Aqueous zinc ion battery system
By adding potassium ferricyanide to the positive electrode electrolyte of NiHCF//Zn batteries and using an anion exchange membrane, the problem of NiHCF positive electrode material dissolution was solved, and the cycle stability and lifespan of the batteries were significantly improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-06
- Publication Date
- 2026-04-10
AI Technical Summary
Existing NiHCF//Zn aqueous batteries have shortcomings in terms of cycle stability and lifespan, mainly due to the loss of active materials and irreversible side reactions caused by the dissolution of NiHCF cathode material in aqueous electrolyte.
Potassium ferricyanide (K3[Fe(CN)6)6) was added to the positive electrode electrolyte, and an anion exchange membrane was used as a separator to inhibit the dissolution of the positive electrode active material.
It significantly improves the cycle stability of NiHCF//Zn batteries, increasing cycle life from 20 cycles to over 200 cycles, maintaining 100% coulombic efficiency, low polarization, and high energy efficiency.
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Figure CN121839918A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of zinc-ion battery technology, and more specifically, to an aqueous zinc-ion battery system. Background Technology
[0002] With the global energy structure transformation and the increasing demand for environmental sustainability, efficient energy conversion and storage technologies have become a research hotspot. Thermal regenerative electrochemical cycle (TREC) technology is a highly promising method for recovering low-grade waste heat. It can directly convert thermal energy under small temperature differences, such as industrial waste heat and geothermal energy, into electrical energy, and has the advantages of high efficiency, low cost, and environmental friendliness.
[0003] Among numerous TREC systems, aqueous zinc-ion battery-based systems stand out due to their high safety and low cost. Among these, the NiHCF / / Zn battery system has attracted widespread attention due to its excellent thermoelectric chemical properties. The NiHCF cathode has a negative temperature coefficient (approximately -0.6 mV / K), while the Zn anode has a positive temperature coefficient in conventional electrolytes (approximately +0.6 mV / K), resulting in a significantly high thermoelectric coefficient (approximately 1.2 mV / K) for the entire cell. This characteristic allows the battery to efficiently convert thermal energy into electrical energy by charging and discharging at different temperatures.
[0004] Problems with Existing Technology: However, existing NiHCF / / Zn aqueous batteries face a key bottleneck in practical applications: poor cycle stability and short lifespan. Research indicates that the rapid capacity decay is primarily attributed to the dissolution of the NiHCF cathode active material in the aqueous electrolyte. This dissolution not only leads to the loss of active material but may also trigger irreversible side reactions, severely limiting the commercial application of NiHCF / / Zn batteries in TREC systems requiring long-term stable operation. For example, conventional NiHCF / / Zn batteries typically have a cycle life of only about 20 cycles at a 1C current rate.
[0005] Therefore, there is an urgent need to develop an effective technical means to fundamentally suppress the dissolution of NiHCF cathode material, thereby significantly improving the cycle stability of NiHCF / / Zn batteries to meet the requirements of TREC systems for high-efficiency, long-life energy storage devices. Summary of the Invention
[0006] Based on the aforementioned technical problems in the prior art, the present invention provides an aqueous zinc-ion battery system. This system effectively inhibits the dissolution of the positive electrode active material by adding potassium ferricyanide (K3[Fe(CN)6]) to the positive electrode electrolyte and using an anion exchange membrane as a separator, thereby improving the cycle stability of the aqueous zinc-ion battery (NiHCF / / Zn battery) system.
[0007] To achieve the above objectives, the technical solution of the present invention is as follows: An aqueous zinc-ion battery system includes a positive electrode chamber, a negative electrode chamber, and a separator for separating the positive electrode chamber and the negative electrode chamber; the positive electrode chamber contains a positive electrolyte and a positive electrode, the negative electrode chamber contains a negative electrolyte and a negative electrode, and the positive and negative electrodes are connected to an external circuit through tabs; The positive electrode active material includes NiHCF, and the positive electrode electrolyte includes K2SO4 and ferricyanide; the negative electrode electrolyte includes ZnSO4; and the membrane is an anion exchange membrane.
[0008] In some embodiments, the concentration of K2SO4 in the positive electrode electrolyte is 0.1-5 mol / L, and the concentration of ferricyanide is 0.01-0.5 mol / L.
[0009] In some embodiments, the ferrocyanide includes at least one selected from K3[Fe(CN)6], Na3[Fe(CN)6], potassium ferrocyanide, sodium ferrocyanide, ammonium ferrocyanide, and ammonium ferrohydride.
[0010] In some embodiments, the concentration of ZnSO4 in the negative electrode electrolyte is 0.1-5 mol / L.
[0011] In some embodiments, the negative electrode electrolyte further includes KCl, the concentration of which is 0.01-0.5 mol / L.
[0012] In some embodiments, the preparation of the positive electrode includes the following steps: NiHCF, conductive agent and binder are mixed, and then solvent is added and mixed evenly to obtain a slurry; the slurry is coated on the surface of the current collector and then dried to obtain the positive electrode.
[0013] In some embodiments, the mass ratio of NiCHF, conductive agent and binder is (6-9):(0.5-2):(0.5-2).
[0014] In some embodiments, the negative electrode comprises elemental zinc.
[0015] In some embodiments, the anion exchange membrane is FumasepFAA-3-50.
[0016] Compared with the prior art, the technical solution of the present invention is as follows: The technical solution of this invention uses NiHCF as the positive electrode active material. By adding ferricyanide to the positive electrode electrolyte and using an anion selective exchange membrane (AEM) as a separator to isolate the positive and negative electrode electrolytes, the dissolution of the positive electrode active material in the positive electrode electrolyte is effectively suppressed, thereby improving the cycle stability of the battery system.
[0017] The NiHCF / / Zn zinc-ion battery obtained through the technical solution of this invention has increased its cycle life at 1C rate from the original 20 cycles to more than 200 cycles, and its cycle stability has been significantly improved. Attached Figure Description
[0018] Figure 1 Figure 1 shows the battery system structure diagrams in the embodiments and comparative examples; wherein, Figure 2a is a schematic diagram of the battery system structure in Embodiment 1; and Figure 3b is a schematic diagram of the half-cell system structure in Embodiment 2 and Comparative Examples 1-3. Figure 2 The figures show the cyclic voltammetry (CV) curves of different battery systems. Figure a shows the CV curves of the 0.05 kFC system at different scan rates; Figure b shows the CV curves of the 0.5 ks system at different scan rates; Figure c shows the CV curves of the 0.5 ks and 0.05 kFC systems at different scan rates; and Figure d compares the CV curves of the three systems at a scan rate of 0.5 mV / s. Figure 3 Figure 1 shows the cycle stability test results of different battery systems. Figures a, b, and c show the cycle stability of the 0.5ks0.05kfc-0.5zs, 0.5kt1zt, and 0.5ks-0.5zs systems, respectively. Figure d shows the charge-discharge curves of the 0.5ks0.05kfc-0.5zs system at a current density of 50mA / g for different numbers of cycles. Figure 4 The following are the inductively coupled plasma optical emission spectrometry (ICP-OES) test results for different battery systems. Figure a shows the Ni concentration in the positive electrolyte of the 0.5ks0.05kfc-0.5zs system before and after 100 cycles at a current density of 1C; Figure b shows the Ni concentration in the positive electrolyte of the 0.5ks-0.5zs system before and after 100 cycles at a current density of 1C; Figure c shows the Ni concentration in the electrolyte of the 0.5kt1zt system before and after 100 cycles at a current density of 1C; and Figure d shows the Fe concentration in the positive electrolyte of the 0.5ks0.05kfc-0.5zs system before and after cycling. Detailed Implementation
[0019] Numerous specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and similar modifications can be made by those skilled in the art without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.
[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
[0021] Example 1
[0022] Preparation of NiHCF electrode: Weigh 140 mg of NiHCF powder, 40 mg of acetylene black, and 20 mg of PVDF. Add all three to an agate mortar and grind for 30 min to form a uniform powder. Then, add the mixture to 2 ml of NMP, add a magnetic stir bar, and stir on a magnetic stirrer for 6 h at 300 r / min. Then, coat the uniformly mixed slurry onto a pre-weighed and labeled titanium mesh to obtain the electrode. Finally, dry the obtained electrode under vacuum at 70℃ for 20 h, weigh it, and record the weight for further use.
[0023] Membrane pretreatment: The anion exchange membrane FumasepFAA-3-50 was completely immersed in 0.5 M NaCl solution at room temperature for 24 h. After rinsing with deionized water, the membrane was then immersed in saturated K2SO4 solution for more than 48 hours to convert the membrane into sulfate form.
[0024] like Figure 1 As shown in Figure a, an aqueous zinc-ion battery system includes a positive electrode chamber, a negative electrode chamber, and a separator located between the positive and negative electrode chambers to separate the positive and negative electrolytes. The positive electrode chamber contains the positive electrolyte and a positive electrode plate, and the negative electrode chamber contains the negative electrolyte and a negative electrode plate. The positive and negative electrode plates are connected to an external circuit via tabs (not shown in the figure). In the negative electrode chamber, the negative electrode electrolyte is a mixed solution of 0.5M ZnSO4 and 0.035 M KCl, and the negative electrode is a zinc sheet; In the positive electrode chamber, the positive electrode electrolyte is a mixed solution of 0.5 M K2SO4 and 0.05 M K3[Fe(CN)6], and the positive electrode is a NiHCF electrode; this battery system is referred to as 0.5ks0.05kfc-0.5zs; The diaphragm is an anion exchange membrane, FumasepFAA-3-50.
[0025] Example 2
[0026] The battery architecture of this embodiment is as follows: Figure 1 Figure b shows a three-electrode electrolytic cell. The working electrode is a NiHCF electrode, the counter electrode is graphite, and the reference electrode is a saturated calomel electrode. The half-cell is assembled, and the cell system is referred to as 0.5ks0.05kfc.
[0027] Comparative Example 1 The battery system structure of this comparative example is the same as that of Example 2, except that K3[Fe(CN)6] is not added to the electrolyte, and the battery system is referred to as 0.5ks.
[0028] Comparative Example 2 The battery system structure of this comparative example is the same as that of Example 2, except that only K3[Fe(CN)6] is added to the electrolyte, and the battery system is referred to as 0.05kfc.
[0029] Comparative Example 3 The battery system structure of this comparative example is the same as that of Example 2. The difference is that this comparative example is a full cell with no reference electrode. The positive electrode is NiHCF, the negative electrode is a zinc sheet, and the electrolyte is a mixed solution of 0.5 M CF3KO3S and 1 M Zn(CF3SO3)2. The battery system is referred to as 0.5kt1zt.
[0030] Comparative Example 4 The battery system structure of this comparative example is the same as that of Example 1, except that the negative electrode electrolyte is a 0.5M ZnSO4 solution and the positive electrode electrolyte is a 0.5M K2SO4 solution. The battery system is referred to as 0.5ks-0.5zs.
[0031] The battery systems in Examples 1-2 and Comparative Examples 1-4 were subjected to relevant performance tests, and the specific test results are as follows: Figure 2-4 As shown, where: The cyclic voltammetry (CV) curves of the battery systems at 0.05 kFC, 0.5 ks, and 0.5 ks and 0.05 kFC at different scan rates are shown below. Figure 2 Figures a, b, and c; the CV curves of the three battery systems at a scan rate of 0.5 mV / s are shown below. Figure 2 As shown in Figure d.
[0032] CV test results show that after adding K3[Fe(CN)6, the redox peak positions and curve shapes of the battery system remain similar, proving that the additive does not change the inherent electrochemical reaction mechanism of NiHCF while achieving stabilization, and maintains high reversibility.
[0033] Depend on Figure 2 It is known that the oxidation potential of potassium ferricyanide is lower than that of NiHCF. Therefore, by controlling the electrochemical window of charge and discharge, potassium ferricyanide can be prevented from participating in the main electrochemical reactions during charge and discharge.
[0034] The cycle stability of the battery systems 0.5ks-0.05kfc-0.5zs, 0.5kt-1zt, and 0.5ks-0.5zs at a current density of 1C (1C=50mA / g) is as follows: Figure 3 Figures a, b, and c are shown; the charge-discharge curves of the 0.5ks0.05kfc-0.5zs battery system at 1C current density for different numbers of cycles are shown below. Figure 3 The d-graph. (From) Figure 3 It can be seen that the potassium ferricyanide-added system (0.5ks0.05kfc-0.5zs) maintains stable cycling for over 200 cycles at a current density of 1C without significant capacity decay, while the coulombic efficiency remains stable at 100%. Observing the charge-discharge curves of different number of cycles in the d-plot, the 0.5ks0.05kfc-0.5zs system still maintains low polarization after multiple cycles, and the energy efficiency is always >92%. In contrast, the 0.5kt1zt and 0.5ks-0.5zs systems without potassium ferricyanide decay to about 20% capacity after only 20 cycles under the same conditions.
[0035] The concentrations of Ni in the positive electrode electrolyte of the battery systems 0.5ks-0.05kfc-0.5zs, 0.5ks-0.5zs, and 0.5kt-1zt before and after 100 cycles at a current density of 1C are as follows: Figure 4 The figures a, b, and c are shown.
[0036] The Fe concentration in the positive electrode electrolyte of the 0.5ks0.05kfc-0.5zs battery system before cycling at a 1C current density and after 100 cycles is as follows: Figure 4 As shown in Figure d.
[0037] Depend on Figure 4 It can be seen that the solubility of the NiHCF cathode in each system can be assessed by measuring the concentration of Ni or Fe in the electrolyte before and after 100 cycles. Since no nickel-containing substances were added to the initial electrolyte, the initial Ni concentration was undetectable in all systems. After 100 cycles, the Ni concentration in the 0.5kt1zt and 0.5ks-0.5zs systems was on the order of 10 mg / L, which is more than 1000 times higher than the Ni concentration in the 0.5ks0.05kfc-0.5zs system. This demonstrates that the solubility of the NiHCF cathode in the 0.5ks0.05kfc-0.5zs system was significantly reduced. Meanwhile, the iron concentration in the 0.5ks0.05kfc-0.5zs system did not change significantly before and after 100 cycles, mainly due to the potassium ferricyanide additive.
[0038] The test results above show that potassium ferricyanide additive effectively inhibits the dissolution of NiHCF cathode and significantly improves the cycle stability of NiHCF / / Zn battery without causing other harmful effects.
[0039] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0040] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.
Claims
1. An aqueous zinc-ion battery system, characterized in that, It includes a positive electrode chamber, a negative electrode chamber, and a diaphragm for separating the positive electrode chamber and the negative electrode chamber; the positive electrode chamber contains a positive electrolyte and a positive electrode, and the negative electrode chamber contains a negative electrolyte and a negative electrode; the positive electrode and the negative electrode are connected to an external circuit through tabs. The positive electrode active material includes NiHCF, and the positive electrode electrolyte includes K2SO4 and ferricyanide; the negative electrode electrolyte includes ZnSO4; and the membrane is an anion exchange membrane.
2. The aqueous zinc-ion battery system according to claim 1, characterized in that, The concentration of K2SO4 in the positive electrode electrolyte is 0.1-5 mol / L, and the concentration of ferricyanide is 0.01-0.5 mol / L.
3. The aqueous zinc-ion battery system according to claim 1, characterized in that, The ferrocyanide includes at least one of K3[Fe(CN)6], Na3[Fe(CN)6], potassium ferrocyanide, sodium ferrocyanide, ammonium ferrocyanide, and ammonium ferrohydride.
4. The aqueous zinc-ion battery system according to claim 1, characterized in that, The concentration of ZnSO4 in the negative electrode electrolyte is 0.1-5 mol / L.
5. The aqueous zinc-ion battery system according to claim 1, characterized in that, The negative electrode electrolyte also includes KCl, and the concentration of KCl is 0.01-0.5 mol / L.
6. The aqueous zinc-ion battery system according to claim 1, characterized in that, The preparation of the positive electrode includes the following steps: NiHCF, conductive agent and binder are mixed, and then solvent is added and mixed evenly to obtain a slurry; the slurry is coated on the surface of the current collector and then dried to obtain the positive electrode.
7. The aqueous zinc-ion battery system according to claim 1, characterized in that, The negative electrode comprises elemental zinc.
8. The aqueous zinc-ion battery system according to claim 1, characterized in that, The anion exchange membrane includes FumasepFAA-3-50.