Preparation method of negative electrode coating material of aqueous zinc ion battery and application thereof

Abstract

The application belongs to the technical field of negative electrode materials of aqueous zinc ion batteries, and discloses a preparation method of a negative electrode coating material of an aqueous zinc ion battery and application thereof. The application uses graphite phase carbon nitride as a matrix material, loads enzymatic hydrolysis lignin in the graphite phase carbon nitride to synthesize enzymatic hydrolysis lignin graphite phase carbon nitride composite material, the synthesized material not only has strong mechanical properties and chemical stability, but also can effectively inhibit the corrosion of electrolyte to the surface of zinc negative electrode. The enzymatic hydrolysis lignin is loaded on the graphite phase carbon nitride to prepare the required zinc negative electrode coating material. The coating material serves as a protective layer of the negative electrode material of the aqueous zinc ion battery, can solve the problems of the zinc ion battery negative electrode in the charging and discharging process, inhibit hydrogen evolution, corrosion, side reaction and dendrite of the zinc negative electrode, and effectively improve the stability and charging and discharging cycle efficiency of the aqueous zinc ion battery.

Description

Technical Field

[0001] This invention belongs to the technical field of aqueous zinc-ion battery anode materials. Specifically, it relates to a method for preparing an anode coating material for aqueous zinc-ion batteries and its application. Specifically, a composite material of graphitic carbon nitride loaded with enzymatically hydrolyzed lignin is used as the anode coating material for aqueous zinc-ion batteries, and this method is applied to the preparation of anode materials for aqueous zinc-ion batteries. Background Technology

[0002] The rapid development of wearable electronics and electric vehicles has spurred a growing demand for exploring emerging energy storage systems. However, lithium-ion batteries have limited energy density and organic electrolytes pose potential safety concerns, while aqueous multivalent ion batteries show great promise due to their high energy supply through multiple electron transfers and the use of aqueous electrolytes. Among major metals, Zn has the theoretical specific capacity (5855 mAh cm⁻¹). -3 It exceeded the theoretical specific capacity of lithium metal (2061 mAh cm⁻¹). -3 Furthermore, Zn possesses a high redox potential (-0.76V relative to a standard hydrogen electrode), enabling it to operate in aqueous electrolytes, and its higher ionic conductivity compared to organic electrolytes will ultimately lead to significant rate performance. Other advantages of Zn include its non-flammability, low cost, and high safety, all of which are particularly beneficial for practical wearable technologies. Despite significant progress to date in the exploration of zinc storage materials and devices, several issues hinder the commercialization of aqueous zinc-ion batteries, primarily dendrite growth, hydrogen evolution, surface corrosion, and byproduct formation at the negative electrode.

[0003] Currently, most research focuses on the application of lignin sulfonates in various fields; for example, sodium lignin sulfonate is used as an electrolyte additive. Enzymatically hydrolyzed lignin may be slightly soluble in the electrolyte and cannot be directly applied as a coating to zinc foil surfaces. Previous studies have used graphitic carbon nitride as a direct modification of the zinc anode coating in aqueous zinc-ion batteries; however, graphitic carbon nitride cannot effectively inhibit electrolyte corrosion of the zinc anode surface, resulting in poor battery cycle performance. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies and address issues such as dendrite growth, hydrogen evolution, and corrosion in zinc anodes, this invention provides a method for preparing an anode coating material for aqueous zinc-ion batteries and its application. The desired zinc anode coating material is prepared by enzymatically hydrolyzing lignin and loading it onto graphitic carbon nitride. As a protective layer for the anode material in aqueous zinc-ion batteries, the coating material can solve problems arising during the charge-discharge process of zinc-ion battery anodes, inhibiting hydrogen evolution, corrosion, side reactions, and dendrite formation, thereby effectively improving the stability and charge-discharge cycle efficiency of aqueous zinc-ion batteries.

[0005] The above-mentioned objective of this invention is achieved through the following technical solution:

[0006] A method for preparing a negative electrode coating material for an aqueous zinc-ion battery includes the following steps:

[0007] (1) A light yellow solid powder was obtained by heat treatment using urea as raw material;

[0008] (2) A pale yellow solid powder, enzymatically hydrolyzed lignin and polyvinylidene fluoride (PVDF) were ball-milled and mixed in a mass ratio, and N-methylpyrrolidone (NMP) was added dropwise and stirred until it became a coating; the negative electrode coating material was obtained.

[0009] Furthermore, in step (1), urea is placed in a crucible and heat-treated in a muffle furnace. The heat treatment conditions are: heating rate 4-5℃ / min, calcination temperature 500-600℃, and calcination time 2-3 hours.

[0010] Further, in step (2), graphite phase carbon nitride, enzymatic hydrolyzed lignin and polyvinylidene fluoride (PVDF) are mixed in a mass ratio of 1-5:1:1, ball milled at a speed of 600-650 r / min for 30-60 min, and 5-7 drops of N-methylpyrrolidone (NMP) are added.

[0011] Preferably, in step (1), urea is placed in a crucible and heat-treated in a muffle furnace. The heat treatment conditions are: heating rate 4.6℃ / min, calcination temperature 550℃, and calcination time 2 hours.

[0012] Preferably, in step (2), graphite phase carbon nitride, enzymatically hydrolyzed lignin and polyvinylidene fluoride (PVDF) are mixed in a mass ratio of 5:1:1 and ball-milled for 30 minutes.

[0013] The enzymatically hydrolyzed lignin was preferably purchased from Shandong Longli Group.

[0014] This invention also claims protection for the application of the negative electrode coating material prepared by the above preparation method in the preparation of zinc negative electrode materials, specifically: using a coating machine to coat the coating material onto zinc foil to prepare zinc negative electrode materials.

[0015] This invention uses graphitic carbon nitride as the matrix material to synthesize an enzymatically hydrolyzed lignin-graphitic carbon nitride composite material by loading enzymatically hydrolyzed lignin onto graphitic carbon nitride. The synthesized material not only has strong mechanical properties and chemical stability, but can also effectively inhibit the corrosion of the zinc anode surface by the electrolyte.

[0016] The advantages of this invention compared to the prior art are:

[0017] (1) This invention uses graphitic carbon nitride as a matrix to support enzymatically hydrolyzed lignin to synthesize an enzymatically hydrolyzed lignin-graphitic carbon nitride composite material. This synthesized material has strong mechanical properties and chemical stability, and it has abundant zinc-loving active sites, which can induce uniform deposition of zinc ions and inhibit dendrite reaction; the active groups contained in this composite material can react with H in the electrolyte. + The formation of hydrogen bonds can suppress the occurrence of side reactions and hydrogen evolution reactions at the zinc anode, thereby improving the cycle life of zinc batteries.

[0018] (2) The present invention uses the synthesized enzymatic hydrolysis lignin graphite phase carbon nitride composite material as a coating material in aqueous zinc-ion batteries, which can effectively inhibit the corrosion of zinc anode by electrolyte and improve the cycle stability of aqueous zinc-ion batteries. Attached Figure Description

[0019] Figure 1 Contact angle diagrams of MCN@Zn prepared in Example 1 (Figure b) and Bare Zn prepared in Comparative Example 1 (Figure a).

[0020] Figure 2 Impedance diagrams of symmetrical cells of MCN@Zn prepared in Example 1 and Bare Zn prepared in Comparative Example 1.

[0021] Figure 3 Cyclic charge-discharge diagrams of the half-cells of MCN@Zn prepared in Example 1 and Bare Zn prepared in Comparative Example 1.

[0022] Figure 4 Cyclic charge-discharge diagrams of the half-cells prepared for Example 1 (MCN@Zn) and Comparative Example 3 (g-C3N4@Zn).

[0023] Figure 5 Cyclic charge-discharge diagrams of the half-cells prepared in Example 1 (MCN@Zn) and Comparative Example 2 (M@Zn).

[0024] Figure 6 Comparison of coating morphology between MCN@Zn prepared in Example 1 and MCN@Zn-1 prepared in Comparative Example 4. Detailed Implementation

[0025] The present invention is described in detail below through specific embodiments, but this does not limit the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can all be obtained commercially.

[0026] Example 1

[0027] (1) Place urea in a covered crucible and heat it in a muffle furnace. The temperature is increased to 550℃ at a rate of 4.6℃ / min for 2 hours. Calcine it at 550℃ for 2 hours to obtain a light yellow solid. Grind it into powder to obtain a light yellow solid powder named g-C3N4.

[0028] (2) G-C3N4, enzymatically hydrolyzed lignin and polyvinylidene fluoride (PVDF) were ball-milled and mixed in a mass ratio of 5:1:1. 5-7 drops of N-methylpyrrolidone (NMP) were added and stirred until a coating-like consistency was achieved. The coating was then applied to zinc foil using a coating machine to prepare a zinc anode material. The prepared zinc anode material was named MCN@Zn.

[0029] Comparative Example 1

[0030] The zinc foil is left untreated and named Bare Zn.

[0031] Comparative Example 2

[0032] (1) Enzymatically hydrolyzed lignin and polyvinylidene fluoride (PVDF) were ball-milled and mixed at a mass ratio of 5:1. 5-7 drops of N-methylpyrrolidone (NMP) were added and stirred until a coating-like consistency was achieved. The coating was then applied to zinc foil using a coating machine to prepare a zinc anode material, which was named M@Zn.

[0033] Comparative Example 3

[0034] (1) Place urea in a covered crucible and heat it in a muffle furnace. The temperature is increased to 550℃ at a rate of 4.6℃ / min for 2 hours. Calcine it at 550℃ for 2 hours to obtain a light yellow solid. Grind it into powder to obtain a light yellow solid powder named g-C3N4.

[0035] (2) G-C3N4 and polyvinylidene fluoride (PVDF) were ball-milled and mixed at a mass ratio of 5:1. 5-7 drops of N-methylpyrrolidone (NMP) were added and stirred until the mixture was in the form of a coating. The coating was then applied to zinc foil using a coating machine to prepare a zinc anode material. The prepared zinc anode material was named g-C3N4@Zn.

[0036] Comparative Example 4

[0037] (1) Place urea in a covered crucible and heat it in a muffle furnace. The temperature is increased to 550℃ at a rate of 4.6℃ / min for 2 hours. Calcine it at 550℃ for 2 hours to obtain a light yellow solid. Grind it into powder to obtain a light yellow solid powder named g-C3N4.

[0038] (2) G-C3N4, enzymatically hydrolyzed lignin and polyvinylidene fluoride (PVDF) were ball-milled and mixed in a mass ratio of 1:1:1. 5-7 drops of N-methylpyrrolidone (NMP) were added and stirred until a coating-like consistency was achieved. The coating was then applied to zinc foil using a coating machine to prepare a zinc anode material. The prepared zinc anode material was named MCN@Zn-1.

[0039] Application Example 1

[0040] Using the MCN@Zn prepared in Example 1 as the negative electrode and copper foil as the positive electrode, the two were assembled into a half-cell. The electrolyte was a 2 mol / L zinc sulfate solution, and charge-discharge cycle tests were conducted.

[0041] Test method: at a current density of 5 mA·cm -2 Capacity up to 1mAh·cm -2 Half-cell tests were conducted under the experimental conditions.

[0042] Test results:

[0043] like Figure 1 The MCN@Zn prepared in Example 1 has a larger contact angle than the Bare Zn prepared in Comparative Example 1. This material is hydrophobic and can effectively isolate the surface of the zinc anode from corrosion by the aqueous electrolyte.

[0044] like Figure 2 The impedance of the MCN@Zn prepared in Example 1 is lower than that of the Bare Zn prepared in Comparative Example 1.

[0045] like Figure 3 The half-cell of MCN@Zn prepared in Example 1 maintained a high CE efficiency after 430 charge-discharge cycles, while the half-cell of Bare Zn prepared in Comparative Example 1 experienced a short circuit after 46 charge-discharge cycles.

[0046] like Figure 6 (a): The MCN@Zn prepared in Example 1 has a good coating effect, uniform distribution, and smooth surface. The graphitic carbon nitride as a carrier material is conducive to the enzymatic hydrolysis of lignin to form a coating on the zinc foil surface. In addition, it has high mechanical strength and isolates the zinc anode surface from corrosion by aqueous electrolyte.

[0047] Application Comparative Example 1

[0048] Using Bare Zn prepared in Comparative Example 1 as the negative electrode and copper foil as the positive electrode, the two were assembled into a half-cell, in which a 2 mol / L zinc sulfate solution was used as the electrolyte for charge-discharge cycle testing.

[0049] Test method: at a current density of 5 mA·cm -2 Capacity up to 1mAh·cm -2Half-cell tests were conducted under the experimental conditions.

[0050] Test results:

[0051] like Figure 2 The impedance of the Bare Zn symmetric cell prepared in Comparative Example 1 reached 786.

[0052] like Figure 3 The half-cell of Bare Zn prepared in Comparative Example 1 short-circuited after 46 charge-discharge cycles.

[0053] Application Comparative Example 2

[0054] Using M@Zn prepared in Comparative Example 2 as the negative electrode and copper foil as the positive electrode, the two were assembled into a half-cell. The electrolyte was a 2 mol / L zinc sulfate solution, and charge-discharge cycle tests were conducted.

[0055] Test method: at a current density of 5 mA·cm -2 Capacity up to 1mAh·cm -2 Half-cell tests were conducted under the experimental conditions.

[0056] Test results:

[0057] like Figure 5 The half-cell of MCN@Zn prepared in Example 1 maintained a high CE efficiency after 430 charge-discharge cycles, while the half-cell of M@Zn prepared in Comparative Example 2 experienced a short circuit after 210 charge-discharge cycles.

[0058] Application Comparative Example 3

[0059] Using g-C3N4@Zn prepared in Comparative Example 1 as the negative electrode and copper foil as the positive electrode, the two were assembled into a half-cell. The electrolyte was a 2 mol / L zinc sulfate solution, and charge-discharge cycle tests were conducted.

[0060] Test method: at a current density of 5 mA·cm -2 Capacity up to 1mAh·cm -2 Half-cell tests were conducted under the experimental conditions.

[0061] Test results:

[0062] like Figure 4 The half-cell CE of the MCN@Zn prepared in Example 1 remained at a high efficiency after 430 charge-discharge cycles, while the half-cell of g-C3N4@Zn prepared in Comparative Example 3 experienced a short circuit after 150 charge-discharge cycles.

[0063] Application Comparative Example 4

[0064] Using MCN@Zn-1 prepared in Comparative Example 1 as the negative electrode and copper foil as the positive electrode, the two were assembled into a half-cell. The electrolyte was a 2 mol / L zinc sulfate solution, and charge-discharge cycle tests were conducted.

[0065] Test method: at a current density of 5 mA·cm -2 Capacity up to 1mAh·cm -2 Half-cell tests were conducted under the experimental conditions.

[0066] Test results:

[0067] like Figure 6 (b): The MCN@Zn-1 prepared in Comparative Example 4 could not form a coating on the zinc foil surface.

[0068] The embodiments described above are merely preferred embodiments of the present invention, and not all feasible embodiments of the present invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a negative electrode coating material for an aqueous zinc-ion battery, characterized in that, Includes the following steps: (1) A light yellow solid powder was obtained by heat treatment using urea as raw material; the light yellow solid powder was graphitic carbon nitride. (2) Graphite phase carbon nitride, enzymatic hydrolyzed lignin and polyvinylidene fluoride are ball-milled and mixed in a mass ratio, and N-methylpyrrolidone is added dropwise and stirred until it becomes a coating; the negative electrode coating material is obtained.

2. The method for preparing a negative electrode coating material for an aqueous zinc-ion battery as described in claim 1, characterized in that, In step (1), urea is placed in a crucible and heat-treated in a muffle furnace. The heat treatment conditions are: heating rate 4-5℃ / min, calcination temperature 500-600℃, and calcination time 2-3 hours.

3. The method for preparing a negative electrode coating material for an aqueous zinc-ion battery as described in claim 1, characterized in that, Step (2) Graphite phase carbon nitride, enzymatic hydrolyzed lignin and polyvinylidene fluoride are mixed in a mass ratio of 1-5:1:1, ball milled at a speed of 600-650 r / min for 30-60 min, and 5-7 drops of N-methylpyrrolidone are added.

4. The method for preparing the negative electrode coating material of an aqueous zinc-ion battery as described in claim 1, characterized in that, In step (1), urea is placed in a crucible and heat-treated in a muffle furnace. The heat treatment conditions are: heating rate 4.6℃ / min, calcination temperature 550℃, and calcination time 2 hours.

5. The method for preparing a negative electrode coating material for an aqueous zinc-ion battery as described in claim 1, characterized in that, Step (2) Graphite phase carbon nitride, enzymatic hydrolyzed lignin and polyvinylidene fluoride are mixed in a mass ratio of 5:1:1 and ball milled for 30 min.

6. The application of the negative electrode coating material prepared by the preparation method according to any one of claims 1-5 in the preparation of zinc negative electrode materials.

7. The application as described in claim 6, characterized in that, Zinc anode materials are prepared by coating materials onto zinc foil using a coating machine.

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