CN114388902B - Method for inhibiting zinc dendrite growth in zinc ion battery - Google Patents

Abstract

The invention relates to a method for preparing an electrolyte with ultra-fast self-repairing performance to construct an electrolyte/zinc cathode dynamic self-adaptive interface to inhibit dendrite growth in a zinc battery. According to the invention, a certain amount of guar gum is completely dissolved into zinc salt solution to form uniform colloid. Subsequently, glycerol was added to the colloid prepared as described above to form a binary solvent system. And finally, adding a neutral organic boron crosslinking agent and curing the gel to obtain the gel with ultra-fast self-repairing performance. The gel is used for electrolyte in quasi-solid state battery, can construct dynamic continuous electrolyte/zinc cathode interface, inhibit dendrite growth and greatly prolong service life of zinc battery. The method has the advantages of low price, simple process, safety and environmental protection, and has the potential of large-scale application.

Description

A method for inhibiting the growth of zinc dendrites in zinc-ion batteries

Technical field

The invention belongs to the technical field of material chemistry, and specifically relates to a method for inhibiting the growth of zinc dendrites in zinc ion batteries.

Background technique

The rapid development of today's society has stimulated the demand for flexible and wearable devices, mainly including portable electronic products and smart wearable systems. Over the past few years, efforts have been devoted to creating high-performance, flexible lithium-ion batteries. However, although lithium-ion batteries provide high energy and power density, safety issues and limitations of lithium metal resources make their practical applications face huge obstacles. In fact, safety and non-toxicity are crucial prerequisites for wearable energy storage devices. In this context, an alternative strategy, zinc-ion batteries, has attracted great attention due to its inherent safety, ease of fabrication, and low cost. However, aqueous zinc-ion batteries have long been severely affected by zinc dendrites and side reactions in the aqueous electrolyte, which will eventually increase the interface impedance and cause a series of problems such as battery short circuit, thereby affecting the cycle performance and service life of zinc-based batteries. performance.

Researchers constructed three-dimensional polymer electrolytes, including anti-aging gels, ion-confined gels and artificial interface layers, and were proven to effectively suppress interfacial side reactions between electrolytes and zinc anodes. However, in the construction of quasi-solid-state batteries, solid-solid interface contact is an urgent problem that needs to be overcome. 1) During the charge and discharge process, the dynamic growth and dissolution of dendrites prevents the static electrolyte interface and the dynamic zinc anode interface from maintaining a tight connection, resulting in micro-gaps, resulting in poor interface contact and reducing the rate capability of the battery. . 2) Most hydrogels tend to severely lose water under dry conditions, which is a fatal flaw for practical applications of hydrogels. Therefore, it is crucial to construct hydrogels with dynamic and strong interfacial contacts as well as reliable water retention capabilities, which are key principles for interfacial strategies for efficient quasi-solid-state zinc-ion batteries.

Here, by cross-linking natural polymers and introducing a second layer of network structure, a hydrogel with ultra-fast self-healing and excellent water retention properties was finally obtained.

Contents of the invention

The purpose of the present invention is to solve the problem of discontinuous solid-solid interface in quasi-solid zinc ion batteries and the severe zinc dendrite growth caused by it, and to propose a method for inhibiting the growth of zinc dendrites in zinc ion batteries.

In order to achieve the above objects, the technical solution of the present invention is: a method for inhibiting the growth of zinc dendrites in zinc ion batteries, which is characterized by comprising the following steps:

1) Completely dissolve a certain amount of guar gum into the zinc salt solution to form a uniform colloid;

2) Add an appropriate amount of glycerol to the colloid prepared above to form a binary solvent system;

3) Add a neutral organic boron cross-linking agent and solidify it to obtain a self-healing and adaptive quasi-solid electrolyte;

4) Assemble zinc anode, cathode materials and adaptive quasi-solid-state electrolyte into a quasi-solid-state zinc-ion battery without dendrite growth.

According to the above scheme, the mass ratio of guar gum and zinc salt solution in step 1) is 1%-6%.

According to the above scheme, the zinc salt solution in step 1) is any one of zinc sulfate, zinc trifluoromethanesulfonate and zinc chloride.

According to the above scheme, the volume ratio of glycerol:zinc salt solution in step 2) is 0.15%-2%.

According to the above scheme, the cathode material in step 4) is any one of polypyrrole, polyaniline, vanadium oxide, Prussian blue and manganese oxide.

The invention prepares an electrolyte with ultra-fast self-healing performance, which dynamically adapts to the shrinkage and expansion of the zinc negative electrode, builds an adaptive interface, inhibits the growth of zinc dendrites, and performs symmetrical battery charging at a certain current density. In the discharge cycle experiment, after 750 cycles, the zinc surface was deposited evenly, without dendrite growth, and the interface between the electrolyte and the negative electrode remained tightly connected.

The beneficial effects of the present invention are: the present invention utilizes the dynamic borate ester formed between the organic boron cross-linking agent and the homeopathic diol in guar gum to construct an electrolyte with ultra-fast self-healing performance. The electrolyte has high water retention and can dynamically adapt to the expansion and contraction of the zinc anode, so that the electrolyte/electrode interface always maintains continuous and close contact and inhibits the growth of zinc anode dendrites. Among them, glycerol can form a large number of intermolecular hydrogen bonds with water molecules, inhibiting the evaporation of water molecules, thereby enhancing the gel's water-locking ability. In addition, the glycerol-water binary system greatly enhances the mechanical toughness of the gel by introducing non-covalent bonds into the polymer network.

The invention has the characteristics of cheap and degradable raw materials, simple and environmentally friendly process, excellent electrochemical properties of the material, and has the potential for large-scale application.

Description of the drawings

Figure 1 is an SEM image of the self-healing electrolyte prepared in Example 1;

Figure 2 is an FTIR pattern of the self-healing electrolyte prepared in Example 1;

Figure 3 is a water retention performance test chart of the self-healing electrolyte prepared in Example 1;

Figure 4 is a macroscopic representation of the self-healing performance of the self-healing electrolyte prepared in Example 1;

Figure 5 is an optical diagram of the in-situ self-healing performance of the self-healing electrolyte prepared in Example 1;

Figure 6 shows the self-healing electrolyte and ordinary guar gum electrolyte obtained by using the present invention as electrolytes in a zinc//zinc symmetrical battery respectively. When the current density is 0.5mA cm ^-2 , the zinc//zinc symmetrical battery The charge and discharge cycle diagram.

Detailed ways

In order to better understand the present invention, the content of the present invention will be further explained below in conjunction with the examples, but the content of the present invention is not limited only to the following examples.

Example 1:

1) Dissolve 0.4g guar gum into 10mL of 1.5M zinc trifluoromethanesulfonate solution.

2) After the above solution is completely dissolved, add 0.1 ml glycerol and stir magnetically for 30 minutes.

3) Slowly add 1 ml of neutral organic boron cross-linking agent into the above mixed solution drop by drop, and stir with a glass rod to obtain a self-healing and adaptive quasi-solid electrolyte.

4) Assemble the zinc anode, manganese oxide cathode and gel electrolyte into a quasi-solid zinc-ion battery without dendrite growth.

The guar gum electrolyte obtained in this example has a porous network structure (Figure 1), and the FTIR energy spectrum shows the formation of dynamic BO bonds (Figure 2), and the gel electrolyte has excellent water retention properties (Figure 3) and ultra-fast self-healing performance (Figures 4 and 5). As can be seen from Figure 3, pure guar gum hydrogel has the lowest water-locking ability, and the water loss weight is 3 grams, which is 70% less than the initial mass. In contrast, the water-locking capacity of the self-healing electrolyte prepared by the present invention slowly increased to 102% within the first 2 days, which can be attributed to the hygroscopicity of guar gum molecules. After that, despite the fluctuations, it remained stable and stayed around 100% for the next 6 days. Figure 4 proves the self-healing properties of the gel from a macro perspective, and Figure 5 demonstrates the self-healing properties of the gel from a micro perspective, and can achieve self-healing within 30 seconds. When the self-repairing electrolyte of the present invention is not used in a zinc battery, when the current density is 1 mA cm ^-2 , the voltage of the battery increases sharply after 550 hours of charge and discharge cycles; when the self-repairing electrolyte of the present invention is used in a zinc battery In the case of electrolyte, when the current density is 1mA cm ^-2 , the voltage of the battery is stable after 1500h of charge and discharge cycles (Figure 6), indicating that zinc is uniformly deposited on the electrode, the growth of zinc dendrites is inhibited, and the service life of the zinc electrode is extended.

Example 2:

1) Dissolve 0.4g guar gum into 10mL of 1.5M zinc trifluoromethanesulfonate solution.

2) After the above solution is completely dissolved, add 0.2 ml of glycerol and stir magnetically for 30 minutes.

3) Slowly add 1 ml of neutral organic boron cross-linking agent into the above mixed solution drop by drop, and stir with a glass rod to obtain a self-healing and adaptive quasi-solid electrolyte.

4) Assemble the zinc anode, polyaniline cathode and gel electrolyte into a quasi-solid zinc-ion battery without dendrite growth.

The materials prepared above were subjected to SEM, FTIR, water retention performance test analysis and electrochemical performance test. The water retention performance remained stable during the 8-day test period. The electrochemical performance test showed uniform zinc deposition, inhibited zinc dendrite growth, and extended the service life of the zinc electrode.

Example 3:

1) Dissolve 0.4g guar gum into 10mL of 1.5M zinc trifluoromethanesulfonate solution.

2) After the above solution is completely dissolved, add 0.1 ml glycerol and stir magnetically for 30 minutes.

3) Slowly add 2 ml of neutral organic boron cross-linking agent into the above mixed solution drop by drop, and stir with a glass rod to obtain a self-healing and adaptive quasi-solid electrolyte.

4) Assemble the zinc anode, polypyrrole cathode and gel electrolyte into a quasi-solid zinc-ion battery without dendrite growth.

The materials prepared above were subjected to SEM, FTIR, water retention performance test analysis and electrochemical performance test. The water retention performance remained stable during the 8-day test period. The electrochemical performance test showed uniform zinc deposition, inhibited zinc dendrite growth, and extended the service life of the zinc electrode.

Example 4:

1) Dissolve 0.6g guar gum into 10mL of 1.5M zinc trifluoromethanesulfonate solution.

2) After the above solution is completely dissolved, add 0.1 ml glycerol and stir magnetically for 30 minutes.

3) Slowly add 1 ml of neutral organic boron cross-linking agent into the above mixed solution drop by drop, and stir with a glass rod to obtain a self-healing and adaptive quasi-solid electrolyte.

4) Assemble the zinc anode, vanadium oxide cathode and gel electrolyte into a quasi-solid zinc-ion battery without dendrite growth.

The materials prepared above were subjected to SEM, FTIR, mechanical property test analysis and electrochemical property test. The water retention performance remained stable during the 8-day test period. The electrochemical performance test showed uniform zinc deposition, inhibited zinc dendrite growth, and extended the service life of the zinc electrode.

Example 5:

1) Dissolve 0.6g guar gum into 10mL of 1.5M zinc chloride solution.

2) After the above solution is completely dissolved, add 0.1 ml glycerol and stir magnetically for 30 minutes.

3) Slowly add 1 ml of neutral organic boron cross-linking agent into the above mixed solution drop by drop, and stir with a glass rod to obtain a self-healing and adaptive quasi-solid electrolyte.

4) Assemble the zinc anode, Prussian blue cathode and gel electrolyte into a quasi-solid zinc-ion battery without dendrite growth.

The materials prepared above were subjected to SEM, FTIR, mechanical property test analysis and electrochemical property test. The water retention performance remained stable during the 8-day test period. The electrochemical performance test showed uniform zinc deposition, inhibited zinc dendrite growth, and extended the service life of the zinc electrode.

Claims (5)

1. A method for inhibiting the growth of zinc dendrites in zinc ion batteries, which is characterized by comprising the following steps: 1) Completely dissolve a certain amount of guar gum into the zinc salt solution to form a uniform colloid; 2) Add an appropriate amount of glycerol to the colloid prepared above to form a binary solvent system; 3) Add a neutral organic boron cross-linking agent and solidify it, and use the dynamic borate ester formed between the organic boron cross-linking agent and the homeopathic diol in guar gum to obtain a self-healing and adaptive quasi-solid electrolyte; 4) Assemble zinc anode, cathode materials and adaptive quasi-solid electrolyte into an aqueous quasi-solid zinc-ion battery without dendrite growth. 2. The method for inhibiting the growth of zinc dendrites in zinc ion batteries according to claim 1, wherein the mass ratio of guar gum to zinc salt solution in step 1) is 1%-6%. 3. The method for inhibiting zinc dendrite growth in zinc ion batteries according to claim 1 or 2, characterized in that: the zinc salt solution in step 1) is zinc sulfate, zinc trifluoromethanesulfonate and zinc chloride. Any kind. 4. The method for inhibiting the growth of zinc dendrites in zinc ion batteries according to claim 1, characterized in that: in step 2), the volume ratio of glycerol:zinc salt solution is 0.15%-2%. 5. The method for inhibiting zinc dendrite growth in zinc ion batteries according to claim 1, characterized in that: the cathode material in step 4) is polypyrrole, polyaniline, vanadium oxide, Prussian blue and manganese oxide. Any kind.