CN110600835B

CN110600835B - Stretchable flexible metal-air battery

Info

Publication number: CN110600835B
Application number: CN201910902420.1A
Authority: CN
Inventors: 谈鹏; 丁毓琪
Original assignee: University of Science and Technology of China USTC
Current assignee: University of Science and Technology of China USTC
Priority date: 2019-09-24
Filing date: 2019-09-24
Publication date: 2021-03-09
Anticipated expiration: 2039-09-24
Also published as: CN110600835A

Abstract

The invention relates to a stretchable flexible metal-air battery. Comprises a metal-air battery matrix and a telescopic pipe; the metal-air battery matrix is positioned in the telescopic pipe in a spring shape, and a negative current collector and a positive current collector are respectively arranged at two ends of the metal-air battery matrix; the metal-air battery matrix comprises a zinc metal wire, and the zinc metal wire is wrapped with a gel electrolyte and a flexible air electrode from inside to outside; embedding a linear metal-air battery matrix into a telescopic pipe, wherein the telescopic pipe provides support for the battery, and air holes in the pipe wall are favorable for oxygen transmission; moreover, the extension tube ensures the ductility of the battery and is suitable for stretching to a greater degree. The original length L of the flexible metal-air battery is 5-6 cm, the output voltage of the flexible metal-air battery is 1.25-1.28V, and the charging voltage is 1.98-2.01V; the output voltage is kept stable in the stretching process, and the maximum stretching degree of the flexible metal-air battery is 125-200%.

Description

Stretchable flexible metal-air battery

Technical Field

The invention belongs to the field of battery application, and particularly relates to a stretchable flexible metal-air battery which can provide power supply for wearable electronic equipment such as a smart watch and a sports bracelet.

Background

Along with the development of wearable electronic equipment such as intelligent wrist-watch, motion bracelet, flexible electrical power generating system with the ability of stretching and bending is the key of guaranteeing its normal work. Although flexible lithium ion batteries and supercapacitors have become a focus of research, the limited energy density has greatly limited the range of electronic devices. The metal air adopts metal and oxygen in the air as active substances, has extremely high energy density, and can be used for long-time continuous functions of electronic equipment. Moreover, the zinc-air battery is mature in development, low in cost, safe and environment-friendly. In order to meet the requirements of flexible electronic devices, a series of researches have been carried out in recent years on flexible metal-air batteries, and the structures of the flexible metal-air batteries can be roughly divided into two types:

the first type is a layered structure: the metal and active substances loaded on a flexible current collector are used as a metal electrode and an air electrode, and are separated by an electrolyte membrane to form a sandwich structure (nat. Commun., 2015, 6, 7892; Small 2018, 14, 1800225).

The second type is a linear structure: a metal wire is used as a metal electrode, a circle of electrolyte membrane is wound on the surface of the metal wire, and finally, a flexible current collector loaded with active substances is wrapped to be used as an air electrode, so that a cable-shaped structure is formed (adv. mater, 2015, 27, 1396; Small, 2016, 12, 3101).

Although both of the above-described cell structures impart better flexibility to the cell by employing a flexible electrolyte membrane and a current collector, the stretchability is limited. In the wire structure, by using a metal zinc spring as a metal electrode, a 10% elongation can be achieved (CN 105244565). In the layered structure, although the degree of elongation is increased to 100% by the copper spring connection by decomposing the metallic lithium into small pieces (j. mater. chem. a, 2016, 4, 13419), the ineffective mass and volume of the battery are increased due to the introduction of the copper spring and the like, and the actual energy density is reduced. Therefore, in order to meet the bending and stretching requirements accompanied by wearable electronic devices in use, it is urgently required to develop a flexible metal-air battery which has high energy density and can achieve large stretching.

Disclosure of Invention

The invention aims to provide a stretchable flexible metal-air battery to achieve the aims of large stretching and flexibility.

A stretchable flexible metal-air battery includes a metal-air battery base 23 and an extension tube 24; the metal-air battery matrix is positioned in the telescopic pipe in a spring shape, and the two ends of the metal-air battery matrix are respectively provided with a negative current collector 21 and a positive current collector 22 for collecting current;

the metal-air battery matrix comprises a zinc metal wire 11, wherein the zinc metal wire 11 is wrapped with a gel electrolyte 12 and a flexible air electrode 13 from inside to outside;

the original length L of the flexible metal-air battery is 5-6 cm, the number n of spirals of the metal-air battery matrix is 20-25, and the maximum stretching distance x is 0.3-0.5 cm; the output voltage of the flexible metal-air battery is 1.25-1.28V, and the charging voltage is 1.98-2.01V; the output voltage is kept stable in the stretching process, and the maximum stretching degree of the flexible metal-air battery is nx/L multiplied by 100 percent, namely 125-200 percent.

The preparation operation steps of the stretchable flexible metal-air battery are as follows:

(1) preparation of gel electrolyte

Dissolving 1g of polyvinyl alcohol (PVA) in 8mL of deionized water at 80 ℃, uniformly stirring, adding 2mL of 10-20M potassium hydroxide (KOH) aqueous solution, and continuously stirring for 1-2 hours to obtain a gel electrolyte;

(2) preparation of Flexible air electrode

Mixing 1-4 mg of cobaltosic oxide (Co)₃O₄) Uniformly mixing nano particles, 0.5-2 mg of conductive carbon powder, 0.5-2 mg of polytetrafluoroethylene binder and 0.5-1 mL of absolute ethyl alcohol to form slurry, uniformly coating the slurry on carbon cloth by scraping, and drying for 12 hours at the temperature of 60 ℃; cobaltosic oxide (Co)₃O₄) The nano particles are used as active substances, and the loading amount of the active substances on the carbon cloth is 1-4 mg/cm²(ii) a Obtaining a flexible air electrode (13);

(3) assembled metal-air battery matrix

(3.1) putting the zinc metal wire into PVA/KOH gel electrolyte for fully soaking for 1-2 min, taking out, enabling the gel electrolyte to uniformly coat the zinc metal wire, freezing for 8 hours at the temperature of-10 ℃, unfreezing at room temperature to enhance physical crosslinking, and enabling the thickness of the gel electrolyte on the zinc metal wire to be 0.5-1 mm to obtain an assembly;

(3.2) uniformly wrapping the flexible air electrode on the assembly to obtain a zinc-air electrode substrate;

(4) assembled battery

(4.1) winding the zinc-air electrode substrate into a spring shape;

(4.2) air holes are uniformly distributed on the extension tube 24;

(4.3) embedding the spring-shaped zinc-air electrode substrate into the telescopic pipe 24, wherein two ends of the zinc-air electrode substrate are respectively positioned outside the telescopic pipe 24, and the two ends are respectively a negative current collector 21 and a positive current collector 22, so as to obtain the flexible metal-air battery.

The technical scheme for further limiting is as follows:

the cobaltosic oxide (Co)₃O₄) The purity of the nano-particles is more than 99.9%, and the average particle size is 10-50 nm, and the nano-particles are used as active substances.

The zinc metal wire is 99% pure and 1-2 mm in diameter.

The telescopic pipe 24 is made of Polyurethane (PU) or polyvinyl chloride (PVC) and has a pipe diameter of 0.8-1 cm.

The aperture of the air holes is 1-2 mm, and the sum of the areas of the air holes is 50-70% of the surface area of the telescopic pipe (24).

The beneficial technical effects of the invention are embodied in the following aspects:

1. the metal-air battery matrix adopts a linear structure, so that the interface separation phenomenon caused by the fact that the mechanical properties of three layers of materials are different in the bending process of the layered structure can be avoided, and the stability of the interface can be kept better. The telescopic pipe is light in weight, has small influence on the total mass of the battery, and is more beneficial to obtaining high energy density. Embedding a linear metal-air battery matrix into the bent part of a telescopic pipe, wherein the telescopic pipe provides support for the battery, and air holes in the pipe wall are favorable for oxygen transmission; moreover, the extension tube ensures the ductility of the battery and is suitable for stretching to a greater degree.

2. The metal electrode adopts metal zinc, and the active material of the air electrode adopts cobaltosic oxide (Co)₃O₄) The nano particles are used as catalysts for oxygen reduction and oxygen precipitation, and the charge-discharge reaction of the zinc-air battery is as follows:

the output voltage can reach more than 1.2V, the charging voltage is about 2.0V, and the battery can be charged and discharged for use for many times.

3. The original length L of the flexible metal-air battery is 5-6 cm, and the maximum stretching degree is 125-200%. The output voltage is 1.25-1.28V, the charging voltage is 1.98-2.01V, and the output voltage is kept stable in the stretching process. The power supply can be used as a power supply of wearable flexible electronic equipment such as a smart watch, a sports bracelet and the like.

Drawings

Fig. 1 is a perspective view of a metal-air battery substrate.

Fig. 2 is a cross-sectional view of a metal-air cell substrate.

11-metal wire; 12-a gel electrolyte; 13-Flexible air electrode.

Fig. 3 is a schematic diagram of the original state of the stretchable flexible metal-air battery, wherein the length is L, and the number of intervals is n.

Fig. 4 is a schematic diagram of the stretching state of the stretchable flexible metal-air battery, wherein the stretching distance is x'.

Fig. 5 is a schematic diagram of the stretchable flexible metal-air battery in a fully stretched state, wherein the stretching distance is x.

Wherein 21-negative current collector; 22-positive current collector; 23-metal-air cell substrate; 24-telescoping tube. The maximum elongation of the cell was found to be nx/L × 100%.

Detailed Description

The invention will now be further described, by way of example, with reference to the accompanying drawings.

Example 1

Referring to fig. 1 and 2, the metal-air battery substrate of the present invention is composed of a zinc wire 11, a gel electrolyte 12, and a flexible air electrode 13.

The zinc wire 11 has a purity of 99% and a diameter of 2 mm.

The gel electrolyte 12 is composed of polyvinyl alcohol (PVA), potassium hydroxide (KOH), and water: dissolving 1g of PVA in 8mL of deionized water at 80 ℃, uniformly stirring, adding 2mL of KOH aqueous solution with the concentration of 10M, and continuously stirring for 1 hour to obtain the PVA/KOH gel electrolyte. Fully soaking the zinc wire in PVA/KOH gel electrolyte for 1min, taking out the zinc wire to ensure that the gel electrolyte uniformly coats the zinc wire, freezing the zinc wire in an environment at the temperature of-10 ℃ for 8 hours, and then thawing the zinc wire at room temperature to strengthen physical crosslinking, wherein the thickness of the gel electrolyte on the zinc wire is 0.5 mm.

The flexible air electrode 13 is made of 1mg of Co with purity of more than 99.9% and average grain diameter of 50nm₃O₄Uniformly mixing nano particles as an active substance, 0.5mg of conductive carbon powder, 0.5mg of polytetrafluoroethylene binder and 0.5mL of absolute ethyl alcohol into slurry, uniformly scraping and coating the slurry on carbon cloth, and drying the carbon cloth at the temperature of 60 ℃ for 12 hours; the active substance loading is 1mg/cm²。

And uniformly wrapping the flexible air electrode on the surface of the gel electrolyte to form a zinc air electrode matrix.

Referring to fig. 3 to 5, the extension tube 24 is a Polyurethane (PU) extension tube with a diameter of 1cm, and the aperture of the vent hole on the tube wall of the extension tube is 1 mm; the sum of the areas of the air holes accounts for 50 percent of the contact surface.

The zinc-air battery base 23 is bent into a spiral shape and inserted into the extension tube, and the two ends of the zinc-air battery base are respectively a negative current collector 21 and a positive current collector 22 for collecting current.

Thereby forming a stretchable flexible zinc-air battery. The original cell length L was 5cm, with the number of intervals n being 20, and the maximum stretch spacing x being 0.5 cm. The output voltage of the battery is 1.25V, and the charging voltage is 2.01V; the output voltage can be kept stable in the stretching process, and the maximum stretching degree reaches 200%.

Example 2

The zinc wire 11 has a purity of 99% and a diameter of 1 mm.

The gel electrolyte 12 is composed of polyvinyl alcohol (PVA), potassium hydroxide (KOH), and water: dissolving 1.0g of PVA in 8mL of deionized water at 80 ℃, uniformly stirring, adding 2mL of KOH aqueous solution with the concentration of 20M, and continuously stirring for 1 hour to obtain the PVA/KOH gel electrolyte. Fully soaking the zinc metal wire in PVA/KOH gel electrolyte for 2min, taking out the zinc metal wire to ensure that the gel electrolyte uniformly coats the zinc metal wire, freezing the zinc metal wire in an environment at the temperature of-10 ℃ for 8 h, and then unfreezing the zinc metal wire at room temperature to enhance physical crosslinking, wherein the thickness of the gel electrolyte on the zinc metal wire is 1 mm.

The flexible air electrode 13 is made of 4mg of Co with purity of more than 99.9% and average grain diameter of 10nm₃O₄Mixing nanoparticles as active substance, 2mg of conductive carbon powder, 2mg of polytetrafluoroethylene binder and 1mL of absolute ethyl alcohol uniformly to form slurry, and uniformly blade-coating the slurry on carbon cloth, wherein the loading capacity of the active substance is 4mg/cm²。

Referring to fig. 3 to 5, the extension tube 24 is a polyvinyl chloride (PVC) extension tube with a diameter of 0.8cm, and the aperture of the air holes on the tube wall of the extension tube is 2 mm; the sum of the areas of the air holes accounts for 70 percent of the contact surface.

Thereby constituting a stretchable flexible aluminum air battery. The original cell length L was 6cm, with the number of intervals n being 25, and the maximum stretch spacing x being 0.3 cm. The output voltage of the battery is 1.28V, and the charging voltage is 1.98V; the output voltage can be kept stable in the stretching process, and the maximum stretching degree reaches 125 percent.

Claims

1. A stretchable flexible metal-air battery is characterized in that: comprising a metal-air battery base body and a telescopic tube; the metal-air battery base body is located in the telescopic tube in a spring shape, and the two ends of the metal-air battery base body are respectively the negative current collector and the telescopic tube. Positive current collector for collecting electricity;

The metal-air battery matrix includes a zinc metal wire, and the zinc metal wire is wrapped with a gel electrolyte and a flexible air electrode from the inside to the outside;

The original length L of the flexible metal-air battery is 5-6 cm, the number of spirals n of the metal-air battery substrate is 20-25, and the maximum stretching distance x is 0.3-0.5 cm; the output voltage of the flexible metal-air battery is 1.25- 1.28V, the charging voltage is 1.98-2.01V; the output voltage is kept stable during the stretching process, and the maximum stretching degree of the flexible metal-air battery is 125-200%;

(1) Preparation of gel electrolyte

At 80°C, dissolve 1 g of polyvinyl alcohol in 8 mL of deionized water, stir evenly and add 2 mL of potassium hydroxide aqueous solution with a concentration of 10 to 20 M, and continue stirring for 1 to 2 hours to obtain a gel electrolyte;

(2) Preparation of flexible air electrodes

Mix 1~4mg cobalt tetroxide nanoparticles, 0.5~2mg conductive carbon powder, 0.5~2mg polytetrafluoroethylene binder and 0.5~1mL absolute ethanol into a slurry, uniformly scrape it on the carbon cloth, at 60 ℃ drying under low temperature for 12h; cobalt tetroxide nanoparticles are used as active material, and the active material loading on the carbon cloth is 1-4 mg/cm ² ; a flexible air electrode is obtained;

(3) Assembling the metal-air battery matrix

(3.1) Put the zinc wire into the PVA/KOH gel electrolyte to fully soak for 1-2 minutes, take it out, make the gel electrolyte evenly coat the zinc wire, freeze at -10℃ for 8 hours, and thaw at room temperature to enhance physical Cross-linking, the layer thickness of the gel electrolyte on the zinc wire is 0.5-1 mm, and an assembly is obtained;

(3.2) Evenly wrap the flexible air electrode on the assembly to obtain the zinc air electrode substrate;

(4) Assemble the battery

(4.1) Wind the zinc-air electrode base into a spring shape;

(4.2) Air holes are evenly distributed on the telescopic tube;

(4.3) Embed the spring-shaped zinc-air electrode base into the telescopic tube, and the two ends of the zinc-air electrode base are respectively located outside the telescopic tube, and the two ends are respectively the negative electrode current collector and the positive electrode current collector to obtain a flexible metal-air battery.

2 . The stretchable flexible metal-air battery according to claim 1 , wherein the purity of the cobalt tetroxide nanoparticles is more than 99.9% and the average particle size is 10-50 nm. 3 .

3 . The stretchable flexible metal-air battery according to claim 1 , wherein the zinc metal wire is a zinc metal wire with a purity of 99% and a diameter of 1-2 mm. 4 .

4 . The stretchable flexible metal-air battery according to claim 1 , wherein the material of the telescopic tube is polyurethane or polyvinyl chloride, and the diameter of the tube is 0.8-1 cm. 5 .

5 . The stretchable flexible metal-air battery according to claim 1 , wherein the diameter of the ventilation holes is 1-2 mm, and the sum of the areas of the ventilation holes is 50% to 70% of the surface area of the telescopic tube. 6 . %.