Preparation and application of a PILs / PPy / GO modified glassy carbon electrode

Abstract

The present invention belongs to the field of electrochemical analysis and specifically relates to the preparation and application of a PILs / PPy / GO modified glassy carbon electrode. 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinyl imidazole bromide is reacted with PPy / GO-(CH2)4Br nanosheets in DMF to prepare PILs / PPy / GO nanosheets; the PILs / PPy / GO nanosheets are dispersed in an organic solvent to prepare a composite modifier; and the composite modifier is drop-coated on the surface of the glassy carbon electrode to obtain a PILs / PPy / GO modified glassy carbon electrode. The PILs / PPy / GO modified glassy carbon electrode prepared by the present invention exhibits strong sulfophilic properties due to the presence of sulfur-containing groups in the PILs. This allows the PILs / PPy / GO nanosheets to enrich polysulfides in the solution on the surface of the working electrode, optimizes the electron transport process of the electrocatalytic oxidation of polysulfides, and enables the detection of polysulfides under conditions close to those used in actual batteries.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemical analysis, and in particular relates to the preparation and application of a PILs / PPy / GO modified glassy carbon electrode. Background Art

[0002] The "shuttle effect" problem caused by the charge and discharge process of lithium-sulfur batteries causes irreversible loss of sulfur active substances and rapid capacity decay, which is the main bottleneck for its practical application. x , 4≤x≤8) to the solid-phase product Li2S2 / Li2S is considered to be an effective means to suppress the "shuttle effect", but it is still impossible to accurately control the multi-step sulfur conversion reaction. Among them, how to accurately measure the concentration of various polysulfides in the electrolyte system has become the key to technological breakthroughs.

[0003] Currently, the main methods for determining polysulfides are high-performance liquid chromatography, fluorescence spectroscopy, and chemiluminescence. However, these methods require disassembly of batteries for sampling, involve complex sample pretreatment, and exhibit low sensitivity. Electrochemical analysis, on the other hand, is widely used due to its advantages such as in-situ testing, low cost, high sensitivity, ease of operation, and rapid reaction speed. Therefore, developing a method capable of rapidly detecting polysulfides is crucial for the rapid development and commercialization of lithium-sulfur batteries. Summary of the Invention

[0004] In order to develop a novel method capable of rapidly detecting polysulfides, the present invention provides a preparation method of a PILs / PPy / GO modified glassy carbon electrode and its application.

[0005] The present invention is achieved through the following technical solutions:

[0006] In a first aspect, the present invention provides a method for preparing a PILs / PPy / GO modified glassy carbon electrode, comprising the following steps:

[0007] S1. Preparation of PPy / GO nanosheets: Pyrrole was in situ chemically polymerized on GO nanosheets to obtain PPy / GO nanosheets;

[0008] S2. Preparation of PPy / GO-(CH2)4Br nanosheets: PPy / GO-(CH2)4Br nanosheets were prepared by substitution reaction of 1,4-dibromobutane with PPy / GO nanosheets in DMF;

[0009] S3. 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide and AIBA solution were mixed, heated for reaction, and washed to obtain a polymer; at room temperature and in an inert gas environment, the polymer was immersed in a FeCl3 solution to obtain a reaction mixture; then, a (NH4)2S2O8 solution was added to the reaction mixture, stirred for reaction, filtered to obtain a doped polymer, washed, and treated with a hydrazine / ethanol solution at room temperature and in an inert gas environment. The product was removed from the solution, filtered and washed to obtain 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide;

[0010] S4. PILs / PPy / GO nanosheets were prepared by reacting 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide with PPy / GO-(CH2)4Br nanosheets in DMF;

[0011] S5. Dispersing PILs / PPy / GO nanosheets in an organic solvent to prepare a composite modifier;

[0012] S6. Drop the composite modifier onto the surface of the glassy carbon electrode and dry it at room temperature to obtain a PILs / PPy / GO modified glassy carbon electrode.

[0013] As a further improvement to the technical solution of the preparation method of the present invention, the preparation method of 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazole bromide is: 3-(10-bromoyloxy)-4-methylthiophene and 1-vinylimidazole are mixed and heated to react to obtain 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazole bromide.

[0014] As a further improvement of the technical solution of the preparation method of the present invention, in step S3, the molar ratio of the 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide and the AIBA in the AIBA solution is 0.23:0.007.

[0015] As a further improvement of the technical solution of the preparation method of the present invention, in step S3, the reaction temperature of the 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide and the AIBA solution is 80-100° C., and the reaction time is 2-5 h.

[0016] As a further improvement to the technical solution of the preparation method of the present invention, in step S3, the time for treating the polymer with the FeCl3 solution is 3-5 hours.

[0017] As a further improvement of the technical solution of the preparation method of the present invention, in step S3, the stirring reaction time of the (NH4)2S2O8 solution and the reaction mixture is 12-48h.

[0018] As a further improvement to the technical solution of the preparation method of the present invention, in step S3, the time for treating the doped polymer with the hydrazine / ethanol solution is 10-24 hours.

[0019] In a second aspect, the present invention provides the application of the PILs / PPy / GO modified glassy carbon electrode prepared by the preparation method of the PILs / PPy / GO modified glassy carbon electrode in the detection of polysulfides.

[0020] As a further improvement of the application technical solution of the present invention, the polysulfide is Li2S4.

[0021] The preparation and application of a PILs / PPy / GO modified glassy carbon electrode provided by the present invention have the following advantages over the prior art:

[0022] (1) The PILs / PPy / GO modified glassy carbon electrode prepared by the present invention has strong sulfur-philic properties due to the sulfur-containing groups in PILs. It can enrich polysulfides in the solution on the surface of the working electrode, optimize the electron transport process of electrocatalytic oxidation of polysulfides, and realize the detection of polysulfides under conditions close to those used in actual batteries.

[0023] (2) The PILs / PPy / GO modified glassy carbon electrode prepared in the present invention exhibits advantages such as high selectivity, good stability and a wide linear range.

[0024] (3) The PILs / PPy / GO modified glassy carbon electrode prepared in the present invention enables the detection of polysulfides at micromolar concentrations, providing new ideas and methods for accurately detecting the concentration of polysulfides in actual battery samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] Figure 1This is the SEM image of the PILs / PPy / GO nanosheets prepared in Example 1 of the present invention.

[0028] Figure 2 Cyclic voltammograms of Li2S4 were tested for a bare electrode and a PILs / PPy / GO modified glassy carbon electrode prepared in Example 2 of the present invention.

[0029] Figure 3 Cyclic voltammograms of the PILs / PPy / GO modified glassy carbon electrode prepared in Example 2 of the present invention detecting Li2S4 at different concentrations.

[0030] Figure 4 Differential pulse voltammograms of the PILs / PPy / GO modified glassy carbon electrode prepared in Example 2 of the present invention detecting Li2S4 at different concentrations.

[0031] Figure 5 This is a linear relationship diagram between the current and Li2S4 concentration change of the PILs / PPy / GO modified glassy carbon electrode prepared in Example 2 of the present invention when detecting Li2S4.

[0032] Figure 6 This is the IT curve diagram of the PILs / PPy / GO modified glassy carbon electrode prepared in Example 2 of the present invention for detecting polysulfides. DETAILED DESCRIPTION

[0033] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all the embodiments.

[0035] The present invention provides a specific embodiment of a method for preparing a PILs / PPy / GO modified glassy carbon electrode, comprising the following steps:

[0036] S1. Preparation of PPy / GO nanosheets: Pyrrole was in situ chemically polymerized on GO nanosheets to obtain PPy / GO nanosheets;

[0037] S2. Preparation of PPy / GO-(CH2)4Br nanosheets: PPy / GO-(CH2)4Br nanosheets were prepared by substitution reaction of 1,4-dibromobutane with PPy / GO nanosheets in DMF;

[0038] S3. 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide and AIBA solution were mixed, heated for reaction, and washed to obtain a polymer; at room temperature and in an inert gas environment, the polymer was immersed in a FeCl3 solution to obtain a reaction mixture; then, a (NH4)2S2O8 solution was added to the reaction mixture, stirred for reaction, filtered to obtain a doped polymer, washed, and treated with a hydrazine / ethanol solution at room temperature and in an inert gas environment. The product was removed from the solution, filtered and washed to obtain 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide;

[0039] S4. Polymeric ionic liquid-modified PPy / GO nanosheets were prepared by reacting 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide with PPy / GO-(CH2)4Br nanosheets in DMF (N,N-dimethylformamide).

[0040] S5. dispersing the polymerized ionic liquid-modified PPy / GO nanosheets in an organic solvent to prepare a composite modifier;

[0041] S6. Drop the composite modifier onto the surface of the glassy carbon electrode and dry it at room temperature to obtain a PILs / PPy / GO modified glassy carbon electrode.

[0042] In an example provided by the present invention, the GO nanosheets are prepared by using the Hummers method.

[0043] The preparation method of PPy / GO nanosheets in step S1 is as follows: ultrasonically disperse graphene oxide in water to prepare a suspension with a concentration of 2-5 mg / mL, then add pyrrole to the suspension with a mass ratio of pyrrole to graphene oxide of 1:1-3:1, and ultrasonically disperse for 60-90 min; finally, add FeCl3 to the system and perform ultrasonic reaction, wherein Fe 3+ The molar ratio of PPy to pyrrole is 3:1. The product is centrifuged, washed and dried to obtain a black flaky solid, which is PPy / GO nanosheets.

[0044] In another example provided herein, the specific preparation method for PPy / GO-(CH2)4Br nanosheets in step S2 is as follows: 30-60 mg of the prepared PPy / GO, 0.35-1.21 mmol of 1,4-dibromobutane, and 0.65-1.4 mmol of potassium hydroxide (KOH) are added to 30-60 mL of DMF and ultrasonically dispersed for 10-25 minutes. The mixture is then heated to 50-90°C under magnetic stirring and allowed to react for 24-60 hours. After the reaction, the product is washed multiple times with water and ethanol, centrifuged, and dried in a vacuum oven at 35-60°C to obtain the PPy / GO-(CH2)4Br nanosheets.

[0045] In one example provided herein, in step S3, the 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide and AIBA solution (azobisisobutylamidine hydrochloride) are heated to 80-100°C for 2-5 hours. Specifically, the heating reaction of the 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide and AIBA solution is performed in a borosilicate glass pipette using an oven.

[0046] Furthermore, in step S3, the molar ratio of the 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide to the AIBA in the AIBA solution is 0.23:0.007.

[0047] In another example provided by the present invention, in step S3, the polymer is treated with the FeCl3 solution for 3-5 hours by immersion.

[0048] Furthermore, in step S3, the stirring reaction time of the (NH4)2S2O8 solution and the reaction mixture is 12-48h.

[0049] In one example provided by the present invention, the preparation method of the 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazole bromide is: 3-(10-bromoyloxy)-4-methylthiophene and 1-vinylimidazole are mixed, heated to react, and 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazole bromide is obtained.

[0050] In another example provided by the present invention, in step S3, the time for treating the doped polymer with the hydrazine / ethanol solution is 10-24 hours.

[0051] Further preferably, in step S5, the organic solvent is ethanol.

[0052] The present invention further provides a method for preparing a PILs / PPy / GO modified glassy carbon electrode and the application of the prepared PILs / PPy / GO modified glassy carbon electrode in detecting polysulfides.

[0053] In specific applications, a PILs / PPy / GO-modified glassy carbon electrode was used as the working electrode, an Ag / AgCl electrode was used as the reference electrode, and a platinum electrode was used as the auxiliary electrode. Differential pulse scanning was performed in a potential range of -0.2 to 0.8 V in a DOL (1,3-dioxolane) / DME (ethylene glycol dimethyl ether) electrolyte containing different concentrations of polysulfides.

[0054] Specifically, the polysulfide is Li2S4.

[0055] The specific embodiments of the present invention are described in detail below.

[0056] Instruments and reagents used in the experiment:

[0057] Unless otherwise noted, the water used in the following examples was double-distilled water (hereinafter referred to as secondary water), and all reagents used were of analytical grade. Furthermore, unless otherwise noted, the solvent used in the following examples for "solutions," "suspensions," and other liquids was water.

[0058] Instruments: A CHI660E electrochemical analyzer (Shanghai Chenhua Instrument Co., Ltd.) was used for electrochemical experiments; a BT224S electronic balance (Sartorius, Germany) was used for weighing drugs; a JEM-2100 transmission electron microscope (Hitachi, Japan) and a Hitachi SU-8010 scanning electron microscope (Hitachi, Japan) were used for morphology characterization; a KH 3200B ultrasonic cleaner (Kunshan Ultrasonic Instrument Co., Ltd.); aluminum oxide polishing powder (Shanghai Chenhua Instrument Reagent Co., Ltd.) was used to treat the glassy carbon electrode (GCE); an Ag / AgCl electrode (Wuhan Gaoshi Ruilian Technology Co., Ltd.) was used as the reference electrode; and a platinum electrode was used as the auxiliary electrode.

[0059] Reagents: graphene oxide, pyrrole, 1,4-dibromobutane (Sinopharm Chemical Reagent Co., Ltd.), 3-(10-bromoacyloxy)-4-methylthiophene, 1-vinylimidazole (Yancheng Pharmaceutical Chemical Plant), potassium hydroxide (Tianjin Bodi Chemical Co., Ltd.), Li2S4 (Alfa Aesar (China) Chemical Co., Ltd.), 1,3-dioxolane (DOL), ethylene glycol dimethyl ether (DME) (Aladdin Reagent (Shanghai) Co., Ltd.), high-purity nitrogen (purity 99.999%, O2 ≤ 0.001%).

[0060] Example 1

[0061] Preparation method of PILs / PPy / GO nanosheets:

[0062] (1) Preparation of PPy / GO nanosheets: Graphene oxide was ultrasonically dispersed in water to form a suspension with a concentration of 2 mg / mL. Pyrrole was then added to the suspension with a mass ratio of pyrrole to graphene oxide of 1:1 and ultrasonically dispersed for 70 min. Finally, FeCl3 was added to the system and ultrasonically reacted. 3+ The molar ratio of PPy to pyrrole is 3:1. The product is centrifuged, washed and dried to obtain a black flaky solid, which is PPy / GO nanosheets.

[0063] (2) Preparation of PPy / GO-(CH2)4Br nanosheets: PPy / GO nanosheets (40 mg), 1,4-dibromobutane (0.67 mmol), and potassium hydroxide (KOH, 0.9 mmol) were added to DMF (N,N-dimethylformamide, 35 mL) and ultrasonically dispersed for 15 min. The mixture was then heated to 60°C under magnetic stirring and reacted for 24 h. After the reaction, the product was washed several times with water and ethanol, centrifuged, and dried in a vacuum drying oven at 45°C for 24 h to obtain PPy / GO-(CH2)4Br nanosheets.

[0064] (3) The synthesis of 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazole bromide is as follows: 3-(10-bromoacyloxy)-4-methylthiophene (3.00 g, 9.00 mmol) and 1-vinylimidazole (18.60 mL, 205.47 mmol) were added to a 100 mL round-bottom flask equipped with a condenser and refluxed at 75°C for 1 day. The brown solid was filtered and removed, and the brown solid was triturated in diethyl ether (3 mL) to obtain a light brown solid. The light brown solid was placed in a vacuum drying oven at 60°C to obtain 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazole bromide.

[0065] (4) The polymerization process of 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide is as follows:

[0066] A solution of 1-(10-(4-methylthiophen-3-oxy)decyl)-3-vinylimidazolium bromide (0.10 g, 0.23 mmol) and AIBA (2.00 mg, 0.007 mmol) (18% w / w water content) was mixed thoroughly in a vial by vortexing. The reaction mixture was filled into a borosilicate glass pipette (approximately 2-3 inches) in air using negative pressure. The sample was placed in an 85°C oven for 3 hours.

[0067] The resulting polymer was removed from the borosilicate glass pipette by breaking it with a razor blade. The recovered polymer was washed with water and ethanol. The synthesized polymer (0.25 g, 0.58 mmol) was treated with 10 mL of FeCl₃ solution (0.11 g, 0.58 mmol) under an Ar flow at 25°C for 4 hours. After 4 hours, 10 mL of (NH₄)₂S₂O₃ solution (0.13 g, 0.55 mmol) was added to the reaction mixture and stirred for an additional 24 hours. The recovered doped polymer was filtered and washed with copious amounts of water. The newly synthesized doped polymer (0.25 g, 0.58 mmol) was treated with 10 mL of a 1:1 (v / v) hydrazine / ethanol solution under an Ar flow at 25°C for 15 hours. The doped polymer was removed from the solution, filtered, and washed with ethanol to obtain 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide.

[0068] (6) Preparation of PILs / PPy / GO nanosheets: The prepared PPy / GO-(CH2)4Br nanosheets (12 mg) and 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide (1.15 mmol) were added to DMF (25 mL) and ultrasonically dispersed for 5 min. The mixture was then heated to 60 °C under magnetic stirring and reacted for 24 h. After the reaction, the product was washed several times with water and ethanol, centrifuged, and dried in a vacuum drying oven at 45 °C for 24 h to prepare PILs / PPy / GO nanosheets.

[0069] Example 2

[0070] (I) Preparation process of PILs / PPy / GO modified glassy carbon electrode:

[0071] (1) Take 1 mg of dried PILs / PPy / GO nanosheets, add 1 mL of ethanol, and ultrasonically disperse for 20 min to obtain a dispersion with a concentration of 1 mg / mL for later use.

[0072] (2) Electrode treatment: The glassy carbon electrode was first polished with a 0.3 μM aluminum oxide suspension on a polishing cloth, then ultrasonically cleaned with secondary water, and then polished into a mirror surface with a 0.05 μM aluminum oxide suspension on a polishing cloth. Finally, it was ultrasonically cleaned with ethanol and secondary water, and dried with high-purity nitrogen.

[0073] (3) Preparation of PILs / PPy / GO modified glassy carbon electrode: Use a microinjector to transfer 2 μL of the above dispersion droplets to the surface of a polished glassy carbon electrode and dry it naturally in air to obtain a glassy carbon electrode modified with PILs / PPy / GO for later use.

[0074] The electron microscope image of the PILs / PPy / GO nanosheets prepared in Example 1 is as follows: Figure 1 As shown in the figure, it can be seen that the surface of PILs / PPy / GO nanosheets exhibits wrinkles and flaky textures, and some nanoscroll structures can be observed on the surface.

[0075] (2) Performance testing

[0076] ① Cyclic voltammetry test of Li2S4 using different glassy carbon electrodes:

[0077] In an electrolytic cell containing 8 mL of DOL / DME (1,3-dioxolane / ethylene glycol dimethyl ether, mass ratio 1:1), a bare (glassy carbon) electrode and a PILs / PPy / GO-modified glassy carbon electrode were used as working electrodes, an Ag / AgCl electrode was used as the reference electrode, and a platinum electrode was used as the auxiliary electrode. The experiments were conducted on a CHI660E electrochemical analyzer, with the accompanying computer software used for data acquisition and processing. Cyclic voltammetry was performed in the potential range of -0.2 V to 0.3 V, and stable cyclic voltammograms were recorded. For detailed results, see [ 1 ] Figure 2 .

[0078] In a DOL / DME (1:1) electrolyte containing different concentrations of Li2S4 (0, 10, 20, 30, and 40 μM), a PILs / PPy / GO-modified glassy carbon electrode was used as the working electrode, an Ag / AgCl electrode was used as the reference electrode, and a platinum electrode was used as the auxiliary electrode. The experiments were conducted on a CHI660E electrochemical analyzer, and the accompanying computer software was used for experimental data acquisition and processing. Cyclic voltammetry tests were performed in the potential range of -0.2 V to 0.3 V, and stable cyclic voltammograms were recorded. For detailed results, see [Chapter 1] for details. Figure 3 .

[0079] like Figure 2 As shown in Figure 2, there is no oxidation peak on the bare electrode, and there is no obvious oxidation peak on the PILs / PPy / GO modified glassy carbon electrode. Figure 3 As shown in the figure, in the DOL / DME electrolyte containing Li2S4, a clear oxidation peak can be observed on the PILs / PPy / GO modified glassy carbon electrode, and the peak intensity also increases significantly with increasing concentration. The comparison shows that the PILs / PPy / GO modified glassy carbon electrode has good electrocatalytic activity in the detection of Li2S4.

[0080] ②Quantitative measurement of Li2S4:

[0081] A PILs / PPy / GO-modified glassy carbon electrode was used as the working electrode, an Ag / AgCl electrode was used as the reference electrode, and a platinum electrode was used as the auxiliary electrode. The experiment was performed on a CHI660E electrochemical analyzer, including the acquisition and processing of experimental data. In a DOL / DME (1:1) electrolyte containing different concentrations of Li2S4 (40-1220 μM), differential pulse scanning was performed in the potential range of -0.2 to 0.8 V, and stable differential pulse voltammograms were recorded.

[0082] Figure 4 The differential pulse voltammograms of the PILs / PPy / GO modified glassy carbon electrode detecting different concentrations of Li2S4 are shown in the figure. As can be seen from the figure, with the increase of Li2S4 concentration, its oxidation peak current also gradually increases.

[0083] Figure 5 The figure shows the linear relationship between the current and the concentration of Li2S4. As can be seen from the figure, in the range of 40-1220μM, the concentration of Li2S4 has a good linear relationship with the current (R 2 =0.9992), with a slope of -0.983 μA / μM. Based on a standard signal-to-noise ratio of 3 (S / N=3), the PILs / PPy / GO-modified glassy carbon electrode demonstrated a detection limit of 17.3 nM and a sensitivity of 0.259 μA / μM for Li2S4, outperforming many existing DA detectors.

[0084] Anti-interference test:

[0085] The PILs / PPy / GO modified glassy carbon electrode was used as the working electrode, the Ag / AgCl electrode was used as the reference electrode, and the platinum electrode was used as the auxiliary electrode. The experiment was performed on a CHI660E electrochemical analyzer, including the acquisition and processing of experimental data.

[0086] The anti-interference performance of the PILs / PPy / GO modified glassy carbon electrode was determined by amperometry (IT). With a detection voltage of 0.2 V, 4 μL of Li2S4, 4 μL of Li2S6, and 4 μL of Li2S8 were gradually added to 8 mL of a DOL / DME (1:1) electrolyte with continuous stirring at 100-s intervals. The concentrations of Li2S4, Li2S6, and Li2S8 in the DOL / DME electrolyte were all 20 μM.

[0087] Figure 6 A comparison chart shows the anti-interference performance of PILs / PPy / GO-modified glassy carbon electrodes. When 20μM Li2S4 was added to the electrolyte, a strong response current was observed, with a response time of approximately 13 seconds. However, no significant response current was observed when other substances were added.

[0088] The above description is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions have been made with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents; and such modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments, and they should all be included in the scope of protection of the claims.

Claims

1. A method for preparing a PILs / PPy / GO modified glassy carbon electrode, characterized in that: The following steps are involved: S1. Preparation of PPy / GO nanosheets: Pyrrole was in situ chemically polymerized on GO nanosheets to obtain PPy / GO nanosheets; S2. Preparation of PPy / GO-(CH2)4Br nanosheets: PPy / GO-(CH2)4Br nanosheets were prepared by substitution reaction of 1,4-dibromobutane with PPy / GO nanosheets in DMF. S3. 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide and AIBA solution are mixed, heated for reaction, washed, and a polymer is obtained; at room temperature and in an inert gas environment, the polymer is immersed in a FeCl3 solution to obtain a reaction mixture; then a (NH4)2S2O8 solution is added to the reaction mixture, stirred for reaction, filtered, and a doped polymer is obtained, washed, and the doped polymer is treated with a hydrazine / ethanol solution at room temperature and in an inert gas environment, the product is removed from the solution, filtered and washed, and 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide is obtained; the preparation method of the 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide is as follows: 3-(10-bromoacyloxy)-4-methylthiophene and 1-vinylimidazole are mixed, heated for reaction, and 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide is obtained; S4. PILs / PPy / GO nanosheets were prepared by reacting 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide with PPy / GO-(CH2)4Br nanosheets in DMF; S5. Dispersing PILs / PPy / GO nanosheets in an organic solvent to prepare a composite modifier; S6. Drop the composite modifier onto the surface of the glassy carbon electrode and dry it at room temperature to obtain a PILs / PPy / GO modified glassy carbon electrode.

2. The method for preparing a PILs / PPy / GO modified glassy carbon electrode according to claim 1, characterized in that: In step S3, the molar ratio of the 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide to the AIBA in the AIBA solution is 0.23:0.

007.

3. The method for preparing a PILs / PPy / GO modified glassy carbon electrode according to claim 1, wherein: In step S3, the reaction temperature of the 1-(10-(4-methylthiophene-3-oxy)decyl)-3-vinylimidazolium bromide and the AIBA solution is 80-100° C., and the reaction time is 2-5 h.

4. The method for preparing a PILs / PPy / GO modified glassy carbon electrode according to claim 1, wherein: In step S3, the FeCl3 solution is used to treat the polymer for 3-5 hours.

5. The method for preparing a PILs / PPy / GO modified glassy carbon electrode according to claim 1, wherein: In step S3, the stirring reaction time of the (NH4)2S2O8 solution and the reaction mixture is 12-48 hours.

6. The method for preparing a PILs / PPy / GO modified glassy carbon electrode according to claim 1, wherein: In step S3, the time for treating the doped polymer with the hydrazine / ethanol solution is 10-24 hours.

7. Use of a PILs / PPy / GO modified glassy carbon electrode prepared by the method for preparing a PILs / PPy / GO modified glassy carbon electrode according to any one of claims 1 to 6 in detecting polysulfides.

8. The use according to claim 7, characterized in that The polysulfide is Li2S4.

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