Aqueous sulfur-based battery and energy storage system

Abstract

The invention belongs to the technical field of flow batteries, and particularly relates to an aqueous sulfur-based battery and an energy storage system. The lithium ion battery comprises a positive electrode, a positive electrode solution, a negative electrode and a negative electrode solution, a diaphragm is arranged between the positive electrode solution and the negative electrode solution, the negative electrode solution comprises polysulfide and a soluble cationic catalyst, and the soluble cationic catalyst has specific adsorption characteristics on the negative electrode. Through specific adsorption of positive ions on the electrode, the electrochemical reaction kinetics of polysulfide is remarkably improved at lower cost, and the energy efficiency of the battery and the utilization rate of active substances are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of liquid flow batteries, and particularly relates to a water-based sulfur-based battery and an energy storage system. BACKGROUND

[0002] Large-scale application of renewable energy cannot be achieved without the development of new energy storage technologies with intrinsic safety, low cost and scalability. Water-based liquid flow batteries store energy in liquid electrolytes and achieve energy storage through electrochemical reactions. They have the advantages of energy and power decoupling design, high safety, high energy conversion efficiency, high power density and flexible site selection, and are of great significance in renewable energy grid-connected applications and peak load shifting.

[0003] The market application of traditional all-vanadium liquid flow batteries is restricted by high vanadium ore prices, high electrolyte costs, strong electrolyte corrosion and low energy density. Therefore, it is necessary to develop low-cost new water-based liquid flow battery systems.

[0004] Water-based sulfur-based liquid flow batteries use polysulfides as active materials and have the advantages of easy availability of raw materials, low cost, high capacity density and environmental friendliness. They are an important branch of future new liquid flow batteries. However, their development is hindered by low power density and serious active material mutual stringing. The slow electrochemical kinetics of polysulfides is an important reason for low battery power density and serious energy loss, and effective catalysts need to be developed to improve the power density of the system and promote its industrialization process.

[0005] To improve the kinetics of polysulfides, various single-atom metals or metal sulfide-based catalysts have been widely proposed to improve electrode conductivity, such as Ni / NiS x (Electrochim. Acta, 2005, 51(6): 1091-1098.; US4485154; WO2000016420A1), Co / CoS x (Nat. Commun., 2019, 10(1): 3367.; US4828942), Cu / Cu x S y(Mater. Today Energy, 2020, 18: 100540; Mater. Chem. Phys., 2020, 250: 123143.; WO2000016420A1), W / WS2 (J. Phys. Energy, 2018, 1(1): 015005.), Pb / PbS (J. Electrochem. Soc., 1980, 127(3): 544.) and the like. However, the above methods have limited catalytic activity area of the catalyst, the material is easy to be poisoned and peeled off, it is difficult to effectively and stably improve the power density of the sulfur-based aqueous flow battery, and the synthesis method involves complex and expensive steps such as high temperature and high pressure, which is not conducive to large-scale production.

[0006] Patent with publication number US20230307682A1 discloses a soluble organic catalyst for aqueous sulfur-based flow battery, which chemically reacts with polysulfide and electrochemically reacts on the electrode, which can reduce the overpotential of polysulfide reaction. However, the organic active substance will degrade and fail after multiple electrochemical reaction cycles, and its calendar life is limited by the activity and structural stability of the organic substance.

[0007] Patent with publication number CN102956866A discloses a non-aqueous metal-sulfur flow battery system, but the patent is only applicable to reactions with organic solvents or ionic liquids, and is not applicable to aqueous systems. SUMMARY

[0008] In view of the above problems in the prior art, the present application provides an aqueous sulfur-based flow battery and energy storage system, which can improve the electrochemical reaction kinetics of polysulfide and has good battery cycle stability.

[0009] To achieve the above-mentioned purpose, the technical scheme provided by the present application is as follows:

[0010] In a first aspect, the present application provides an aqueous sulfur-based battery, which comprises a positive electrode, a positive electrode liquid, a negative electrode and a negative electrode liquid, a diaphragm is arranged between the positive electrode liquid and the negative electrode liquid, the negative electrode liquid contains polysulfide and a soluble cation catalyst, and the soluble cation catalyst has specific adsorption properties on the negative electrode.

[0011] Optionally, the soluble cation catalyst comprises one or more of quaternary ammonium salt, quaternary phosphonium salt, imidazole type, pyridine type, piperidine type or pyrrole type cation.

[0012] Optionally, the polysulfide is one or more of M x S y , M x S yM is Li, Na, K, Zn, Ni, or Cu; x is 1 or 2; and y is 1, 2, or 4.

[0013] Optionally, M is Li, Na, K, Zn, Ni, or Cu.

[0014] Optionally, the quaternary ammonium salt soluble cationic catalyst comprises a chain quaternary ammonium salt, a cyclic quaternary ammonium salt, a quaternary ammonium salt containing one N + center, a quaternary ammonium salt containing multiple N + centers, or a combination thereof; and the quaternary phosphonium salt soluble cationic catalyst comprises a chain quaternary phosphonium salt, a cyclic quaternary phosphonium salt, a quaternary phosphonium salt containing one P + center, a quaternary phosphonium salt containing multiple P + centers, or a combination thereof.

[0015] Optionally, the concentration of the soluble cationic catalyst is 0.1 mM-1 M, and the concentration of the polysulfide is 0.1 M to 8 M.

[0016] Optionally, the concentration of the soluble cationic catalyst is 0.006 M-0.1 M.

[0017] Optionally, the negative electrode is loaded with a conductive agent.

[0018] Optionally, the conductive agent is loaded onto the negative electrode material by the following method: the conductive agent and polyvinylidene fluoride are dissolved in a 1-methyl-2-pyrrolidone solvent at a ratio of 8:1 to obtain a slurry, the slurry is added dropwise to the negative electrode material at a conductive agent loading of 10-300 mg cm -2 , and then the negative electrode material loaded with the conductive agent is placed in an oven at 60-70°C for drying, and then transferred to a tube furnace and placed in an air atmosphere at 400-600°C for 2-5 h.

[0019] Optionally, the conductive agent is a carbon material, and the carbon material is one or more of Ketjen black, activated carbon, carbon nanotubes, or graphene.

[0020] When the above loading is not performed on the negative electrode, the purpose of improving the electrochemical reaction kinetics of the polysulfide and the stability of the battery of the present application can also be achieved, and loading a certain mass of Ketjen black carbon material on the negative electrode can further enhance the adsorption capacity of the electrode to the cationic catalyst.

[0021] Optionally, the aqueous sulfur-based battery is an aqueous sulfur-based static battery or an aqueous sulfur-based flow battery.

[0022] Optionally, the separator is an ion exchange membrane or other porous membrane.

[0023] Optionally, the negative electrode liquid is an alkaline aqueous solution or a neutral aqueous solution.

[0024] The electrolyte in the negative electrode solution is 0.1-10 M of LiOH, NaOH, KOH, LiCl, NaCl, KCl, NH4Cl or a combination thereof.

[0025] Optionally, the electrolyte in the positive electrode solution is selected from halogens, [Fe(CN)6], etc. 4- / [Fe(CN)6] 3- Fe 2+ / Fe 3+ Mn 2 + / Mn 3+ / MnO2、MnO4 2- / MnO4 - NiOOH / Ni 2+ VO 2+ / VO2 + Ferrocene, Zn / Zn 2+ or Zn / Zn(OH)4 2- The positive electrode solution contains 2,2,6,6-tetramethylpiperidine nitrogen oxide or a combination thereof, wherein the electrolyte concentration is from 0.1 M to 6 M.

[0026] Optionally, the positive and negative electrode materials are selected from carbon felt, carbon paper, carbon cloth, or metal current collectors.

[0027] On the other hand, this application also provides an energy storage system including the aforementioned aqueous sulfur-based battery.

[0028] Compared with existing technologies, the aqueous sulfur-based battery and energy storage system provided in this application have at least the following beneficial effects:

[0029] 1. This invention, by adding a soluble cationic catalyst, effectively shields the negative charge on the electrode during the reduction process through the specific adsorption of cations on the electrode, alleviates the strong electrostatic repulsion of the electrode to polysulfide anions, improves the reaction rate of polysulfides, and achieves a significant improvement in the electrochemical reaction kinetics of polysulfides at a lower cost, thereby improving battery energy efficiency and active material utilization.

[0030] 2. The present invention maintains good stability during long-term battery cycling, has high compatibility with various separators, electrode materials and electrolyte supporting electrolyte components, and has good versatility.

[0031] 3. This invention does not involve expensive raw materials, does not require expensive equipment, and effectively improves the energy efficiency of aqueous sulfur-based flow batteries at a lower cost; moreover, the preparation method is simple and requires less professional skills from operators. Attached Figure Description

[0032] Figure 1The effect of soluble cationic catalysts on the cyclic voltammetry curves of polysulfides is shown in the following: (a) Comparison of cyclic voltammetry curves after adding equal amounts of symmetrical chain quaternary ammonium salt cationic catalysts with different side chain lengths; (b) Comparison of cyclic voltammetry curves after adding equal amounts of asymmetric cyclic quaternary ammonium salt cationic catalysts with different side chain lengths.

[0033] Figure 2 The effect of the soluble cationic catalyst in Examples 2-3 on the static battery cycle performance: (a) Static battery at 60 mA cm⁻¹ –2 (a) Constant current charge-discharge curves from 1 to 400 cycles at the current density; (b) Capacity retention and coulombic efficiency from 1 to 1000 cycles.

[0034] Figure 3 The effect of soluble cationic catalysts on the rate performance of aqueous sulfur-based flow batteries in Examples 4-5: (a) The flow battery with soluble cationic catalysts added to the negative electrode liquid from 150 mA cm⁻¹ -2 up to 40 mA cm -2 (a) Rate testing of the flow cell without catalyst from 150 mA cm⁻¹ -2 up to 40 mA cm -2 (c) Rate test of sulfur-based flow battery;

[0035] Figure 4 Cycle stability test results of aqueous sulfur-based flow batteries with cationic catalysts added to the negative electrode liquid in Examples 4, 5, and 6; (a) Flow batteries using negative electrode liquids with catalysts at 60 mA cm⁻¹ -2 (a) 1800 cycles; (b) flow cell using a catalyst-containing negative electrode solution at 80 mA cm⁻¹ -2 Comparison of the cycle performance of flow batteries with blank negative electrode liquid after 1800 cycles at 40 ℃. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings:

[0037] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0038] All reagents and materials used in this example can be purchased routinely. The quantitative experiments involved in the examples were all repeated at least three times, and the results were averaged.

[0039] Example 1:

[0040] A glassy carbon electrode was used as the working electrode, a saturated calomel electrode as the reference electrode, and a platinum mesh electrode as the counter electrode. The polysulfide in the electrolyte was 20 mM K2S2. The electrolyte also contained equal amounts of soluble cationic catalysts with different side chains. The contents of the soluble cationic catalysts in each group are as follows:

[0041] Group 1: 0.94M KCl + 0.06M TMACl;

[0042] Group 2: 0.94M KCl + 0.06M TEACl;

[0043] Group 3: 0.94M KCl + 0.06M TBACl;

[0044] Group 4: 0.94M KCl + 0.06M EMPBr;

[0045] Group 5: 0.94M KCl + 0.06M BMPBr;

[0046] Control group 1: 1M KCll.

[0047] Cyclic voltammetry tests were performed on each group under an argon atmosphere, and the test results are shown below. Figure 1 The chemical structural formulas corresponding to soluble cationic catalysts are as follows:

[0048] .

[0049] Depend on Figure 1 As can be seen from point a, the addition of symmetrical chain quaternary ammonium salts reduces the potential gap between the anodic and cathodic peaks of the polysulfide cyclic voltammetry, indicating a decrease in the overpotential and improved polysulfide kinetics. Furthermore, the longer the cation side chain of the symmetrical chain quaternary ammonium salt, the more pronounced the catalytic effect. Based on... Figure 1 b, Long-chain cyclic quaternary ammonium salt cations (BMP) + ) compared to short-chain cyclic quaternary ammonium salt cations (EMP) + It has a better catalytic effect.

[0050] Example 2:

[0051] In this embodiment, the aqueous sulfur-based static battery includes a positive electrode, a negative electrode, a positive electrolyte, a negative electrolyte, and a separator disposed between the positive electrolyte and the negative electrolyte.

[0052] In this embodiment, the diaphragm is a potassium ion type Nafion 117 diaphragm.

[0053] A carbon felt electrode with a diameter of 16 mm and a thickness of 3 mm was used as the positive and negative electrodes of the battery. The carbon felt electrode of the negative electrode underwent the following pretreatment: To enhance the adsorption capacity of the electrode for the cationic catalyst, the carbon felt could be loaded with a certain mass of Ketjen black carbon material. The loading method was as follows: Ketjen black and polyvinylidene fluoride were dissolved in 1-methyl-2-pyrrolidone solvent at a ratio of 8:1 to prepare a slurry, and then loaded with 225 mg / cm³ of the slurry. -2 The slurry loaded with Ketjen black was dropped onto the carbon felt electrode, and then the carbon felt electrode loaded with Ketjen black was placed in a 60°C oven to dry, and then transferred to a tube furnace to be activated at 500°C for 4 hours in an air atmosphere.

[0054] The negative electrode electrolyte includes: water, 1 M K2S4, 1 M KOH, and 0.1 M catalyst 1-methyl-1-ethylpyrrolidine bromide; the positive electrode electrolyte includes: water, 0.5 M K4Fe(CN)6, and 1 M KCl. The volume of both the positive and negative electrode electrolytes is 0.4 mL.

[0055] Example 3

[0056] The difference between this embodiment and Embodiment 2 is as follows:

[0057] No catalyst was added to the negative electrode solution; the carbon felt electrode of the negative electrode was not loaded and was directly activated in a tube furnace at 500 °C for 4 hours in an air atmosphere.

[0058] Constant current charge-discharge tests were performed on the static batteries assembled in Examples 2 and 3. The test results are shown in [Figure Number]. Figure 2 The current density is 60 mA cm⁻¹ -2 Charging stops at 1.6 V and discharging stops at 0.2 V.

[0059] Figure 2 The cycling stability of an aqueous sulfur-based static battery with a soluble cationic catalyst was demonstrated. At 60 mAcm⁻¹ -2 At a given current density, the aqueous sulfur-based static battery with 0.1 M 1-methyl-1-ethylpyrrolidine bromide added to the negative electrode achieved a capacity utilization rate of 84.0% in the first cycle. In contrast, the aqueous sulfur-based static battery without a soluble cationic catalyst achieved a capacity utilization rate of only 57.8% in the first cycle. After 1000 cycles, the static battery with the soluble cationic catalyst retained a capacity of 93.3%, while the static battery without the catalyst retained only 51.6%. Therefore, the cationic catalyst can effectively reduce the over-charge potential of the aqueous sulfur-based static battery, enabling the battery to maintain a high capacity utilization rate and retention rate even after 1000 cycles.

[0060] Example 4

[0061] In this embodiment, the aqueous sulfur-based flow battery includes a positive electrode, a negative electrode, a positive electrode liquid and its fluid frame, a negative electrode liquid and its fluid frame, a separator, a storage tank, a pump, and pipes. The connection methods of the various parts of the flow battery are conventional techniques in the art and will not be described in detail here.

[0062] In this embodiment, the diaphragm is a potassium ion type Nafion 117 diaphragm.

[0063] Take an area of ​​3×3 cm 2 A 3 mm thick carbon felt electrode is used as the positive and negative electrodes of the battery. The negative carbon felt electrode undergoes the following pretreatment: To enhance the electrode's adsorption capacity for the cationic catalyst, the carbon felt is loaded with a certain mass of Ketjen black carbon material. The loading method is as follows: Ketjen black and polyvinylidene fluoride are dissolved in 1-methyl-2-pyrrolidone solvent at a ratio of 8:1 to prepare a slurry, and then loaded with 225 mg / cm³ of the slurry. -2 The slurry was dripped onto the carbon felt electrode with a certain amount of Ketjen black loading. The carbon felt electrode loaded with Ketjen black was then dried in a 60°C oven and then transferred to a tube furnace and placed at 500°C in air atmosphere for 4 hours.

[0064] The negative electrode electrolyte includes: solvent water, 1 M polysulfide K2S4, 1 M KOH, and 0.006 M catalyst 1-methyl-1-ethylpyrrolidine bromide; the positive electrode electrolyte includes: solvent water, 0.5 M K4Fe(CN)6, and 1 M KCl. The volume of both the positive and negative electrode electrolytes is 7.5 mL.

[0065] Example 5

[0066] No catalyst was added to the negative electrode solution; the carbon felt electrode of the negative electrode was not loaded and was directly dried in a tube furnace at 500 °C for 4 hours in air atmosphere.

[0067] The flow batteries assembled in Examples 4-5 were from 150 mA cm⁻¹ -2 up to 40 mA cm -2 A magnification test was conducted, and the results are shown below. Figure 3 It runs for 3 cycles at each current density, charging is cut off at 1.6 V or 100% positive electrode liquid charge, and discharging is cut off at 0.2 V.

[0068] Figure 3 The rate performance of an aqueous sulfur-based flow battery with a negative electrode containing a soluble cationic catalyst (1-methyl-1-ethylpyrrolidine bromide) and without a catalyst was compared. At 150 mA cm⁻¹ -2 At current densities, flow batteries containing soluble cationic catalysts can achieve a capacity utilization rate of 99.3%, while the capacity utilization rate of flow batteries without catalysts is only 18.1%.

[0069] Example 6

[0070] The difference between this embodiment and Example 4 is that the catalyst in the negative electrode solution is 0.024M 1-methyl-1-ethylpyrrolidine bromide.

[0071] Constant current charge-discharge tests were performed on the flow batteries assembled in Examples 4, 5, and 6. The test results are shown in [Figure Number]. Figure 4 Current density is 80 mA cm -2 Charging is stopped at 1.6 V or 95% charge of the positive electrode liquid, and discharging is stopped at 0.2 V.

[0072] Figure 4 This demonstrates the long-term cycling stability of a cationic catalytic aqueous sulfur-based flow battery. At 60 mA cm⁻¹ -2 At a current density of 80 mA cm⁻¹, the aqueous sulfur-based flow battery in Example 6, containing 0.024 M 1-methyl-1-ethylpyrrolidine bromide as the negative electrode, can stably cycle up to 1800 cycles. Furthermore, the aqueous sulfur-based flow battery in Example 4, containing 0.006 M 1-methyl-1-ethylpyrrolidine bromide as the negative electrode, can cycle stably up to 1800 cycles at a current density of 80 mA cm⁻¹. -2 Furthermore, the battery can stably cycle up to 1800 times at a stack temperature of 40 °C. The battery's capacity utilization rate is 95%, compared to only 51.65% for the catalyst-free battery in Example 5 during the first cycle, with rapid capacity decay. This demonstrates that aqueous sulfur-based flow batteries with a cationic catalyst added to the negative electrode exhibit excellent stability at higher current densities.

[0073] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and optimizations can be made based on the content of this specification. The embodiments selected and specifically described in this specification are intended to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and apply the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An aqueous sulfur-based battery, characterized in that, It includes a positive electrode, a positive electrode solution, a negative electrode, and a negative electrode solution. A membrane is provided between the positive electrode solution and the negative electrode solution. The negative electrode solution contains polysulfides and a soluble cationic catalyst. The soluble cationic catalyst has specific adsorption characteristics on the negative electrode.

2. The aqueous sulfur-based battery according to claim 1, characterized in that, The soluble cationic catalyst includes one or more of the following: quaternary ammonium salts, quaternary phosphate salts, imidazole type, pyridine type, piperidine type, or pyrrole type cations.

3. The aqueous sulfur-based battery according to claim 1, characterized in that, The polysulfide is M x S y One or more of them, M x S y It is a metal sulfide, where x is 1 or 2, and y is 1, 2, or 4.

4. The aqueous sulfur-based battery according to claim 2, characterized in that, The quaternary ammonium salt-based soluble cationic catalysts include chain-like quaternary ammonium salts, cyclic quaternary ammonium salts, and those containing one nitrogen atom. + The central quaternary ammonium salt, multiple N + The central quaternary ammonium salt or combination thereof; the quaternary phosphate salt-based soluble cationic catalyst includes chain quaternary phosphate salts, cyclic quaternary phosphate salts, and those containing a single phosphorus group. + The central quaternary phosphate, multiple P + The central quaternary phosphate salt or a combination thereof.

5. The aqueous sulfur-based battery according to claim 1, characterized in that, The concentration of the soluble cationic catalyst is from 0.1 mM to 1 M, and the concentration of the polysulfide is from 0.1 M to 8 M.

6. The aqueous sulfur-based battery according to claim 1, characterized in that, The positive and negative electrode materials are selected from carbon felt, carbon paper, carbon cloth or metal current collectors; the negative electrode is loaded with a conductive agent.

7. The aqueous sulfur-based battery according to claim 1, characterized in that, The aqueous sulfur-based battery is either an aqueous sulfur-based static battery or an aqueous sulfur-based flow battery.

8. The aqueous sulfur-based battery according to claim 1, characterized in that, The negative electrode solution is an alkaline aqueous solution or a neutral aqueous solution.

9. The aqueous sulfur-based battery according to claim 1, characterized in that, The electrolyte in the positive electrode solution is selected from halogens and [Fe(CN)6]. 4- / [Fe(CN)6] 3- Fe 2+ / Fe 3+ Mn 2+ / Mn 3+ / MnO2、MnO4 2- / MnO4 - NiOOH / Ni 2+ VO 2+ / VO2 + Ferrocene, Zn / Zn 2+ or Zn / Zn(OH)4 2- The positive electrode solution contains 2,2,6,6-tetramethylpiperidine nitrogen oxide or a combination thereof, wherein the electrolyte concentration is from 0.1 M to 6 M.

10. An energy storage system, characterized in that, This includes an aqueous sulfur-based battery according to any one of claims 1-9.

Images