Cellulose acetylpropionate optimized aqueous zinc ion battery electrolyte and preparation method thereof

Abstract

This invention discloses a cellulose levulinate-optimized aqueous zinc-ion battery electrolyte and its preparation method. The aqueous zinc-ion battery electrolyte contains cellulose levulinate. The preparation method includes: S1. preparing an aqueous zinc-ion battery electrolyte; S2. adding cellulose levulinate to the aqueous zinc-ion battery electrolyte to obtain the optimized aqueous zinc-ion battery electrolyte. The preparation method of the aqueous zinc-ion battery electrolyte of this invention is simple, uses readily available materials, and is environmentally friendly. Furthermore, this invention is the first to utilize cellulose ester macromolecular compounds to optimize an aqueous zinc-ion battery electrolyte, solving technical problems such as zinc dendrite growth and parasitic side reactions in aqueous zinc-ion battery electrolytes. In addition, compared with traditional water-soluble cellulose-optimized aqueous zinc-ion battery electrolytes, the optimized aqueous zinc-ion battery electrolyte of this invention has a stronger ability to inhibit zinc dendrite growth, fewer side reactions, faster zinc ion transport, and superior electrochemical performance.

Description

Technical Field

[0001] This invention relates to an aqueous zinc-ion battery electrolyte and its preparation method, particularly a cellulose acetylpropionate-optimized aqueous zinc-ion battery electrolyte and its preparation method. Background Technology

[0002] Rechargeable aqueous zinc-ion batteries (ZIBs) benefit from the intrinsic safety of aqueous electrolytes and the significant advantages of zinc metal anodes, such as abundant resources, low toxicity, and high theoretical capacity (820 mAh g). -1 Or 5855mAhcm -3 Its characteristics, such as low redox potential (-0.762V vs. standard hydrogen electrode), have attracted widespread attention and are considered a strong competitor to lithium-ion batteries.

[0003] Despite the numerous advantages of aqueous zinc-ion battery electrolytes (ZIBs), the following issues must be addressed before their large-scale application. First, the highly concentrated anions and free water solvent molecules at the zinc anode / electrolyte interface can lead to undesirable side reactions during electroplating / stripping, such as pH changes on the zinc anode surface, gas generation, uneven zinc deposition, and byproduct accumulation. Second, during the desolvation process of aqueous zinc-ion battery electrolytes, some bound water is lost from [Zn(H₂O)₆]. 2+ The hydrogen released from the solvated sheath to the zinc anode interface promotes the hydrogen evolution reaction, and the resulting electrochemical corrosion is very detrimental to the zinc anode, usually accompanied by severe zinc dendrite formation and corrosion.

[0004] To unlock the potential of zinc anodes, researchers have proposed numerous interface control methods, such as artificial interface layers, double-layer reconstruction, and electrolyte formulation optimization. Among these, electrolyte formulation optimization is a direct and effective method to mitigate or eliminate side reactions of zinc anodes in aqueous electrolytes.

[0005] Traditional electrolyte formulation optimization methods employ small-molecule additives to improve the solvation structure and reconstruct the hydrogen bond network of aqueous zinc-ion battery electrolytes, thereby suppressing parasitic water side reactions and severe zinc dendrite formation. While most small-molecule additives can improve the stability of the zinc anode / electrolyte interface to some extent, allowing zinc ions to deposit in a planar manner, these additives often require excessive use of low-boiling-point, highly polar organic solvents, such as acetone, tetrahydrofurfuryl alcohol, and tetrahydrofuran. This increases environmental, safety, and cost pressures, contradicting the principles of advanced aqueous ZIBs and hindering their large-scale deployment. Furthermore, these small-molecule additives cannot fundamentally suppress zinc anode-water contact because they cannot form a high-quality protective layer quickly enough. Some additives may also decompose by consuming electrons from the zinc anode, leading to poor coulombic efficiency and reversibility.

[0006] In recent years, macromolecular additives with high structural stability and abundant functional groups have shown great potential in regulating the solvation structure of zinc ions and suppressing side reactions. During electroplating / stripping, macromolecular additives can often adsorb onto the zinc anode surface to form a high-quality protective layer. For example, traditional water-soluble cellulose macromolecules such as water-soluble methyl cellulose (MC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), and carboxymethyl cellulose (CMC) can largely overcome the aforementioned technical problems when added to aqueous zinc-ion battery electrolytes. However, these water-soluble celluloses require etherification reactions, which produce byproducts such as hydrogen chloride, and the preparation process is not environmentally friendly.

[0007] Patent CN109134670A discloses a cellulose levulinate and its preparation method. A water-soluble cellulose levulinate is obtained through a transesterification reaction using cellulose and levulinic esters or angelic lactone as raw materials. This cellulose levulinate and its process have advantages such as simple preparation, no by-product generation (an atom-economic reaction), and environmentally friendly use of natural biomass as raw material. It is worth noting that traditional nonionic alkyl cellulose esters have high substitution degrees and glass transition temperatures, are insoluble in water, and are even difficult to disperse in water. This is also true for similar cellulose levulinates and mixed esters.

[0008] In other words, although this cellulose levulinate belongs to the cellulose ester class, its biggest difference from other cellulose esters is its water solubility, and no other water-soluble cellulose esters have been reported to date. Furthermore, compared to traditional water-soluble celluloses such as methylcellulose (MC), hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), and carboxymethylcellulose (CMC), the cellulose levulinate described in this application belongs to a completely different type of cellulose-based macromolecular compound.

[0009] For the two reasons mentioned above, there is currently no evidence to suggest that cellulose ester macromolecular compounds have been used in aqueous zinc-ion battery electrolytes to solve scientific problems such as zinc dendrite growth, side reactions, and slow zinc ion transport kinetics in aqueous zinc-ion batteries. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention provides a cellulose levulinate-optimized aqueous zinc-ion battery electrolyte and its preparation method. The preparation method of this invention's cellulose levulinate-optimized aqueous zinc-ion battery electrolyte is simple, uses readily available materials, and is environmentally friendly. Furthermore, this invention is the first to utilize cellulose ester macromolecular compounds to optimize an aqueous zinc-ion battery electrolyte, solving technical problems such as zinc dendrite growth in aqueous zinc-ion battery electrolytes. In addition, compared to traditional water-soluble cellulose-optimized aqueous zinc-ion battery electrolytes, the optimized aqueous zinc-ion battery electrolyte of this invention exhibits stronger inhibition of zinc dendrite growth, fewer side reactions, faster zinc ion transport, and superior electrochemical performance.

[0011] The technical solution of the present invention:

[0012] A cellulose levulinate-optimized aqueous zinc-ion battery electrolyte, wherein cellulose levulinate is added to the aqueous zinc-ion battery electrolyte.

[0013] Preferably, the aforementioned cellulose levulinate optimizes the aqueous zinc-ion battery electrolyte, wherein the molar concentration of the cellulose levulinate in the aqueous zinc-ion battery electrolyte is 0.001-1M.

[0014] Preferably, the aforementioned cellulose levulinate optimizes the aqueous zinc-ion battery electrolyte, wherein the molar concentration of the cellulose levulinate in the aqueous zinc-ion battery electrolyte is 0.01-0.5M.

[0015] Preferably, the aforementioned cellulose acetylpropionate-optimized aqueous zinc-ion battery electrolyte is wherein the zinc source in the aqueous zinc-ion battery electrolyte is one or any combination of ZnSO4, ZnCl2, Zn(ClO4)2, Zn(CH3COO)2 or Zn(CF3SO3)2.

[0016] Preferably, the aforementioned cellulose acetylpropionate optimizes the aqueous zinc-ion battery electrolyte, wherein the molar concentration of the zinc source in the aqueous zinc-ion battery electrolyte is 0.1-3M.

[0017] Preferably, the aforementioned cellulose acetylpropionate optimizes the aqueous zinc-ion battery electrolyte, wherein the molar concentration of the zinc source in the aqueous zinc-ion battery electrolyte is 0.5-2M.

[0018] A method for preparing the aforementioned cellulose levulinate-optimized aqueous zinc-ion battery electrolyte includes the following steps:

[0019] S1. Take a zinc source and add water to prepare an aqueous zinc-ion battery electrolyte;

[0020] S2. Take cellulose levulinate and add it to the aqueous zinc-ion battery electrolyte of S1. Stir well to obtain the cellulose levulinate-optimized aqueous zinc-ion battery electrolyte.

[0021] Preferably, in the aforementioned method for preparing the optimized aqueous zinc-ion battery electrolyte using cellulose levulinate, the cellulose levulinate is prepared by the following method:

[0022] S1. Mix cellulose, organic base and organic solvent, wherein the mass percentage of cellulose is 1-20%, the mass percentage of organic base is 0.5-30%, and the remainder is organic solvent; react in a CO2 atmosphere at a pressure of 1-10 MPa and a temperature of 30-100℃ for 1-12 hours to obtain a cellulose solution;

[0023] S2. Add levulinic acid ester or angelica lactone to the cellulose solution, wherein the molar ratio of the amount of levulinic acid ester or angelica lactone added to the amount of hydroxyl groups on glucose units in the cellulose in the cellulose solution is 0.5-10:1; react at 50-150℃ for 0.1-48 hours to obtain a cellulose levulinic acid ester solution.

[0024] S3. Pour the cellulose levulinate solution into C1-C4 lower fatty alcohols, ethyl acetate or water, and after washing, precipitation, filtration and drying, obtain cellulose levulinate.

[0025] Preferably, in the aforementioned method for preparing the cellulose acetylpropionate-optimized aqueous zinc-ion battery electrolyte, the cellulose is selected from microcrystalline cellulose, α-cellulose, or any combination of one or more plant celluloses isolated from cotton, wood pulp, bamboo pulp, or agricultural and forestry lignocellulose waste.

[0026] The organic base has an acid-base dissociation constant greater than 20 and has the following structural characteristics:

[0027]

[0028] The organic solvent is selected from one or more of dimethyl sulfoxide, N-methylpyrrolidone, tetramethylurea, tetraethylurea, N,N-dimethylimidazolinone, N,N-dimethylformamide, N,N-diethylacetamide, pyrrolidone, 2-azahexanecyclohexanone, N,N-dimethylpropenylurea or sulfolane;

[0029] In S3, the volume ratio of cellulose acetopropionate solution to C1-C4 lower fatty alcohols, ethyl acetate, or water is 0.5-10:1.

[0030] A battery containing the aforementioned cellulose levulinate-optimized aqueous zinc-ion battery electrolyte.

[0031] The beneficial effects of this invention are:

[0032] 1. The cellulose levulinate used in this invention to optimize the electrolyte of aqueous zinc-ion batteries is completely different from traditional water-soluble cellulose. It is a cellulose ester macromolecular compound that can be prepared using natural cellulose and levulinate ester or angelic lactone as raw materials. The preparation method is simple, the materials are readily available, and it is environmentally friendly.

[0033] 2. This invention is the first to utilize cellulose ester macromolecular compounds to optimize the electrolyte of aqueous zinc-ion batteries. Similar to traditional water-soluble cellulose, it can alter the zinc ion solvation structure, improve zinc ion transport kinetics, solve the zinc anode / electrolyte interface problem, and suppress zinc dendrites and other side reactions. Furthermore, cellulose levulinate preferentially adsorbs and forms a polymer protective layer in situ, creating an inorganic-organic bilayer solid electrolyte interface rich in ZnCO3, ZnF2, and ZnS components. This homogenizes zinc deposition and improves the electrochemical performance of aqueous zinc-ion batteries.

[0034] 3. Compared with traditional water-soluble cellulose-optimized aqueous zinc-ion battery electrolytes, the cellulose acetopropionate used in this invention for optimizing aqueous zinc-ion battery electrolytes has functional groups such as hydroxyl, ether, ester, and carbonyl groups, and exhibits superior performance in inhibiting zinc dendrite growth and improving electrochemical performance. Attached Figure Description

[0035] Figure 1 This invention provides a comparison of the water-soluble cellulose acetylpropionate and its synthetic route with existing reports on water-soluble cellulose.

[0036] Figure 2 These are optical images of the 1M Zn(CF3SO3)2 electrolyte of Comparative Example 1 and the electrolytes optimized with water-soluble cellulose levulinate in Examples 1-4. The images demonstrate the excellent miscibility and long-term stability of water-soluble cellulose levulinate in the Zn(CF3SO3)2 zinc salt solution.

[0037] Figure 3 This is a comparison chart of the battery cycle performance of the 1M Zn(CF3SO3)2 electrolyte in Comparative Example 1 and the electrolytes optimized with water-soluble cellulose levulinate in Examples 1-4. As can be seen from the chart, at 1 mA / cm²... -2 Current density and 1mAhcm -2 In the cycling of Zn / / Zn symmetric cells with areal capacity, water-soluble cellulose acetylacetate additives can significantly improve the reversible electroplating / stripping life of zinc ions.

[0038] Figure 4This is a comparison graph of the cycle performance of Zn / / Zn symmetric batteries in Comparative Examples 2-4 and Example 3 of the present invention. As can be seen from the graph, at 1 mA / cm... -2 Current density and 1mAhcm -2 In the cycling of Zn / / Zn symmetric cells at the areal capacity, compared with commercially available methylcellulose (571 hours of cycling), hydroxypropylcellulose (678 hours of cycling), and carboxymethylcellulose (1000 hours of cycling), the water-soluble cellulose levulinate additive can significantly improve the reversible electroplating / stripping life of zinc ions, and has excellent ability to inhibit zinc dendrite growth and better cycle life (1800 hours of cycling).

[0039] Figure 5 Optical images and Fourier transform infrared (FTIR) images of pure zinc foil after seven days of immersion in the electrolyte of 1MZn(CF3SO3)2 (Comparative Example 1) and the electrolyte optimized with water-soluble cellulose levulinate (Example 3). The images show that when the zinc foil is irradiated with a 365nm UV lamp, the electrolyte optimized with water-soluble cellulose levulinate rapidly forms a dense and uniform protective layer on the zinc foil surface, effectively blocking water contact with the zinc foil and inhibiting side reactions and corrosion of the zinc foil. FTIR further confirms the formation of the in-situ protective layer of water-soluble cellulose levulinate.

[0040] Figure 6 After assembling a Zn / / Zn symmetric cell with Zn(CF3SO3)2 electrolyte as Comparative Example 1 of this invention, at 1 mA cm -2 Current density and 1mAhcm -2 The image shows a SEM image of the zinc anode after 100 cycles at the specified area capacity. Due to uneven zinc ion deposition and an unstable zinc anode / electrolyte interface, a large number of zinc dendrites grow on the zinc anode surface, which can pierce the battery separator, leading to battery short circuits and failure.

[0041] Figure 7 After assembling a Zn / / Zn symmetric cell with the electrolyte optimized for water-soluble cellulose levulinate in Example 3 of this invention, at 1 mA cm⁻¹ -2 Current density and 1mAhcm -2 SEM images of the zinc anode after 100 cycles at the area capacity. Water-soluble cellulose levulinate can induce uniform deposition of zinc ions and construct a stable polymer interface layer in situ, allowing zinc ions to grow along the (002) plane, further stabilizing the zinc anode / electrolyte interface.

[0042] Figure 8 After assembling Zn / / Zn symmetric cells with the Zn(CF3SO3)2 electrolyte of Comparative Example 1 and the water-soluble cellulose levulinate-optimized electrolyte of Example 3, the cells were tested at 1 mA / cm. -2Current density and 1mAhcm -2 The image shows the XRD pattern of the zinc anode after 100 cycles at the area capacity. It can be seen from the figure that a large number of zinc dendrite byproducts grew on the surface of the zinc anode using the Zn(CF3SO3)2 electrolyte of Comparative Example 1, which are Zn... x OTf y (OH) 2x-y ·nH2O. In contrast, the zinc anode surface using an electrolyte optimized with water-soluble cellulose levulinate showed only weak byproduct peaks. Further analysis of the (002) / (100) and (002) / (101) ratios revealed that the electrolyte optimized with water-soluble cellulose levulinate preferentially deposited zinc ions onto the (002) crystal plane, resulting in a flat, uniform, and dense zinc anode interface.

[0043] Figure 9 After assembling an in-situ Zn / / Zn symmetric cell with the electrolyte optimized for water-soluble cellulose levulinate in Example 3, at 10 mA / cm -2 X-ray photoelectron spectroscopy (XPS) spectra of zinc anodes at different etching depths after 60 min of current density deposition were obtained. The XPS spectra at different depths revealed that the zinc deposition process formed an inorganic layer rich in ZnF2 and ZnS (near the zinc anode), while a ZnCO3-rich organic layer was formed further away from the zinc anode. This organic-inorganic bilayer solid electrolyte interface accelerated zinc ion transport, which is beneficial for improving electrochemical performance.

[0044] Figure 10 The Arrhenius-fitted activation energies of the Zn(CF3SO3)2 electrolyte in Comparative Example 1 and the optimized electrolyte of water-soluble cellulose levulinate in Example 3 are used to react with [Zn(H2O)6]. 2+ The desolvation ability, the activation energy of Comparative Example 1 is 47.3 kJ / mol. -1 The electrolyte was greater than that optimized with water-soluble cellulose levulinate in Example 3 (44.6 kJ / mol). -1 This indicates that the electrolyte optimized with water-soluble cellulose levulinate in Example 3 requires lower energy to achieve desolvation, thereby improving the transport power of zinc ions and enhancing the electrochemical performance of the battery.

[0045] Figure 11 The activation energies for Arrhenius fitting in Comparative Examples 2-4 and Example 3 are 46.7, 45.4, and 44.7 kJ / mol, respectively. -1 Slightly larger than the electrolyte optimized with water-soluble cellulose levulinate in Example 3 (44.6 kJ / mol). -1 This indicates that the electrolyte optimized with water-soluble cellulose levulinate in Example 3 requires lower energy to achieve desolvation, thereby enhancing the transport power of zinc ions.

[0046] Figure 12 Cycle stability of Zn / / MnO2 batteries assembled with Comparative Example 1 Zn(CF3SO3)2 electrolyte and the water-soluble cellulose levulinate-optimized electrolyte of Example 3. The Zn / / MnO2 battery using Comparative Example 1 Zn(CF3SO3)2 electrolyte was tested at 2Ag. -1 After 3000 cycles at the current density, only 26.3% of the capacity was retained. In contrast, the Zn / / MnO2 battery using the electrolyte optimized with water-soluble cellulose levulinate from Example 3 showed better capacity retention at 2Ag. -1 After 3000 cycles at the current density, the capacity retention rate reached 78.6%, further demonstrating the improvement of battery electrochemical performance by water-soluble cellulose levulinate.

[0047] Figure 13 To assess the cycle stability of the Zn / / MnO2 batteries in Comparative Examples 2-4 and Example 3, the Zn / / MnO2 batteries with electrolytes from Comparative Examples 2-4 were tested at 2 Ag. -1 After 3000 cycles at current density, the capacity retention rates were 33.6%, 36.2%, and 46.6%, respectively, which were much lower than those in Example 3, demonstrating that the electrolyte optimized with water-soluble cellulose levulinate has significantly improved cycling stability.

[0048] Figure 14 The Zn / / MnO2 battery pouch cell assembled using the water-soluble cellulose levulinate-optimized electrolyte of Example 3 of this invention, with two pouch cells connected in series to power an electronic watch and a 3V thermometer, demonstrates that the water-soluble cellulose levulinate-optimized electrolyte of this invention has great potential for practical applications. Detailed Implementation

[0049] The present invention will be further described below with reference to embodiments, but these embodiments are not intended to limit the scope of the invention.

[0050] Embodiments of the present invention

[0051] Comparative Example 1 of the Invention

[0052] Prepare an aqueous solution of 1M Zn(CF3SO3)2 zinc salt and stir until homogeneous to obtain the electrolyte.

[0053] Comparative Example 2 of the Invention

[0054] (1) Prepare an aqueous solution of 1MZn(CF3SO3)2, stir it evenly to obtain the electrolyte, and set it aside for use.

[0055] (2) Take 0.2g of commercially available water-soluble methylcellulose and add it to 20ml of 1MZn(CF3SO3)2 aqueous solution. Stir well to obtain an optimized electrolyte of water-soluble cellulose acetylpropionate.

[0056] Comparative Example 3 of the present invention

[0057] (1) Prepare an aqueous solution of 1MZn(CF3SO3)2, stir it evenly to obtain the electrolyte, and set it aside for use.

[0058] (2) Take 0.2g of commercially available water-soluble hydroxypropyl cellulose and add it to 20ml of 1MZn(CF3SO3)2 aqueous solution. Stir well to obtain an optimized electrolyte of water-soluble cellulose acetylpropionate.

[0059] Comparative Example 4 of the Invention

[0060] (1) Prepare an aqueous solution of 1MZn(CF3SO3)2, stir it evenly to obtain the electrolyte, and set it aside for use.

[0061] (2) Take 0.2g of commercially available water-soluble carboxymethyl cellulose and add it to 20ml of 1MZn(CF3SO3)2 aqueous solution. Stir well to obtain an optimized electrolyte of water-soluble cellulose acetopropionate.

[0062] Embodiment 1 of the present invention

[0063] (1) 1.0 g cotton pulp cellulose, 2.8 g 1,8-diazabicyclo[5.4.0]undec-7-ene and 13.4 g dimethyl sulfoxide were placed in a reaction vessel and charged with 2.0 MPa CO2. The reaction was carried out in an oil bath at 50 °C for 3 h with magnetic stirring to prepare a 5 wt% cotton pulp cellulose solution.

[0064] (2) Take the above 5wt% cotton pulp cellulose solution into a two-necked flask, add α-angelicin (molar ratio of 3:1 to cotton pulp cellulose hydroxyl group), stir the reaction at 120℃ for 0.5h, after the reaction is completed, use 100mL of isopropanol to precipitate the product, wash, precipitate, filter and dry to obtain water-soluble cellulose acetylpropionate.

[0065] (3) Prepare an aqueous solution of 1MZn(CF3SO3)2, stir it evenly to obtain the electrolyte, and set it aside for later use.

[0066] (4) Take 0.04g of the water-soluble cellulose levulinate from step (3) and add it to 20ml of 1MZn(CF3SO3)2 aqueous solution. Stir well to obtain the optimized electrolyte of water-soluble cellulose levulinate.

[0067] Embodiment 2 of the present invention

[0068] (1) 1.0 g cotton pulp cellulose, 2.8 g 1,8-diazabicyclo[5.4.0]undec-7-ene and 13.4 g dimethyl sulfoxide were placed in a reaction vessel and charged with 2.0 MPa CO2. The reaction was carried out in an oil bath at 50 °C for 3 h with magnetic stirring to prepare a 5 wt% cotton pulp cellulose solution.

[0069] (2) Take the above 5wt% cotton pulp cellulose solution into a two-necked bottle, add 5ml of α-angelicinolone (molar ratio of 3:1 to cotton pulp cellulose hydroxyl group), stir the reaction at 120℃ for 0.5h, after the reaction is completed, use 100mL of isopropanol to precipitate the product, wash, precipitate, filter and dry to obtain water-soluble cellulose acetylpropionate.

[0070] (3) Prepare an aqueous solution of 1MZn(CF3SO3)2, stir it evenly to obtain the electrolyte, and set it aside for later use.

[0071] (4) Take 0.1g of the water-soluble cellulose acetopropionate from step (3) and add it to 20ml of 1MZn(CF3SO3)2 zinc salt aqueous solution. Stir well to obtain the optimized electrolyte of water-soluble cellulose acetopropionate.

[0072] Embodiment 3 of the present invention

[0073] (1) 1.0 g cotton pulp cellulose, 2.8 g 1,8-diazabicyclo[5.4.0]undec-7-ene and 13.4 g dimethyl sulfoxide were placed in a reaction vessel and charged with 2.0 MPa CO2. The reaction was carried out in an oil bath at 50 °C for 3 h with magnetic stirring to prepare a 5 wt% cotton pulp cellulose solution.

[0074] (2) Take 20g of the above 5wt% cotton pulp cellulose solution into a two-necked flask, add 5ml of α-angelicinolone (molar ratio of 3:1 to cotton pulp cellulose hydroxyl group), stir and react at 120℃ for 0.5h. After the reaction is completed, use 100mL of isopropanol to precipitate the product, wash, precipitate, filter and dry to obtain water-soluble cellulose acetylpropionate.

[0075] (3) Prepare an aqueous solution of 1MZn(CF3SO3)2, stir it evenly to obtain the electrolyte, and set it aside for later use.

[0076] (4) Take 0.2g of the water-soluble cellulose acetopropionate from step (3) and add it to 20ml of 1MZn(CF3SO3)2 zinc salt aqueous solution. Stir well to obtain the optimized electrolyte of water-soluble cellulose acetopropionate.

[0077] Embodiment 4 of the present invention

[0078] (1) 1.0 g cotton pulp cellulose, 2.8 g 1,8-diazabicyclo[5.4.0]undec-7-ene and 13.4 g dimethyl sulfoxide were placed in a reaction vessel and charged with 2.0 MPa CO2. The reaction was carried out in an oil bath at 50 °C for 3 h with magnetic stirring to prepare a 5 wt% cotton pulp cellulose solution.

[0079] (2) Take the above 5wt% cotton pulp cellulose solution into a two-necked bottle, add 5ml of α-angelicinolone (molar ratio of 3:1 to cotton pulp cellulose hydroxyl group), stir the reaction at 120℃ for 0.5h, after the reaction is completed, use 100mL of isopropanol to precipitate the product, wash, precipitate, filter and dry to obtain water-soluble cellulose acetylpropionate.

[0080] (3) Prepare an aqueous solution of 1MZn(CF3SO3)2, stir it evenly to obtain the electrolyte, and set it aside for later use.

[0081] (4) Take 0.4g of the water-soluble cellulose acetopropionate from step (3) and add it to 20ml of 1MZn(CF3SO3)2 zinc salt aqueous solution. Stir well to obtain the optimized electrolyte of water-soluble cellulose acetopropionate.

[0082] Embodiment 5 of the present invention

[0083] (1) In accordance with Example 3, 1.0g of different types of cellulose, 2.8g of 1,8-diazabicyclo[5.4.0]undec-7-ene and 13.4g of dimethyl sulfoxide were placed in a reaction vessel and charged with 2.0MPa CO2. The reaction was carried out in an oil bath at 50°C for 3h with magnetic stirring to prepare a 5wt% cellulose solution.

[0084] (2) Take the above 5wt% cellulose solution into a two-necked flask, add 5ml of α-angelicinolone (molar ratio of 3:1 to the hydroxyl group of cotton pulp cellulose), stir the reaction at 120℃ for 0.5h, after the reaction is completed, use 100mL of isopropanol to precipitate the product, wash, precipitate, filter and dry to obtain water-soluble cellulose acetylpropionate.

[0085] (3) Prepare an aqueous solution of 1MZn(CF3SO3)2, stir it evenly to obtain the electrolyte, and set it aside for later use.

[0086] (4) Take 0.2g of water-soluble cellulose acetopropionate and add it to 20ml of 1MZn(CF3SO3)2 zinc salt aqueous solution. Stir well to obtain the optimized electrolyte of water-soluble cellulose acetopropionate.

[0087] Table 1. Comparison of cycle performance of water-soluble cellulose levulinate prepared from cellulose from different sources and symmetrical Zn / / Zn batteries.

[0088] microcrystalline cellulose 1800 1 / 1 α-cellulose 1766 1 / 1 cotton pulp cellulose 1772 1 / 1 Wood pulp cellulose 1797 1 / 1 Bamboo pulp cellulose 1704 1 / 1

[0089] Embodiment 6 of the present invention

[0090] (1) In accordance with Example 3, 1.0 g of microcrystalline cellulose, 2.8 g of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), triethylamine (TEA) or 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) and 13.4 g of dimethyl sulfoxide were placed in a reaction vessel and charged with 2.0 MPa CO2. The reaction was carried out in an oil bath at 50 °C for 3 h with magnetic stirring to prepare a 5 wt% microcrystalline cellulose solution.

[0091] (2) Take the above 5wt% microcrystalline cellulose solution into a two-necked flask, add 5ml of α-angelicinolone (molar ratio of 3:1 to cotton pulp cellulose hydroxyl group), stir the reaction at 120℃ for 0.5h, after the reaction is completed, use 100mL of isopropanol to precipitate the product, wash, precipitate, filter and dry to obtain water-soluble cellulose acetylpropionate.

[0092] (3) Prepare an aqueous solution of 1MZn(CF3SO3)2, stir it evenly to obtain the electrolyte, and set it aside for later use.

[0093] (4) Take 0.2g of water-soluble cellulose acetopropionate and add it to 20ml of 1MZn(CF3SO3)2 zinc salt aqueous solution. Stir well to obtain the optimized electrolyte of water-soluble cellulose acetopropionate.

[0094] Table 2. Comparison of cycle performance of symmetrical Zn / / Zn batteries prepared with different organic bases and water-soluble cellulose levulinate.

[0095]

[0096] Embodiment 7 of the present invention

[0097] (1) In accordance with Example 3, 1.0 g of microcrystalline cellulose, 2.8 g of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and 13.4 g of dimethyl sulfoxide (DMSO) / N,N-dimethylformamide (DMF) / N-methylpyrrolidone (NMP) were charged into a reaction vessel with 2.0 MPa CO2 and reacted in an oil bath at 50 °C for 3 h with magnetic stirring to prepare a 5 wt% microcrystalline cellulose solution.

[0098] (2) Take the above 5wt% microcrystalline cellulose solution into a two-necked flask, add 5ml of α-angelicinolone (molar ratio of 3:1 to cotton pulp cellulose hydroxyl group), stir the reaction at 120℃ for 0.5h, after the reaction is completed, use 100mL of isopropanol to precipitate the product, wash, precipitate, filter and dry to obtain water-soluble cellulose acetylpropionate.

[0099] (3) Prepare an aqueous solution of 1MZn(CF3SO3)2, stir it evenly to obtain the electrolyte, and set it aside for later use.

[0100] (4) Take 0.2g of water-soluble cellulose acetopropionate and add it to 20ml of 1MZn(CF3SO3)2 zinc salt aqueous solution. Stir well to obtain the optimized electrolyte of water-soluble cellulose acetopropionate.

[0101] Table 3. Comparison of cycle performance of symmetrical Zn / / Zn batteries prepared with different solvents for water-soluble cellulose levulinate.

[0102] Dimethyl sulfoxide (DMSO) 1800 1 / 1 N,N-Dimethylformamide (DMF) 1749 1 / 1 N-Methylpyrrolidone (NMP) 1616 1 / 1

[0103] Embodiment 8 of the present invention

[0104] (1) In accordance with Example 3, 1.0 g of microcrystalline cellulose, 2.8 g of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 13.4 g of dimethyl sulfoxide (DMSO) were charged into a reaction vessel with 2.0 MPa CO2 and reacted in an oil bath at 50 °C for 3 h with magnetic stirring to prepare a 5 wt% microcrystalline cellulose solution.

[0105] (2) Take 5 wt% microcrystalline cellulose solution into a two-necked flask, add α-angelicol / ethyl acetopropionate / butyl acetopropionate / n-propyl acetopropionate (molar ratio of α-angelicol / ethyl acetopropionate / butyl acetopropionate / n-propyl acetopropionate to cellulose hydroxyl groups in cotton pulp of 3:1), stir the reaction at 120℃ for 0.5 h, after the reaction is completed, use 100 mL of isopropanol to precipitate the product, wash, precipitate, filter and dry to obtain water-soluble cellulose acetopropionate.

[0106] (3) Prepare an aqueous solution of 1MZn(CF3SO3)2, stir it evenly to obtain the electrolyte, and set it aside for later use.

[0107] (4) Take 0.2g of water-soluble cellulose acetopropionate and add it to 20ml of 1MZn(CF3SO3)2 zinc salt aqueous solution. Stir well to obtain the optimized electrolyte of water-soluble cellulose acetopropionate.

[0108] Table 4. Comparison of cycle performance of water-soluble cellulose levulinate prepared with different levulinic acid esters and symmetrical Zn / / Zn batteries.

[0109] α-Angelactone (α-AL) 1800 1 / 1 Ethyl levulinate (EL) 1709 1 / 1 Butyl levulinate (BL) 1811 1 / 1 propyl levulinate (PL) 1742 1 / 1

[0110] Embodiment 9 of the present invention

[0111] (1) In accordance with Example 3, 1.0 g of microcrystalline cellulose, 2.8 g of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 13.4 g of dimethyl sulfoxide (DMSO) were charged into a reaction vessel with 2.0 MPa CO2 and reacted in an oil bath at 50 °C for 3 h with magnetic stirring to prepare a 5 wt% microcrystalline cellulose solution.

[0112] (2) Take 5 wt% microcrystalline cellulose solution in a two-necked flask, add α-angelicin (molar ratio of 0.5-10:1 to cellulose hydroxyl group in cotton pulp), stir and react at 50-150℃ for 0.1-48h. After the reaction is completed, use 100mL isopropanol to precipitate the product, wash, precipitate, filter and dry to obtain water-soluble cellulose acetylpropionate with different degrees of substitution.

[0113] (3) Prepare an aqueous solution of 1MZn(CF3SO3)2, stir it evenly to obtain the electrolyte, and set it aside for later use.

[0114] (4) Take 0.2g of water-soluble cellulose acetopropionate with different degrees of substitution and add it to 20ml of 1MZn(CF3SO3)2 zinc salt aqueous solution. Stir evenly to obtain the optimized electrolyte of water-soluble cellulose acetopropionate with different degrees of substitution.

[0115] Table 5. Comparison of cycle performance of water-soluble cellulose levulinate with different degrees of substitution and symmetrical Zn / / Zn batteries.

[0116] 2.04 2270 1 / 1 1.38 1800 1 / 1 0.93 1593 1 / 1 0.14 732 1 / 1

[0117] Embodiment 10 of the present invention

[0118] (1) In accordance with Example 3, 1.0 g of microcrystalline cellulose, 2.8 g of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 13.4 g of dimethyl sulfoxide (DMSO) were charged into a reaction vessel with 2.0 MPa CO2 and reacted in an oil bath at 50 °C for 3 h with magnetic stirring to prepare a 5 wt% microcrystalline cellulose solution.

[0119] (2) Take the above 5wt% microcrystalline cellulose solution into a two-necked flask, add 5ml of α-angelicinolone (molar ratio of 3:1 to cotton pulp cellulose hydroxyl group), stir the reaction at 120℃ for 0.5h, after the reaction is completed, use 100mL of isopropanol to precipitate the product, wash, precipitate, filter and dry to obtain water-soluble cellulose acetylpropionate.

[0120] (3) Prepare an aqueous solution of 1M Zn(CF3SO3)2 / ZnSO4 / ZnCl2 / Zn(ClO4)2 zinc salt, stir well to obtain electrolyte, and set aside for use.

[0121] (4) Take 0.2g of water-soluble cellulose levulinate and add it to 20ml of 1M Zn(CF3SO3)2 / ZnSO4 / ZnCl2 / Zn(CH3COO)2 / Zn(ClO4)2 aqueous solution. Stir well to obtain the optimized electrolyte of water-soluble cellulose levulinate.

[0122] Table 6 Comparison of cycle performance of symmetric Zn / / Zn batteries with different zinc salts

[0123] <![CDATA[Zinc trifluoromethanesulfonate (Zn(CF3SO3)2)]]> 1800 1 / 1 <![CDATA[Zinc sulfate (ZnSO4)]]> 1915 1 / 1 <![CDATA[Zinc chloride (ZnCl2)]]> 1576 1 / 1 <![CDATA[Zinc acetate (Zn(CH3COO)2)]]> 1495 1 / 1 <![CDATA[Zinc perchlorate (Zn(ClO4)2)]]> 1297 1 / 1

[0124] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A cellulose acetate propionate optimized aqueous zinc-ion battery electrolyte, characterized in that: Cellulose acetylpropionate is added to the electrolyte of aqueous zinc-ion batteries.

2. The cellulose acetate propionate optimized aqueous zinc-ion battery electrolyte of claim 1, wherein: The molar concentration of the cellulose acetylacetate in the aqueous zinc-ion battery electrolyte is 0.001-1M.

3. The cellulose levulinate-optimized aqueous zinc-ion battery electrolyte according to claim 2, characterized in that: The molar concentration of the cellulose acetylacetate in the aqueous zinc-ion battery electrolyte is 0.01-0.5M.

4. The cellulose levulinate-optimized aqueous zinc-ion battery electrolyte according to claim 1, characterized in that: The zinc source in the aqueous zinc-ion battery electrolyte is one or more of ZnSO4, ZnCl2, Zn(ClO4)2, Zn(CH3COO)2 or Zn(CF3SO3)2.

5. The cellulose levulinate-optimized aqueous zinc-ion battery electrolyte according to claim 4, characterized in that: The molar concentration of the zinc source in the aqueous zinc-ion battery electrolyte is 0.1-5M.

6. The cellulose levulinate-optimized aqueous zinc-ion battery electrolyte according to claim 4, characterized in that: The molar concentration of the zinc source in the aqueous zinc-ion battery electrolyte is 0.5-2M.

7. A method for preparing a cellulose levulinate-optimized aqueous zinc-ion battery electrolyte according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Take a zinc source and add water to prepare an aqueous zinc-ion battery electrolyte; S2. Take cellulose levulinate and add it to the aqueous zinc-ion battery electrolyte of S1. Stir well to obtain the cellulose levulinate-optimized aqueous zinc-ion battery electrolyte.

8. The method for preparing the cellulose levulinate-optimized aqueous zinc-ion battery electrolyte according to claim 7, characterized in that, The cellulose levulinate was prepared by the following method: S1. Mix cellulose, organic base and organic solvent, wherein the mass percentage of cellulose is 1-20%, the mass percentage of organic base is 0.5-30%, and the remainder is organic solvent; react in a CO2 atmosphere at a pressure of 1-10 MPa and a temperature of 30-100℃ for 1-12 hours to obtain a cellulose solution; S2. Add levulinic acid ester or angelica lactone to the cellulose solution, wherein the molar ratio of the amount of levulinic acid ester or angelica lactone added to the amount of hydroxyl groups on glucose units in the cellulose in the cellulose solution is 0.5-10:1; react at 50-150℃ for 0.1-48 hours to obtain a cellulose levulinic acid ester solution. S3. Pour the cellulose levulinate solution into C1-C4 lower fatty alcohols, ethyl acetate or water, and after washing, precipitation, filtration and drying, obtain cellulose levulinate.

9. The method for preparing the cellulose levulinate-optimized aqueous zinc-ion battery electrolyte according to claim 8, characterized in that: The cellulose is selected from one or more of microcrystalline cellulose, α-cellulose, or plant cellulose isolated from cotton, wood pulp, bamboo pulp, or agricultural and forestry lignocellulosic waste; The organic base has an acid-base dissociation constant greater than 20 and has the following structural characteristics: The organic solvent is selected from one or more of dimethyl sulfoxide, N-methylpyrrolidone, tetramethylurea, tetraethylurea, N,N-dimethylimidazolinone, N,N-dimethylformamide, N,N-diethylacetamide, pyrrolidone, 2-azahexanecyclohexanone, N,N-dimethylpropenylurea or sulfolane; In S3, the volume ratio of cellulose acetopropionate solution to C1-C4 lower fatty alcohols, ethyl acetate, or water is 0.5-10:

1.

10. A battery comprising the cellulose levulinate optimized aqueous zinc-ion battery electrolyte according to any one of claims 1-6.

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