Long-life, high-rate performance aqueous zinc-quinone secondary battery

Abstract

The application discloses a long-life and high-rate water-based zinc-quinhydrone secondary battery, a positive electrode of the water-based zinc-quinhydrone secondary battery comprising a positive electrode current collector and a positive electrode coating layer covering the positive electrode current collector, wherein the positive electrode coating layer comprises an active material and a halogen catalyst, and the ratio of the active material to the halogen catalyst is (15-25):1 in mass fraction. The water-based zinc-quinhydrone secondary battery with long life and high rate is constructed, and the halogen catalyst can effectively accelerate the reaction speed of zinc and quinhydrone during the working process, so that the battery has high rate and long life. The water-based zinc-quinhydrone secondary battery has good capacity stability, and after adding the halogen catalyst, the water-based zinc-quinhydrone secondary battery is subjected to 18000 cycles of high-rate 10.0C cyclic charging and discharging, the capacity is 178.0 mAh g ‑1 , and the capacity retention rate is close to 100%.

Description

Technical Field

[0001] This invention belongs to the field of aqueous electrolyte secondary battery technology, specifically relating to an aqueous zinc-benzoquinone secondary battery with long lifespan and high rate performance. Background Technology

[0002] Renewable energy sources are gradually transitioning from alternative energy sources to primary energy sources. Secondary batteries, as an electrochemical energy storage technology, are considered a key component in achieving broad coverage of clean and renewable energy and carbon neutrality due to their relative safety, high efficiency, low cost, and flexible application. Among many emerging secondary battery systems, zinc-benzoquinone batteries have become a highly competitive new energy storage system due to their high energy density, low cost, and abundant raw material reserves. With the rapid development of the new energy era, the demand for high-frequency and timely use of energy storage batteries is becoming increasingly urgent, and high-rate charge-discharge is one of the most effective means to solve these problems. However, due to the poor conductivity of benzoquinone molecules, the reaction kinetics of benzoquinone molecules in electrochemical reactions are slow. Therefore, aqueous zinc-benzoquinone secondary batteries suffer from poor rate performance, short cycle life, and low high-rate charge-discharge capacity.

[0003] Therefore, it is urgent to improve the reaction kinetics of aqueous zinc-benzoquinone batteries, accelerate their redox reaction rate, and enhance their rate performance and lifespan. Those skilled in the art are dedicated to developing an aqueous zinc-benzoquinone battery that exhibits good cycle stability, is simple to fabricate, and has a low cost. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a long-life, high-rate-performance aqueous zinc-benzoquinone secondary battery. This aqueous zinc-benzoquinone secondary battery incorporates a halogen catalyst into the battery system to enhance its high-rate, long-cycle performance, solving the problems of poor reversibility and inadequate stability in traditional zinc-benzoquinone batteries. It improves the cycle stability of the battery under high-rate charge and discharge conditions, demonstrating great potential and promising application prospects in improving energy storage.

[0005] The objective of this invention is achieved through the following technical solution.

[0006] A long-life, high-rate-performance aqueous zinc-benzoquinone secondary battery, wherein the positive electrode of the aqueous zinc-benzoquinone secondary battery comprises: a positive electrode current collector and a positive electrode coating covering the positive electrode current collector, wherein the positive electrode coating comprises: an active material and a halogen catalyst, wherein the ratio of the active material to the halogen catalyst is (15-25):1 by mass.

[0007] In the above technical solution, the halogen catalyst is elemental iodine.

[0008] In the above technical solution, the positive electrode coating further includes: a conductive agent and a binder, and the ratio of the active material, the conductive agent and the binder by mass parts is (60-90):(5-30):(5-10).

[0009] In the above technical solution, the active substance includes benzoquinone and activated carbon material, wherein the benzoquinone content in the active substance is 20-60 wt%, and the activated carbon material is hierarchical porous carbon or activated carbon fiber.

[0010] In the above technical solution, the average pore size of the activated carbon material is 1-5 nm, and the specific surface area is 2000-2500 m². 2 / g, pore volume is 0.80~1.10cm³ 3 / g, tap density is 0.30~0.45g / cc.

[0011] In the above technical solution, the conductive agent is one or a mixture of several of Super P, acetylene black and Ketjen black, the binder is polytetrafluoroethylene or sodium carboxymethyl cellulose, and the positive electrode current collector is aluminum foil, stainless steel foil or titanium foil.

[0012] In the above technical solution, the aqueous zinc-benzoquinone secondary battery includes: the positive electrode, the negative electrode, the separator, and the electrolyte, wherein the electrolyte is an aqueous solution of zinc salt.

[0013] In the above technical solution, the concentration of the electrolyte in the zinc salt aqueous solution is 1.0–5.0 mol / L. -1 The electrolyte is one or a mixture of zinc sulfate, zinc nitrate, zinc chloride, and zinc bis(trifluoromethanesulfonyl)imide.

[0014] In the above technical solution, the negative electrode is zinc foil or zinc-based alloy, and the zinc content in the zinc-based alloy is 60-80 wt%.

[0015] In the above technical solution, the diaphragm is a polypropylene diaphragm (PP), a glass fiber diaphragm (GF), or a perfluorosulfonic acid (Nafion) proton exchange membrane.

[0016] The above-mentioned method for preparing the positive electrode:

[0017] 1) Mix the benzoquinone aqueous solution and activated carbon material evenly, let stand for at least 3 hours to obtain a composite solution, and dry the composite solution to obtain the active substance;

[0018] In step 1), the concentration of benzoquinone in the benzoquinone aqueous solution is 20–60 wt%.

[0019] 2) Mix the active material, halogen catalyst, conductive agent and binder evenly, add water and stir evenly to obtain a slurry, coat the slurry onto the positive electrode current collector to form the positive electrode coating on the positive electrode current collector, and dry to obtain the positive electrode.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. The benzoquinone used in this invention is simple to synthesize, has a wide range of raw material sources, is inexpensive, and can be directly extracted from biomass, which is in line with the concept of green environmental protection and sustainability.

[0022] 2. This invention constructs a long-life, high-rate aqueous zinc-benzoquinone secondary battery by combining a halogen catalyst and activated carbon materials. During operation, the halogen catalyst can effectively accelerate the reaction rate between zinc and benzoquinone, ensuring that the battery has high-rate and long-life performance.

[0023] 3. The aqueous zinc-benzoquinone secondary battery constructed in this invention exhibits good capacity stability. After adding a halogen catalyst, the aqueous zinc-benzoquinone secondary battery maintains a capacity of 178.0 mAh g after 18,000 charge-discharge cycles at a high rate of 10.0C. -1 The capacity retention rate is close to 100%. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the aqueous zinc-benzoquinone secondary battery constructed in Example 1;

[0025] Figure 2 The aqueous zinc-benzoquinone secondary battery constructed in Example 1 was tested at 0.5 mV s. -1 Cyclic voltammetry at scan rate;

[0026] Figure 3 The electrochemical impedance spectroscopy diagram of the aqueous zinc-benzoquinone secondary battery constructed in Example 1;

[0027] Figure 4 The graph shows the charge-discharge curves of the aqueous zinc-benzoquinone secondary battery constructed in Example 1 at a rate of 0.5C.

[0028] Figure 5 The graph shows the charge-discharge cycle of the aqueous zinc-benzoquinone secondary battery constructed in Example 1 at rates of 0.1C to 10.0C.

[0029] Figure 6 The aqueous zinc-benzoquinone secondary battery constructed in Example 2 was tested at 0.5 mV s. -1 Cyclic voltammetry at scan rate;

[0030] Figure 7The electrochemical impedance spectroscopy diagram of the aqueous zinc-benzoquinone secondary battery constructed in Example 2;

[0031] Figure 8 The graph shows the charge-discharge curves of the aqueous zinc-benzoquinone secondary battery constructed in Example 2 at a rate of 0.5C.

[0032] Figure 9 The graph shows the charge-discharge cycle of the aqueous zinc-benzoquinone secondary battery constructed in Example 2 at rates of 0.1C to 10.0C.

[0033] Figure 10 The graph shows the performance of the aqueous zinc-benzoquinone secondary battery constructed in Example 2 after 18,000 cycles at a 10.0C rate.

[0034] Figure 11 The aqueous zinc-benzoquinone secondary battery constructed in Example 3 was tested at 0.5 mV s. -1 Cyclic voltammetry at scan rate;

[0035] Figure 12 The electrochemical impedance spectroscopy diagram of the aqueous zinc-benzoquinone secondary battery constructed in Example 3;

[0036] Figure 13 The graph shows the charge-discharge cycle of the aqueous zinc-benzoquinone secondary battery constructed in Example 3 at a rate of 0.5C.

[0037] Figure 14 The aqueous zinc-benzoquinone secondary battery constructed in Example 4 was tested at 0.5 mV s. -1 Cyclic voltammetry at scan rate;

[0038] Figure 15 The electrochemical impedance spectroscopy diagram of the aqueous zinc-benzoquinone secondary battery constructed in Example 4;

[0039] Figure 16 The graph shows the charge-discharge cycle of the aqueous zinc-benzoquinone secondary battery constructed in Example 4 at a rate of 0.5C. Detailed Implementation

[0040] This invention provides a long-life, high-rate-performance aqueous zinc-benzoquinone secondary battery. During the discharge process of the constructed aqueous zinc-benzoquinone secondary battery, I₂ is first reduced to I₂ by the addition of a halogen catalyst. - It further reacts with I2 to form I3. - During the charging process, elemental iodine can stably act as Zn. 2+ Support, Zn-BQ (benzoquinone) and I3 - The oxidation reaction occurs simultaneously.

[0041] Without the addition of a halogen catalyst, the cathode reaction process can be summarized by equations (1) to (2):

[0042] Discharge: BQ+Zn 2+ +2e - →ZnBQ (1)

[0043] Charge: ZnBQ-2e - →Zn 2+ +BQ (2)

[0044] After adding a halogen catalyst, the possible positive electrode reactions can be represented by equations (3) to (5):

[0045] Discharge: BQ+Zn 2+ +I2+4e - →ZnBQ+2I - (3)

[0046]

[0047]

[0048] Iodine acts as a catalyst during the reaction, reducing the activation energy of the redox reaction of benzoquinone and promoting the reaction kinetics of the aqueous zinc-benzoquinone secondary battery, enabling it to maintain a high discharge capacity while charging and discharging rapidly at high rates.

[0049] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0050] The pharmaceuticals involved in the following examples were purchased from the following sources: titanium foil was purchased from Haiyuan Scientific Metals; benzoquinone, zinc sulfate, acetylene black and sodium carboxymethyl cellulose were all purchased from Aladdin; hierarchical porous carbon (NCP-4) and carbon nanotubes were all purchased from Nanjing Jicang Nano; glass fiber diaphragm was purchased from Chongqing Ouli Chemical.

[0051] The hierarchical porous carbon used in the following examples has a large number of micro-mesopores, with an average pore size of 4 nm and a specific surface area of ​​2236 m². 2 / g, pore volume 1.06cm 3 / g, tap density is 0.360g / cc.

[0052] In the examples described below, the carbon nanotubes have an average pore size of 6 nm and a specific surface area of ​​1530 m². 2 / g, pore volume is 0.79cm 3 / g, tap density is 0.135g / cc.

[0053] Example 1

[0054] An aqueous zinc-benzoquinone secondary battery includes: a positive electrode, a negative electrode, a separator, and an electrolyte, wherein,

[0055] The positive electrode comprises: a 0.02 mm thick positive electrode current collector and a 0.30 mm thick positive electrode coating covering the current collector; the current collector is titanium foil. The positive electrode coating comprises: active material, conductive agent, and binder, in a mass ratio of 80:10:10. The active material is benzoquinone and activated carbon; the benzoquinone content in the active material is 50 wt%, and the activated carbon is hierarchical porous carbon. The conductive agent is acetylene black, and the binder is sodium carboxymethyl cellulose.

[0056] The positive electrode is prepared using a coating method. The preparation method for the positive electrode is as follows:

[0057] 1) Stir a 20wt% benzoquinone aqueous solution and activated carbon material in a sealed container for 30 minutes and let it stand for 8 hours to obtain a composite solution. Dry the composite solution in a freeze dryer for 24 hours to obtain the active substance.

[0058] 2) According to the aforementioned mass ratio, the active material, conductive agent and binder are mixed and ground for 10 minutes to mix evenly. Water is added and stirred for 2 hours until uniform to obtain a slurry. The slurry is coated onto the positive electrode current collector to form a positive electrode coating. The coating is dried at room temperature under vacuum for 5 hours to obtain the positive electrode. The ratio of active material to water by mass is 3:10.

[0059] The electrolyte is an aqueous solution of zinc salt, and the concentration of the electrolyte in the zinc salt aqueous solution is 3 mol / L. -1 The electrolyte is zinc sulfate. The electrolyte is prepared by dissolving the electrolyte in deionized water and stirring until homogeneous.

[0060] The negative electrode is a 0.2mm thick zinc foil (99.999% purity). The zinc foil, which has been mechanically polished for 10 minutes (to remove the surface oxide layer), is rolled using a roller press to make it flat. After being cleaned with alcohol, it is then cut using a slicing machine.

[0061] The diaphragm is a glass fiber diaphragm (GF).

[0062] The positive electrode, negative electrode, separator, electrolyte, battery casing, spring and gasket of the aforementioned aqueous zinc-benzoquinone secondary battery are assembled into a CR2032 type button cell.

[0063] Figure 1 This is a schematic diagram of the aqueous zinc-benzoquinone secondary battery prepared in Example 1. The diagram visually illustrates the reversible redox process between zinc and benzoquinone in the aqueous zinc-benzoquinone secondary battery constructed in Example 1.

[0064] The aqueous zinc-benzoquinone secondary battery prepared in Example 1 was tested using an electrochemical workstation (CHI660E) at 0.5 mV / s. -1 Cyclic voltammetry tests were performed at scan rate, such as... Figure 2 As shown, the reduction peak of benzoquinone in this aqueous zinc-benzoquinone secondary battery is at 1.05V, and the oxidation peak is at 1.26V.

[0065] Electrochemical impedance spectroscopy (EIS) was performed on the aqueous zinc-benzoquinone secondary battery prepared in Example 1 using an electrochemical workstation (CHI660E). The test results are as follows: Figure 3 As shown, the results indicate that the charge transfer resistance of this aqueous zinc-benzoquinone secondary battery is 49.81Ω and the intrinsic impedance is 1.78Ω.

[0066] The charge-discharge curves at 0.5C rate at room temperature were tested using the Wuhan Landian multi-channel battery testing system (CT2001A). Figure 4 As shown, the results indicate that the voltage drop (ΔE) at a 0.5C rate is 90mV.

[0067] The aqueous zinc-benzoquinone secondary battery prepared in Example 1 was subjected to charge-discharge cycles at rates from 0.1C to 10.0C using the Wuhan Landian multi-channel battery testing system (CT2001A). The results are as follows: Figure 5 As shown, this aqueous zinc-benzoquinone secondary battery exhibits good rate cycling performance at different rates from 0.1C to 10.0C, with a coulombic efficiency of approximately 98.5%. However, at a high rate of 10.0C, the aqueous zinc-benzoquinone secondary battery only shows a efficiency of 99.8 mAh g⁻¹. -1 The discharge capacity.

[0068] Example 2

[0069] A long-life, high-rate-performance aqueous zinc-benzoquinone secondary battery includes: a positive electrode, a negative electrode, a separator, and an electrolyte, wherein...

[0070] The positive electrode comprises: a 0.02 mm thick positive electrode current collector and a 0.30 mm thick positive electrode coating covering the current collector; the current collector is titanium foil. The positive electrode coating comprises: active material, halogen catalyst, conductive agent, and binder, with a mass ratio of 80:4:10:10. The active material is benzoquinone and activated carbon; the benzoquinone content is 50 wt%, and the activated carbon is hierarchical porous carbon. The halogen catalyst is elemental iodine. The conductive agent is acetylene black, and the binder is sodium carboxymethyl cellulose.

[0071] The positive electrode is prepared using a coating method. The preparation method for the positive electrode is as follows:

[0072] 1) Stir a 20wt% benzoquinone aqueous solution and activated carbon material in a sealed container for 30 minutes and let it stand for 8 hours to obtain a composite solution. Dry the composite solution in a freeze dryer for 24 hours to obtain the active substance.

[0073] 2) According to the aforementioned mass ratio, the active material, halogen catalyst, conductive agent and binder are mixed and ground for 10 minutes to mix evenly. Water is added and stirred for 2 hours until uniform to obtain a slurry. The slurry is coated onto the positive electrode current collector to form a positive electrode coating. The coating is dried at room temperature under vacuum for 5 hours to obtain the positive electrode. The ratio of active material to water by mass is 3:10.

[0074] The electrolyte is an aqueous solution of zinc salt, and the concentration of the electrolyte in the zinc salt aqueous solution is 3 mol / L. -1 The electrolyte is zinc sulfate. The electrolyte is prepared by dissolving the electrolyte in deionized water and stirring until homogeneous.

[0075] The negative electrode is a 0.2mm thick zinc foil (99.999% purity). The zinc foil, which has been mechanically polished for 10 minutes (to remove the surface oxide layer), is rolled using a roller press to make it flat. After being cleaned with alcohol, it is then cut using a slicing machine.

[0076] The diaphragm is a glass fiber diaphragm (GF).

[0077] The positive electrode, negative electrode, separator, electrolyte, battery casing, spring and gasket of the aforementioned aqueous zinc-benzoquinone secondary battery are assembled into a CR2032 type button cell.

[0078] The aqueous zinc-benzoquinone secondary battery prepared in Example 2 was tested using an electrochemical workstation (CHI660E) at 0.5 mV / s. -1 Cyclic voltammetry tests were performed at scan rate, such as... Figure 6 As shown, with elemental iodine as a halogen catalyst, the reduction peak of benzoquinone in the aqueous zinc-benzoquinone secondary battery is at 1.08 V and the oxidation peak is at 1.20 V. This indicates that the addition of the halogen catalyst improved the cycling kinetics and overpotential of BQ and Zn, reduced the redox peaks, decreased polarization, and improved the utilization rate of benzoquinone. This is mainly attributed to the fact that the addition of the halogen catalyst makes it easier and faster to capture zinc during the battery reaction, thereby significantly improving the electrochemical performance of the aqueous zinc-benzoquinone secondary battery.

[0079] Electrochemical impedance spectroscopy (EIS) was performed on the aqueous zinc-benzoquinone secondary battery prepared in Example 2 using an electrochemical workstation (CHI660E). The test results are as follows: Figure 7As shown, the results indicate that the charge transfer resistance of the aqueous zinc-benzoquinone secondary battery after the addition of a halogen catalyst is 25.95 Ω, and the intrinsic impedance is 0.97 Ω. This further demonstrates that the halogen catalyst can rapidly enhance the electrochemical reaction kinetics of the aqueous zinc-benzoquinone secondary battery, effectively promote electron transfer reactions, accelerate the conversion of reactant molecules, and thus reduce the intrinsic impedance and charge transfer resistance of the electrode.

[0080] The charge-discharge curves at 0.5C rate at room temperature were tested using the Wuhan Landian multi-channel battery testing system (CT2001A). Figure 8 As shown, the results indicate that the voltage drop (ΔE) at 0.5C rate is 75mV after the addition of a halogen catalyst.

[0081] The aqueous zinc-benzoquinone secondary battery prepared in Example 2 was subjected to charge-discharge cycles at rates from 0.1C to 10.0C using the Wuhan Landian multi-channel battery testing system (CT2001A). The results are as follows: Figure 9 As shown, the aqueous zinc-benzoquinone secondary battery with added halogen catalyst exhibits good rate cycling performance at different rates from 0.1C to 10.0C, with a coulombic efficiency of approximately 99.2%. The aqueous zinc-benzoquinone secondary battery with added halogen catalyst also shows a capacity of 215.1 mAh g⁻¹ at a high rate of 10.0C. -1 The discharge capacity was further demonstrated. This further proves that halogen catalysts accelerate the redox reaction process in aqueous zinc-benzoquinone secondary batteries at higher rates, thereby improving the cycle life of aqueous zinc-benzoquinone secondary batteries.

[0082] Figure 10 This is a graph showing the performance of the aqueous zinc-benzoquinone secondary battery prepared in Example 2 after 18,000 cycles at 10.0C. The graph illustrates that, with the addition of a halogen catalyst, this aqueous zinc-benzoquinone secondary battery still exhibits a capacity of 178.3 mAh g / L after 18,000 cycles at a high rate of 10.0C. -1 It exhibits high discharge specific capacity and near 100% coulombic efficiency. This results in excellent charge-discharge stability and ultra-long cycle life of the aqueous zinc-benzoquinone secondary battery at high rates.

[0083] Tests showed that activated carbon materials with an average pore size of 1–5 nm and a specific surface area of ​​2000–2500 m² were suitable for applications where the material's surface area was optimal. 2 / g, pore volume is 0.80~1.10cm³ 3 When the tap density is 0.310–0.420 g / cc, the same technical effect as in Example 2 can be obtained.

[0084] Example 3

[0085] An aqueous zinc-benzoquinone secondary battery includes: a positive electrode, a negative electrode, a separator, and an electrolyte, wherein,

[0086] The positive electrode comprises: a 0.02 mm thick positive electrode current collector and a 0.30 mm thick positive electrode coating covering the current collector; the current collector is titanium foil. The positive electrode coating comprises: active material, halogen catalyst, conductive agent, and binder, with a mass ratio of 80:8:10:10. The active material is benzoquinone and activated carbon; the benzoquinone content is 50 wt%, and the activated carbon is hierarchical porous carbon. The halogen catalyst is elemental iodine. The conductive agent is acetylene black, and the binder is sodium carboxymethyl cellulose.

[0087] The positive electrode is prepared using a coating method. The preparation method for the positive electrode is as follows:

[0088] 1) Stir a 20wt% benzoquinone aqueous solution and activated carbon material in a sealed container for 30 minutes and let it stand for 8 hours to obtain a composite solution. Dry the composite solution in a freeze dryer for 24 hours to obtain the active substance.

[0089] 2) According to the aforementioned mass ratio, the active material, halogen catalyst, conductive agent and binder are mixed and ground for 10 minutes to mix evenly. Water is added and stirred for 2 hours until uniform to obtain a slurry. The slurry is coated onto the positive electrode current collector to form a positive electrode coating. The coating is dried at room temperature under vacuum for 5 hours to obtain the positive electrode. The ratio of active material to water by mass is 3:10.

[0090] The electrolyte is an aqueous solution of zinc salt, and the concentration of the electrolyte in the zinc salt aqueous solution is 3 mol / L. -1 The electrolyte is zinc sulfate. The electrolyte is prepared by dissolving the electrolyte in deionized water and stirring until homogeneous.

[0091] The negative electrode is a 0.2mm thick zinc foil (99.999% purity). The zinc foil, which has been mechanically polished for 10 minutes (to remove the surface oxide layer), is rolled using a roller press to make it flat. After being cleaned with alcohol, it is then cut using a slicing machine.

[0092] The diaphragm is a glass fiber diaphragm (GF).

[0093] The positive electrode, negative electrode, separator, electrolyte, battery casing, spring and gasket of the aforementioned aqueous zinc-benzoquinone secondary battery are assembled into a CR2032 type button cell.

[0094] The aqueous zinc-benzoquinone secondary battery prepared in Example 3 was tested using an electrochemical workstation (CHI660E) at 0.5 mV / s. -1 Cyclic voltammetry tests were performed at scan rate, such as... Figure 11As shown, when the ratio of active material, halogen catalyst, conductive agent and binder by mass is 80:8:10:10, the reduction peak of benzoquinone in this aqueous zinc-benzoquinone secondary battery is 1.09V and the oxidation peak is 1.25V. Compared with the aqueous zinc-benzoquinone secondary battery in Example 2, it still has a larger degree of polarization and is better than Example 1.

[0095] Electrochemical impedance spectroscopy (EIS) was performed on the aqueous zinc-benzoquinone secondary battery prepared in Example 3 using an electrochemical workstation (CHI660E). The test results are as follows: Figure 12 As shown, the results indicate that the charge transfer resistance of the aqueous zinc-benzoquinone secondary battery prepared in Example 3 is 148.6 Ω, suggesting that excessive mass fraction of halogen catalyst does not significantly reduce the electrochemical impedance of the aqueous zinc-benzoquinone secondary battery.

[0096] Charge-discharge cycle tests were performed at 0.5C rate at room temperature using the Wuhan Landian multi-channel battery testing system (CT2001A). Figure 13 As shown, the results indicate that the discharge capacity of the aqueous zinc-benzoquinone secondary battery prepared in Example 3 increased from 493.4 mAh g after 130 cycles. -1 Decayed to 312.5mAh g -1 Compared to Example 2, its cyclic stability is poor.

[0097] Example 4

[0098] An aqueous zinc-benzoquinone secondary battery includes: a positive electrode, a negative electrode, a separator, and an electrolyte, wherein,

[0099] The positive electrode comprises: a 0.02 mm thick positive electrode current collector and a 0.30 mm thick positive electrode coating covering the current collector; the current collector is titanium foil. The positive electrode coating comprises: an active material, a halogen catalyst, a conductive agent, and a binder, with a mass ratio of 80:4:10:10. The active material is benzoquinone and activated carbon; the benzoquinone content is 50 wt%, and the activated carbon material is carbon nanotubes. The halogen catalyst is elemental iodine. The conductive agent is acetylene black, and the binder is sodium carboxymethyl cellulose.

[0100] The positive electrode is prepared using a coating method. The preparation method for the positive electrode is as follows:

[0101] 1) Stir a 20wt% benzoquinone aqueous solution and activated carbon material in a sealed container for 30 minutes and let it stand for 8 hours to obtain a composite solution. Dry the composite solution in a freeze dryer for 24 hours to obtain the active substance.

[0102] 2) According to the aforementioned mass ratio, the active material, halogen catalyst, conductive agent and binder are mixed and ground for 10 minutes to mix evenly. Water is added and stirred for 2 hours until uniform to obtain a slurry. The slurry is coated onto the positive electrode current collector to form a positive electrode coating. The coating is dried at room temperature under vacuum for 5 hours to obtain the positive electrode. The ratio of active material to water by mass is 3:10.

[0103] The electrolyte is an aqueous solution of zinc salt, and the concentration of the electrolyte in the zinc salt aqueous solution is 3 mol / L. -1 The electrolyte is zinc sulfate. The electrolyte is prepared by dissolving the electrolyte in deionized water and stirring until homogeneous.

[0104] The negative electrode is a 0.2mm thick zinc foil (99.999% purity). The zinc foil, which has been mechanically polished for 10 minutes (to remove the surface oxide layer), is rolled using a roller press to make it flat. After being cleaned with alcohol, it is then cut using a slicing machine.

[0105] The diaphragm is a glass fiber diaphragm (GF).

[0106] The positive electrode, negative electrode, separator, electrolyte, battery casing, spring and gasket of the aforementioned aqueous zinc-benzoquinone secondary battery are assembled into a CR2032 type button cell.

[0107] The aqueous zinc-benzoquinone secondary battery prepared in Example 4 was tested using an electrochemical workstation (CHI660E) at 0.5 mV / s. -1 Cyclic voltammetry tests were performed at scan rate, such as... Figure 14 As shown, in an aqueous zinc-benzoquinone secondary battery with activated carbon nanotubes, the reduction peak of benzoquinone is at 0.93V and the oxidation peak is at 1.32V, indicating a high degree of polarization.

[0108] Electrochemical impedance spectroscopy (EIS) was performed on the aqueous zinc-benzoquinone secondary battery prepared in Example 4 using an electrochemical workstation (CHI660E). The test results are as follows: Figure 15 As shown, the impedance of the aqueous zinc-benzoquinone secondary battery assembled in this example is 203.4Ω, which is much higher than that of the aqueous zinc-benzoquinone secondary batteries assembled in Examples 1 to 3. This indicates that despite the addition of elemental iodine as a catalyst, the electrochemical impedance of this aqueous zinc-benzoquinone secondary battery is very high and its conductivity is very poor.

[0109] The aqueous zinc-benzoquinone secondary battery prepared in Example 4 was tested using the Wuhan Landian multi-channel battery testing system (CT2001A) at room temperature and charged / discharge cycled at a rate of 0.5C. Figure 16 As shown, this aqueous zinc-benzoquinone secondary battery can only cycle 55 times, with a discharge capacity of 498.2 mAh g. -1 Decayed to 374.6 mAh g-1 Its cyclic stability is very poor.

[0110] In the technical solution of this invention, by adjusting the mass ratio of activated carbon material, active substance, and halogen catalyst, the same technical effect as the aqueous zinc-benzoquinone secondary battery in Example 2 can be obtained. The present invention has been described above as exemplary. It should be noted that any simple modifications, alterations, or other equivalent substitutions that can be made by those skilled in the art without creative effort, without departing from the core of the present invention, fall within the protection scope of this invention.

Claims

1. A long-life, high-rate-performance aqueous zinc-benzoquinone secondary battery, characterized in that, The positive electrode of the aqueous zinc-benzoquinone secondary battery includes: a positive electrode current collector and a positive electrode coating covering the positive electrode current collector. The positive electrode coating includes: an active material and a halogen catalyst. By mass, the ratio of the active material to the halogen catalyst is (15-25):

1. The halogen catalyst is elemental iodine.

2. The aqueous zinc-benzoquinone secondary battery according to claim 1, characterized in that, The positive electrode coating further includes a conductive agent and a binder. By mass, the ratio of the active material, the conductive agent and the binder is (60-90):(5-30):(5-10). The conductive agent is one or a mixture of several of Super P, acetylene black and Ketjen black. The binder is polytetrafluoroethylene or sodium carboxymethyl cellulose.

3. The aqueous zinc-benzoquinone secondary battery according to claim 1, characterized in that, The active material includes benzoquinone and activated carbon material, wherein the benzoquinone content in the active material is 20-60 wt%, and the activated carbon material is hierarchical porous carbon or activated carbon fiber.

4. The aqueous zinc-benzoquinone secondary battery according to claim 1, characterized in that, The aqueous zinc-benzoquinone secondary battery includes: a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the electrolyte is an aqueous solution of zinc salt.

5. The aqueous zinc-benzoquinone secondary battery according to claim 4, characterized in that, The concentration of the electrolyte in the zinc salt aqueous solution is 1.0–5.0 mol / L. -1 The electrolyte is one or a mixture of zinc sulfate, zinc nitrate, zinc chloride and zinc bis(trifluoromethanesulfonyl)imide.

6. The aqueous zinc-benzoquinone secondary battery according to claim 4, characterized in that, The negative electrode is zinc foil or a zinc-based alloy, wherein the zinc content of the zinc-based alloy is 60-80 wt%.

7. The aqueous zinc-benzoquinone secondary battery according to claim 4, characterized in that, The diaphragm is a polypropylene diaphragm, a glass fiber diaphragm, or a perfluorosulfonic acid proton exchange membrane.

8. The aqueous zinc-benzoquinone secondary battery according to claim 1, characterized in that, The positive current collector is made of aluminum foil, stainless steel foil, or titanium foil.

9. The method for preparing the positive electrode in the aqueous zinc-benzoquinone secondary battery as described in claim 1, characterized in that, Includes the following steps: 1) Mix the benzoquinone aqueous solution and activated carbon material evenly, let stand for at least 3 hours to obtain a composite solution, and dry the composite solution to obtain the active substance; 2) Mix the active material, halogen catalyst, conductive agent and binder evenly, add water and stir evenly to obtain a slurry, coat the slurry onto the positive electrode current collector to form the positive electrode coating on the positive electrode current collector, and dry to obtain the positive electrode.

10. The preparation method according to claim 9, characterized in that, In step 1), the concentration of benzoquinone in the benzoquinone aqueous solution is 20–60 wt%.

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