nickel-zinc battery negative electrode, which lead to the cycle life attenuation of the battery, by combining a functional material with a base tab.

[0005] To achieve the above application purposes, the technical solutions adopted by the application are as follows:

[0006] In the first aspect of the present application, the present application provides a composite zinc-based negative electrode, comprising a substrate electrode sheet and a functional material, the functional material being coated on the substrate electrode sheet to form a coating layer, wherein the functional material comprises poly(3,4-ethylenedioxythiophene), dodecylbenzenesulfonic acid and 3-glycidoxypropyltrimethoxysilane, the poly(3,4-ethylenedioxythiophene) and the dodecylbenzenesulfonic acid form a PEDOT:DBSA material, and the 3-glycidoxypropyltrimethoxysilane is added to the PEDOT:DBSA material to form the functional material.

[0007] Preferably, the thickness of the coating layer is 0.02-20 μm.

[0008] Preferably, the substrate electrode sheet comprises zinc oxide, metallic zinc, a conductive agent and a binder, and the mass ratio of the zinc oxide, the metallic zinc, the conductive agent and the binder is (60-90):(5-30):(3-15):(2-10).

[0009] More preferably, the thickness of the substrate electrode sheet is 180-200 μm.

[0010] In the second aspect of the present application, the present application provides a preparation method of the composite zinc-based negative electrode, as follows:

[0011] Preparation of the functional material: Triton X-100 and 3,4-ethylenedioxythiophene (EDOT) are added to a sodium dodecylbenzenesulfonate aqueous solution, stirred uniformly to form an emulsion, then a salt solution is added dropwise to the emulsion, the salt solution being a solution containing persulfate and ferric salt, the emulsion is broken and centrifuged after reaction for 48 h and dried to obtain a PEDOT:DBSA powder, the PEDOT:DBSA powder is dispersed in an ethanol aqueous solution, and 3-glycidoxypropyltrimethoxysilane is added to prepare a dispersion of the functional material;

[0012] Coating: the dispersion containing the PEDOT:DBSA powder and the GOPS crosslinking agent is drop-coated on the substrate electrode sheet, vacuum dried at 40℃, the solvent of the dispersion is dried, then transferred to 80℃ for further drying and solidification for 2 h to form the composite zinc-based negative electrode containing the coating layer.

[0013] Preferably, the PEDOT:DBSA powder is dispersed in ultrapure water containing 20% anhydrous ethanol by mass fraction to prepare a dispersion of 1% by mass fraction, and the GOPS accounts for 0.05-2 vol.% of the dispersion.

[0014] Preferably, the concentration of the sodium dodecylbenzenesulfonate aqueous solution is 0.125 mol / L, and the molar ratio of SDBS to EDOT is 1:2.

[0015] Preferably, in the salt solution, the persulfate salt comprises Na2S2O8, the molar ratio of the persulfate salt to EDOT is 1:1, the trivalent iron salt comprises FeCl3·6H2O, and the mass of the trivalent iron salt in the salt solution accounts for 1wt.% of the mass of the persulfate salt.

[0016] Preferably, the preparation method further comprises the preparation of the base electrode sheet:

[0017] The zinc oxide, the metal zinc, the conductive agent, and the binder are uniformly mixed, then coated on the current collector and roll-formed, the thickness of the base electrode sheet is controlled in the rolling process, and the base electrode sheet is dried in a vacuum drying oven at 60-100℃ to form the porous zinc-based negative electrode.

[0018] In the third aspect of the present application, the present application further provides an application of the composite zinc-based negative electrode, and the composite zinc-based negative electrode is used in an alkaline nickel-zinc battery.

[0019] Beneficial effects:

[0020] The present application only adds a functional material dispersion liquid coating process to the production process of the existing nickel-zinc battery negative electrode, does not need to greatly improve the negative electrode production process, avoids the secondary conductive coating treatment of the conventional zinc oxide powder, and simplifies the production process. The coating layer formed by the functional material on the base electrode sheet is chemically cross-linked and interfacially bonded, which greatly reduces the swelling rate of the coating layer and improves the interfacial bonding strength between the coating layer and the base electrode sheet. Through the combination of the functional material and the base electrode sheet, the present application effectively solves the problems of zinc dendrite growth, corrosion and hydrogen evolution, and surface passivation of the alkaline nickel-zinc battery negative electrode, which leads to the attenuation of the cycle life of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Shown is a 1C cycle comparison chart of the comparative examples 1, 3, and 4 of the present application;

[0022] Figure 2 Shown is a 1C cycle comparison chart of the example 2 and the comparative examples 1 and 2 of the present application;

[0023] Figure 3 Shown is a 1C cycle comparison chart of the examples 1-3 and the comparative example 1 of the present application;

[0024] Figure 4 Shown is an SEM photo of the prepared electrode sheet in the comparative example 1 of the present application.

[0025] Figure 5 Shown is an SEM photo of the example 3 of the present application before cycling.

[0026] Figure 6Shown are Fourier transform infrared spectrograms of PEDOT:DBSA, GOPS, (PEDOT:DBSA) / GOPS and Example 2 (ZnO@(PEDOT:DBSA) / GOPS) in the present application.

[0027] Figure 7 Shown are SEM photos of Comparative Example 1 after 100 cycles in the present application.

[0028] Figure 8 Shown are SEM photos of Example 3 after 100 cycles in the present application.

[0029] Figure 9 Shown is a comparison chart of the swelling rates of PEDOT:PSS, PEDOT:DBSA and (PEDOT:DBSA) / GOPS.

[0030] Figure 10 Shown is a chart of experimental results of PEDOT:PSS, PEDOT:DBSA and (PEDOT:DBSA) / GOPS film layers after one-week immersion.

[0031] Figure 11 Shown are photos of the separators of Comparative Example 1, Comparative Example 2 and Example 2 after cycle failure in the present application. DETAILED DESCRIPTION

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, specific implementation manners of the present application will be described below with reference to the drawings. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor, and other embodiments can also be obtained.

[0033] The present application provides a composite zinc-based negative electrode, which comprises (1) a substrate electrode sheet and (2) a functionalized material, the functionalized material being coated on the substrate electrode sheet to form a coating layer on the substrate electrode sheet, the coating layer having high conductivity and establishing a three-dimensional electron transmission channel while blocking the corrosion of the substrate electrode sheet by electrolyte.

[0034] (1) The substrate electrode sheet is a conventional zinc-based negative electrode, for example, the substrate electrode sheet can be a porous zinc-based negative electrode, which comprises zinc oxide, metallic zinc, a conductive agent and a binder, wherein the mass ratio of zinc oxide, metallic zinc, the conductive agent and the binder is (60-90):(5-30):(3-15):(2-10). Preferably, the thickness of the substrate electrode sheet is 180-200 μm.

[0035] The preparation of the base electrode sheet is as follows: zinc oxide, metallic zinc, a conductive agent and a binder are mixed uniformly, then coated on a current collector and roll-formed, the thickness of the base electrode sheet is controlled during the roll-forming, and the base electrode sheet is dried in a vacuum drying oven at 60-100°C, such as 80°C, for 6 hours, to form a porous zinc-based negative electrode.

[0036] Preferably, the conductive agent comprises one or more of carbon black, graphene and carbon nanotubes.

[0037] Preferably, the binder comprises one or more of polytetrafluoroethylene, carboxymethyl cellulose and styrene butadiene rubber.

[0038] (2) a functionalized material comprising poly(3,4-ethylenedioxythiophene) (PEDOT), dodecylbenzenesulfonic acid (DBSA) and 3-glycidoxypropyltrimethoxysilane (GOP S), wherein the poly(3,4-ethylenedioxythiophene) and the dodecylbenzenesulfonic acid form a PEDOT:DBSA material, and the 3-glycidoxypropyltrimethoxysilane is added to the PEDOT:DBSA material to form the functionalized material. The functionalized material is coated on the base electrode sheet to form a coating layer. Preferably, the thickness of the coating layer is 0.02-20 μm.

[0039] In the present application, the contents of the poly(3,4-ethylenedioxythiophene) (PEDOT), the dodecylbenzenesulfonic acid (DBSA) and the 3-glycidoxypropyltrimethoxysilane (GOP S) in the functionalized material are determined according to the raw materials in the preparation process thereof.

[0040] The preparation of the functionalized material is as follows: Triton X-100 (i.e. polyoxyethylene octylphenyl ether) and 3,4-ethylenedioxythiophene (EDOT) are added to an aqueous solution of sodium dodecylbenzenesulfonate (SDBS), wherein the mass ratio of Triton X-100 to solvent water in the aqueous solution of sodium dodecylbenzenesulfonate is 1:400, the mixture is stirred uniformly to form an emulsion, then a salt solution, i.e. a solution containing persulfate and ferric salt, is added dropwise to the emulsion, the emulsion is allowed to react for 48 hours, then broken and centrifuged and dried, to obtain a PEDOT:DBSA powder, the PEDOT:DBSA powder is dispersed in an aqueous ethanol solution, and 3-glycidoxypropyltrimethoxysilane is added, to prepare a dispersion of the functionalized material.

[0041] Preferably, the PEDOT:DBSA powder is dispersed in an ultrapure water containing 20% by mass of anhydrous ethanol, i.e. an aqueous ethanol solution, to prepare a dispersion of the PEDOT:DBSA powder having a mass fraction of 1%, and the GOPS is added, the GOPS accounting for 0.05-2 vol.% of the dispersion. The GOPS is in a liquid state, and is added to the dispersion in a volume fraction of 0.05-2 vol.%.

[0042] The concentration of the sodium dodecyl benzene sulfonate aqueous solution is 0.125 mol / L, and the molar ratio of SDBS to EDOT is 1:2.

[0043] In the salt solution, the persulfate is preferably Na2S2O8, the molar ratio of the persulfate to EDOT is 1:1, the trivalent iron salt is preferably FeCl3·6H2O, and the mass of the trivalent iron salt accounts for 1 wt.% of the mass of the persulfate in the salt solution.

[0044] In the preparation of the functionalized material, the solvent content in the reaction system formed after the salt solution is added dropwise to the emulsion is relatively small, and 48 h after the reaction, the volume of solvent, i.e., water, is three times the volume of the solvent in the reaction system, and demulsification is performed.

[0045] In the present application, the content of poly(3,4-ethylenedioxythiophene), dodecyl benzene sulfonic acid and 3-glycidyloxypropyl trimethoxysilane in the functionalized material is determined based on the amount of EDOT during preparation.

[0046] The preparation method of the composite zinc-based negative electrode of the present application comprises the preparation of the above-mentioned base electrode sheet and the preparation of the functionalized material, and further comprises coating, as follows:

[0047] The dispersion liquid containing the PEDOT:DBSA powder and the GOPS crosslinking agent is drop-coated on the base electrode sheet, vacuum dried at 40℃, the solvent of the dispersion liquid is dried, and then transferred to 60-100℃, such as 80℃, for further drying and solidification for 2 h to form the composite zinc-based negative electrode containing the coating layer.

[0048] In conventional nickel-zinc batteries, the negative electrode active material is metallic zinc, which is oxidized to zinc hydroxide during discharge and eventually converted to zinc oxide. During charging, the zinc oxide is converted to zinc. Generally, the negative electrode can be in the form of metallic zinc or zinc oxide, and zinc oxide is added to improve the stability of the electrode. However, during the charge and discharge process, the uneven deposition of zinc ions is prone to form dendrites, which can cause a short circuit if the diaphragm is pierced. In addition, the spontaneous reaction of zinc in alkaline electrolyte: Zn+H2O→ZnO+H2 causes capacity loss and hydrogen evolution. The present invention uses PEDOT and DBSA to construct a continuous coating layer of a highly conductive polymer. The PEDOT:DBSA system composed of PEDOT and DBSA is stable in aqueous solution and will not dissolve in potassium hydroxide electrolyte. The coating layer formed based on PEDOT:DBSA has a good electrolyte barrier effect. On this basis, the coating layer establishes a three-dimensional electron transmission channel, which makes the coating layer have high conductivity and does not affect the performance of the negative electrode. The GOPS crosslinker covalently bonds with the sulfonate groups in PEDOT:DBSA to form a stable three-dimensional cross-linked network structure, reducing the penetration of water molecules into the coating layer and improving the stability of the coating layer. In addition, the silanol groups generated by the hydrolysis of GOPS interact with the zinc oxide of the base negative electrode, thereby improving the bonding strength between the coating layer and the base negative electrode.

[0049] This invention adds a single step, coating the cathode with a functionalized material dispersion, to the existing nickel-zinc battery negative electrode production process. This eliminates the need for significant negative electrode production process modifications, avoids the conventional secondary conductive coating of zinc oxide powder, and simplifies the production process. The functionalized material forms a coating on the substrate electrode through the dual effects of chemical crosslinking and interfacial bonding, significantly reducing the coating's swelling rate while simultaneously improving the interfacial bonding strength between the coating and the substrate electrode.

[0050] The conductive polymer network of the coating layer of the present invention forms a multi-level protection mechanism: the three-dimensional conductive skeleton uniformizes the electric field distribution on the electrode surface through the electrostatic shielding effect, blocking the preferred orientation growth path of the dendrite; the coating layer blocks the direct contact between the electrolyte and the base electrode, inhibits hydrogen evolution and corrosion reaction, and limits the Zn(OH)4 2- The diffusion of Zn(OH)4 2- Decomposition produces ZnO deposition, which passivates the electrodes and blocks the pores of the diaphragm.

[0051] The technical solution of the present invention is described in detail below with reference to specific embodiments.

[0052] In the examples and comparative examples of the present invention, if no specific conditions are specified, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. All raw materials and reagents used without specifying the manufacturer were commercially available conventional products.

[0053] Example 1

[0054] Zinc oxide, zinc metal powder, conductive carbon (C45) and PTFE emulsion (emulsion containing polytetrafluoroethylene macromolecular chemical material, solid content 60%) with a mass ratio of 75:10:10:5 were mixed into a paste with a volume fraction of 95% ethanol solution, uniformly rolled on the surface of a brass mesh current collector to make a P-ZnO base electrode sheet.

[0055] A 1 wt.% PEDOT:DBSA dispersion was prepared, 0.05 vol.% of GOPS was added, and ultrasonic dispersion was performed for 10 min to obtain a dispersion of functionalized material. 20 μL of the dispersion was drop-coated on the P-ZnO electrode sheet, vacuum dried at 40°C, and then cured at 80°C for 2 h to prepare a composite zinc-based negative electrode (ZnO@(PEDOT:DBSA) / 0.05% GOPS).

[0056] Example 2

[0057] Zinc oxide, zinc metal powder, conductive carbon (C45) and PTFE emulsion (emulsion containing polytetrafluoroethylene macromolecular chemical material, solid content 60%) with a mass ratio of 75:10:10:5 were mixed into a paste with a volume fraction of 95% ethanol solution, uniformly rolled on the surface of a brass mesh current collector to make a P-ZnO base electrode sheet.

[0058] A 1 wt.% PEDOT:DBSA dispersion was prepared, 0.5 vol.% of GOPS was added, and ultrasonic dispersion was performed for 10 min to obtain a dispersion of functionalized material. 20 μL of the dispersion was drop-coated on the P-ZnO electrode sheet, vacuum dried at 40°C, and then cured at 80°C for 2 h to prepare a composite zinc-based negative electrode (ZnO@(PEDOT:DBSA) / GOPS).

[0059] Example 3

[0060] Zinc oxide, zinc metal powder, conductive carbon (C45) and PTFE emulsion (emulsion containing polytetrafluoroethylene macromolecular chemical material, solid content 60%) with a mass ratio of 75:10:10:5 were mixed into a paste with a volume fraction of 95% ethanol solution, uniformly rolled on the surface of a brass mesh current collector to make a P-ZnO base electrode sheet.

[0061] A 1 wt.% PEDOT:DBSA dispersion was prepared, 2 vol.% of GOPS was added, and ultrasonic dispersion was performed for 10 min to obtain a dispersion of functionalized material. 20 μL of the dispersion was drop-coated on the P-ZnO electrode sheet, vacuum dried at 40°C, and then cured at 80°C for 2 h to prepare a composite zinc-based negative electrode (ZnO@(PEDOT:DBSA) / 2% GOPS).

[0062] Comparative Example 1

[0063] The comparative example does not add a functional material.

[0064] Zinc oxide, zinc powder, conductive carbon (C45) and PTFE emulsion (emulsion containing polytetrafluoroethylene polymer chemical material, solid content 60%) with a mass ratio of 75:10:10:5 are mixed into a paste with an ethanol solution with a volume fraction of 95%, and uniformly rolled on the surface of a brass mesh current collector to prepare a P-ZnO base electrode sheet.

[0065] Comparative Example 2

[0066] The comparative example replaces DBSA with PSS (polystyrene sulfonic acid) compared with Example 2, and PEDOT:PSS is commercially available PEDOT:PSS OE-000, same below.

[0067] Zinc oxide, zinc powder, conductive carbon (C45) and PTFE emulsion (emulsion containing polytetrafluoroethylene polymer chemical material, solid content 60%) with a mass ratio of 75:10:10:5 are mixed into a paste with an ethanol solution with a volume fraction of 95%, and uniformly rolled on the surface of a brass mesh current collector to prepare a P-ZnO base electrode sheet.

[0068] A 1wt.% PEDOT:PSS dispersion is prepared, 0.5vol.% of GOPS is added, ultrasonic dispersion is performed for 10 min, 20μL of the dispersion is drop-coated on the P-ZnO electrode sheet, vacuum drying is performed at 40°C, and solidification is performed at 80°C for 2h to prepare a composite zinc-based negative electrode (ZnO@(PEDOT:PSS) / GOPS).

[0069] Comparative Example 3

[0070] The comparative example does not add GOPS compared with Comparative Example 2.

[0071] Zinc oxide, zinc powder, conductive carbon (C45) and PTFE emulsion (emulsion containing polytetrafluoroethylene polymer chemical material, solid content 60%) with a mass ratio of 75:10:10:5 are mixed into a paste with an ethanol solution with a volume fraction of 95%, and uniformly rolled on the surface of a brass mesh current collector to prepare a P-ZnO base electrode sheet.

[0072] A 1wt.% PEDOT:PSS dispersion is prepared, 20μL of the dispersion is drop-coated on the P-ZnO electrode sheet, vacuum drying is performed at 40°C, and solidification is performed at 80°C for 2h to prepare a composite zinc-based negative electrode (ZnO@(PEDOT:PSS)).

[0073] Comparative Example 4

[0074] The comparative example does not add GOPS compared with Examples 1-3.

[0075] A paste was prepared by mixing zinc oxide, zinc metal powder, conductive carbon (C45) and PTFE emulsion (emulsion containing polytetrafluoroethylene macromolecular chemical material, solid content 60%) with a mass ratio of 75:10:10:5 and an ethanol solution with a volume fraction of 95%, and then uniformly rolling the paste on the surface of a brass mesh current collector to form a P-ZnO base electrode sheet.

[0076] A 1 wt.% PEDOT:DBSA dispersion was prepared, 20 μL of the dispersion was drop-coated on the P-ZnO electrode sheet, and after vacuum drying at 40°C and solidification at 80°C for 2 h, a composite zinc-based negative electrode (ZnO@(PEDOT:DBSA)) was prepared.

[0077] The negative electrodes of Examples 1-3 and Comparative Examples 1-4 were assembled into nickel-zinc batteries with Ni(OH)2 positive electrodes, cellulose / glass cellulose composite separators, and a ZnO electrolyte saturated with 7M KOH, and the 1C rate long cycle performance was tested, as shown in Figures 1-3 .

[0078] The SEM images of the electrode sheets prepared in Example 2 and Comparative Example 1 before cycling are shown in Figures 4-5 , and the SEM images after 100 cycles are shown in Figures 7-8 .

[0079] The results show that the cycle life of the ZnO@(PEDOT:PSS) electrode (176 cycles) is improved compared to P-ZnO (102 cycles), but is still significantly lower than that of ZnO@(PEDOT:DBSA) (241 cycles) Figure 1 .

[0080] In combination with Figure 9 , 10 , it is shown that the improvement in film stability indeed helps to improve the cycle stability of the battery. The ZnO@(PEDOT:DBSA) / GOPS of Example 2 exhibits the longest cycle life. This is because the GOPS, through the dual action of chemical cross-linking and interfacial bonding, greatly reduces the swelling rate of the coating layer while improving the interfacial bonding strength, enhancing the mechanical strength and chemical stability of the coating layer Figure 6 , 9 , 10). The conductive network and zincophilic groups (-SO3 - and -S-) in the coating promote the efficient transport of electrons and ions, while inducing preferential adsorption of Zn(OH)4 2- , reconfiguring the double electric layer, reducing the desolvation energy of Zn(OH)4 2- , reducing the occurrence of side reactions, and accelerating the interfacial reaction kinetics. In addition, the uniformization of current density by the conductive polymer network and the electrostatic shielding effect effectively inhibit the growth of dendrites Figure 7 , 8 . The coating layer limits the migration of Zn(OH)42- The diffusion of Zn(OH)4 2- decomposition to produce ZnO deposition passivation of the counter electrode and blockage of the membrane pores Figure 11 resulting in excellent electrochemical comprehensive performance of ZnO@(PEDOT:DBSA) / GOPS. 1C stable cycle for 370 cycles in full cell test.

[0081] The above detailed the embodiments provided by the present application. The principles and implementation of the present application are described by applying specific examples. The above description of the embodiments is only to help understand the core idea of the present application. It should be noted that, for those skilled in the art, without departing from the principles of the present application, the present application can be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A composite zinc-based negative electrode, characterized in that It includes a base electrode and a functionalized material, wherein the functionalized material is coated on the base electrode to form a coating layer on the base electrode, wherein the functionalized material includes poly(3,4-ethylenedioxythiophene), dodecylbenzenesulfonic acid and 3-glycidyloxypropyltrimethoxysilane, wherein poly(3,4-ethylenedioxythiophene) and dodecylbenzenesulfonic acid form a PEDOT:DBSA material, and 3-glycidyloxypropyltrimethoxysilane is added to the PEDOT:DBSA material to form a functionalized material.

2. The composite zinc-based negative electrode according to claim 1, characterized in that The base electrode includes zinc oxide, metallic zinc, a conductive agent and a binder, wherein the mass ratio of zinc oxide, metallic zinc, the conductive agent and the binder is (60-90):(5-30):(3-15):(2-10).

3. The composite zinc-based negative electrode according to claim 2, characterized in that The thickness of the coating layer is 0.02 to 20 μm.

4. The composite zinc-based negative electrode according to claim 2, characterized in that The thickness of the substrate is 180-200 μm.

5. A method for preparing a composite zinc-based negative electrode, characterized in that: The composite zinc-based negative electrode according to any one of claims 2 to 4 is prepared as follows: Preparation of the functionalized material: Triton X-100 and 3,4-ethylenedioxythiophene (EDOT) were added to an aqueous solution of sodium dodecylbenzenesulfonate and stirred to form an emulsion. A salt solution containing persulfate and trivalent iron was then added dropwise to the emulsion. After 48 hours of reaction, the emulsion was demulsified and centrifuged to dry to obtain PEDOT:DBSA powder. The PEDOT:DBSA powder was dispersed in an aqueous ethanol solution, and 3-glycidoxypropyltrimethoxysilane was added to prepare a dispersion of the functionalized material. Coating: A dispersion containing PEDOT:DBSA powder and GOPS crosslinker is dropwise applied to the substrate electrode, dried in a vacuum at 40°C to dry the solvent of the dispersion, and then transferred to 80°C for further drying and curing for 2 hours to form a composite zinc-based negative electrode containing a coating layer.

6. The preparation method according to claim 5, characterized in that PEDOT:DBSA powder was dispersed in ultrapure water containing 20% ​​anhydrous ethanol to prepare a dispersion with a mass fraction of 1%, and GOPS was added, with GOPS accounting for 0.05 to 2 vol.% of the dispersion.

7. The preparation method according to claim 5, characterized in that The concentration of the sodium dodecylbenzenesulfonate aqueous solution is 0.125 mol / L, and the molar ratio of SDBS to EDOT is 1:

2.

8. The preparation method according to claim 5, characterized in that In the salt solution, the persulfate includes Na2S2O8, the molar ratio of the persulfate to EDOT is 1:1, the ferric salt includes FeCl3·6H2O, and in the salt solution, the mass of the ferric salt accounts for 1 wt.% of the mass of the persulfate.

9. The preparation method according to any one of claims 5 to 8, characterized in that The preparation method also includes the preparation of the substrate electrode: Zinc oxide, metallic zinc, conductive agent and binder are mixed evenly, then coated on the current collector and roll-formed. The thickness of the base electrode is controlled during the rolling process, and the electrode is dried in a vacuum drying oven at 60-100°C to form a porous zinc-based negative electrode.

10. An application of a composite zinc-based negative electrode, characterized in that: The composite zinc-based negative electrode as described in claims 1 to 4 is used in an alkaline nickel-zinc battery.

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