Aqueous acidic stannous ion electrolyte

Abstract

The invention relates to an aqueous acidic stannous ion electrolyte. The electrolyte is prepared by mixing stannous salt, acid, an additive and water in an ultrasonic manner. The selected stannous salt is tin trifluoromethanesulfonate, and trifluoromethanesulfonate radicals and divalent tin ions are subjected to coordination, so that a solvation structure is regulated and controlled, tin is induced to be uniformly deposited / stripped, and the cycling stability of the tin foil negative electrode is enhanced. The selected additive is a carbohydrate compound, a nitrogen-containing compound and a sulfonate compound additive, and the carbohydrate compound, the nitrogen-containing compound and the sulfonate compound additive improve the performance of the electrolyte through a synergistic effect. Nitrogen atoms in the nitrogen-containing compound can be coordinated with Sn < 2 + > and H < + > to form a low-coordination solvation structure, so that ion desolvation is promoted, and electrode reaction kinetics is accelerated. Sulfonate can be used as auxiliary conducting salt, and charge distribution on the surface of the electrode is adjusted through anion competitive adsorption. A battery assembled by the electrolyte prepared by the invention has relatively excellent performance, and the problems that stannous salt is easy to hydrolyze and a tin negative electrode is poor in cycling stability are solved.

Description

Technical Field

[0001] The present invention relates to an aqueous acidic stannous ion electrolyte, belonging to the technical field of aqueous tin ion batteries. Background Art

[0002] With the rapid development of the global economy and the continuous growth of the population, the demand for energy has increased explosively. Traditional fossil fuels such as coal, oil, and natural gas not only have limited reserves and are facing the dilemma of increasing depletion, but also release a large amount of greenhouse gases such as carbon dioxide and sulfur dioxide during use. These gases have led to a series of serious environmental problems such as global warming and acid rain. Renewable energy sources such as wind energy and solar energy have become ideal alternatives to traditional fossil fuels due to their clean and sustainable characteristics. However, these renewable energy sources have characteristics such as intermittency, uncontrollability, and uneven distribution, which pose challenges for large-scale energy storage. In addition, lithium-ion batteries, which are widely used in the energy storage field, although have achieved remarkable achievements in fields such as electronic products and electric vehicles, also have safety problems that cannot be ignored. The electrolyte of lithium-ion batteries is usually an organic solution, which is flammable and explosive. Once the battery overheats, short-circuits, or is subjected to external impact, it is extremely likely to cause fires or even explosion accidents, posing a great threat to people's lives and property safety. Therefore, it is necessary to develop a new battery system with high safety, low cost, and environmental friendliness.

[0003] Aqueous metal batteries use aqueous solutions as electrolytes, which can effectively solve the battery safety problem and can be assembled in an air environment, greatly reducing the production cost of the battery. At the same time, aqueous electrolytes have high ionic conductivity and have unique advantages in achieving high-rate performance of the battery. Currently, among aqueous batteries, zinc-ion batteries have been widely studied, but the uneven deposition of Zn 2+ on the zinc negative electrode surface will lead to the growth of zinc dendrites, and side reactions such as corrosion and hydrogen evolution are likely to occur on the zinc surface, resulting in low Coulombic efficiency of the zinc negative electrode and poor cycle reversibility, seriously restricting its development. In comparison, tin foil has a high hydrogen evolution overpotential, is not easy to form dendrites, and also has advantages such as good capacity, non-toxicity, acid resistance, low cost, and easy processing, and has great application potential in aqueous batteries. However, stannous salts are prone to hydrolysis, and tin is easily formed into inactive tin during cycling, resulting in poor reversibility, which hinders its development. Summary of the Invention

[0004] Based on the above background, this patent has developed an aqueous acidic stannous ion electrolyte. Using an aqueous solution as a solvent has advantages such as high safety, low cost, and convenient processing. By adding trifluoromethanesulfonic acid to inhibit the hydrolysis of stannous salts, and at the same time having a large-volume CF3SO3 − anion can reduce Sn 2+The surrounding water molecules reduce the solvation effect, thus promoting the migration of Sn 2+ between the electrolyte and the electrode, greatly reducing the possibility of side reactions. A ternary synergistic compounding strategy of saccharide compounds (such as glucose, sucrose or fructose), nitrogen-containing compounds (such as 2-aminopyrimidine, 5-sulfonic acid-2-aminopyrimidine or 5-carboxylic acid-2-aminopyrimidine), and sulfonates (such as sodium p-toluenesulfonate, sodium dodecylbenzenesulfonate or sodium methanesulfonate) is used as an electrolyte additive, and performance improvement is achieved through three mechanisms: hydrogen bond network construction, interfacial coordination adsorption and ion channel optimization. Glucose, as a hydrogen bond donor, forms a reticular association structure with water molecules in the electrolyte through its polyol hydroxyl groups, reducing the free water activity and inhibiting the hydrogen evolution side reaction. At the same time, the hydroxyl groups can preferentially adsorb on the electrode surface to regulate the interfacial charge distribution. The lone pair electrons of the nitrogen atom in 2-aminopyrimidine coordinate with Sn 2+ to form a molecular-level protective layer by directional adsorption on the electrode surface, regulating the ion deposition path. The sulfonate group (SO3 − -) of sodium p-toluenesulfonate is anchored on the electrode surface through electrostatic interaction, and its aromatic ring structure enhances the compactness of the adsorption layer through π–π conjugation. At the same time, as an "ion transport assistant", it participates in the construction of the solvation sheath, reducing the ion migration resistance and improving the electrolyte conductivity. The three work together to form a composite interface regulation system of "hydrogen bond stabilizing water - coordination forming film - sulfonic acid guiding ions", effectively inhibiting side reactions such as hydrogen evolution and corrosion, optimizing the ion transport kinetics, and significantly improving the battery cycle life and safety.

[0005] The present invention proposes an aqueous acidic stannous ion electrolyte, in which trifluoromethanesulfonic acid and stannous trifluoromethanesulfonate can work together to induce uniform deposition / stripping of tin, significantly enhancing its cycle life. At the same time, a ternary synergistic compounding strategy of saccharide compounds (such as glucose, sucrose or fructose), nitrogen-containing compounds (such as 2-aminopyrimidine, 5-sulfonic acid-2-aminopyrimidine or 5-carboxylic acid-2-aminopyrimidine), and sulfonates (such as sodium p-toluenesulfonate, sodium dodecylbenzenesulfonate or sodium methanesulfonate) is used as an electrolyte additive, and performance improvement is achieved through three mechanisms: hydrogen bond network construction, interfacial coordination adsorption and ion channel optimization. This electrolyte has excellent comprehensive electrochemical performance and has potential application value in aqueous tin-ion batteries.

[0006] The preparation method of the electrolyte includes the following steps: An aqueous acidic stannous ion electrolyte, and the preparation method of the electrolyte includes the following steps: (1) Add stannous salt to the acid solution and stir until the stannous salt is completely dissolved; (2) Add a certain amount of sulfonate to the above solution and continuously stir until it is evenly dispersed; (3) After dissolving a certain amount of nitrogen-containing compound with ethanol, drop it into the solution in step (2); (4) Add a certain amount of saccharide compound to the solution in step (3), and stir until completely dissolved to obtain the aqueous acidic stannous ion electrolyte.

[0007] The acid is trifluoromethanesulfonic acid, methanesulfonic acid or sulfuric acid, and the concentration of the acid solution is 1 - 5 M.

[0008] The stannous salt is stannous trifluoromethanesulfonate, stannous methanesulfonate or stannous sulfate, and the concentration of the stannous salt is 0.5 - 3 M.

[0009] The sulfonate is one of sodium p-toluenesulfonate, sodium dodecylbenzenesulfonate or sodium methanesulfonate, and the mass fraction of the sulfonate is 0.5 - 2%.

[0010] The nitrogen-containing compound is one of 2-aminopyrimidine, 5-sulfo-2-aminopyrimidine or 5-carboxy-2-aminopyrimidine, and the mass fraction of the nitrogen-containing compound is 0.5 - 2%.

[0011] The saccharide compound is one of glucose, sucrose or fructose, and the mass fraction of the saccharide compound is 1 - 3%.

[0012] In some preferred embodiments, the method for preparing the aqueous acidic stannous ion electrolyte includes the following steps: (1) Add a certain amount of deionized water to a glass bottle; (2) Prepare a CF3SO3H solution with an appropriate concentration; (3) Take an appropriate amount of the prepared CF3SO3H solution and add it to the glass bottle, and ultrasonically mix evenly; (4) Weigh a certain mass of Sn(CF3SO3)2, add it to the CF3SO3H solution in step (3), and stir until Sn(CF3SO3)2 is completely dissolved; (5) Add a certain amount of sodium p-toluenesulfonate to the above solution, and continuously stir until it is evenly dispersed; (6) After dissolving a certain amount of aminopyrimidine with ethanol, drop it into the solution in step (5); (7) Add a certain amount of glucose to the solution in step (6), and stir until completely dissolved to obtain the novel aqueous stannous ion battery electrolyte.

[0013] Preferably, the deionized water added in step (1) depends on the volume of the specific electrolyte to be prepared.

[0014] Preferably, the concentration of the CF3SO3H solution prepared in step (2) is 2 - 5 M.

[0015] Preferably, the CF3SO3H solution added in step (3) depends on the concentration of the specific electrolyte to be prepared, and the volume ratio of water to the acid prepared in step (2) is 1 - 3:1 - 3.

[0016] Preferably, the mass fraction of sodium p-toluenesulfonate in step (5) is 0.5 - 2%.

[0017] Preferably, the mass fraction of 2-aminopyrimidine in step (6) is 0.5 - 2%.

[0018] Preferably, the mass fraction of glucose in step (7) is 1 - 3%.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The preparation process is simple and has strong repeatability.

[0020] (2) The CF3SO3H used can slow down the hydrolysis of stannous salts, and CF3SO3 − can coordinate with Sn 2+ to form a coordination bond, regulate the solvation structure, and enable Sn 2+ to be uniformly deposited / stripped on the electrode surface.

[0021] (3) The ternary synergistic compounding strategy of using saccharide compounds (such as glucose, sucrose or fructose), nitrogen-containing compounds (2-aminopyrimidine, 5-sulfo-2-aminopyrimidine or 5-carboxy-2-aminopyrimidine), and sulfonates (such as sodium p-toluenesulfonate, sodium dodecylbenzenesulfonate or sodium methanesulfonate) as electrolyte additives can improve the performance through three mechanisms: hydrogen bond network construction, interfacial coordination adsorption, and ion channel optimization.

[0022] (4) The Sn / / Cu half-cell assembled with the prepared novel electrolyte has a long cycle life, and the average coulombic efficiency can reach 99.28%. The Sn / / Sn symmetric cell also has excellent cycle performance. Description of the Drawings

[0023] Figure 1 SEM image of the original Sn foil.

[0024] Figure 2 SEM images of the Sn foil on the positive electrode side of the Sn / / Sn symmetric cell assembled in Example 1 after depositing 2.5 mAh. (a) Low-magnification SEM, (b) High-magnification SEM.

[0025] Figure 3 Cycle performance graph of the Sn / / Cu half-cell assembled in Example 1.

[0026] Figure 4 Time-voltage graph of the Sn / / Sn symmetric cell assembled in Example 1.

[0027] Figure 5SEM images of the Sn foil on the positive electrode side of the Sn / / Sn symmetric battery assembled in Example 2 after depositing 2.5 mAh. (a) Low-magnification SEM, (b) high-magnification SEM.

[0028] Figure 6 Cycling performance graph of the Sn / / Cu half-cell assembled in Example 2.

[0029] Figure 7 Time-voltage graph of the Sn / / Sn symmetric battery assembled in Example 2.

[0030] Figure 8 SEM images of the Sn foil on the positive electrode side of the Sn / / Sn symmetric battery assembled in Example 3 after depositing 2.5 mAh. (a) Low-magnification SEM, (b) high-magnification SEM.

[0031] Figure 9 Cycling performance graph of the Sn / / Cu half-cell assembled in Example 3.

[0032] Figure 10 Time-voltage graph of the Sn / / Sn symmetric battery assembled in Example 3.

[0033] Figure 11 Cycling performance graph of the Sn / / Cu half-cell assembled in Example 4.

[0034] Figure 12 Time-voltage graph of the Sn / / Sn symmetric battery assembled in Example 4.

[0035] Figure 13 Cycling performance graph of the Sn / / Cu half-cell assembled in Example 5.

[0036] Figure 14 Time-voltage graph of the Sn / / Sn symmetric battery assembled in Example 5.

[0037] Figure 15 Cycling performance graph of the Sn / / Cu half-cell assembled in Example 6.

[0038] Figure 16 Time-voltage graph of the Sn / / Sn symmetric battery assembled in Example 6. Detailed implementation manners

[0039] Combined with the specific embodiments shown in the accompanying drawings, the technical solutions of the present invention will be more clearly and completely described. It should be noted that these embodiments are only used to explain the technical solutions of the present invention and do not constitute a limitation on the scope of the claims. All improvement solutions obtained by those skilled in the art through conventional technical means or equivalent replacements without departing from the core idea of the present invention fall within the protection scope of the present invention.

[0040] Example 1 The preparation method of the 4 M CF3SO3H solution used in this example is as follows: Take 2.57 mL of deionized water, then add 1.43 mL of trifluoromethanesulfonic acid, and stir evenly to obtain 4 mL of 4 M CF3SO3H solution.

[0041] The electrolyte in this example is 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine, and its preparation method is as follows: Take 1.5 mL of deionized water, add 0.5 mL of 4 M CF3SO3H solution, and after ultrasonic homogenization, add 0.5836 g of Sn(CF3SO3)2, and stir evenly to obtain 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 basic electrolyte. Add 0.01 g of sodium p-toluenesulfonate to the above basic electrolyte, and continuously stir until it is evenly dispersed. At the same time, dissolve 0.01 g of 2-aminopyrimidine with ethanol, and then drop it into the basic electrolyte after adding sodium p-toluenesulfonate. Finally, add 0.02 g of glucose, and stir until it is completely dissolved to obtain 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine.

[0042] The aqueous tin-ion battery in this example includes a positive electrode material, an electrolyte, a separator, and a negative electrode material. Cut a copper foil with a thickness of 10 μm into a circular piece with a diameter of 14 mm as the positive electrode. Cut a tin foil with a thickness of 100 μm into a circular piece with a diameter of 8 mm as the negative electrode. Use a glass fiber filter membrane GF / D as the separator, and the prepared 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine as the electrolyte, and assemble it into a CR2032 type battery in an air environment. After the battery is assembled, let it stand for 1 h, and then perform a constant current charge-discharge test using a CT3001 battery test system.

[0043] As Figure 2 shown, the Sn / / Sn symmetric battery assembled with 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine electrolyte still has long stripes, a flat and smooth surface on the positive electrode side Sn foil after depositing 2.5 mAh at a current density of 1 mA cm -2 -. As Figure 3As shown, the Sn / / Cu half-cell assembled with 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine as the electrolyte was cycled 1300 times at 0.25 mA cm -2 , 0.125 mAhcm -2 . The initial Coulombic efficiency was 92.02%, and the average Coulombic efficiency was 99.28%. As Figure 4 shown, the assembled Sn / / Sn symmetric cell was able to stably cycle for 1600 h at 1 mA cm -2 , 1 mAh cm -2 . The battery using 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine as the electrolyte has excellent cycling performance.

[0044] Example 2 In this example, the preparation method of the 4 M CH3SO3H solution used is as follows: Take 2.96 mL of deionized water, then add 1.04 mL of methanesulfonic acid, and stir evenly to obtain 4 mL of 4 M CH3SO3H solution.

[0045] The electrolyte in this example is 1 M CH3SO3H + 0.7 M Sn(CH3SO3)2 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine, and its preparation method is as follows: Take 0.942 mL of deionized water, add 0.5 mL of 4 M CH3SO3H solution, after ultrasonic homogenization, add 0.558 mL of Sn(CH3SO3)2, and obtain the 1 M CH3SO3H + 0.7 M Sn(CH3SO3)2 basic electrolyte after ultrasonic treatment again. Add 0.01 g of sodium p-toluenesulfonate to the above basic electrolyte and continuously stir until it is evenly dispersed. At the same time, dissolve 0.01 g of 2-aminopyrimidine with ethanol as a co-solvent, and then drop it into the basic electrolyte after adding sodium p-toluenesulfonate. Finally, add 0.02 g of glucose and stir until completely dissolved to obtain 1 M CH3SO3H + 0.7 M Sn(CH3SO3)2 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine.

[0046] In this example, the assembly of the aqueous tin-ion battery is the same as that in Example 1, except that 1 M CH3SO3H + 0.7 M Sn(CH3SO3)2 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine is used as the electrolyte.

[0047] As Figure 5As shown, for the Sn / / Sn symmetric battery assembled with an electrolyte of 1 M CH3SO3H + 0.7 M Sn(CH3SO3)2 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine, at a current density of 1 mA cm -2 −2, after depositing 2.5 mAh, the striped texture of the Sn foil on the positive electrode side disappeared, and the surface became highly porous and irregular. As Figure 6 shown, for the Sn / / Cu half-cell assembled with 1 M CH3SO3H + 0.7 M Sn(CH3SO3)2 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine as the electrolyte, at 0.25 mA cm -2 −2 and 0.125 mAh cm -2 −2, it was cycled for 750 cycles, and the average coulombic efficiency was 98.56%. As Figure 7 shown, the assembled Sn / / Sn symmetric battery short-circuited after being cycled for 723 h at 1 mA cm -2 −2 and 1 mAh cm -2 −2.

[0048] Example 3 The preparation method of the 4 M H2SO4 solution used in this example is as follows: Take 2.85 mL of deionized water, then add 1.15 mL of sulfuric acid, and stir evenly to obtain 4 mL of 4 M CH3SO3H solution.

[0049] The electrolyte in this example is 0.5 M H2SO4 + 0.7 M SnSO4 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine, and its preparation method is as follows: Take 1.75 mL of deionized water, add 0.25 mL of 4 M H2SO4 solution, after ultrasonic homogenization, add 0.3007 g of SnSO4, and stir evenly to obtain the 0.5 M H2SO4 + 0.7 M SnSO4 basic electrolyte. Add 0.01 g of sodium p-toluenesulfonate to the above basic electrolyte, and continuously stir until it is evenly dispersed. At the same time, dissolve 0.01 g of 2-aminopyrimidine with the help of ethanol, and then drop it into the basic electrolyte after adding sodium p-toluenesulfonate. Finally, add 0.02 g of glucose, and stir until it is completely dissolved to obtain 0.5 M H2SO4 + 0.7 M SnSO4 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine.

[0050] In this example, the aqueous tin-ion battery was assembled in the same way as in Example 1, only using 0.5 M H2SO4 + 0.7 M SnSO4 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine as the electrolyte.

[0051] As Figure 8As shown, the Sn / / Sn symmetric battery assembled with an electrolyte of 0.5 M H2SO4 + 0.7 M SnSO4 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine has the striped texture of the positive electrode side Sn foil disappear after depositing 2.5 mAh at a current density of 1 mA cm -2 −2, and the surface becomes highly porous and irregular. As Figure 9 shown, the Sn / / Cu half-cell assembled with 0.5 M H2SO4 + 0.7 M SnSO4 + glucose + sodium p-toluenesulfonate + 2-aminopyrimidine as the electrolyte has a coulombic efficiency that starts to stabilize after 50 cycles at 0.25 mA cm -2 −2 and 0.125 mAh cm -2 −2, and starts to decay after 476 cycles. As Figure 10 shown, the assembled Sn / / Sn symmetric battery shorts after cycling for 390 h at 1 mA cm -2 −2 and 1 mAh cm -2 −2.

[0052] Example 4 The electrolyte preparation method in this example is the same as that in Example 1, except that no compound additive is added to prepare 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2. The aqueous tin-ion battery assembly in this example is the same as that in Example 1, except that 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 is used as the electrolyte.

[0053] As Figure 11 shown, the Sn / / Cu half-cell assembled with 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 as the electrolyte has a coulombic efficiency that starts to show large fluctuations after 400 cycles at 0.25 mA cm -2 −2 and 0.125 mAh cm -2 −2, with an average efficiency of 97.36%. As Figure 12 shown, the assembled Sn / / Sn symmetric battery shorts after cycling for 115 h at 1 mA cm -2 −2 and 1 mAh cm -2 −2.

[0054] Example 5 The electrolyte preparation method in this example is the same as that in Example 2, except that no compound additive is added to prepare 1 M CH3SO3H + 0.7 M Sn(CH3SO3)2. The aqueous tin-ion battery assembly in this example is the same as that in Example 1, except that 1 M CH3SO3H + 0.7 M Sn(CH3SO3)2 is used as the electrolyte.

[0055] As Figure 13As shown, the Sn / / Cu half-cell assembled with 1 M CH3SO3H + 0.7 M Sn(CH3SO3)2 as the electrolyte started to show large fluctuations after 200 cycles at 0.25 mA cm -2 , 0.125 mAh cm -2 . As Figure 14 shown, the assembled Sn / / Sn symmetric cell short-circuited after 100 h of cycling at 1 mA cm -2 , 1 mAh cm -2 .

[0056] Example 6 The electrolyte preparation method in this example is the same as that in Example 3, except that no compound additive is added to prepare 0.5 M H2SO4 + 0.7 M SnSO4. The aqueous tin-ion battery assembly in this example is the same as that in Example 1, except that 0.5 M H2SO4 + 0.7 M SnSO4 is used as the electrolyte.

[0057] As Figure 15 shown, the Sn / / Cu half-cell assembled with 0.5 M H2SO4 + 0.7 M SnSO4 as the electrolyte started to show fluctuations in coulombic efficiency after only 5 cycles at 0.25 mA cm -2 , 0.125 mAh cm -2 . As Figure 16 shown, the assembled Sn / / Sn symmetric cell short-circuited after only 65 h of cycling at 1 mA cm -2 , 1 mAh cm -2 .

[0058] Example 7 The preparation method of the 4 M CF3SO3H solution used in this example is as follows: Take 2.57 mL of deionized water, then add 1.43 mL of trifluoromethanesulfonic acid, and stir evenly to obtain 4 mL of 4 M CF3SO3H solution.

[0059] The electrolyte in this example is 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 5-sulfonyl-2-aminopyrimidine, and its preparation method is as follows: Take 1.5 mL of deionized water, then add 0.5 mL of 4 M CF3SO3H solution. After ultrasonic homogenization, add 0.5836 g of Sn(CF3SO3)2. After stirring evenly, a 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 basic electrolyte is obtained. Add 0.01 g of sodium p-toluenesulfonate to the above basic electrolyte and continuously stir until it is evenly dispersed. At the same time, dissolve 0.01 g of 5-sulfonic acid-2-aminopyrimidine with ethanol and then drop it into the basic electrolyte after adding sodium p-toluenesulfonate. Finally, add 0.02 g of glucose and stir until completely dissolved to obtain 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 5-sulfonic acid-2-aminopyrimidine.

[0060] In this example, the assembly of the aqueous tin-ion battery is the same as that in Example 1.

[0061] The Sn / / Cu half-cell assembled with 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 5-sulfonic acid-2-aminopyrimidine as the electrolyte was cycled 1420 times at 0.25 mA cm -2 , 0.125 mAh cm -2 . The initial Coulombic efficiency was 94.5%, and the average Coulombic efficiency was 99.72%. The assembled Sn / / Sn symmetric cell could stably cycle for 1950 h at 1 mA cm -2 , 1 mAh cm -2 . The battery with 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 5-sulfonic acid-2-aminopyrimidine electrolyte has excellent cycling performance.

[0062] Example 8 The preparation method of the 4 M CF3SO3H solution used in this example is as follows: Take 2.57 mL of deionized water, then add 1.43 mL of trifluoromethanesulfonic acid and stir evenly to obtain 4 mL of 4 M CF3SO3H solution.

[0063] The electrolyte in this example is 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 5-carboxylic acid-2-aminopyrimidine, and its preparation method is as follows: Take 1.5 mL of deionized water, then add 0.5 mL of 4 M CF3SO3H solution. After ultrasonic homogenization, add 0.5836 g of Sn(CF3SO3)2. After stirring evenly, a 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 basic electrolyte is obtained. Add 0.01 g of sodium p-toluenesulfonate to the above basic electrolyte and continuously stir until it is evenly dispersed. At the same time, dissolve 0.01 g of 5-carboxy-2-aminopyrimidine with the help of ethanol and then drop it into the basic electrolyte after adding sodium p-toluenesulfonate. Finally, add 0.02 g of glucose and stir until completely dissolved to obtain 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 5-carboxy-2-aminopyrimidine.

[0064] In this example, the assembly of the aqueous tin-ion battery is the same as that in Example 1.

[0065] The Sn / / Cu half-cell assembled with 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 5-carboxy-2-aminopyrimidine as the electrolyte was cycled 1420 times at 0.25 mA cm -2 , 0.125 mAh cm -2 . The initial Coulombic efficiency was 94.6%, and the average Coulombic efficiency was 99.66%. The assembled Sn / / Sn symmetric cell was stable at 1 mA cm -2 , 1 mAh cm -2 for 2000 h. The battery with 1 M CF3SO3H + 0.7 M Sn(CF3SO3)2 + glucose + sodium p-toluenesulfonate + 5-carboxy-2-aminopyrimidine electrolyte has excellent cycling performance.

Claims

1. An aqueous acidic stannous ion electrolyte, characterized in that, The preparation method of the electrolyte includes the following steps: (1) Add stannous salt to the acid solution and stir until the stannous salt is completely dissolved; (2) Add a certain amount of sulfonate to the above solution and continuously stir until it is evenly dispersed; (3) After dissolving a certain amount of nitrogen-containing compound with ethanol, drop it into the solution in step (2); (4) Add a certain amount of saccharide compound to the solution in step (3) and stir until it is completely dissolved to obtain the aqueous acidic stannous ion electrolyte.

2. The aqueous acidic stannous ion electrolyte according to claim 1, characterized in that, The acid is trifluoromethanesulfonic acid, methanesulfonic acid or sulfuric acid, and the concentration of the acid solution is 1-5 M.

3. The aqueous acidic stannous ion electrolyte according to claim 1, characterized in that, The stannous salt is stannous trifluoromethanesulfonate, stannous methanesulfonate or stannous sulfate, and the concentration of the stannous salt is 0.5-3 M.

4. The aqueous acidic stannous ion electrolyte according to claim 1, wherein The sulfonate is one of sodium p-toluenesulfonate, sodium dodecylbenzenesulfonate or sodium methanesulfonate, and the mass fraction of the sulfonate is 0.5-2%.

5. The aqueous acidic stannous ion electrolyte according to claim 1, wherein The nitrogen-containing compound is one of 2-aminopyrimidine, 5-sulfonic acid-2-aminopyrimidine or 5-carboxylic acid-2-aminopyrimidine, and the mass fraction of the nitrogen-containing compound is 0.5-2%.

6. The aqueous acidic stannous ion electrolyte according to claim 1, wherein The saccharide compound is one of glucose, sucrose or fructose, and the mass fraction of the saccharide compound is 1-3%.

7. The aqueous acidic stannous ion electrolyte according to any one of claims 1-6, characterized in that, This electrolyte uses water as a solvent and is safe and non-toxic.

8. An aqueous tin-ion battery, characterized in that, It includes the aqueous acidic stannous ion electrolyte described in claim 7.

9. A half-cell, characterized in that, It includes the aqueous acidic stannous ion electrolyte described in claim 7.

10. A full cell, characterized in that, It includes the aqueous acidic stannous ion electrolyte described in claim 7.

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