A low-temperature resistant, high-power aqueous organic-bromine battery

Abstract

This invention discloses a low-temperature resistant, high-power aqueous organic-bromine battery, belonging to the field of electrochemical energy storage technology. The invention uses a low-freezing-point bromine-based salt solution with added bromine solid complexing agent as the electrolyte, and a pseudocapacitive organic material as the negative electrode, which possesses ionic universality and can bind metal ions in the solution during the reaction. The positive electrode uses a carbon material as a substrate, where a bromine redox reaction occurs. Simultaneously, the complexing agent can complex bromine in solid form onto the carbon surface, ensuring good stability at both room temperature and low temperatures. The aqueous organic-bromine battery of this invention exhibits high energy density and ultra-high power density at room temperature, maintains high energy density even at low temperatures, and is inexpensive, showing promising application prospects.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage technology, specifically relating to a novel low-temperature resistant, high-power aqueous organic-bromine battery. Background Technology

[0002] Large-scale energy storage technology is key to achieving efficient utilization of renewable energy. Aqueous metal-ion batteries (AMIBs) have attracted widespread attention from researchers due to their advantages such as high safety and low cost. However, AMIBs are difficult to operate normally at low temperatures due to limitations imposed by the freezing point of water and the materials used in the positive and negative electrodes.

[0003] Specifically, there are two main reasons why AMIBs struggle to operate normally at low temperatures. First, due to the freezing point of water, aqueous electrolytes are prone to solidification at low temperatures. This leads to a significant increase in impedance at the solution-phase interface, and the solidified electrolyte can also damage the battery structure, such as the membrane. Furthermore, even if the electrolyte does not solidify, the resistance to ion desolvation and diffusion in the bulk material increases at low temperatures, resulting in a sharp decline in battery performance. Therefore, low-temperature environments pose challenges to both the electrolyte and materials used in AMIBs.

[0004] Adding organic solvents (such as dimethyl sulfoxide or ethylene glycol) to construct a water / organic mixed electrolyte is an effective method to lower the freezing point of aqueous electrolytes. However, the addition of organic electrolytes will reduce the conductivity of aqueous electrolytes and increase their toxicity and flammability.

[0005] For battery materials, common AMIBs (Amphi-Injection-Extraction Types) such as lithium iron phosphate and lithium manganese oxide experience a significant decrease in the desolvation rate of ions and the diffusion rate in the bulk phase of the material when operating at low temperatures, resulting in a significant reduction in the actual capacity and rate performance of the battery.

[0006] Organic materials (such as polyimide, anthraquinone, etc.) and conversion couples (such as Br2 / Br) - The redox reaction of this substance occurs on the surface, which can significantly alleviate the limitations of ion desolvation rate and bulk diffusion rate at low temperatures. It can maintain high capacity and rate performance at low temperatures, and can be used to construct aqueous organic-bromine batteries to replace traditional AMIBs, showing potential for application in low-temperature batteries. Researching and developing novel low-temperature resistant, high-power aqueous organic-bromine batteries has become an important research topic urgently needed. Summary of the Invention

[0007] To address the problem of poor low-temperature performance of existing aqueous metal-ion batteries, the purpose of this invention is to provide a novel low-temperature resistant, high-power aqueous organic-bromine battery.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] This invention uses a low-freezing-point bromine-based salt solution with a bromine solid complexing agent as the electrolyte. A pseudocapacitive organic material is used as the negative electrode, which possesses ionic universality and can bind metal ions in the solution during the reaction. The positive electrode uses a carbon substrate for the redox reaction of bromine, while the complexing agent binds bromine in solid form to the carbon surface, ensuring good stability at both room and low temperatures.

[0010] A low-temperature resistant, high-power aqueous organic-bromine battery mainly comprises: an aqueous electrolyte composed of a highly soluble bromine base salt and a bromine solid complexing agent; and a carbon material as the positive electrode, where the redox reaction of bromine mainly occurs.

[0011] (2Br - +2e - ←→Br2), while the complexing agent can complex bromine in solid form on the surface of carbon materials (Br2+TPABr←→TPABr3↓, or Br2+TBABr←→TPABr3↓). Using an organic polymer capable of reversibly storing metal ions as the negative electrode, reversible charge storage can be achieved through the conversion between enol and quinone structures and the binding of metal ions, i.e., C=O←→CO—Metal ions + +e - .

[0012] Furthermore, the bromine salt is selected from one or more of potassium bromide, lithium bromide, calcium bromide, magnesium bromide, and sodium bromide, and the bromide ion concentration in the aqueous electrolyte is 1-20M, preferably 5-11M.

[0013] Furthermore, the bromine solid complexing agent is selected from one or two of tetrapropylammonium bromide (TPABr) and tetrabutylammonium bromide (TBABr), and the concentration of the bromine solid complexing agent in the aqueous electrolyte is 0.1-4M, preferably 0.5-2M.

[0014] Furthermore, the positive electrode is a carbon material, which is selected from one or more of carbon paper, carbon felt, carbon cloth, porous carbon, activated carbon, and conductive carbon black; the porous carbon is selected from one or more of disordered microporous carbon, ordered microporous carbon, ordered mesoporous carbon, disordered mesoporous carbon, and hierarchical porous carbon; and the conductive carbon black is selected from one or more of Super P, Ketjen black, and acetylene black.

[0015] Further, the organic polymer includes poly(naphthalene-1,4,5,8-tetracarboxylic dianhydride) (PNTCDA) and poly(3,4,9,10-perylenetetracarboxylic dianhydride) (PPTCDA), wherein the general formula of poly(naphthalene-1,4,5,8-tetracarboxylic dianhydride) is as follows:

[0016]

[0017] The general formula of the poly(3,4,9,10-perylenetetracarboxylic dianhydride) is as follows:

[0018]

[0019] Furthermore, the aqueous organic-bromine battery also includes a separator, which is a porous conductive membrane. The separator material is selected from one or more of glass fiber, polyolefin, polyaromatic hydrocarbon, and cellulose acetate. The membrane thickness is 10-100 μm, the porosity is 10-80%, and the pore size range is 0.5-100 μm.

[0020] Furthermore, the aqueous organic-bromine battery also includes positive / negative current collectors, which are selected from graphite plates, metal mesh, or metal foil.

[0021] Furthermore, the conductive agent in the positive / negative electrode is selected from one or more of Super P, Ketjen black, conductive carbon black, acetylene black, and microcrystalline graphite, and the binder is selected from one or two of polytetrafluoroethylene or polyvinylidene fluoride.

[0022] The advantages of this invention over the prior art are as follows:

[0023] 1. This invention uses highly soluble bromine salts to break the hydrogen bond interactions between water molecules, thereby lowering the freezing point of the solution. This allows the electrolyte containing a high concentration of bromine salts to remain unsolidified at extremely low temperatures and maintain high conductivity.

[0024] 2. The cathode of this invention undergoes a bromine redox reaction, exhibiting high potential and specific capacity. The reaction occurs on the surface and demonstrates rapid kinetics at both room and low temperatures. Simultaneously, the complexing agent can complex bromine in solid form onto the carbon material surface, fundamentally avoiding the shuttle problem of bromine products, thus ensuring good stability of the cathode at both room and low temperatures.

[0025] 3. This invention uses an organic negative electrode material, which undergoes a surface reaction and exhibits pseudocapacitive properties, ensuring rapid kinetics at both room temperature and low temperature.

[0026] 4. Aqueous metal-ion batteries using high-conductivity bromide salt solutions and kineticly excellent positive and negative electrodes exhibit high energy density and ultra-high power density at room temperature, while also maintaining high energy density at low temperatures. These batteries demonstrate high cycle stability and low cost, showing promising application prospects. Attached Figure Description

[0027] To more clearly illustrate the embodiments of the present invention, the accompanying drawings involved in the embodiments will be briefly described below.

[0028] Figure 1 Photographs of LiBr solution at different temperatures in Example 1.

[0029] Figure 2 Photographs of the electrolyte at different temperatures in Example 2.

[0030] Figure 3 Conductivity of the electrolyte at different temperatures in Example 2.

[0031] Figure 4 Rate performance of carbon cathode at room temperature in Example 3.

[0032] Figure 5 Charge-discharge curves of the porous carbon cathode at different temperatures in Example 4.

[0033] Figure 6 Rate performance of the polyimide anode at room temperature in Example 5.

[0034] Figure 7 Charge-discharge curves of the PNTCDA negative electrode at different temperatures in Example 6.

[0035] Figure 8 : Schematic diagram of the aqueous organic-bromine battery of the present invention.

[0036] Figure 9 Example 7: Rate performance of the full cell at room temperature.

[0037] Figure 10 Example 7: Charge-discharge curves of the full battery at different temperatures.

[0038] Figure 11 Example 7: Relationship between specific power density and specific energy density of a full cell at different temperatures.

[0039] Figure 12 Example 7: Cyclic stability of the full cell at different temperatures.

[0040] Figure 13 Charge-discharge curves of porous carbon cathode at room temperature and low temperature under the condition of no complexing agent in Comparative Example 1. Detailed Implementation

[0041] The present invention will be described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments can be obtained without creative effort and all fall within the protection scope of the present invention.

[0042] Example 1

[0043] LiBr solutions of 3M, 4M, 5M, 6M, 6.5M, 7M, 7.5M, 8M, 9M, 10M, and 11M were prepared, and the physical state of the electrolytes at different temperatures was photographed in a low-temperature chamber. The test results are as follows: Figure 1 As shown, LiBr solutions in the concentration range of 6M-11M do not solidify at -60℃.

[0044] Example 2

[0045] LiBr was selected as the bromide salt, and tetrapropylammonium bromide (TPABr) was selected as the bromine solid complexing agent. Electrolytes of 0.5M TPABr + 8.3M LiBr (0.5M TPAB), 1M TPABr + 9.1M LiBr (1M TPAB), 1.5M TPABr + 9.9M LiBr (1.5M TPAB), and 2M TPABr + 10.7M LiBr (2M TPAB) were prepared. The physical state of the electrolytes at different temperatures was photographed in a low-temperature chamber, and the conductivity at different temperatures was measured using a conductivity meter.

[0046] Test results are as follows Figure 2-3 As shown. Except for 2M TPAB, the electrolytes of 0.5M TPAB, 1M TPAB, and 1.5M TPAB do not solidify at -60℃. At -40℃, the conductivity of the electrolytes of 0.5M TPAB, 1M TPAB, 1.5M TPAB, and 2M TPAB are 17.48 mS / cm. -1 9.31mS cm -1 4.79mS cm -1 2.37mS cm -1 At -60℃, the conductivity of the electrolytes 0.5M TPAB, 1M TPAB, 1.5M TPAB, and 2M TPAB was 4.34 mS / cm. -1 ,1.89mS cm -1 0.794mS cm -1 0.436mScm -1 .

[0047] Example 3

[0048] Positive half-cell test:

[0049] Electrode preparation: High specific surface area disordered porous carbon (Nanjing Xianfeng Nanomaterials Technology Co., Ltd.) and activated carbon (Kuraray 80F) were used as positive electrode carbon materials, Super P was used as a conductive agent, and polyvinylidene fluoride (PVDF) was used as a binder. The porous carbon: conductive agent: binder were uniformly dispersed in N-methylpyrrolidone at a mass ratio of 8:1:1 and coated on a 30μm titanium foil.

[0050] Electrolyte: 9.1M LiBr + 1M TPABr aqueous solution.

[0051] A three-electrode system was used, with Ag / AgBr as the reference electrode and activated carbon as the counter electrode. The specific capacity of the cathode material at room temperature was measured. The specific capacity was calculated based on the mass of porous carbon or activated carbon. The following reaction occurs at the cathode: TPABr + 2Br - -2e - ←→TPABr3↓

[0052] Test results are as follows Figure 4 As shown. The positive electrode using porous carbon exhibits a capacity of 600 mAh g at 25°C. -1 Extremely high specific capacity, at 30A g -1 Even under high current density, it can still maintain 197mAh g. -1 It exhibits a high specific capacity and excellent rate performance. Simultaneously, the activated carbon cathode maintains a capacity of 480 mAh g / L at 25°C. -1 The specific capacity at 10A g -1 At a current density, it can still maintain 227mAh g -1 Specific capacity.

[0053] Example 4

[0054] Using the porous carbon electrode from Example 3, low-temperature performance tests were conducted at -20℃, -40℃, and -60℃, under the same test conditions.

[0055] Test results are as follows Figure 5 As shown, the porous carbon cathode retains a capacity of 450 mAh g⁻¹ at -20, -40, and -60 °C. -1 343mAh g -1 and 201mAh g -1 Specific capacity.

[0056] Example 5

[0057] Negative electrode half-cell test:

[0058] Poly(naphthalene-1,4,5,8-tetracarboxylic dianhydride) (PNTCDA) and poly(3,4,9,10-perylenetetracarboxylic dianhydride) (PPTCDA) were used as negative electrode active materials, Super P was used as a conductive agent, and polyvinylidene fluoride (PVDF) was used as a binder. The active material: conductive agent: binder was dispersed evenly in N-methylpyrrolidone at a mass ratio of 6:3:1 and coated onto a 30μm titanium foil.

[0059] Electrolyte: 9.1M LiBr + 1M TPABr aqueous solution.

[0060] A three-electrode system was used, with Ag / AgBr as the reference electrode and activated carbon as the counter electrode. The specific capacity of the negative electrode material at room temperature was tested, and the specific capacity was calculated based on the mass of organic matter.

[0061] Test results are as follows Figure 6 As shown. PNTCDA has a capacity of 146 mAh g at 25°C. -1 The specific capacity is at 50A g. -1 Even under high current density, it can still maintain 121mAh g. -1 Specific capacity. PPTCDA has a specific capacity of 110mAh g. -1 The specific capacity is at 50A g. -1 Even under high current density, it can still maintain 92mAh g. -1 Specific capacity.

[0062] Example 6

[0063] Using the PNTCDA electrode from Example 5, low-temperature performance tests were conducted at -20℃, -40℃, and -60℃, under the same test conditions.

[0064] Test results are as follows Figure 7 As shown, the PNTCDA anode can still maintain a capacity of 137 mAh g at -20, -40, and -60°C. -1 120mAh g -1 and 97mAh g -1 Specific capacity.

[0065] Example 7

[0066] Based on the porous carbon positive electrode and PNTCDA negative electrode used in Examples 3 and 5, a full cell was matched with a porous carbon:PNTCDA mass ratio of 1:2. The full cell used a 9.1M LiBr + 1M TPABr electrolyte and a Whatman glass fiber membrane as the separator. Battery performance was tested at different temperatures. The specific capacity, energy density, and power density of the full cell were calculated based on the sum of the masses of the porous carbon positive electrode and the PNTCDA negative electrode. A schematic diagram of the full cell is shown below. Figure 8The overall reaction is as follows:

[0067] TPABr + PNTCDA + 2Br - +2Li + ←→TPABr3↓+PNTCDA-2Li + (3)

[0068] Test results are as follows Figure 9-12 As shown. The full cell has a capacity of 100 mAh g at 25°C. -1 The specific capacity corresponds to 98Wh / kg. -1 Energy density. At 50 A g. -1 Even under high current density, it can still maintain 76mAh g. -1 The specific capacity is 24.6 kW kg. -1 It can still maintain 52Wh / kg at a power density. -1 The energy density is [missing information]. Meanwhile, the battery maintains a capacity of 91 mAh g at -20, -40, and -60°C. -1 72mAh g -1 46mAh g -1 The specific capacity corresponds to an energy density of 88 Wh / kg. -1 64Wh kg -1 32Wh kg -1 Furthermore, the entire battery exhibits good cycle stability at both 25℃ and -40℃.

[0069] Comparative Example 1

[0070] Using the porous carbon electrode from Example 3, and selecting 7.5M LiBr as the electrolyte, the half-cell reaction behavior of the positive electrode at room temperature and low temperature (-40°C) was investigated without a complexing agent.

[0071] Test results are as follows Figure 13 As shown, without a complexing agent, the reaction product Br2 cannot be adsorbed onto the electrode surface, resulting in a low coulombic efficiency of the half-cell. Especially at room temperature, Br2 diffuses more rapidly, and only a small amount of capacity is released.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-temperature-resistant, high-power aqueous organic-bromine battery, characterized in that, It includes an aqueous electrolyte composed of a bromide salt and a bromine complexing agent, a carbon positive electrode, and an organic polymer negative electrode; The bromide ion concentration in the aqueous electrolyte is 6 - 11 M; The bromine complexing agent is selected from one or both of tetrapropylammonium bromide and tetrabutylammonium bromide, and the concentration of the bromine complexing agent in the aqueous electrolyte is 0.1 - 4 M; The organic polymer includes poly(naphthalene-1,4,5,8-tetracarboxylic dianhydride) (PNTCDA) and poly(3,4,9,10-perylenetetracarboxylic dianhydride) (PPTCDA), and the general formulas of the poly(naphthalene-1,4,5,8-tetracarboxylic dianhydride) and poly(3,4,9,10-perylenetetracarboxylic dianhydride) are shown as follows: 。 2. The aqueous organic-bromine battery of claim 1, wherein, The bromide salt is selected from one or more of potassium bromide, lithium bromide, calcium bromide, magnesium bromide, and sodium bromide.

3. The aqueous organic-bromine battery of claim 1, wherein, The concentration of the bromine complexing agent in the aqueous electrolyte is 0.5 - 2 M.

4. The aqueous organic-bromine battery of claim 1, wherein, The carbon positive electrode is selected from one or more of carbon paper, carbon felt, carbon cloth, porous carbon, activated carbon, and conductive carbon black.

5. The aqueous organic-bromine battery of claim 4, wherein, The carbon positive electrode is selected from porous carbon or activated carbon.

6. The aqueous organic-bromine battery of any one of claims 1-5, wherein, The aqueous organic-bromine battery further includes a separator, which is a porous conductive membrane, and the separator material is selected from one or more of glass fiber, polyolefin, polyarene, and cellulose acetate.

7. The aqueous organic-bromine battery of claim 6, wherein, Separator film thickness: 10 - 100 μm, separator porosity: 10 - 80%, separator pore size range: 0.5 - 100 μm.

8. The aqueous organic-bromine battery of claim 6, wherein, The aqueous organic-bromine battery further includes positive / negative electrode current collectors, and the positive / negative electrode current collectors are selected from graphite plates, metal meshes, or metal foils.

9. The aqueous organic-bromine battery of claim 6, wherein, The conductive agent in the positive / negative electrode is selected from one or more of Super P, Ketjenblack, acetylene black, and microcrystalline graphite.

10. The aqueous organic-bromine battery of claim 6, wherein, The binder in the positive / negative electrode is selected from one or both of polytetrafluoroethylene and polyvinylidene fluoride.

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