Amorphous aluminum phosphonate array modified current collector, preparation method and negative electrode-free sodium metal battery

Abstract

The present application relates to a kind of amorphous aluminum phosphonate array modified current collector and preparation method and negative electrode-free sodium metal battery.The aluminum substrate is activated by argon plasma pretreatment, then in-situ electrochemical etching and self-assembly are carried out by introducing electric field in electrolyte containing organic phosphonic acid, and an amorphous organic-inorganic hybrid aluminum phosphonate array is constructed on the surface of aluminum substrate.The core advantage of the present application is that the amorphous phase eliminates the uneven ion transport caused by grain boundary, realizes the isotropic fast migration of ions;Three-dimensional array structure not only homogenizes local current density, but also provides sufficient volume buffer space for metal deposition;At the same time, P-O-Al inorganic skeleton is strongly anchored with substrate, and exposed organic functional groups give the interface fast desolvation ability, which greatly reduces the nucleation energy barrier.The preparation process of the present application is efficient and controllable, can significantly induce metal uniform and dense deposition, greatly improves the cycle life and safety of negative electrode-free metal battery.

Description

Technical Field

[0001] This invention relates to the field of new energy battery technology, specifically to an aluminum phosphonate modified current collector, its preparation process, and its application in sodium metal batteries without negative electrodes. Background Technology

[0002] With the rapid development of new energy vehicles and large-scale energy storage, the demand for high-energy-density energy storage systems is becoming increasingly urgent. Electrodeless metal batteries (such as electrodeless sodium metal batteries and lithium metal batteries), due to the absence of negative electrode active materials in the initial manufacturing stage, not only maximize the theoretical volumetric and gravimetric energy density of the battery but also significantly simplify the production process and reduce costs, making them a highly promising next-generation high-energy-density battery technology. However, the practical application of electrodeless metal batteries is severely constrained. Due to the lack of a host material buffer, metal deposition on exposed current collector surfaces often faces extremely high nucleation overpotentials; simultaneously, repeated deposition / stripping processes are accompanied by drastic volume expansion and contraction, easily leading to uncontrolled dendrite growth and interface pulverization failure, severely reducing the battery's coulombic efficiency and cycle life.

[0003] To stabilize the solid-liquid interface, artificial interface protective layers are typically constructed on the surface of the current collector. However, existing single-component interface layers exhibit inherent defects that are difficult to overcome when dealing with the harsh electrochemical environment of anode-free systems: On the one hand, although inorganic modified layers (such as alumina, inorganic fluorides, etc.) have high mechanical modulus, they often lack strong chemical bonds with the current collector substrate, relying mainly on weak physical adhesion. Under the huge volumetric stress impact of anode-free systems, such interface layers are prone to brittle peeling and pulverization failure; in addition, traditional inorganic layers are mostly polycrystalline structures, and the grain boundaries can easily lead to anisotropic ion transport, causing local current concentration; moreover, their surfaces lack specific affinity sites, making it difficult to reduce the concentration of metal ions (such as Na+). + The desolvation energy barrier of the electrolyte makes initial nucleation extremely difficult. On the other hand, although the pure organic polymer protective layer is rich in metalophilic functional groups, the organic layer is easily swollen by the electrolyte during long-term cycling, thus completely losing its protective effect on the interface.

[0004] Therefore, there is an urgent need in the field to develop a novel hybrid interface layer that combines high mechanical strength, strong chemical anchoring to the substrate, isotropic ion transport, and abundant induced nucleation sites, while also providing a three-dimensional physical buffer space, in order to fundamentally overcome the cycle life bottleneck of metal batteries without negative electrodes. Summary of the Invention

[0005] To address the shortcomings of existing electrodeless metal batteries, such as weak physical adhesion of the current collector interface protective layer leading to easy pulverization and detachment, uneven ion transport due to crystal phase boundaries, high metal nucleation overpotential, and lack of volume expansion buffer space, this invention aims to provide an amorphous aluminum phosphonate array modified current collector, its preparation method, and an electrodeless metal battery. This current collector, driven by an in-situ electric field, constructs isotropic ion transport channels with strong chemical anchoring force and no grain boundary obstruction, as well as sufficient three-dimensional physical buffer space. This fundamentally induces uniform metal nucleation and inhibits dendrite growth, significantly improving the battery's high-rate performance and long cycle life.

[0006] To achieve the above objectives, the technical solution proposed by this invention is as follows:

[0007] A method for preparing an amorphous aluminum phosphonate array modified current collector, comprising the following steps: 1) Place the raw aluminum foil in an argon plasma cleaner. Under normal temperature and vacuum conditions, introduce argon gas at a flow rate of 30-100 sccm and perform a pre-etching treatment on the aluminum foil for 5-30 seconds with a radio frequency power of 1-5 kW to remove impurities and oil stains from the surface of the raw aluminum foil, expose the highly active aluminum metal surface, and provide excellent reaction sites for subsequent electrochemical etching and self-assembly of amorphous aluminum phosphonate. 2) Using the aluminum foil treated in 1) as the working electrode (WE), a platinum sheet electrode as the counter electrode (CE), and an Ag / AgCl electrode as the reference electrode (RE), a mixed electrolyte containing 3 wt% AlCl3 and 1-10 wt% organophosphonic acid was prepared. The solution was adjusted to a weakly acidic state (pH = 4.0-6.0) with NaOH. The electrochemical workstation was used in constant potential mode at a pH of 0.05-0.3 Ag. -1 Etching was performed at a current density of 10-60 min; during this process, the aluminum foil surface was etched to form a three-dimensional array, while the organophosphonate groups combined with aluminum ions in the system under the drive of the electric field, and self-assembled in situ to form a disordered amorphous organic-inorganic hybrid aluminum phosphonate thin layer.

[0008] 3) The aluminum foil treated in (2) is repeatedly washed with deionized water and anhydrous ethanol 2-3 times, and finally dried in a vacuum drying oven to obtain aluminum foil with amorphous aluminum phosphonate array.

[0009] Preferably, in step 1), the argon flow rate is 60 sccm, the radio frequency power is 3 kW, and the aluminum foil pretreatment time is 15 s.

[0010] Preferably, the organophosphonic acid in the electrolyte of step 2) includes one of phenylphosphonic acid, phytic acid, aminomethylphosphonic acid, ethylenephosphonic acid, hydroxymethylphosphonic acid and n-octylphosphonic acid, with hydroxymethylphosphonic acid being the most preferred.

[0011] Preferably, in step 2), the electrolyte contains 5 wt% hydroxymethylphosphonic acid, has a pH of 5.0, and an electrochemical etching current density of 0.15 A g. -1 The electrochemical etching time was 30 min.

[0012] This invention also provides the application of the above-mentioned amorphous aluminum phosphonate array modified current collector in a sodium metal battery without a negative electrode, and the positive electrode preparation and battery assembly process are as follows: The method for manufacturing the positive electrode sheet of the sodium metal battery without a negative electrode comprises the following steps: Commercial sodium vanadium phosphate (Na3V2(PO4)3) cathode material, carbon nanotubes (CNTs) and polyvinylidene fluoride (PVDF) were thoroughly ground and mixed in N-methylpyrrolidone (NMP) solvent at a mass ratio of 7:2:1 to obtain a uniformly dispersed slurry. The slurry was then uniformly coated onto an aluminum current collector and dried overnight in a vacuum drying oven at 120 °C.

[0013] The assembly process of a sodium metal battery without a negative electrode involves the following steps: Half-cell: Aluminum foil and sodium foil of amorphous aluminum phosphonate array are cut into 14 mm discs and used as working electrode and counter / reference electrode, respectively. Glass fiber is used as separator, and 60 μL of NaPF6 (DME) electrolyte is added to assemble a CR-2025 coin cell.

[0014] Full cell: The positive electrode and the aluminum foil of the amorphous aluminum phosphonate array are cut into 14 mm round pieces, which are used as the positive and negative electrodes respectively. Glass fiber is used as the separator, and 60 μL of NaPF6 (DME) electrolyte is added to assemble a CR-2025 coin cell.

[0015] Compared with the prior art, the advantages and benefits of the present invention are: This invention uses argon plasma to perform efficient and environmentally friendly pretreatment on the surface of aluminum foil, which not only removes the surface passivation layer and oil stains, but also significantly improves the surface energy and activity of the aluminum foil, which is beneficial to the efficient formation of array structures and the strong bonding of inorganic-organic functional groups during electrochemical etching.

[0016] By synergistically controlling the electrochemical etching parameters and the electrolyte microenvironment, a dense and uniform amorphous inorganic-organic hybrid aluminum phosphonate array was rapidly and stably constructed on an aluminum substrate. The aluminum phosphonate array, grown by electrochemical etching driven by an in-situ electric field, not only forms a strong chemical anchor with the aluminum substrate, but its amorphous phase also eliminates grain boundary barriers in the crystal structure, avoiding localized ion concentration and ensuring isotropic rapid transport of sodium ions.

[0017] The constructed three-dimensional aluminum phosphonate array provides ample physical confinement space, effectively alleviating local current density, homogenizing sodium ion flux, and providing sufficient volume for sodium metal deposition, fundamentally mitigating volumetric stress expansion during cycling. Simultaneously, the organic functional groups significantly enhance the desolvation capability of sodium ions, accelerating ion transport efficiency. Furthermore, its amorphous phase greatly enhances the affinity at the electrode-electrolyte interface, significantly reducing the sodium nucleation barrier and guiding uniform sodium ion nucleation.

[0018] The three-dimensional aluminum phosphonate array modified current collector prepared by this invention can directly replace the ultra-thick sodium metal anode in traditional batteries, achieving extreme lightweighting at the physical level of the battery, significantly improving the energy density, cycle life and overall safety of sodium metal batteries, and exhibiting strong process compatibility. Attached Figure Description

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] Figure 1 The images are scanning electron microscope images of aluminum-based current collectors, where (a) is Example 1 and (b) is Comparative Example 1.

[0021] Figure 2 The following are contact angle test diagrams for Example 1 and Comparative Example 1, where (a) is Comparative Example 1 and (b) is Example 1.

[0022] Figure 3 The Fourier transform infrared (FTIR) spectra of Example 1 and Comparative Example 1 are shown.

[0023] Figure 4 The images show the X-ray photoelectron spectroscopy (XPS) spectra of Example 1 and Comparative Example 1.

[0024] Figure 5 The X-ray diffraction (XRD) patterns are for Example 1 and Comparative Example 1.

[0025] Figure 6 The aluminum-based current collectors prepared in Examples 1-5 and Comparative Example 1 were used at 1 mA cm⁻¹ -2 1 mAh cm -2 Half-cell cycle efficiency under certain conditions.

[0026] Figure 7 The aluminum-based current collectors prepared in Examples 1, 6-10, and Comparative Example 1 were used at a current density of 1 mA cm⁻¹. -2 The capacity is 1 mAh cm -2 Half-cell cycle efficiency under certain conditions.

[0027] Figure 8 The aluminum-based current collectors prepared in Example 1 and Comparative Examples 1-2 were used at 1 mA cm⁻¹-2 1 mAh cm -2 Half-cell cycle efficiency under certain conditions.

[0028] Figure 9 The graphs show the cycle performance of the electrodeless full cells of Example 1 and Comparative Examples 1-2. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings, so as to more clearly understand the purpose, technical solution and advantages of the present invention.

[0030] Example 1 A method for preparing an amorphous aluminum phosphonate array modified current collector and its application in a negative electrode-free metal battery is as follows: Step 1: Place the raw aluminum foil in an argon plasma cleaner. Under normal temperature and vacuum conditions, introduce argon gas at a flow rate of 60 sccm and perform a 15-second pre-etching process on the aluminum foil surface using a radio frequency power of 3 kW.

[0031] Step two: The pretreated aluminum foil is placed as the working electrode in a mixed electrolyte (pH=5.0) containing 3 wt% AlCl3 and 5 wt% hydroxymethylphosphonic acid, at 0.15 A g. -1 Etching was performed at a current density of 30 min.

[0032] Step 3: After repeatedly cleaning the etched aluminum foil with deionized water and anhydrous ethanol, place it in a vacuum drying oven at 120 °C and dry overnight. The final product is an amorphous aluminum phosphonate array aluminum foil (Al PNFs).

[0033] Example 2 The implementation of this embodiment is the same as that of Example 1, except that the mass percentage of hydroxymethylphosphonic acid in the electrolyte in step two is 1 wt%, and the remaining preparation steps are the same as in Example 1. The final sample is denoted as P-Al-1.

[0034] Example 3 The implementation of this embodiment is the same as that of Example 1, except that the mass percentage of hydroxymethylphosphonic acid in the electrolyte in step two is 10 wt%, and the remaining preparation steps are the same as in Example 1. The final sample is denoted as P-Al-10.

[0035] Example 4 The implementation of this embodiment is the same as that of Example 1, except that the electrochemical etching time in step two is 10 min, while the remaining preparation steps are the same as in Example 1. The final sample is denoted as T-Al-10.

[0036] Example 5 The implementation of this embodiment is the same as that of Example 1, except that the electrochemical etching time in step two is 60 min, while the remaining preparation steps are the same as in Example 1. The final sample is denoted as T-Al-60.

[0037] Example 6 The implementation of this embodiment is the same as that of Example 1, except that hydroxymethylphosphonic acid in step two is replaced with phenylphosphonic acid, while the remaining preparation steps are the same as in Example 1. The final sample is denoted as PPA@Al.

[0038] Example 7 The implementation of this embodiment is the same as that of Example 1, except that hydroxymethylphosphonic acid in step two is replaced with phytic acid, while the remaining preparation steps are the same as in Example 1. The final sample is denoted as PA@Al.

[0039] Example 8 The implementation of this embodiment is the same as that of Example 1, except that hydroxymethylphosphonic acid in step two is replaced with aminomethylphosphonic acid, and the remaining preparation steps are the same as in Example 1. The final sample is denoted as NHPA@Al.

[0040] Example 9 The implementation of this embodiment is the same as that of Example 1, except that hydroxymethylphosphonic acid in step two is replaced with ethylenephosphonic acid, while the remaining preparation steps are the same as in Example 1. The final sample is denoted as EPA@Al.

[0041] Example 10 The implementation of this embodiment is the same as that of Example 1, except that hydroxymethylphosphonic acid in step two is replaced with n-octylphosphonic acid, while the remaining preparation steps are the same as in Example 1. The final sample is denoted as NPA@Al.

[0042] Comparative Example 1 The aluminum foil in this comparative example was not treated in any way, and its sample is denoted as Bare Al.

[0043] Comparative Example 2 The comparative example was performed in the same manner as in Example 1, except that the organophosphonic acid (hydroxymethylphosphonic acid) in step two was replaced with inorganic phosphoric acid (H3PO4). The remaining preparation steps were the same as in Example 1. The final sample was denoted as IGP@Al.

[0044] Based on surface morphology and structural phase, the amorphous aluminum phosphonate array modified current collector prepared in this invention is described as follows: Figure 1 As shown, a comparison using scanning electron microscopy (SEM) reveals that untreated aluminum foil (Comparative Example 1) Figure 1 b) The surface is smooth and flat; while the aluminum foil of Example 1 ( Figure 1a) A uniformly distributed and highly dense three-dimensional nanoarray structure was successfully grown in situ on the surface. Figure 2 The contact angle test shown verifies the wetting ability of different current collectors to the electrolyte. The contact angle of Example 1 is only 4.8°, far lower than the 33.8° of Comparative Example 1. Meanwhile, Figure 3 , Figure 4 Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) tests showed that PO, Al-OP bonds and -OH functional groups were introduced into the three-dimensional array structure of Example 1, proving that the organophosphonic acid underwent a strong chemical self-assembly reaction with the aluminum substrate. Figure 5 The X-ray diffraction (XRD) patterns showed that, apart from the characteristic peaks of aluminum metal, there were no other obvious crystalline diffraction peaks in Example 1, confirming that the grown hybrid layer was an amorphous amorphous structure. Therefore, this invention successfully constructed an amorphous hybrid array with strong chemical anchoring, three-dimensional physical buffering, and high interfacial affinity by synergistically controlling process parameters such as etching time and organic acid concentration.

[0045] Implementation Results Example The samples prepared in Examples 1-10 and Comparative Examples 1-2 were assembled with sodium foil to form half-cells to evaluate their coulombic efficiency and cycle stability. The specific assembly and testing steps for the half-cells are as follows: Step 1, Electrode pretreatment: The samples obtained in Examples 1-10 and Comparative Examples 1-4 were placed in a vacuum oven at 80 °C and dried overnight.

[0046] Step 2, Battery Assembly: Cut the electrode sheet and sodium foil pretreated in Step 1 into 14 mm round pieces, which are used as working electrode and counter electrode / reference electrode, respectively. Place polypropylene and glass fiber separators and add 80 μL of electrolyte (1M NaPF6 in DME) to assemble a CR-2025 coin cell.

[0047] Step 3, Battery Testing: After battery assembly, it is left to stand at room temperature for 12 hours. Subsequently, it is tested on a battery charge / discharge system at 1 mA cm⁻¹. -2 The current density, 1 mAh cm⁻¹ -2 The deposition capacity and stripping voltage of 0.5 V were tested under constant current charge-discharge conditions.

[0048] Figure 6 The influence of the process parameters of this invention on the performance of the half-cell is shown. It can be seen that when Examples 2-5 and Comparative Example 1 are used as current collectors, their coulombic efficiencies fluctuate greatly, indicating poor reversibility of sodium deposition / stripping. In contrast, Example 1 can be stably cycled for 300 cycles, and its coulombic efficiency is very stable, with a calculated average coulombic efficiency as high as 99.92%.

[0049] Figure 7 The effects of different organic acids on half-cell performance in this invention can be seen. The coulombic efficiency of Examples 1 and 6-10 is very stable, but Example 1 shows a better cycle life than Examples 6-10. This is mainly due to the specific polar organic functional groups at its interface and the special organic-inorganic anchoring.

[0050] Figure 8 This illustrates the performance difference between the organic acid system of this invention and the traditional inorganic acid system. Although Comparative Example 2 can increase the specific surface area of ​​the aluminum foil, its cycle life is lower than that of Example 1 due to the lack of interfacial induction effect of organic functional groups and strong chemical anchoring force with the substrate. This demonstrates the core advantage of the amorphous organic-inorganic hybrid aluminum phosphonate array constructed in this invention.

[0051] Table 1. First-cycle coulombic efficiency and number of cycles for the half-cell.

[0052] Based on the half-cell cycling data in Table 1, it can be seen that the half-cell performance of Example 1 is the best. Therefore, the amorphous aluminum phosphonate array modified current collector constructed in this invention can significantly improve the reversibility of sodium deposition / stripping, and is expected to be applied in anode-free sodium metal batteries.

[0053] Application effect example This invention utilizes an amorphous aluminum phosphonate array modified current collector constructed through in-situ electric field driving, solving problems such as weak physical adhesion, easy pulverization and detachment, and uneven ion transport caused by crystal phase boundaries in traditional artificial interface layers. The practical application of this invention in a cathode-less full cell is further described below.

[0054] The specific steps for assembling and testing a negative electrode-free battery are as follows: Step 1, preparation of positive electrode: Commercial sodium vanadium phosphate (NVP) positive electrode material, carbon nanotubes (CNTs) and polyvinylidene fluoride (PVDF) are thoroughly ground and mixed in N-methylpyrrolidone (NMP) solvent at a mass ratio of 7:2:1 to obtain a uniformly dispersed slurry. Then, the slurry is uniformly coated on aluminum current collector and dried overnight in a vacuum drying oven at 120 °C.

[0055] Step 2, Battery Assembly: Cut the positive electrode sheet and the aluminum foil from Example 1 or Comparative Examples 1-2 into 14 mm round pieces, which serve as the positive and negative electrodes, respectively. Use polypropylene and glass fiber as separators, add 80 μL of electrolyte (1 M NaPF6 in DME), and assemble into a CR-2025 coin cell.

[0056] Step 3, Battery Testing: After battery assembly, it is left to stand at room temperature for 12 hours. Subsequently, it is tested on a battery charge / discharge system at 1C (1C = 0.117 A g).-1 The current density was measured, and constant current charge-discharge tests were performed within a voltage range of 2.5-3.8 V.

[0057] Figure 9 This study compares the long-cycle performance of electrodeless full cells assembled using different current collectors. Experimental results show that the electrodeless full cell assembled in Comparative Example 1 fails rapidly in the early stages of cycling. Comparative Example 2's capacity rapidly decays to zero after only 20 cycles. In contrast, Example 1 exhibits an initial discharge specific capacity of 101 mAh g⁻¹. -1 Furthermore, after 100 deep discharge cycles, it still maintained a high capacity retention of 97.4%. These results demonstrate the potential of the amorphous aluminum phosphonate array modified current collector constructed in this invention for practical applications in electrodeless batteries.

Claims

1. A method for preparing an amorphous aluminum phosphonate array modified current collector for use in a negative electrode-free metal battery, characterized in that, The aluminum foil was pretreated in an argon plasma cleaner to remove surface impurities and activate the aluminum foil substrate. Then, it was subjected to constant potential electrochemical etching in an electrolyte containing aluminum salt and organophosphonic acid to finally obtain an amorphous aluminum phosphonate array modified current collector for a negative electrode-free metal battery.

2. The method for preparing an amorphous aluminum phosphonate array modified current collector according to claim 1, characterized in that, The preparation steps of the modified current collector are as follows: (1) Pretreatment activation: The aluminum foil is placed in an argon plasma cleaner for pretreatment to remove surface impurities and activate the aluminum substrate; (2) In-situ electrochemical etching: The aluminum foil pretreated in (1) is used as the working electrode and constant potential electrochemical etching is performed in an electrolyte containing aluminum salt and organophosphonic acid. During this process, the aluminum surface is etched to form a three-dimensional array structure. At the same time, the organophosphonate ions undergo an in-situ self-assembly reaction with aluminum ions under the drive of the electric field, generating disordered amorphous aluminum phosphonate on the aluminum foil surface. (3) Cleaning and drying: The aluminum foil in (2) after in-situ electrochemical etching was repeatedly cleaned with deionized water and anhydrous ethanol, and finally placed in a vacuum drying oven to dry overnight to obtain an amorphous aluminum phosphonate array modified current collector.

3. The preparation method according to claim 2, characterized in that, The process parameters for plasma pretreatment in step (1) are: room temperature vacuum state, radio frequency ion source power of 1-5 kW, argon flow rate of 30-100 sccm, and pretreatment time of 5-30 s.

4. The preparation method according to claim 2, characterized in that, In step (2), the electrolyte is a mixed aqueous solution containing AlCl3 and organophosphonic acid, wherein the mass fraction of AlCl3 is 3 wt% and the mass fraction of organophosphonic acid is 1~10 wt%, and the pH value of the electrolyte is adjusted to a weakly acidic range (4.0~6.0) using NaOH.

5. The preparation method according to claim 4, characterized in that, The organophosphonic acid mentioned in step (2) includes any one of phenylphosphonic acid, aminomethylphosphonic acid, ethylenephosphonic acid, phytic acid, hydroxymethylphosphonic acid, and n-octylphosphonic acid; the electrochemical etching process parameters are: using a platinum sheet electrode as the counter electrode, an Ag / AgCl electrode as the reference electrode, and an etching current density of 0.05-0.3 Ag. -1 The etching time is 10-60 min.

6. An amorphous aluminum phosphonate array modified current collector prepared by the preparation method according to any one of claims 2-5.

7. The application of the amorphous aluminum phosphonate array modified current collector according to claim 6 in a sodium metal battery without a negative electrode.

8. A sodium metal battery without a negative electrode, characterized in that, It includes a positive electrode, a separator, an electrolyte, and the amorphous aluminum phosphonate array modified current collector as described in claim 7, wherein the modified current collector is used directly as the negative electrode of the battery.

9. The sodium metal battery without a negative electrode according to claim 8, characterized in that, The positive electrode sheet includes a positive electrode active material, a conductive agent, and a binder; the positive electrode active material includes any one of sodium vanadium phosphate, sodium vanadium fluorophosphate, and sodium iron pyrophosphate; the conductive agent includes any one of carbon nanotubes, acetylene black, and Super P; the binder includes any one of polytetrafluoroethylene, polyvinylidene fluoride, carboxymethyl cellulose, and polyacrylic acid.

10. The sodium metal battery without a negative electrode according to claim 8, characterized in that, The electrolyte comprises a sodium salt and an organic solvent. The sodium salt comprises any one or more of sodium hexafluorophosphate, sodium perchlorate, sodium trifluoromethanesulfonate, and sodium bis(trifluoromethanesulfonyl)imide; the organic solvent comprises any one or more of propylene carbonate, fluoroethylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether; the membrane comprises any one or more of polyethylene, glass fiber, polyethylene porous membrane, and polypropylene porous membrane.

Images