Electrolyte taking phosphonate as organic additive and aqueous zinc ion battery

Abstract

The invention discloses an electrolyte taking phosphonate as an organic additive and an aqueous zinc ion battery, and belongs to the field of batteries. The invention relates to an electrolyte taking phosphonate ester as an organic additive, the electrolyte comprises the organic additive, and the organic additive comprises a phosphonate ester substance; the phosphonate substance is selected from at least one of triethyl 3-phosphonyl propionate, triethyl 4-phosphonyl butyrate, phosphonyl acetic acid and 2-phosphonyl propionic acid. The 1, 3-triethyl phosphonyl propionate (EP) is used as an interface structure modified AZIBs additive to protect a zinc negative electrode material, inhibit side reaction of a zinc negative electrode interface and induce uniform deposition of zinc dendrites, so that the cycling stability of the zinc ion battery is improved. Compared with a bare electrolyte, the cycle index of the Zn / / Na2V6O16 total battery added with the EP is increased from 200 circles to 1100 circles, and the capacity retention ratio is increased from 71% to 90.95%.

Description

TECHNICAL FIELD

[0001] The application relates to a phosphonate electrolyte as an organic additive and a water-based zinc ion battery, and belongs to the battery field. BACKGROUND

[0002] In recent years, breakthroughs in renewable energy technologies have spurred a surge in research and development of new energy storage devices. Among water-based battery systems, zinc ion batteries (AZIBs) have emerged as a promising candidate for large-scale energy storage due to their unique advantages: the negative electrode zinc metal not only has a theoretical capacity of 820 mAh g -1 -0.76 V (vs. SHE) and an ideal redox potential, but also has environmental friendliness, resource abundance, and intrinsic safety, making it a potential candidate for large-scale energy storage.

[0003] However, this system faces key bottlenecks in the industrialization process. Zinc metal negative electrodes exhibit complex behavior characteristics during electrochemical cycling: under room temperature conditions, the non-uniform electric field distribution at the electrolyte / electrode interface exacerbates the anisotropy of zinc deposition, leading to the formation of whisker-like dendritic structures with puncture risks. More seriously, the hydrogen evolution side reaction triggered by the coordination of water molecules in the Zn 2+ solvent sheath induces simultaneous electrode corrosion and the generation of zinc-based byproducts (such as Zn4SO4(OH)6·xH2O, etc.), which severely restricts the cycle life and safety of the battery.

[0004] As the "ion highway" of AZIBs systems, the electrolyte system has a multi-dimensional regulatory effect on battery performance. Its composition not only determines the ion migration rate and electrochemical stability window, but also deeply affects the electrode interface reaction kinetics through the reconstruction of the solvation structure. Studies have shown that the introduction of functional additives into zinc sulfate or zinc triflate-based electrolytes can effectively break the traditional solvation configuration: by reducing the coordination number of water molecules to suppress hydrogen evolution activity, while directionally inducing the preferential growth of the Zn(002) crystal plane, the synergistic effect of dendrite inhibition and side reaction mitigation is achieved. This strategy of optimizing the interface stability through electrolyte engineering is simple and effective, and has become an important technical path to promote the commercialization of AZIBs. In particular, organic molecular additives have unique functional group characteristics in regulating the solvation microenvironment and constructing interface protection layers, providing a new idea for the development of high-performance AZIBs. SUMMARY

[0005] In view of the problems of dendrite growth of Zn anode and side reactions (such as hydrogen evolution and zinc corrosion) caused by free water in aqueous zinc ion batteries, the application provides an electrolyte for aqueous zinc ion batteries. The electrolyte can use a phosphonate organic additive as a modifier of the electrolyte and zinc anode interface structure, so as to optimize the solvation structure, reduce the dendritic growth of the zinc anode and the side reactions caused by active water, and enhance the cycle stability of the AZIBs.

[0006] According to a first aspect of the application, an electrolyte is provided. 3-ethylidene-1-hydroxy-2, 1-oxaphosphonate (EP) is used as an AZIBs additive for interface structure modification, which protects the zinc anode material, inhibits the side reactions of the zinc anode interface, and induces uniform deposition of zinc dendrites, thereby improving the cycle stability of zinc ion batteries. Compared with the bare electrolyte, the Zn / / Na2V6O 16 The number of full cell cycles is increased from 200 to 1100, and the capacity retention rate is increased from 71% to 90.95%.

[0007] An electrolyte with a phosphonate as an organic additive, the electrolyte comprising an organic additive, the organic additive comprising a phosphonate;

[0008] The phosphonate is selected from at least one of 3-ethylidene-1-hydroxy-2, 1-oxaphosphonate, 4-ethylidene-1-hydroxy-2, 1-oxaphosphonate, phosphonate acetic acid, and 2-ethylidene-1-hydroxy-2, 1-oxaphosphonate.

[0009] Organic phosphoric acid is a compound containing an organic group and a phosphoric acid group (P-O-C bond). Such compounds exist widely in nature. The basic structure of such compounds is that a phosphorus atom is connected to four oxygen atoms, two of which are connected to an organic group through an ester bond (O-C). Phosphoric acid can destroy the solvation structure of Zn 2+ in the solution, and can also be adsorbed on the surface of the zinc anode to induce uniform deposition of zinc. This structure optimizes the desolvation of Zn 2+ , so that Zn 2+ is deposited more uniformly on the surface of the zinc anode.

[0010] The main difference between the phosphonate organic solvent and the organic phosphoric acid is that the phosphoric acid group (P-O-C bond) is replaced by the phosphonate group (C-P bond), so that the phosphorus atom is directly connected to the carbon chain (R-PO(OEt)2). Compared with the phosphoric acid group, the phosphonate group has stronger hydrolysis resistance and thermal degradation performance, and also shows stronger metal chelating ability.

[0011] Triethyl diphosphate modifies the surface of zinc negative electrode by strong ion-dipole interaction between phosphate group and zinc to improve the performance of aqueous zinc ion battery; while triethyl 3-phosphonopropionate modifies the aqueous zinc ion battery by a synergistic mechanism of dual functional groups formed by phosphonate group and hydrophobic alkyl chain. The close combination of triethyl 3-phosphonopropionate and Zn 2+ results in the hydrophobic alkyl end of triethyl 3-phosphonopropionate facing outward, thus effectively reducing the side reactions (such as hydrogen evolution and zinc corrosion) caused by desolvated H2O on the electrode surface, and optimizing the environment on the electrode surface.

[0012] Further, the application adopts phosphonate substances as electrolyte additives, such as triethyl 3-phosphonopropionate (EP, alias: 3-diethyl phosphonopropionate ethyl ester), the structural formula is:

[0013]

[0014] In the prior art (CN2024118134343), triethyl diphosphate is used as an electrolyte additive, and the structural formula is

[0015]

[0016] The difference between the two is the hydrophobic alkyl chain (-C3H7). The phosphonate group of the 3-phosphonopropionate triethyl ester (EP) of the application is (C-P bond), and the phosphate group of the triethyl diphosphate of the prior art is (P-O-C bond). The phosphorus atom of the application is directly connected to the carbon chain (R-PO(OEt)2). The cycle stability is better, and the cycle stability at low current density is better.

[0017] In specific use, the phosphate substance can be used together with the phosphonate substance as an additive. For example, the additive is triethyl phosphate, trimethyl phosphate and triethyl 3-phosphonopropionate.

[0018] Optionally, the electrolyte further comprises a zinc salt and water.

[0019] Optionally, the mass ratio of the phosphonate substance in the electrolyte is 1wt%-20wt%

[0020] Optionally, the mass ratio of the phosphonate substance in the electrolyte is 5wt%-10wt%.

[0021] Optionally, the mass ratio of the phosphonate substance in the electrolyte is independently selected from any value or range between any two values of 1wt%, 3wt%, 5wt%, 7wt%, 8wt%, 10wt%, 12wt%, 14wt%, 16wt%, 18wt%, 20wt%.

[0022] Optionally, the molar concentration of the zinc salt is 0.1 mol / L-5 mol / L.

[0023] Optionally, the molar concentration of the zinc salt is 1.5 mol / L-2.5 mol / L.

[0024] Optionally, the molar concentration of the zinc salt is independently selected from any value or range of values between any two values of 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 0.7 mol / L, 1.0 mol / L, 1.2 mol / L, 1.5 mol / L, 1.7 mol / L, 2.0 mol / L, 2.5 mol / L, 3.0 mol / L, 3.5 mol / L, 4.0 mol / L, 4.5 mol / L, 5.0 mol / L.

[0025] Optionally, the zinc salt is selected from at least one of zinc sulfate, zinc chloride, zinc nitrate, zinc trifluoromethanesulfonate, zinc trifluoromethanesulfonate, zinc acetate.

[0026] According to a second aspect of the present application, there is provided a water-based zinc ion battery.

[0027] A water-based zinc ion battery, comprising a positive electrode, a negative electrode and an electrolyte;

[0028] The positive electrode comprises a zinc, copper or vanadium-based material;

[0029] The negative electrode comprises zinc;

[0030] The electrolyte is selected from the electrolyte described above.

[0031] Optionally, the vanadium-based material is selected from at least one of sodium vanadate, potassium vanadate, vanadium pentoxide.

[0032] Optionally, the negative electrode is selected from at least one of zinc foil, zinc sheet, foamed zinc, zinc powder, zinc rod.

[0033] The water-based zinc ion battery comprises a positive electrode, a negative electrode and a separator for separating the positive electrode and the negative electrode, and the cavity between the positive electrode and the negative electrode is filled with the electrolyte.

[0034] The electrolyte according to the present application has high specific capacity, good rate performance and cycle stability when used in a water-based zinc ion battery.

[0035] The beneficial effects that can be produced by the present application include:

[0036] This application provides phosphonates as organic additives in electrolytes and aqueous zinc-ion batteries. Phosphonate organic compounds possess excellent interface regulation capabilities; their phosphate groups have a strong affinity for the zinc anode surface, preferentially adsorbing and participating in the formation of a more stable interfacial protective layer. This film effectively guides uniform zinc ion deposition, significantly inhibits dendrite growth, and physically blocks water molecule contact, greatly reducing hydrogen evolution reaction and zinc corrosion. Furthermore, phosphonate groups can partially enter the zinc ion solvation sheath, reducing the activity of coordinated water molecules, further suppressing side reactions and potentially optimizing deposition kinetics. The 3-phosphonopropionate triethyl ester used in this patent utilizes a bifunctional synergistic mechanism between its phosphonate group (-PO(OEt)2) and the ethyl propionate flexible segment (-CH2COOCH2CH3) to achieve Zn… 2+ Coordinated water molecule substitution, enhanced interfacial compatibility, and directional deposition of zinc (002) crystal planes ultimately enabled the full cell to achieve a 1Ag... -1 After 1100 cycles at high current density, the capacity retention rate still reaches over 80%. This effectively improves the initial capacity and cycle stability of aqueous zinc-ion batteries, representing a significant technological advancement and a strong potential for industrialization. Attached Figure Description

[0037] Figure 1 The zinc-zinc symmetric cells prepared for Examples 1-3 and Comparative Example 1 were tested at 1 mA / cm². -2 At a current density of 1 mAh / cm -2 SEM images of the zinc foil surface after 50 cycles of fixed capacity charge and discharge, (a) corresponds to Example 1, and (b), (c), and (d) correspond to Examples 1, 2, and 3, respectively;

[0038] Figure 2 The full cell prepared for Comparative Example 2 was in 1Ag -1 Specific capacity data measured at current density;

[0039] Figure 3 The full cell prepared for Comparative Example 3 was in 1Ag -1 Specific capacity data measured at current density;

[0040] Figure 4 The full cell prepared for Comparative Example 4 was in 1Ag -1 Specific capacity data measured at current density;

[0041] Figure 5 The zinc zinc symmetric samples prepared for Example 2 and Comparative Example 1 were subjected to different current densities (1, 1.5, 2, 2.5, 3 mA / cm²). -2 ) below, with 1mAh cm -2 The fixed capacity, and the charge / discharge rate data;

[0042] Figure 6 The zinc zinc symmetric samples prepared in Examples 1-3 and Comparative Example 1 were subjected to a current density of 1 mA cm⁻¹. -2 Below, with 1mAh cm -2 The fixed capacity is used to perform charge and discharge cycle data;

[0043] Figure 7 The full cells prepared for Examples 1-3 and Comparative Example 1 were measured at 1 A g. -1 Specific capacity data measured at the current density;

[0044] Figure 8 The full cells prepared for Comparative Examples 1, 2, 3 and 2 were tested at 1 Ag. -1 The specific capacity data were measured at the current density. Detailed Implementation

[0045] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0046] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0047] Unless otherwise specified, all test methods are standard and all instrument settings are those recommended by the manufacturer.

[0048] Material:

[0049] Triethyl 3-phosphonopropionate, triethyl diphosphate, trimethyl phosphate, triethyl phosphate, vanadium pentoxide, and sodium hydroxide were all purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0050] Zinc trifluoromethanesulfonate and N-methylpyrrolidone were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0051] Anhydrous ethanol and conductive carbon black were purchased from Sinopharm Group.

[0052] The fiberglass diaphragm was purchased from Whatman, GE Healthcare Life Sciences.

[0053] The graphite paper comes from Langfang Hengtong Sealing Materials Co., Ltd.

[0054] The rest are commercially available.

[0055] All materials were used without further purification.

[0056] Morphological characterization was performed using a scanning electron microscope (SEM, SU8010).

[0057] Cyclic voltammetry (CV) tests were performed on a cathode || Zn battery on a Princeton electrochemical workstation at a scan rate of 0.1 mV s-1, and the voltage range was 0.2-1.6 V. The CV test voltage range of Zn||Cu and Zn||Ti was -0.3 V-0.2 V, and the scan rate was 0.1 mV s -1 . The electrochemical impedance spectroscopy (EIS) was collected in the range of 100000 Hz-0.1 Hz. Constant current charge and discharge tests and galvanostatic intermittent titration technique (GITT) tests were performed on a Newar test system. Linear sweep voltammetry (LSV) and linear polarization curve tests were performed in different electrolytes in a three-electrode system with zinc foil as the working electrode (W), platinum wire as the counter electrode (C), and Ag / Ag Cl as the reference electrode (R). The scan rate was 2 mV s-1, and the scan potential range was -1.25- -0.75 V. All batteries were assembled in the open air and aged for 6 hours before electrochemical testing.

[0058] Example 1

[0059] Preparation of the negative electrode material: pure zinc foil was cut into 14 mm diameter electrodes using a slicer, and the electrodes were ultrasonically cleaned in anhydrous ethanol solution for 1-2 seconds. The cleaned electrodes were laid flat and dried in a natural environment for use as negative electrodes.

[0060] Preparation of 3-phosphonopropionic acid triethyl ester electrolyte: at room temperature, 3-phosphonopropionic acid triethyl ester was added to 10 mL of deionized water at a volume ratio of 1% of the additive solution, and stirred and dispersed for 24 hours to obtain a uniform clear solution, i.e., an additive aqueous solution, and then 2 mol / L zinc trifluoromethanesulfonate was added to the above additive aqueous solution and stirred and dispersed for 24 hours to obtain the 3-phosphonopropionic acid triethyl ester electrolyte.

[0061] Battery assembly: 1) Zinc-zinc symmetric battery: Two pieces of the same zinc foil as the positive and negative electrodes. Put a piece of cut zinc foil into the positive electrode shell, put in the glass fiber diaphragm, use a pipette to drop 70 μL of 3-phosphonopropionic acid triethyl ester electrolyte, then put another piece of zinc foil on top of the diaphragm, then put in a piece of stainless steel gasket, then the spring, and finally the negative electrode shell is buckled, and the battery is packaged with a battery packaging machine, and a water-based zinc ion symmetric button cell modified by electrolyte is obtained, which is marked as Zn@Zn-EP1 symmetric button cell. 2) Full battery: A piece of zinc foil as the negative electrode. Put a piece of cut vanadium-based positive electrode material into the positive electrode shell, put in the glass fiber diaphragm, use a pipette to drop 70 μL of 3-phosphonopropionic acid triethyl ester electrolyte, then put a piece of zinc foil negative electrode on top of the diaphragm, then put in a piece of stainless steel gasket, then the spring, and finally the negative electrode shell is buckled, and the battery is packaged with a battery packaging machine, and a water-based zinc ion button cell modified by electrolyte is obtained, which is marked as Zn@V-EP1 button cell.

[0062] Example 2

[0063] Example 2 provides a method for preparing 3-phosphonopropionic acid triethyl ester electrolyte, the raw materials and preparation method are the same as in Example 1, the difference is that the volume ratio of added 3-phosphonopropionic acid triethyl ester to deionized water is 2%, the obtained water-based zinc ion symmetric button cell is marked as Zn@Zn-EP2 symmetric button cell, and the water-based zinc ion button cell is marked as Zn@V-EP2 button cell.

[0064] Example 3

[0065] Example 3 provides a method for preparing 3-phosphonopropionic acid triethyl ester electrolyte, the raw materials and preparation method are the same as in Example 1, the difference is that the volume ratio of added 3-phosphonopropionic acid triethyl ester to deionized water is 3%, the obtained water-based zinc ion symmetric button cell is marked as Zn@Zn-EP3 symmetric button cell, and the water-based zinc ion button cell is marked as Zn@V-EP3 button cell.

[0066] Example 4

[0067] The difference from the example is that 3-phosphonopropionic acid triethyl ester is replaced by 4-phosphonobutyric acid triethyl ester, and the raw materials and preparation method are the same as in Example 1.

[0068] Example 5

[0069] The difference from the example is that 3-phosphonopropionic acid triethyl ester is replaced by phosphonoacetic acid, and the raw materials and preparation method are the same as in Example 1.

[0070] Example 6

[0071] The difference from the example is that 3-phosphonopropionic acid triethyl ester is replaced by 2-phosphonoacetic acid, and the raw materials and preparation method are the same as in Example 1.

[0072] Comparative Example 1

[0073] Preparation of negative material: The pure zinc foil was cut into 14 mm diameter electrode pieces by a slicer, and the electrode pieces were ultrasonically cleaned in anhydrous ethanol solution for 1-2 seconds. The cleaned electrode pieces were laid flat and dried in a natural environment for use as negative electrodes.

[0074] Preparation of zinc sulfonate electrolyte: At room temperature, 2 mol / L zinc sulfonate was dissolved in 10 mL of deionized water, and stirred and dispersed for 24 hours to obtain a uniform and clear solution, i.e. zinc sulfonate aqueous solution.

[0075] Battery assembly: 1) Zinc-zinc symmetric battery: Two identical zinc foils were used as positive and negative electrodes. One cut zinc foil was placed in the positive electrode shell, a glass fiber separator was placed, 70 μL of zinc sulfonate electrolyte was dropped using a pipette, and then another zinc foil was placed on top of the separator. A stainless steel gasket was then placed, followed by a spring, and finally the negative electrode shell was buckled, and the battery was packaged using a battery packaging machine, to obtain a water-based zinc ion symmetric button cell modified by electrolyte, marked as Zn@Zn symmetric button cell. 2) Full cell: One zinc foil was used as the negative electrode. One cut vanadium-based positive electrode material was placed in the positive electrode shell, a glass fiber separator was placed, 70 μL of zinc sulfonate electrolyte was dropped using a pipette, and then another zinc foil negative electrode was placed on top of the separator. A stainless steel gasket was then placed, followed by a spring, and finally the negative electrode shell was buckled, and the battery was packaged using a battery packaging machine, to obtain a water-based zinc ion button cell modified by electrolyte, marked as Zn@V button cell.

[0076] Comparative Example 2

[0077] Comparative Example 2 provides a preparation method of trimethyl phosphate electrolyte, the raw materials and preparation method are the same as Example 2, the difference is that the additive of the electrolyte is trimethyl phosphate, and the obtained water-based zinc ion button cell is marked as Zn@V-TMP button cell.

[0078] Comparative Example 3

[0079] Comparative Example 3 provides a preparation method of triethyl phosphate electrolyte, the raw materials and preparation method are the same as Example 2, the difference is that the additive of the electrolyte is triethyl phosphate, and the obtained water-based zinc ion button cell is marked as Zn@V-TEP button cell.

[0080] Comparative Example 4

[0081] Comparative Example 4 provides a preparation method of triethyl diphosphate electrolyte, the raw materials and preparation method are the same as Example 2, the difference is that the additive of the electrolyte is triethyl diphosphate, and the obtained water-based zinc ion button cell is marked as Zn@V-TP button cell.

[0082] Performance test and characterization: The aqueous zinc-ion symmetric coin cells assembled with electrolyte prepared by the above examples and comparative examples, the full cells composed of vanadium-based materials, the electrolytic cells composed of three-electrode method (working electrode: zinc sheet; reference electrode: silver chloride; counter electrode: platinum wire) were used for morphology characterization and electrochemical performance test. The following performance test and characterization were carried out at room temperature.

[0083] Figure 1 In the figure, (a) is the morphology of zinc foil after 50 cycles of charge and discharge of the zinc-zinc symmetric battery prepared by comparative example 1; (b) is the morphology of zinc foil after 50 cycles of charge and discharge of the zinc-zinc symmetric battery prepared by example 1; (c) is the morphology of zinc foil after 50 cycles of charge and discharge of the zinc-zinc symmetric battery prepared by example 2; (d) is the morphology of zinc foil after 50 cycles of charge and discharge of the zinc-zinc symmetric battery prepared by example 3. From Figure 1 It can be seen that compared with comparative example 1 without additive modification, the zinc foil morphology in example 2 is smoother. It shows that the zinc deposition in the example is transverse growth, and the deposition is more uniform, which effectively inhibits the growth of zinc negative electrode dendrites.

[0084] Figure 2 The discharge specific capacity data of the full cell prepared by comparative example 2 was measured under the condition of 1 A g -1 From Figure 2 It can be found that the full cell of comparative example 2 appeared multiple data fluctuation phenomenon in the cycle process, and accompanied by capacity attenuation.

[0085] Figure 3 The discharge specific capacity data of the full cell prepared by comparative example 3 was measured under the condition of 1 A g -1 From Figure 3 It can be found that the capacity of the full cell of comparative example 3 decreased in the later stage of the cycle process.

[0086] Figure 4 The discharge specific capacity data of the full cell prepared by comparative example 4 was measured under the condition of 1 A g -1 From Figure 4 It can be found that the capacity of the full cell of comparative example 4 decreased in the later stage of the cycle process.

[0087] Figure 5 The rate data of the zinc-zinc symmetric battery prepared by example 2 and comparative example 1 was carried out at different current densities (1, 1.5, 2, 2.5, 3 mA cm -2 ) under the condition of fixed capacity of 1 mAh cm -2 From Figure 5 It can be found that the polarization potential of the modified electrolyte in example 2 is smaller than that of the unmodified electrolyte in comparative example 1, and example 2 has better rate performance than comparative example 1.

[0088] Figure 6 The discharge specific capacity data of the full batteries prepared for Example 1, Example 2, Example 3 and Comparative Example 1 were measured under the condition of 1 Ag -2 The cycle data of the charge and discharge were carried out under the condition of 1 mAh cm -2 The discharge specific capacity data of the full batteries prepared for Example 1, Example 2, Example 3 and Comparative Example 1 were measured under the condition of 1 Ag Figure 6 It can be found that the modified electrolyte in Example 2 has better cycle performance than Comparative Example 1, Example 1 and Example 3.

[0089] Figure 7 The discharge specific capacity data of the full batteries prepared for Example 1, Example 2, Example 3 and Comparative Example 1 were measured under the condition of 1 Ag -1 The discharge specific capacity data of the full batteries prepared for Example 1, Example 2, Example 3 and Comparative Example 1 were measured under the condition of 1 Ag Figure 7 It can be found that the full batteries of Example 1, Example 2 and Example 3 using the modified electrolyte have higher specific capacity retention rate, and especially the specific capacity retention rate of Example 2 after 1100 cycles reaches more than 90%. It can be seen that the capacity retention rate of the present embodiment is improved, further verifying the modification effect of the phosphonate additive.

[0090] Figure 8 The discharge specific capacity data of the full batteries prepared for Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 were measured under the condition of 1 Ag -1 The discharge specific capacity data of the full batteries prepared for Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 were measured under the condition of 1 Ag Figure 8 It can be found from the comparison that the performance of Example 2 is much better than that of Comparative Example 1, Comparative Example 2 and Comparative Example 3, and the cycle life is much higher than that of Comparative Example 4, and the comprehensive performance is the best.

[0091] It can be proved by the comparison of Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 that the phosphonate additive indeed has good inhibition effect on dendrite growth, hydrogen evolution corrosion and formation of by-products of zinc negative electrode, and the performance is better than that of organic phosphoric acid additive. The aqueous zinc ion battery obtained by adding the phosphonate additive in the present embodiment has high specific capacity, good rate performance and cycle stability.

[0092] The above is only a few embodiments of the present application, and does not limit the present application in any form. Although the present application is disclosed with the preferred embodiments, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the disclosed technical content without departing from the scope of the technical solution of the present application, which are equivalent to equivalent embodiments, and belong to the scope of the technical solution.

Claims

1. An electrolyte using phosphonates as organic additives, characterized in that, The electrolyte includes organic additives, including phosphonates. The phosphonate is selected from at least one of triethyl 3-phosphonopropionate, triethyl 4-phosphonobutyrate, phosphonoacetic acid, and 2-phosphonopropionic acid.

2. The electrolyte according to claim 1, characterized in that, The electrolyte also includes zinc salt and water.

3. The electrolyte according to claim 2, characterized in that, The phosphonate esters are present in an electrolyte solution at a mass ratio of 1 wt% to 20 wt%.

4. The electrolyte according to claim 2, characterized in that, The phosphonate esters are present in the electrolyte at a mass ratio of 5 wt% to 10 wt%.

5. The electrolyte according to claim 2, characterized in that, The molar concentration of zinc salt is 0.1 mol / L-5 mol / L.

6. The electrolyte according to claim 2, characterized in that, The molar concentration of zinc salt is 1.5 mol / L-2.5 mol / L.

7. The electrolyte according to claim 2, characterized in that, The zinc salt is selected from at least one of zinc sulfate, zinc chloride, zinc nitrate, zinc trifluoromethanesulfonate, zinc trifluoroformylsulfonate, and zinc acetate.

8. An aqueous zinc-ion battery, characterized in that, The aqueous zinc-ion battery includes a positive electrode, a negative electrode, and an electrolyte; The positive electrode includes zinc, copper, or vanadium-based materials; The negative electrode comprises zinc; The electrolyte is selected from the electrolytes described in any one of claims 1 to 7.

9. The aqueous zinc-ion battery according to claim 8, characterized in that, The vanadium-based material is selected from at least one of sodium vanadate, potassium vanadate, and vanadium pentoxide.

10. The aqueous zinc-ion battery according to claim 8, characterized in that, The negative electrode is selected from at least one of zinc foil, zinc sheet, zinc foam, zinc powder, and zinc rod.

Images