Aqueous zinc battery electrolyte, preparation method and application thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SICHUAN EVERSEY TECHNOLOGY CO LTD
- Filing Date
- 2026-04-22
- Publication Date
- 2026-08-07
AI Technical Summary
[0006]针对现有技术中所存在的不足，本发明提供了一种水系锌电池电解液及其制备方法和应用，解决了现有技术中水系锌电池所面临的析氢反应严重、枝晶生长不均匀等问题
[0017]相比于现有技术，本发明具有如下有益效果：本发明的电池电解液引入了两种及以上的有机溶剂，较单一组分的添加剂，本发明可以有效地调节了电解液的溶剂化结构，使电解液具有优异的循环稳定性和界面稳定性，为水系锌电池在实际中的应用提供了切实可行的解决方案。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of aqueous zinc battery technology, and in particular to an aqueous zinc battery electrolyte, its preparation method, and its application. Background Technology
[0002] Aqueous zinc batteries have attracted widespread attention in the field of electrochemical energy storage in recent years due to their unique advantages. Compared with commercial lithium-ion batteries, aqueous zinc batteries use metallic zinc as the anode, resulting in higher volumetric capacity, and zinc resources are abundant and inexpensive. At the same time, the aqueous electrolyte endows the batteries with outstanding advantages such as high intrinsic safety, environmental friendliness, and relaxed assembly conditions, making them show great application potential in large-scale energy storage, wearable electronic devices, and other fields.
[0003] However, the commercialization of aqueous zinc batteries still faces a series of key scientific issues and technological challenges. First, the uneven deposition / dissolution of zinc anodes in aqueous electrolytes easily induces irregular zinc dendrite growth. Dendrites can not only puncture the separator, causing short circuits, but also lead to electrode surface pulverization and active material shedding, resulting in capacity decay and shortened cycle life. Second, water has a narrow electrochemical window, making hydrogen evolution reactions prone to occur near the zinc deposition potential. Hydrogen evolution not only reduces the battery's coulombic efficiency, but the generated hydrogen gas can also increase internal battery pressure, cause electrolyte drying, and even lead to battery expansion or explosion. Furthermore, zinc anodes exhibit thermodynamic instability in aqueous solutions, making them susceptible to corrosion reactions and the formation of byproducts, further deteriorating interfacial stability and accelerating performance degradation.
[0004] To address the aforementioned issues, researchers have proposed various modification strategies, including coating the zinc anode surface with an artificial protective layer, replacing the liquid electrolyte with a gel polymer electrolyte, controlling the solvation structure using a eutectic solvent, and introducing functional additives into the electrolyte. Among these, the electrolyte additive strategy is particularly favored due to its ease of operation, significant effects, and controllable cost.
[0005] Currently, organic additives used in aqueous zinc batteries include small molecule alcohols / esters / amides / amines, fluorinated organic compounds, and carbonates. Most existing organic additives are single-component additives, which can only achieve local optimization for a single pain point and cannot simultaneously solve the four core problems of aqueous zinc batteries: zinc dendrite growth, hydrogen evolution side reaction, instability of the positive and negative electrode interfaces, and dissolution of active materials. When applied to aqueous zinc batteries, they result in rapid performance degradation after 1000 hours of battery cycling, and multi-target synergistic optimization cannot be achieved. Summary of the Invention
[0006] To address the shortcomings of existing technologies, this invention provides an aqueous zinc battery electrolyte, its preparation method, and its application, solving problems such as severe hydrogen evolution reaction and uneven dendrite growth faced by aqueous zinc batteries in existing technologies.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] In a first aspect, the present invention provides an aqueous zinc battery electrolyte, comprising zinc salt, deionized water and an organic solvent, wherein the organic solvent comprises any two or more of ethylene glycol, 1,2-propanediol, trifluoroethanol, polyethylene glycol, methyl difluoroacetate, ethyl difluoroacetate, methyl trifluoroacetate and ethyl trifluoroacetate.
[0009] Furthermore, by mass percentage, it includes: 1%–50% zinc salt, 10%–50% deionized water, and the balance being other mixed solvents.
[0010] Furthermore, the zinc salt includes at least one of zinc sulfate, zinc trifluoromethanesulfonate, zinc perchlorate, zinc acetate, and zinc bis(trifluoromethanesulfonyl)imide.
[0011] Further, the concentration of the zinc salt is 0.5–3.0 mol / L. Preferably, the concentration of the zinc salt is 1.0–2.5 mol / L.
[0012] Secondly, the present invention also provides a method for preparing the above-mentioned electrolyte, comprising the following steps:
[0013] Step (1) Mix deionized water and organic solvent thoroughly and stir to obtain a pre-purified solution;
[0014] Step (2) Dissolve the zinc salt in the pre-purified solution obtained in step (1);
[0015] After mixing evenly in step (3), the aqueous zinc battery electrolyte is obtained.
[0016] Thirdly, the present invention also provides an electrochemical device, particularly an aqueous zinc battery comprising the electrolyte described above.
[0017] Compared with the prior art, the present invention has the following beneficial effects: The battery electrolyte of the present invention introduces two or more organic solvents. Compared with single-component additives, the present invention can effectively adjust the solvation structure of the electrolyte, so that the electrolyte has excellent cycle stability and interface stability, providing a practical solution for the application of aqueous zinc batteries in practice. Attached Figure Description
[0018] Figure 1 A comparison graph showing the battery cycle performance of four Zn||Zn symmetric batteries composed of four electrolytes from Examples 1-3 and Comparative Example 1, respectively.
[0019] Figure 2A comparison graph showing the coulombic efficiency of four Zn||Cu batteries composed of four electrolytes from Examples 1-3 and Comparative Example 1, respectively.
[0020] Figure 3 Comparison of cycle performance of four Zn||PANI full cells composed of four electrolytes from Examples 1-3 and Comparative Example 1;
[0021] Figure 4 The charge-discharge curves of a Zn||PANI full cell using the electrolyte of Example 1 of this invention are shown. Detailed Implementation
[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0023] This invention provides an aqueous zinc battery electrolyte, comprising zinc salt, deionized water, and an organic solvent, wherein the organic solvent comprises any two or more of ethylene glycol (EG), 1,2-propanediol (1,2-PG), trifluoroethanol (TFE), polyethylene glycol (PEG), methyl difluoroacetate (MDFA), ethyl difluoroacetate (DFEA), methyl trifluoroacetate (TFAM), and ethyl trifluoroacetate (ETFA).
[0024] Furthermore, the aqueous zinc battery electrolyte comprises, by mass percentage: 1%–50% zinc salt, 10%–50% deionized water, and the remainder being other mixed solvents.
[0025] Further, the zinc salt includes at least one of zinc sulfate (ZnSO4), zinc trifluoromethanesulfonate (Zn(OTf)2), zinc perchlorate (Zn(ClO4)2), zinc acetate (Zn(Ac)2), and zinc bis(trifluoromethanesulfonyl)imide (Zn(TFSI)2).
[0026] Further, the concentration of the zinc salt is 0.5–3.0 mol / L. Preferably, the concentration of the zinc salt is 1.0–2.5 mol / L.
[0027] Secondly, the present invention also provides a method for preparing the above-mentioned electrolyte, comprising the following steps:
[0028] Step (1) Mix deionized water and organic solvent thoroughly and stir to obtain a pre-purified solution;
[0029] Step (2) Dissolve the zinc salt in the pre-purified solution obtained in step (1);
[0030] After mixing evenly in step (3), the aqueous zinc battery electrolyte is obtained.
[0031] Thirdly, the present invention also provides an electrochemical device, particularly an aqueous zinc battery comprising the electrolyte described above.
[0032] The battery electrolyte of this invention incorporates two or more organic solvents. Compared with single-component additives, this invention can effectively adjust the solvation structure of the electrolyte, giving it excellent cycle stability and interfacial stability, and providing a practical solution for the application of aqueous zinc batteries.
[0033] The features and performance of the present invention will be further described in detail below with reference to embodiments.
[0034] Example 1
[0035] This embodiment provides an aqueous zinc battery electrolyte, the preparation method of which includes the following steps: mixing 45% deionized water, 8% TFE and 6% DFEA by mass to obtain a mixed solvent, adding 41% Zn(OTf)2 by mass to the mixed solution, and mixing to obtain the aqueous zinc battery electrolyte of Example 1.
[0036] Example 2
[0037] This embodiment provides an aqueous zinc battery electrolyte, the preparation method of which includes the following steps: mixing 39% deionized water, 15% TFE and 6% DFEA by mass to obtain a mixed solvent, adding 40% Zn(OTf)2 by mass to the mixed solution, and mixing to obtain the aqueous zinc battery electrolyte of Example 2.
[0038] Example 3
[0039] This embodiment provides an aqueous zinc battery electrolyte, the preparation method of which includes the following steps: mixing 39% deionized water, 12% TFE and 8% DFEA by mass to obtain a mixed solvent, adding 41% Zn(OTf)2 by mass to the mixed solution, and mixing to obtain the aqueous zinc battery electrolyte of Example 3.
[0040] Comparative Example 1
[0041] This embodiment provides an aqueous zinc battery electrolyte. The difference between the electrolyte provided in this embodiment and that in Example 1 is that it does not contain organic solvents.
[0042] To verify the effectiveness of the electrolyte of the present invention, the present invention selected the electrolytes of Examples 1-3 and Comparative Example 1 for experiments.
[0043] 1. In this invention, the four electrolytes from Examples 1-3 and Comparative Example 1 were assembled into Zn||Zn symmetric batteries (zinc foil was cut into 12mm diameter circular pieces for assembly). The six Zn||Zn symmetric batteries were then subjected to cycle performance tests, yielding the following results: Figure 1 The graphic.
[0044] pass Figure 1 The data shows that:
[0045] The batteries using electrolyte from Comparative Example 1 exhibited extremely drastic and irregular fluctuations in their cycling curves during the initial cycling phase (0-100 hours). The polarization range expanded instantaneously, and the batteries became completely unstable within a very short cycling time, unable to maintain a stable charge / discharge voltage plateau. Their cycle life was less than 100 hours, only achieving the most basic zinc deposition / dissolution reaction in the initial few cycles. This indicates that the battery has extremely poor zinc dendrite suppression capabilities, exhibiting severe irregular dendrite growth in the early stages of cycling, facing short-circuit failure in a very short time, and failing to form an effective passivation interface, thus failing to meet the basic requirements for practical applications.
[0046] The battery using the electrolyte of Example 2 showed a gradual expansion of the voltage polarization range during cycling from 0 to 200 hours, exhibiting significant fluctuations. The polarization value rapidly increased from ±0.05V initially to approximately ±0.15V, and completely became unstable after about 200 hours of cycling. Compared to the comparative example, the battery demonstrated improved ability to suppress side reactions and reversibility of zinc deposition.
[0047] The battery using the electrolyte of Example 3 exhibited a relatively stable voltage curve and a stable polarization value maintained at around ±0.05V within the 0-500h cycling range. Compared with all comparative examples and Example 2, the stability and cycle life were significantly improved, achieving a stable 500h cycle. The polarization value was low and stable in the early stage of the cycle, and the reversibility of zinc deposition / dissolution was significantly improved.
[0048] The battery using the electrolyte of Example 1 maintained a highly stable voltage curve from the start of cycling to the end of the 1500+ hour test, with the polarization value consistently within ±0.05V. There were no voltage fluctuations, polarization spikes, or jumps. The voltage plateau remained stable throughout the entire cycle, showing no signs of instability. This indicates that the battery exhibits extremely strong dendrite suppression capabilities, maintaining a smooth and uniform zinc deposition throughout the 1500-hour ultra-long cycle, with no dendrite growth or risk of short circuits. Furthermore, the electrode / electrolyte interface demonstrates excellent long-term stability, forming a dense and stable SEI passivation film. No continuous side reactions occur during cycling, and the polarization value remains at an extremely low level. Simultaneously, the zinc deposition / dissolution reversibility is extremely high, with no irreversible loss of active material during the ultra-long cycle. Therefore, the cycle life of this battery far exceeds that of other groups, possessing excellent long-term stability and fully meeting the long-cycle requirements of large-scale energy storage, consumer electronics, and other commercial applications.
[0049] 2. In this invention, the four electrolytes from Examples 1-3 and Comparative Example 1 were assembled into Zn||Cu batteries (using 12mm Zn foil and 16mm Cu foil for assembly). The coulombic efficiency of the six Zn||Cu batteries was tested, and the results were as follows: Figure 2 The graphic.
[0050] pass Figure 2 The data shows that:
[0051] The battery using the electrolyte in Comparative Example 1 experienced a precipitous drop in coulombic efficiency from nearly 100% during the initial cycling phase (within 0-100 cycles), accompanied by extremely drastic and irregular fluctuations throughout. The coulombic efficiency remained concentrated in the 50%-90% range for the vast majority of cycles, with some cycles even falling below 50%. It completely lost its stable charge-discharge capability in less than 200 cycles, exhibiting no effective reversible cycling. This indicates that the battery in the comparative example has an extremely short cycle life and cannot meet the basic requirements of practical applications.
[0052] The battery using the electrolyte of Example 2 maintained a coulombic efficiency of nearly 100% for approximately 0-350 cycles with only minor fluctuations. Compared to all comparative examples, it showed a qualitative improvement in reversibility and cycle stability, significantly enhanced ability to suppress side reactions and reversibility of zinc deposition, and achieved stable cycling for approximately 350 cycles. In the short term, it effectively suppressed side reactions such as hydrogen evolution and corrosion, forming a relatively stable electrode interface.
[0053] The battery using the electrolyte of Example 3 maintained a stable coulombic efficiency of nearly 100% for approximately 0-450 cycles, with a much smaller fluctuation range than that of Example 2 and all comparative examples. The number of stable cycles far exceeded that of Example 2. Compared with the comparative examples and Example 2, the reversibility of zinc deposition / dissolution and interface stability were further improved, and the number of stable cycles was longer, achieving a high coulombic efficiency stable cycle of approximately 450 cycles. The coulombic efficiency fluctuations in the early and middle stages of the cycle were minimal, and the interface stability was better.
[0054] The battery using the electrolyte of Example 1 maintained a stable coulombic efficiency of approximately 100% throughout the entire 600-cycle test, from the start to the end, without any significant fluctuations, drops, or sharp decreases. The curve remained flat and stable throughout the entire cycle, demonstrating extremely high reversibility. This battery's cycle life far exceeds that of other groups, exhibiting exceptionally high long-term reliability and fully meeting the long-cycle requirements for commercial applications of aqueous zinc batteries.
[0055] 3. In this invention, the four electrolytes from Examples 1-3 and Comparative Example 1 are respectively assembled into Zn||PANI full cells (wherein, the PANI loading is 1 mg cm⁻¹). -2(Zn foil is a 12 mm disc), and the cycle performance of four Zn||PANI full cells was tested respectively, and the results are as follows. Figure 3 The graphic.
[0056] pass Figure 3 The data shows that:
[0057] The battery using the electrolyte of Comparative Example 1 has a cycle-start discharge specific capacity of approximately 85 mAh g. -1 After a slight increase in specific capacity from 0 to 100 cycles, a continuous and rapid linear decline begins from 100 cycles. By the end of 300 cycles, the specific capacity is only about 75 mAh g. -1 The capacity retention rate was only about 88%; meanwhile, the coulombic efficiency fluctuated significantly throughout the cycle, never stabilizing around 100%, with a noticeable drop in efficiency later in the cycle. This indicates that the battery has poor charge-discharge reversibility, drastic fluctuations in coulombic efficiency throughout the cycle, severe side reactions, and continuous irreversible consumption of active materials; moreover, its long-cycle performance completely fails to meet the basic requirements for commercial applications, with a significant capacity drop occurring after only 300 cycles.
[0058] The battery using the electrolyte of Example 2 has a cycle-start discharge specific capacity of approximately 83 mAh g. -1 The capacity increases to a peak of approximately 88mAh after 0-100 cycles. -1 After 100 cycles, the capacity begins to decrease slowly, and at the end of 300 cycles, the specific capacity is approximately 82 mAhg. -1 The capacity retention rate was approximately 93%; the coulombic efficiency was more stable compared to Comparative Example 1, generally remaining above 90%, but still showing slight fluctuations, with a slight decrease in the later stages of cycling. The continued fluctuation in the coulombic efficiency of this battery indicates that side reactions were not completely suppressed, and the interface will still deteriorate under long-term cycling, failing to meet the commercialization requirements for ultra-long cycling.
[0059] The battery using the electrolyte of Example 3 has a cycle-start discharge specific capacity of approximately 82 mAh g. -1 The capacity increases to a peak of approximately 87mAh after 0-100 cycles. -1 After 100 cycles, the capacity begins to decrease slowly, at a rate slightly slower than in Example 2. At the end of 300 cycles, the specific capacity is approximately 81 mAh g. -1 The capacity retention rate was approximately 92%; the coulombic efficiency was similar to that of Example 2, remaining relatively stable throughout the cycle, although there was still a slight decrease in efficiency and capacity decay in the later stages of cycling. The coulombic efficiency of this battery did not achieve 100% stability throughout the cycle, side reactions were not completely eliminated, and ultra-long stable cycling was not possible.
[0060] The battery using the electrolyte of Example 1 has a cycle-start discharge specific capacity of approximately 84 mAh g. -1 The capacity steadily increases to a peak of approximately 88mAh from 0 to 50 cycles. -1Subsequently, throughout the 300-cycle period, the specific capacity remained stable with almost no significant decrease, and at the end of the 300-cycle period, the specific capacity was still maintained at approximately 85 mAhg. -1 The battery exhibits a capacity retention rate exceeding 96%, while maintaining a stable coulombic efficiency close to 100% throughout the cycle without any significant fluctuations, demonstrating extremely high charge-discharge reversibility. This battery exhibits exceptionally good dual-interface regulation between the positive and negative electrodes, showing almost no capacity decay within 300 cycles, with a capacity retention rate far exceeding other groups. It perfectly suppresses the dissolution of active materials in the PANI positive electrode and fundamentally solves the side reaction problems of dendrite growth and hydrogen evolution corrosion in the zinc negative electrode. Furthermore, it boasts extremely high charge-discharge reversibility, with a stable coulombic efficiency close to 100% throughout the cycle. Side reactions within the entire cell are effectively suppressed, with no irreversible loss of active materials. Moreover, the battery demonstrates extremely strong cycle stability, with no capacity drop or performance degradation throughout the cycle, fully meeting the long-cycle requirements for commercial applications of aqueous zinc batteries and possessing extremely high practical value.
[0061] 4. The Zn||PANI full cell prepared using the electrolyte of Example 1 was subjected to charge-discharge tests, and the results were as follows: Figure 4 The charge / discharge curves shown are shown below.
[0062] pass Figure 4 The data shows that the charging curve of this battery indicates no significant rise in the charging voltage plateau, and the cutoff voltage remains above 1.5V throughout the cycle. Polarization does not increase significantly throughout the cycle, indicating that the interfacial charge transfer impedance has not continuously deteriorated. The discharge curve shows that the discharge voltage plateau hardly decreases, maintaining a stable output characteristic. The discharge specific capacity remains stable at 85 mAhg after 300 cycles. -1 The battery exhibits no abrupt capacity decay. After 300 cycles, the overall shape and redox characteristics (curve slope change) of the charge-discharge curve are highly consistent with those of the first cycle. There is no curve distortion, no plateau disappearance, and no abnormal voltage fluctuations caused by side reactions. This indicates that the electrochemical reaction mechanism of the battery is stable throughout the process, and no irreversible electrode structure damage or interface failure has occurred.
[0063] In summary, Example 1 at 5mAh / cm 2 At the desired deposition level, the Zn||Cu asymmetric cell in Example 1 can cycle stably for over 1500 hours, while Examples 2-3 and Comparative Examples 1-3 exhibit short circuits or a sharp increase in polarization voltage during cycling. The coulombic efficiency of the Zn||Cu asymmetric cell in Example 1 is significantly higher than that of the other examples, demonstrating that the introduction of organic solvents significantly improves the reversibility of zinc deposition / stripping. The Zn||PANI full cell at 0.5 Ag... -1 The capacity retention rate was 91.5% after 300 cycles. It can be seen that the overall performance of the electrolyte prepared in Example 1 is significantly better than that of other examples and comparative examples.
[0064] The battery electrolyte of this invention incorporates two or more organic solvents. Compared with single-component additives, this invention can effectively adjust the solvation structure of the electrolyte, giving it excellent cycle stability and interfacial stability, and providing a practical solution for the application of aqueous zinc batteries.
[0065] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
Claims
1. An aqueous zinc battery electrolyte, characterized in that, It includes zinc salt, deionized water, and organic solvents, wherein the organic solvents include any two or more of ethylene glycol, 1,2-propanediol, trifluoroethanol, polyethylene glycol, methyl difluoroacetate, ethyl difluoroacetate, methyl trifluoroacetate, and ethyl trifluoroacetate.
2. The electrolyte according to claim 1, characterized in that, The composition by mass percentage is: 1%–50% zinc salt, 10%–50% deionized water, and the balance being other mixed solvents.
3. The electrolyte according to claim 1 or 2, characterized in that, The zinc salt includes at least one of zinc sulfate, zinc trifluoromethanesulfonate, zinc perchlorate, zinc acetate, and zinc bis(trifluoromethanesulfonyl)imide.
4. The electrolyte according to claim 3, characterized in that, The concentration of zinc salt is 0.5–3.0 mol / L.
5. The electrolyte according to claim 4, characterized in that, The concentration of zinc salt is 1.0–2.5 mol / L.
6. The electrolyte according to claim 1 or 2, characterized in that, The concentration of zinc salt is 0.5–3.0 mol / L.
7. The electrolyte according to claim 6, characterized in that, The concentration of zinc salt is 1.0–2.5 mol / L.
8. A method for preparing the electrolyte according to any one of claims 1-7, characterized in that, Includes the following steps: Step (1) Mix deionized water and organic solvent thoroughly and stir to obtain a pre-purified solution; Step (2) Dissolve the zinc salt in the pre-purified solution obtained in step (1); After mixing evenly in step (3), the aqueous zinc battery electrolyte is obtained.
9. An electrochemical device, characterized in that, Includes the electrolyte as described in any one of claims 1-7.