Design of aqueous zinc ion battery electrolyte and application of aqueous zinc ion battery electrolyte in stabilizing zinc anode interface layer

Abstract

The invention discloses a novel aqueous zinc ion battery electrolyte and application thereof in stabilizing a zinc anode interface layer, the electrolyte comprises a zinc salt and a solvent, and the solvent comprises water and L-calcium aspartate (Ca-ASP). The molar concentration of the Ca-ASP ranges from 0 mol / L to 0.07 mol / L. The mixed electrolyte is formed by adding a proper amount of Ca-ASP into the zinc salt solution, so that the zinc anode interface is effectively protected, and the stability of the zinc anode is improved. And uniform zinc deposition is realized, and side reactions such as hydrogen evolution reaction are inhibited. The cycle time of the zinc ion battery under regulation and control of Ca-ASP can reach 2832 hours at normal temperature, and the zinc ion battery has excellent coulombic efficiency and rate capability.

Description

Technical Field

[0001] The invention relates to the field of electrochemical energy storage, and in particular to the preparation of aqueous zinc ion battery electrolytes and applications of batteries. Background Art

[0002] As global energy demand continues to grow, it is increasingly urgent to find sustainable, clean and efficient energy storage systems. As a key component of energy storage, secondary batteries play a vital role in promoting the use of renewable energy and the development of electric vehicles. However, the current mainstream lithium-ion batteries face challenges such as limited resources, high costs, and low safety. In this context, aqueous zinc-ion batteries have received increasing attention due to their abundant zinc resources, low cost, high safety, and environmental friendliness.

[0003] However, aqueous zinc-ion batteries still face some challenges in practical application and commercialization. During the charging process, zinc ions are deposited on the anode to form zinc dendrites, which may cause internal short circuits and shorten the cycle life of the battery. At the same time, the zinc anode may also corrode and passivate in an aqueous environment. In addition, hydrogen evolution reaction and the generation of by-products are also major challenges hindering its commercialization.

[0004] The researchers overcame these problems by soaking the zinc anode, artificially coating, and modifying the electrolyte. Among them, adjusting the stability of the zinc anode by introducing electrolyte additives is considered to be the simplest and most efficient strategy. It mainly includes ionic liquid electrolytes (ILEs), hydrogel electrolytes (HEs), and deep eutectic electrolytes (DEEs). The improved technical solution of the patent of this invention inhibits the occurrence of side reactions such as hydrogen evolution reaction and promotes uniform zinc deposition. At room temperature, it can stably cycle for 2832 hours. Summary of the invention

[0005] The purpose of the present invention is to provide a universal AZIBs electrolyte and its application, so as to solve the problem that the growth of dendrites and the generation of side reactions such as hydrogen evolution reaction in conventional AZIBs lead to the deterioration of the electrochemical performance of AZIBs at room temperature. By adding an appropriate amount of Ca-ASP to the zinc salt solution, reversible zinc deposition / dissolution at room temperature is achieved, the cycle stability of the positive electrode material is improved, and thus the cycle performance of the zinc ion battery at room temperature is improved.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] Aqueous zinc-ion battery electrolyte is mainly composed of zinc salt, organic solvent additives and water.

[0008] Based on the above scheme, preferably, the zinc salt is any one of zinc sulfate, zinc chloride, zinc nitrate, zinc acetate, zinc phosphate, zinc trifluoromethanesulfonate, zinc bis(trifluoromethanesulfonylimide), zinc tetrafluoroborate, zinc hexafluorophosphate, and zinc bis(oxalate borate), or a combination of at least two thereof, and is further preferably zinc sulfate.

[0009] Based on the above scheme, the organic solvent additive is an amino acid salt.

[0010] Based on the above scheme, preferably, the amino acid salt is one or a combination of at least two of sodium glutamate, zinc glycine, and calcium L-aspartate, and more preferably calcium L-aspartate.

[0011] The concentration of the electrolyte salt is 0.01M to 0.07M, where M is the mass concentration, that is, the ratio of the molar number of the electrolyte salt to the mass of the solvent: mol kg -1 .

[0012] Based on the above scheme, preferably, the zinc salt concentration is 0.1-2.5 mol kg -1 (M), more preferably 2M.

[0013] Based on the above scheme, preferably, the content of Ca-ASP in the electrolyte is 0.01-0.07 g L -1 The aqueous ion battery electrolyte is specifically ZSO, 0.01Ca-ASP, 0.03Ca-ASP, 0.05Ca-ASP, 0.07Ca-ASP.

[0014] Based on the above scheme, preferably, the zinc ion battery is composed of a positive electrode, a membrane and a zinc negative electrode material. The positive electrode is a zinc ion insertion and extraction type material, and the manganese-based material is MnO2, Ca 0.28 The vanadium-based material is one or more of V2O5, V2O3, Zn2V2O7 and KV3O8; the membrane is a glass fiber membrane or a Celgard membrane; the zinc negative electrode is zinc foil or zinc powder.

[0015] The present invention also provides the application of aqueous ion battery electrolyte in stabilizing the zinc anode interface layer.

[0016] Innovation

[0017] The introduction of Ca-ASP into the electrolyte enhances the stability of the zinc anode interface. Ca-ASP is biodegradable and environmentally friendly. The abundant -COOH and -NH2 in Ca-ASP tend to attach to the Zn anode. The adsorption layer formed can repel water molecules from contacting the zinc anode, forming a water-poor layer. Secondly, the -COOH in the aspartic acid anion has a strong effect on the Zn 2+It has strong adsorption capacity and can promote Zn 2+ The deposition kinetics of the zinc deposits were improved to obtain a dense and uniform zinc deposit. 2+ It can preferentially and selectively adsorb on the Zn surface to form an electrostatic shielding layer and inhibit the growth of zinc dendrites

[0018] Beneficial effects of the present invention:

[0019] The innovative use of a new electrolyte can produce reversible deposition and uniform fine zinc particles, greatly stabilizing the zinc anode and Zn||NH4V4O 10 Full cell. The functional electrolyte enables long-lasting Zn||Zn symmetric cells at 0.5 mA cm -2 and 0.5 mA h cm -2 The battery can be cycled for more than 2000 hours at room temperature. It has a high DOD of 86.2% within 300 hours. In particular, the battery using 0.05Ca-ASP electrolyte has a high DOD of 86.2% at 5 mA cm -2 and 1mA h cm -2 The Zn||NH4V4O has a stable cycle life of over 1800 hours, indicating that the zinc battery has good cycle stability. 10 The full battery still retains 81.03% of its specific capacity even after 2000 cycles. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The infrared spectra of various electrolytes in Example 1 are shown in FIG.

[0021] Figure 2 2 is the Raman spectrum of various electrolytes in Example 2.

[0022] Figure 3 This is a comparison diagram of the activation energies of ZSO and 0.05Ca-ASP electrolytes in Example 3.

[0023] Figure 4 This is the XRD diagram of the zinc foil in Example 4 after cycling in ZSO and 0.05Ca-ASP electrolyte.

[0024] Figure 5 This is the SEM image of the zinc foil in Example 5 after cycling in various electrolytes.

[0025] Figure 6 0.5 mA cm-2 for the Zn||Zn symmetric cell in Example 6 in various electrolytes 2 and 0.5 mA h cm -2 Circular diagram of .

[0026] Figure 75 mA cm for the Zn||Zn symmetric battery in Example 7 in various electrolytes -2 and 1mA hcm -2 Circular diagram of .

[0027] Figure 8 The Zn||Zn symmetric battery in Example 8 in various electrolytes at 10 mA cm -2 and 1mA hcm -2 cycle stability.

[0028] Fig. 9 Zn||NH4V4O in Example 9 10 Cycle diagram of a button cell battery.

[0029] Fig.10 Zn||NH4V4O in Example 10 10 Cycle diagram of a pouch cell.

[0030] Fig.11 1 mA cm for the Zn||Zn symmetric cell in Example 11 in various electrolytes -2 and 1mA h cm -2 Circular diagram of . DETAILED DESCRIPTION

[0031] The following examples are provided to further illustrate the present invention, but are not intended to limit the scope of the present invention.

[0032] Embodiment 1:

[0033] A mixed electrolyte solution with 2M zinc sulfate and water as solvent was prepared, and the addition amount of Ca-ASP was 0.00M (ZSO).

[0034] A mixed electrolyte solution with 2M zinc sulfate and water as solvent was prepared, and the amount of Ca-ASP added was 0.01M (0.01Ca-ASP).

[0035] A mixed electrolyte solution with 2M zinc sulfate and water as solvent was prepared, and the amount of Ca-ASP added was 0.03M (0.03Ca-ASP).

[0036] A mixed electrolyte solution with 2M zinc sulfate and water as solvent was prepared, and the amount of Ca-ASP added was 0.05M (0.05Ca-ASP).

[0037] A mixed electrolyte solution with 2M zinc sulfate and water as solvent was prepared, and the amount of Ca-ASP added was 0.07M (0.07Ca-ASP).

[0038] Fourier transform infrared spectroscopy was used to study different electrolytes.

[0039] Test results see Figure 1With the increase of Ca-ASP concentration, the absorption peak slightly blue-shifted, indicating that the activity of water was further reduced.

[0040] Embodiment 2:

[0041] The ZSO, 0.01Ca-ASP, 0.03Ca-ASP, 0.05Ca-ASP and 0.07Ca-ASP electrolytes in Example 1 were subjected to Raman spectroscopy tests at room temperature using a Raman spectrometer.

[0042] Test results see Figure 2 As the concentration of Ca-ASP increases, the peak position red-shifts, indicating that Ca-ASP can induce H2O to participate in the solvation structure.

[0043] Embodiment 3:

[0044] The desolvation activation energy (Ea) of the ZSO and 0.05Ca-ASP electrolytes in Example 1 was tested at 30°C, 40°C, 50°C, 60°C, and 70°C.

[0045] Test results see Figure 3 The Ea of the zinc anode in 0.05Ca-ASP electrolyte is significantly lower than that in ZSO, indicating that 0.05Ca-ASP electrolyte can accelerate the Zn 2+ of desolvation.

[0046] Embodiment 4:

[0047] ZSO and 0.05Ca-ASP electrolyte in Example 1.

[0048] The button cell test was conducted to assemble a Zn||Zn symmetrical battery. ZSO and 0.05Ca-ASP were used as electrolytes at 1 mA cm -2 , 1mA cm -2 Constant current charge and discharge test was carried out under the conditions of

[0049] After 25 cycles of deposition, the zinc negative electrode was washed with deionized water, dried, and the surface of the zinc foil was analyzed by XRD. Figure 4 After cycling in ZSO, a large amount of Zn4SO4(OH)6·xH2O hydrogen evolution byproduct appeared on the surface of zinc foil. However, the amount of byproduct on the surface of zinc foil after cycling in 0.05Ca-ASP was less. The above results show that hydrogen evolution corrosion of zinc is greatly inhibited in 0.05Ca-ASP electrolyte.

[0050] Embodiment 5:

[0051] The zinc negative electrode after the ZSO and 0.05Ca-ASP electrolyte cycles in Example 4.

[0052] The surface of zinc foil was analyzed by SEM. The test results are shown in Figure 5 In 0.05Ca-ASP, the zinc deposition is uniform and dense, while in ZSO, the zinc deposition is loose and there are a large number of irregular particles. This shows that the electrolyte can significantly improve the zinc deposition morphology, making the zinc deposition more uniform and dense, thereby inhibiting the formation of zinc dendrites.

[0053] Embodiment 6:

[0054] In Example 1, ZSO, 0.01Ca-ASP, 0.03Ca-ASP, 0.05Ca-ASP, and 0.07Ca-ASP electrolytes.

[0055] The five electrolytes were used to assemble Zn||Zn symmetric cells at 0.5 mA cm -2 , 0.5mAh cm -2 The test conditions are to carry out charge and discharge tests at room temperature.

[0056] Test results see Figure 6 At room temperature, compared with the traditional ZSO electrolyte, the Zn||Zn symmetric battery using 0.05Ca-ASP mixed electrolyte can stably cycle for h. This shows that the 0.05Ca-ASP electrolyte significantly improves the battery's cycling performance by inhibiting zinc dendrites and hydrogen evolution reaction.

[0057] Embodiment 7:

[0058] In Example 1, ZSO, 0.01Ca-ASP, 0.03Ca-ASP, 0.05Ca-ASP, and 0.07Ca-ASP electrolytes.

[0059] The five electrolytes were used to assemble Zn||Zn symmetric cells at 5 mA cm -2 , 1mAh cm -2 The test conditions are to carry out charge and discharge tests at room temperature.

[0060] Test results see Figure 7 At room temperature, the Zn||Zn symmetric battery using 0.05Ca-ASP electrolyte has a longer stable cycle time than the conventional ZSO electrolyte. This indicates that the stability of the zinc anode is greatly improved due to the inhibition of zinc dendrites and hydrogen evolution reaction by 0.05Ca-ASP electrolyte.

[0061] Embodiment 8:

[0062] The ZSO, 0.01Ca-ASP, 0.03Ca-ASP, 0.05Ca-ASP, and 0.07Ca-ASP electrolytes in Example 1 were used to assemble Zn||Zn symmetric cells at 10 mA cm -2, 1mAh cm -2 The test conditions are to carry out charge and discharge tests at room temperature.

[0063] Test results see Figure 8 The zinc symmetric battery using ZSO electrolyte can only stably cycle for 430 h, while the zinc symmetric battery using 0.05Ca-ASP electrolyte can stably cycle for h. This shows that 0.05Ca-ASP electrolyte can achieve reversible deposition and dissolution of zinc at room temperature.

[0064] Embodiment 9:

[0065] The ZSO and 0.05Ca-ASP electrolytes in Example 1 were used.

[0066] Preparation of NH4V4O 10 Positive electrode material: First, dissolve 1.17 g of ammonium metavanadate powder in 70 mL of deionized water, and then dissolve 1.891 g of oxalic acid powder in it and mix them evenly. Stir continuously for 20 min. Transfer the obtained mixed solution to a 100 mL polytetrafluoroethylene autoclave and heat it at 140 ° C for 12 hours. After cooling, the solid precipitate is collected by centrifugation with ethanol and deionized water several times and dried at 70 ° C overnight. 10 A well-mixed slurry (mass ratio of 7:2:1) of powder, conductive carbon (SuperP) and polyvinylidene fluoride (PVDF) binder was cast on a stainless steel mesh (diameter: 12 mm) to make NH4V4O 10 Cathode. The prepared electrode was dried in a vacuum oven at 70 °C for 8 h.

[0067] Battery assembly: ZSO and 0.05Ca-ASP electrolytes in Example 1 were used to assemble Zn||NH4V4O 10 The full battery was charged and discharged at room temperature under the test condition of 5A g-1.

[0068] Test results see Fig. 9 Zn||NH4V4O using ZSO electrolyte 10 The specific capacity of the full battery is significantly attenuated. 10 After 2000 cycles of the full battery, the specific capacity retention rate is 81.03%, indicating that the 0.05Ca-ASP electrolyte can achieve stable operation of the full battery.

[0069] Example 10: Using Zn||NH4V4O in Example 9 using ZSO and 0.05Ca-ASP electrolyte 10 At room temperature, the soft pack battery is 1A g -1 The current density was tested for cyclic stability.

[0070] Test results see Fig.10 Zn||NH4V4O using 0.05Ca-ASP electrolyte 10 Soft-pack batteries have better capacity retention and cycle stability than ZSO.

[0071] Example 11: Using Zn||NH4V4O in Example 10 using 0.05Ca-ASP electrolyte 10 The soft pack battery lights up the light strip.

[0072] Test results see Fig.11 The soft-pack battery using 0.05Ca-ASP electrolyte can light up the light strip at room temperature, indicating that 0.05Ca-ASP electrolyte has practical application value.

Claims

1. An aqueous zinc ion battery electrolyte, characterized in that The electrolyte comprises zinc salt and solvent, and the solvent comprises water and a Ca-ASP additive.

2. The electrolyte according to claim 1, characterized in that The molar concentration of the Ca-ASP is 0-0.07 mol / L.

3. The electrolyte according to claim 2, characterized in that The content of Ca-ASP in the solvent is 0-12.2 g / L.

4. The electrolyte according to claim 1, characterized in that The zinc salt is any one of zinc sulfate, zinc chloride, zinc nitrate, zinc acetate, zinc phosphate, zinc trifluoromethanesulfonate, zinc bistrifluoromethanesulfonyl imide, zinc tetrafluoroborate, zinc hexafluorophosphate, and zinc bisoxalate borate, or a combination of at least two thereof.

5. The electrolyte according to claim 4, characterized in that The zinc salt is zinc sulfate.

6. The electrolyte according to claim 1, characterized in that The concentration of the zinc salt in the electrolyte is 2 mol / L.

7. An aqueous zinc ion battery, characterized in that: The aqueous zinc ion battery comprises the electrolyte according to any one of claims 1 to 6.

8. The zinc ion battery according to claim 7, characterized in that: The zinc ion battery comprises a positive electrode, a membrane and a zinc negative electrode; the positive electrode is made of a zinc ion embedding and releasing material, and the zinc ion embedding and releasing material is a manganese-based material, a vanadium-based material or a combination thereof; the manganese-based material is MnO2, Ca 0.28 The vanadium-based material is one or more of V2O5, V2O3, Zn2V2O7 and KV3O8; the membrane is a glass fiber membrane or a Celgard membrane; the zinc negative electrode is zinc foil or zinc powder.

9. The zinc ion battery according to claim 8, characterized in that: The positive electrode is NH4V4O 10 ; The membrane is a glass fiber membrane; the zinc negative electrode is zinc foil.

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