CN112886100A

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Info

Publication number: CN112886100A
Application number: CN202110155677.2A
Authority: CN
Inventors: 吴明在; 汤坤; 胡海波
Original assignee: Anhui University
Current assignee: Anhui University
Priority date: 2021-02-04
Filing date: 2021-02-04
Publication date: 2021-06-01
Anticipated expiration: 2041-02-04
Also published as: CN112886100B

Abstract

Translated fromChinese

本发明公开一种高韧性凝胶电解质，利用霍夫梅斯特效应，将原有的弱PAA‑Fe³⁺/CS水凝胶浸泡在盐溶液中，制备了具有优异力学性能的增强韧性PAA‑Fe³⁺/CS水凝胶电解质。本发明采用氯化铵和氯化锌作为电解质中的离子导体，采用聚丙烯酸作为聚合物骨架,以过硫酸铵为引发剂，在壳聚糖和氯化铁存在下，通过一锅法自由基聚合制备了PAA‑Fe³⁺/CS水凝胶，在构建了PAA‑Fe³⁺网络后，采用了浸泡策略来诱导壳聚糖的链缠结，得到高韧性的用于锌空气电池的电解质。该电解质高的韧性,组装成电池可以避免了因弯曲应变而引起的相对位移或分离，增强了界面接触以促进电化学动力学，展现出良好工作时间和耐用性。

The invention discloses a high-toughness gel electrolyte. By utilizing the Hofmeister effect, the original weak PAA-Fe³⁺ /CS hydrogel is soaked in a salt solution to prepare an enhanced toughness PAA with excellent mechanical properties. ‑Fe³⁺ /CS hydrogel electrolyte. The present invention adopts ammonium chloride and zinc chloride as ion conductors in the electrolyte, adopts polyacrylic acid as the polymer backbone, and uses ammonium persulfate as the initiator, in the presence of chitosan and ferric chloride, free radicals are produced by a one-pot method. The PAA‑Fe³⁺ /CS hydrogel was prepared by polymerization, and after the PAA‑Fe³⁺ network was constructed, a soaking strategy was adopted to induce the chain entanglement of chitosan, resulting in a highly tough electrolyte for zinc-air batteries . The electrolyte’s high toughness, assembled into batteries, avoids relative displacement or separation due to bending strain, enhances interfacial contact to facilitate electrochemical kinetics, and exhibits good working time and durability.

Description

Preparation method of high-toughness gel electrolyte and all-solid-state zinc-air battery with firm interface

Technical Field

The invention belongs to the field of energy storage devices, and particularly relates to a high-toughness gel electrolyte and a preparation method of an all-solid-state zinc-air battery with a firm interface.

Background

Zinc-air batteries are being investigated as promising new energy devices due to their low cost, environmental friendliness and high energy density. It is becoming increasingly attractive to explore solid state zinc-air cells with high flexibility and intrinsic safety. The solid zinc-air battery can meet the requirements of wearable and stretchable electronic products, and the traditional zinc-air battery consists of a zinc electrode, an electrolyte and an air electrode. However, conventional sandwich battery constructions inevitably suffer from relative displacement or separation under bending strain between two adjacent components, which severely degrades the performance of the flexible battery.

Disclosure of Invention

The invention aims to: overcomes the defects of the prior art and provides a preparation method of a high-toughness gel electrolyte and an all-solid-state zinc-air battery with a firm interface. The working time and the cycle life of the battery can be greatly improved, and in addition, the hydrogel electrolyte is enhanced to ensure that the zinc-air battery has the required flexibility and structural stability, and has excellent electrochemical dynamics and stable electrochemical performance in different bending states.

In order to achieve the above purpose, the invention provides the following technical scheme:

a high-toughness gel electrolyte, which is PAA-Fe reinforced by mixed aqueous solution of ammonium chloride and zinc chloride³⁺Solid electrolyte of/CS hydrogel.

A preparation method of a high-toughness gel electrolyte comprises the following specific steps:

(1) dispersing chitosan powder in deionized water, and then stirring at room temperature to obtain a uniform and transparent solution;

(2) adding acrylic acid, a crosslinking agent N, N' -methylene bisacrylamide and ferric chloride hexahydrate into the solution obtained in the step (1) to form a transparent precursor solution, and removing oxygen bubbles by using ultrasound;

(3) adding initiator ammonium persulfate and catalyst tetramethyl ethylene diamine into the solution obtained in the step (2), stirring, and injecting the obtained transparent solution into a glass cylindrical mold;

(4) keeping the temperature of the mould at 55-65 ℃ for 1.5-2.5h to obtain PAA-Fe³⁺A CS hydrogel;

(5) mixing PAA-Fe³⁺NH/CS hydrogel₄Cl and ZnCl₂Soaking in the mixed aqueous solution of (1) at room temperatureObtaining enhanced PAA-Fe³⁺the/CS hydrogel is high-toughness gel electrolyte.

Preferably, the mass ratio of the acrylic acid to the chitosan is (10-20): (1-2); said PAA-Fe³⁺In the CS hydrogel, the mass percent of polyacrylic acid is 20-40 wt%, and the mass percent of chitosan is 2-4 wt%.

Preferably, the stirring time in step (3) is 5 to 15 s.

Preferably, the stirring time in step (3) is 10 s.

Preferably, the NH used for soaking in step (5)₄The concentration of Cl is 1-5mol/L, ZnCl₂The concentration of (B) is 0.1-2.5 mol/L.

A method for preparing all-solid-state zinc-air battery with firm interface includes applying carbon cloth as air electrode and PAA-Fe³⁺Cutting the/CS hydrogel and zinc sheet into required size, bonding, heating in glove box, and adding NH₄Cl and ZnCl₂Soaking the mixed aqueous solution for 1-5 h.

Preferably, said NH₄Cl and ZnCl₂NH in the mixed aqueous solution of₄The concentration of Cl is 1-5mol/L, ZnCl₂The concentration of (B) is 0.1-2.5 mol/L.

Preferably, the heating time is 10-40min, and the heating temperature is 40-80 ℃.

Compared with the prior art, the invention has the following beneficial effects:

the invention adopts the PAA-Fe with high toughness³⁺the/CS hydrogel electrolyte, and the unique adhesion process triggered by the hofmeis response, integrates the zinc anode, bifunctional catalyst, hydrogel electrolyte and air cathode into one entity, called the integrated electrode, enabling long cycle life and extremely high flexibility for zinc-air cells in aqueous electrolytes. The seamless connection to adjacent layers not only avoids relative displacement or separation due to bending strain, but enhances interfacial contact to promote electrochemical kinetics. The concrete advantages are as follows:

(1) using PAA-Fe³⁺And CS as polymer bone in electrolyteThe electrolyte for the zinc-air battery with high toughness is obtained by soaking in a salt solution;

(2) the continuous seamless connection enhanced interface contact greatly reduces the interface contact resistance and reduces the polarization of the battery;

(3) cathode material and PAA-Fe³⁺The strong adhesion between/CS hydrogels avoids the increase of the internal contact resistance of the cathode upon detachment and bending of the active material.

Drawings

Fig. 1 is a schematic structural diagram of an all-solid-state zinc-air battery with a firm interface according to the present invention, wherein 1 is a zinc electrode, 2 is an electrolyte, and 3 is a carbon cloth air electrode.

FIG. 2 shows an all-solid-state zinc-air cell of the invention (cell of example 1) at 5mA cm with a robust interface^-2Cycling stability curve at current density.

Fig. 3 is a schematic diagram of a 90 ° peel test for an all-solid-state zinc-air cell with a robust interface of the present invention.

FIG. 4 shows the cell of comparative example 1 at 5mA cm^-2Cycling stability curve at current density.

Fig. 5 shows the electrochemical performance of the solid-state zinc-air cell with robust interface of the present invention in various destructive tests (including bending test, torsion test, hammer test, freezing test).

Detailed Description

The technical solution of the present invention will be described in detail with reference to specific examples.

Example 1

1. Preparation of carbon cloth air electrode

The air electrode is composed of carbon cloth loaded with octa-cobalt sulfide powder. And cleaning and drying the carbon cloth in alcohol and deionized water. The electrode slurry is prepared from octa-cobalt sulfide powder, conductive carbon black, deionized water, isopropanol and a Nafion solution. Uniformly coating the catalyst on the cleaned carbon cloth by using the catalyst slurry prepared by ultrasonic treatment for 30min, wherein the loading amount is about 1mg cm^-2Subsequently, the prepared air electrode was dried at room temperature overnight. Can be prepared to be finishedThe carbon cloth air electrode of (1).

2. Preparation of electrolyte

PAA-Fe³⁺CS hydrogel: firstly, 1-2g of chitosan is weighed and dissolved in water solution, and magnetic stirring is carried out at normal temperature. Acrylic acid (AA,10-20g), crosslinker N, N' -methylenebisacrylamide (MBA,90ul, 20mg/mL) and ferric chloride hexahydrate (FeCl) were then added₃6H2O,1g) was stirred at room temperature to give a homogeneous and transparent solution. Then, ammonium persulfate as an initiator (KPS,2g, 40mg/mL) and tetramethylethylenediamine as a catalyst (TEMED,15ul) were added to the solution, and after stirring, the resulting clear solution was injected into a glass cylindrical mold. And keeping the temperature of the die at 60 ℃ for 2h to form the solid electrolyte.

Enhanced PAA-Fe³⁺CS hydrogel: mixing PAA-Fe³⁺NH/CS hydrogel₄Cl and ZnCl₂The mixed aqueous solution of (A) is soaked at room temperature to obtain the enhanced PAA-Fe³⁺the/CS hydrogel is high-toughness gel electrolyte.

3. Preparation of all-solid-state zinc-air battery with firm interface

The zinc electrode is made of pure zinc sheets with the thickness of 0.3-0.5mm, the zinc sheets are cut into rectangles with the length of 2-3 cm and the width of 1-2 cm, and the rectangles are polished by abrasive paper to remove oxides. The prepared air electrode and electrolyte are cut into strips with the length of 2cm-3cm and the width of 1cm-2cm, so that the zinc-air battery is convenient to assemble. Then, the zinc electrode, the electrolyte and the air electrode are smoothly assembled (bonded together) in a sandwich structure mode, then the whole battery is placed in a glove box and heated at the temperature of 40-60 ℃ for 10-30min, and finally soaked in 2.5M ammonium chloride and 0.5M zinc chloride solution for 1-5 hours.

Comparative example 1

1. Preparation of carbon cloth air electrode

The air electrode is composed of carbon cloth loaded with octa-cobalt sulfide powder. And cleaning and drying the carbon cloth in alcohol and deionized water. The electrode slurry is prepared from octa-cobalt sulfide powder, conductive carbon black, deionized water, isopropanol and a Nafion solution. Uniformly coating the catalyst on the cleaned carbon cloth by using the catalyst slurry prepared by ultrasonic treatment for 30min, wherein the loading amount is about 1mg cm^-2Followed byAfter that, the prepared air electrode was dried at room temperature overnight. And obtaining the prepared carbon cloth air electrode.

2. Preparation of electrolyte

Preparation of PVA electrolyte: the PVA gel polymer electrolyte membrane was prepared by a freeze-thaw technique. The PVA particles were completely dissolved in water under mechanical stirring at 90 ℃. After cooling to room temperature, the PVA solution was cast onto a glass plate. The membrane was then immediately immersed in acetone for 10 minutes to solidify and then frozen for 24 hours. The resulting porous film was then melted at 30 ℃ and this process was repeated several times to effect crosslinking. The membrane was washed with deionized water, immersed in KOH solution and equilibrated for 24 hours. Thereby obtaining a PVA gel electrolyte membrane.

3. Preparation of PVA-based sandwich structure zinc-air battery

And cutting a zinc sheet with the thickness of 0.3-0.5mm into strips with the length and the width of 2-3 cm, cutting the prepared air electrodes into the same size, respectively placing the air electrodes on two sides of the prepared PVA gel electrolyte membrane, and bonding the air electrodes together to form the common PVA-based sandwich structure zinc-air battery.

Analysis of results

1. Sandwich zinc-air cells using PVA system were tested using wuhan blue cell test system CT2001A, shown in fig. 4, and operated at current density for approximately 10 hours.

2. Enhanced PAA-Fe using ammonium chloride and zinc chloride system using Wuhan blue electric cell test system CT2001A³⁺The zinc-air cell with/CS solid electrolyte assembly was tested and still operated at this current density for nearly 120 hours as shown in fig. 2; in addition, as shown in fig. 5, the battery can provide stable charging and discharging current under different test environments.

3. Use of extensometer for reinforced PAA-Fe³⁺The zinc-air cell assembled with/CS solid electrolyte was subjected to a peel test, and fig. 3 is a schematic 90 ° peel test of an all-solid zinc-air cell with a robust interface according to the present invention. Adhesion was measured using a 90 degree peel method with an electronic universal tester. All the pieces of the material having a width of 2.5 cm were prepared,an adhesive substrate having a length of 7.5 cm and a thickness of 1 mm. The carbon cloth and the zinc plate were bonded to the glass plate using a double-sided adhesive tape. The PET film will act as a rigid backing for the hydrogel. Using a standard 90 degree peel test at 50mm min^-1The resulting samples were tested for constant peel speed. As can be seen in fig. 3: enhanced PAA-Fe³⁺the/CS hydrogel provides much greater interfacial toughness than the base PVA gel.

The above description is only illustrative of the concept of the present invention, and the adjustment of the process parameters according to the present invention can achieve the technical objects of the present invention and show substantially the same performance as the embodiments. It should be noted that any simple variations, modifications or other equivalent substitutions which a person skilled in the art can make without inventive effort, are within the scope of the present invention, as long as they do not depart from the spirit of the invention or exceed the scope defined by the claims.

Claims

1. A high-toughness gel electrolyte, characterized in that the electrolyte is PAA-Fe reinforced by a mixed aqueous solution of ammonium chloride and zinc chloride³⁺Solid electrolyte of/CS hydrogel.

2. The method for preparing the high-toughness gel electrolyte according to claim 1, which comprises the following steps:

(5) mixing PAA-Fe³⁺NH/CS hydrogel₄Cl and ZnCl₂The mixed aqueous solution of (A) is soaked at room temperature to obtain the enhanced PAA-Fe³⁺the/CS hydrogel is high-toughness gel electrolyte.

3. The method for producing a high-toughness gel electrolyte according to claim 1, wherein the mass ratio of acrylic acid to chitosan is (10-20): (1-2); said PAA-Fe³⁺In the CS hydrogel, the mass percent of polyacrylic acid is 20-40 wt%, and the mass percent of chitosan is 2-4 wt%.

4. The method for producing a high toughness gel electrolyte according to claim 1, wherein the stirring time in step (3) is 5 to 15 seconds.

5. The method for producing a high toughness gel electrolyte according to claim 4, wherein the stirring time in step (3) is 10 s.

6. The method for producing a high toughness gel electrolyte according to claim 1, wherein NH used for the soaking in step (5)₄The concentration of Cl is 1-5mol/L, ZnCl₂The concentration of (B) is 0.1-2.5 mol/L.

7. A preparation method of an all-solid-state zinc-air battery with a firm interface is characterized by comprising the following steps: carbon cloth air electrode, PAA-Fe³⁺Cutting the/CS hydrogel and zinc sheet into required size, bonding, heating in glove box, and adding NH₄Cl and ZnCl₂Soaking the mixed aqueous solution for 1-5 h.

8. The method of claim 7, wherein the method comprises the steps of: the NH₄Cl and ZnCl₂NH in the mixed aqueous solution of₄The concentration of Cl is 1-5mol/L, ZnCl₂The concentration of (B) is 0.1-2.5 mol/L.

9. The method of claim 7, wherein the method comprises the steps of: the heating time is 10-40min, and the heating temperature is 40-80 ℃.