CN109932380A - A nuclear magnetic resonance-electrochemical combined electrode characterization device, detection system and method for characterizing electrodes using the electrode characterization device - Google Patents

Abstract

The invention discloses a combined nuclear magnetic resonance-electrochemical electrode characterizing device, a detection system and a method for characterizing an electrode by using the foregoing device; the electrode characterizing device comprises a solid electrolyte in-situ electrochemical cell, which has a sealed, wrapped and encapsulated electrode to be characterized. The sealing frame of the electrode sample to be measured, the metal current collector sheet, the solid electrolyte membrane stacked in sequence, the metal counter electrode and the solid nuclear magnetic sample tube arranged opposite the metal current collector sheet; when the electrode sample to be tested is detected, the solid electrolyte is in place The electrochemical cell is encapsulated in a solid nuclear magnetic sample tube, and the membrane material of the solid electrolyte membrane includes but is not limited to any one of perfluorosulfonic acid polymer membrane, polyether ether ketone polymer membrane, and polybenzimidazole polymer membrane . The invention solves the drawbacks that the existing two-electrode or three-electrode system for electrochemical detection is difficult to effectively integrate with the nuclear magnetic technology, and the relevant detection signals are also unsatisfactory, and provides an electrochemical device that can be effectively coupled with the nuclear magnetic detection technology. .

Description

A nuclear magnetic resonance-electrochemical combined electrode characterization device, detection system and utilization Electrode Characterization Apparatus Method for Characterizing Electrodes

technical field

The invention belongs to the technical field of electrochemical energy, and in particular relates to a nuclear magnetic resonance-electrochemical combined electrode characterizing device, a detection system and a method for characterizing electrodes by using the electrode characterizing device.

Background technique

The analysis and detection technology based on nuclear magnetic resonance has important application significance in the fields of chemistry, materials, biotechnology, medicine and so on. Nuclear magnetic resonance refers to the physical process in which the nuclear magnetic moment is not zero in the nucleus, under the action of the external magnetic field, the nuclear spin energy level undergoes Zeeman splitting, and the resonance absorbs the radio frequency radiation of a certain frequency. Solid-state nuclear magnetic resonance technology is an analytical technology that takes solid samples as the research object. In liquid samples, the rapid movement of molecules will average out various interactions that lead to NMR spectral line broadening (such as chemical shift anisotropy and dipole-dipole interactions, etc.), thereby obtaining high-resolution liquid NMR spectra Figure; For solid samples, the rapid movement of molecules is limited, and the presence of various effects such as chemical shift anisotropy causes the spectral line to widen seriously, so the resolution of solid-state NMR techniques is lower than that of liquids.

In the field of energy technology research, especially in the electrochemical energy technology through chemical energy-electrical energy mutual conversion, the migration behavior mechanism of ions in electrodes and solid electrolytes has always been one of the key basic scientific issues that puzzle researchers around the world. It is also an important research basis for electrode material development and structural design. The significant advantages of NMR technology in the analysis and characterization of elements including H, Li, etc., make it a powerful tool for the analysis of ion migration behavior of electrode materials. But so far, due to the inherent characteristics of NMR detection devices, especially solid-state NMR devices, it is difficult to effectively integrate the two-electrode or three-electrode system of electrochemical detection with NMR technology, and the relevant detection signals are also unsatisfactory.

In view of this, it is necessary to develop an electrochemical device that can be effectively coupled with nuclear magnetic detection technology, which has high-resolution nuclear magnetic signals to provide a strong basic research guarantee for electrochemical energy technology and other related materials and biotechnology fields.

SUMMARY OF THE INVENTION

In view of the defects of the prior art, the purpose of the present invention is to provide a combined NMR-electrochemical electrode characterization device, which can effectively detect ion behavior signals in solid samples under different electrochemical conditions, and make the signal The resolution is greatly improved.

In order to achieve the above purpose, technical scheme of the present invention:

A nuclear magnetic resonance-electrochemical combined electrode characterization device, characterized in that it includes:

A solid electrolyte in-situ electrochemical cell, which at least has a sealing frame for sealing the wrapped and encapsulated electrode samples to be tested, a metal current collector sheet, a solid electrolyte membrane and a metal pair disposed opposite to the metal current collector sheet stacked in sequence electrodes; and solid NMR sample tubes.

Wherein, when the electrode sample to be tested is detected, the solid electrolyte in-situ electrochemical cell is encapsulated in the solid NMR sample tube.

Based on the above scheme, further preferably,

The encapsulation material corresponding to the electrode sample to be tested includes but is not limited to any one of gel material, plastic crystal material and polymer material.

Based on the above scheme, further preferably,

The membrane material of the solid electrolyte membrane includes, but is not limited to, any one of perfluorosulfonic acid polymer membrane, polyether ether ketone polymer membrane, and polybenzimidazole polymer membrane.

Based on the above scheme, further preferably,

The material corresponding to the metal current collector includes but is not limited to any one of gold, copper, and silver.

Based on the above scheme, further preferably,

The material corresponding to the metal counter electrode includes but is not limited to any one of platinum, gold, and silver.

Another object of the present invention is to provide a detection system including the electrode characterizing device described in any of the above solutions.

Another object of the present invention is to provide a method for characterizing electrodes using the electrode characterizing device, which comprises the following steps:

S1. Encapsulate the electrode sample to be tested;

S2. Preparation and packaging of the detection electrode, that is, under the conditions of a lamination temperature of 100 to 150°C and a pressure of 200 to 2000kgcm ^-2 , a metal current collector sheet of a certain size and a metal counter electrode sheet of a certain size are respectively pressed on the Both sides of the solid electrolyte membrane, and the electrode wires are welded to the edge positions of the metal current collector sheet and the counter electrode respectively;

S3, pressing the sealing frame with the wrapped and encapsulated electrode sample to be tested on the metal current collector sheet side of the detection electrode and tightly fixed to form a solid electrolyte in-situ electrochemical cell;

S4, encapsulating the solid electrolyte in-situ electrochemical cell in the solid NMR sample tube.

Based on the above scheme, further preferably,

The S1 includes the following steps:

S11. Add a certain quality of the solid sample to be tested into a certain amount of ethanol solution for ultrasonic dispersion until it is completely uniform, then add the coating material solution and mix it evenly, drop it into a fixed mold and dry it under vacuum conditions at room temperature for several hours; The quality of the coating material solution is 0.5 to 10 times the quality of the solid test sample to be tested, and the coating material solution is carried out according to the selected material for each corresponding solution preparation process; if a gel material is used, the It is dissolved into an aqueous solution to make its concentration 1 to 10%, then mixed with the sample dispersion evenly, heated to 60 to 90 °C, cooled and then dropped into a fixed mold to dry for use; if a plastic crystal material is used, then Dissolve it in acetone so that the concentration is 1 to 10%. After mixing evenly at room temperature, drop it into a fixed mold and dry it for later use; if a polymer material is used, directly mix the polymer material with a concentration of 1 to 10% with it. The sample solution to be tested is mixed evenly and then dried for use;

S12, moisturizing the fixed mold with the solid sample to be tested.

Compared with the prior art, the beneficial effects of the present invention:

1. The present invention can perform electrochemical in-situ detection: it can detect ion behavior signals under different electrochemical conditions; it can detect solid samples: 2. It can effectively detect ion behavior signals in solid samples and the signal resolution High: 3. Since the present invention performs humidity control, the signal resolution can be greatly improved, and the detection process is controllable and effective; 4. Its use process is simple and controllable, and its practicability is strong. The detection of hydrogen ions, hydroxide ions, and lithium ions of various electrode materials including fuel cells, lithium ion batteries, and metal-air batteries has the advantage of a wide range of applications.

Description of drawings

Figure 1a is a schematic structural diagram corresponding to the device of the present invention;

Figure 1b is a schematic structural diagram corresponding to the solid electrolyte in-situ electrochemical cell according to the present invention;

Figure 1c is a schematic diagram of the disassembly of the structure corresponding to the solid electrolyte in-situ electrochemical cell according to the present invention;

Figure 1d is a schematic top-view structure diagram corresponding to the solid electrolyte in-situ electrochemical cell according to the present invention;

FIG. 1e is a schematic side view structure diagram corresponding to the solid electrolyte in-situ electrochemical cell according to the present invention;

FIG. 2 corresponds to the detection result of electrochemical in-situ hydrogen nuclear magnetic resonance spectrum corresponding to Example 1 of the invention.

In the figure: 1. Sealing frame, 2. Metal current collector, 3. Solid electrolyte membrane, 4. Metal counter electrode, 5. Gel.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the implementation of the present invention. examples, but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In view of the fact that the existing two-electrode or three-electrode system electrochemical detection devices are difficult to effectively integrate with nuclear magnetic technology, and the relevant detection signals are not satisfactory. The present invention provides a nuclear magnetic resonance-electrochemical combined electrode characterization device (FIG. 1), comprising:

A solid electrolyte in-situ electrochemical cell, which at least has a sealing frame 1 for sealing the wrapped and encapsulated electrode sample 5 to be tested, a metal current collector 2, a metal counter electrode 4 disposed opposite the metal current collector 2, and a solid Electrolyte membrane 3; and a solid NMR sample tube; wherein, when the electrode sample to be tested is detected, the solid electrolyte in-situ electrochemical cell is packaged in the solid NMR sample tube. This device is based on the principle of nuclear magnetic resonance detection. Due to the serious limitation of molecular motion in solid materials, and the shortcomings of insufficient signal strength and resolution compared with liquid or colloidal materials, colloidal or polymer encapsulation technology is used to encapsulate the ion migration channel of the sample to be tested. In solid materials, the migration of ions in the channel can still be close to the behavior mechanism in the liquid phase under humidified conditions, thus greatly eliminating the signal intensity of the auxiliary solid material, and the ion migration signal of the sample to be tested is greatly enhanced. At the same time, without using the high-speed rotation detection mode of traditional solid-state NMR, the metal electrodes can be smoothly connected to the electrochemical workstation for in-situ characterization.

Based on the above scheme, further preferred example 1,

The encapsulation material corresponding to the electrode sample to be tested includes but is not limited to any one of gel material, plastic crystal material and polymer material; preferably, the gel material can be agar, and the plastic crystal material is polymer material. Any one of ether ether ketone, polyethylene, nylon and other materials, the polymer material is ethylene oxide.

Based on the above preferred example 1, further preferred example 2,

The membrane material of the solid electrolyte membrane includes, but is not limited to, any one of perfluorosulfonic acid polymer membrane, polyether ether ketone polymer membrane, and polybenzimidazole polymer membrane.

Based on the above preferred example 2, further preferred example 3,

The material corresponding to the metal current collector includes but is not limited to any one of gold, copper, and silver.

Based on the above preferred example 3, further preferred example 4,

The material corresponding to the metal counter electrode includes but is not limited to any one of platinum, gold, and silver.

Based on the above scheme, it can be seen that the novel NMR-electrochemical combined electrode characterization device constructed by the present invention has a miniature two-electrode system, the electrolyte adopts a solid electrolyte membrane, and the packaging material of the detection electrode sample adopts such as gel 5 or Solid materials and other materials are packaged and can be easily disassembled. The current collecting material is made of metal current collectors, which can be prepared by micro welding process, and the entire electrode system formed is packaged into the nuclear magnetic resonance sample detection tube; this detection device can be used In the detection of in-situ electrochemical nuclear magnetic resonance devices of various electrode materials, the range of detection electrode materials includes proton exchange membrane fuel cells, direct liquid fuel cells, metal-air batteries and supercapacitors, lithium-ion batteries, etc.

Another object of the present invention is to provide a detection system including the electrode characterizing device described in any of the above solutions.

Another object of the present invention is to provide a preparation method for preparing the electrode characterization device described in any of the above schemes, which comprises the following steps:

S1, encapsulate the electrode sample to be tested; the S1 includes the following steps:

S11. Add a certain quality of the solid sample to be tested into a certain amount of ethanol solution for ultrasonic dispersion until it is completely uniform, then add the coating material solution and mix it evenly, drop it into a fixed mold and dry it under vacuum conditions at room temperature for several hours; The quality of the coating material solution is 0.5 to 10 times the quality of the solid test sample to be tested, and the coating material solution is carried out according to the selected material for each corresponding solution preparation process; if a gel material is used, the It is dissolved into an aqueous solution so that its concentration is 1% to 10%, then mixed with the sample dispersion evenly, heated to 60 to 90 ° C, cooled and then dropped into a fixed sealing frame mold to dry for use; if a plastic crystal is used material, dissolve it in acetone to make the mass concentration of 1% to 10%, after mixing evenly at room temperature, drop it into a fixed mold and dry it for later use; when using polymer materials, directly adjust the concentration to 1 to 10% % The polymer material is mixed with the sample solution to be tested and dried for use;

S12, moisturizing the fixed mold with the solid sample to be tested;

S2. Preparation and packaging of the detection electrode, that is, under the conditions of a lamination temperature of 100 to 150°C and a pressure of 200 to 2000kgcm ^-2 , a metal current collector sheet of a certain size and a metal counter electrode sheet of a certain size are respectively pressed on the Both sides of the solid electrolyte membrane, and the electrode wires are welded to the edge positions of the metal current collector sheet and the counter electrode respectively;

S3. Pressing the coated and encapsulated electrode sample to the electrode side of the metal current collector sheet through a sealing frame and tightly fixing it to form a solid electrolyte in-situ electrochemical cell;

S4, encapsulating the solid electrolyte in-situ electrochemical cell in the solid NMR sample tube, so that the wire is connected with the electrochemical workstation to obtain an electrochemical detection device for combined NMR-electrochemistry.

Based on the above scheme, further preferred example 5, the ethanol solution adopts the ethanol solution of 1 to 5 times the mass;

Vacuum drying conditions refer to drying under vacuum conditions at room temperature for 1 to 24 hours; the humidification treatment refers to placing the fixed mold with the solid sample to be tested in a temperature range from room temperature to 90°C and a humidity range from 20 to 100%. The humidification treatment is carried out in the environment, and the holding time is 2 to 48 hours.

Above-mentioned scheme is described below with actual experimental embodiment:

Example 1:

Encapsulate the electrode material to be tested: add 10 mg of a mixed sample of 60% carbon-supported platinum catalyst and perfluorosulfonic acid polyion in a mass ratio of 5:1 to 3 times of ethanol solution for ultrasonic dispersion until it is completely uniform. The 5% polyether ether ketone acetone solution was thoroughly mixed, and dropped into the fixed mold, and dried under vacuum at room temperature for 12 hours; at the same time, the above electrode material samples fixed in the fixed mold were placed in a temperature range of 60 ° C and humidity. Humidification is carried out in a 100% environment and the holding time is 24 hours.

Preparation and packaging of detection electrodes: A gold current collector sheet with a size of 2x2mm and a thickness of 50μm and a metal platinum sheet of the counter electrode of the same size are respectively pressed on both sides of the perfluorosulfonic acid polymer film with a size of 5x5mm. The pressing temperature is 120°C and the pressure is 1000kg cm ^-2 ; the electrode wires are welded to the edge positions of the metal current collector sheet and the counter electrode respectively; the above-mentioned electrode samples fixed in the mold are pressed to the electrode of the metal current collector sheet The detection electrode is fixed in the sample tube of the nuclear magnetic resonance detection device, and the electrode wire is connected with the electrochemical workstation to obtain the combined nuclear magnetic resonance-electrochemical electrochemical detection device.

Comparative Example 1: 10 mg of a mixed sample of 60% carbon-supported platinum catalyst and perfluorosulfonic acid polyion in a mass ratio of 5:1 was directly loaded into a solid NMR sample tube for NMR characterization.

Example 2:

Encapsulate and encapsulate the electrode material to be tested: add 10 mg of carbon powder sample to 3 times of ethanol solution for ultrasonic dispersion, add 2% agar aqueous solution by mass after it is completely uniform, mix well at 70 °C, and then cool down. Drop into a fixed mold and dry under vacuum at room temperature for 12 hours;

The electrode material sample in the above-mentioned fixed mold is placed in an environment with a temperature range of 90° C. and a humidity of 80% for humidification treatment, and the holding time is 48 hours;

Preparation and packaging of detection electrodes: A gold current collector sheet with a size of 2x2mm and a thickness of 50μm and a metal platinum sheet of the counter electrode of the same size are respectively pressed on both sides of the perfluorosulfonic acid polymer film with a size of 5x5mm. The pressing temperature is 120℃, and the pressure is 1000kg cm-2; the metal wires are welded to the edge positions of the metal current collector sheet and the metal counter electrode respectively;

Press the electrode sample in the above-mentioned fixed mold to the electrode side of the metal current collector sheet, and fix it tightly;

The above detection electrode is fixed in the sample tube of the nuclear magnetic resonance detection device, and the metal wire is connected with the electrochemical workstation to obtain the combined nuclear magnetic resonance-electrochemical electrochemical detection device.

Example 3:

Encapsulate the electrode material to be tested: add 10 mg of perfluorosulfonic acid polyion mass sample to 3 times the ethanol solution for ultrasonic dispersion, add ethylene oxide to complete uniformity, mix well, and drop it into a fixed mold. Dry under vacuum at room temperature for 12 hours; place the electrode material sample in the above-mentioned fixed mold in an environment with a temperature range of 50° C. and a humidity of 50% for humidification treatment for 12 hours.

Preparation and packaging of detection electrodes: A gold current collector sheet with a size of 2x2mm and a thickness of 50μm and a metal platinum sheet of the counter electrode of the same size are respectively pressed on both sides of the perfluorosulfonic acid polymer film with a size of 5x5mm. The temperature is 120℃, the pressure is 1000kg cm-2, and the electrode wires are welded to the edge positions of the metal current collector sheet and the counter electrode respectively;

Press the electrode sample in the above-mentioned fixed mold to the electrode side of the metal current collector sheet, and fix it tightly;

The above-mentioned detection electrode is fixed in the sample tube of the nuclear magnetic resonance detection device, and the electrode wire is connected with the electrochemical workstation to obtain the combined nuclear magnetic resonance-electrochemical electrochemical detection device.

Based on FIG. 2 composed of the above-mentioned embodiment and comparative example, it can be seen from the figure that the detection device prepared by the present invention can clearly distinguish the migration kinetic signals of hydrogen ions under different electrode potential conditions.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. The equivalent replacement or change of the inventive concept thereof shall be included within the protection scope of the present invention.

Claims (9)

1. electrode characterization apparatus associated with a kind of nuclear magnetic resonance-electrochemistry characterized by comprising

Solid electrolyte electrochemical in-situ pond, the sealing frame for the electrode sample to be measured that at least there is sealing to be wrapped after encapsulation, And metal flow collection sheet, solid electrolyte film and the metal being oppositely arranged with the metal flow collection sheet stacked gradually is to electrode； And solid state nmr sample cell；

Wherein, when detecting to electrode sample to be measured, solid electrolyte electrochemical in-situ pond is encapsulated in described solid In body nuclear-magnetism sample cell.

2. electrode characterization apparatus according to claim 1, it is characterised in that:

Wrapping and encapsulating material corresponding to the electrode sample to be measured include but is not limited to gel rubber material, plastic crystal material and Any one in polymer material.

3. electrode characterization apparatus according to claim 1, it is characterised in that: the membrane material of the solid electrolyte film includes But it is not limited to perfluorinated sulfonic acid polymer film, polyetheretherketonepolymer polymer film, any one in polybenzimidazole polymer film.

4. electrode characterization apparatus according to claim 1, it is characterised in that: material packet corresponding to the metal flow collection sheet Include but be not limited to gold, copper, silver in any one.

5. electrode characterization apparatus according to claim 1, it is characterised in that: the metal is to material packet corresponding to electrode Include but be not limited to platinum, any one in gold, silver.

6. a kind of detection system, it is characterised in that: including electrode characterization apparatus described in claim 1-5 any one.

7. a kind of method using the characterization electrode of electrode characterization apparatus described in claim 1-5 any one comprising as follows Step:

S1, cladding encapsulation is carried out to electrode sample to be measured；

The preparation and encapsulation of S2, detecting electrode, the metal of the metal afflux thin slice of certain size and certain size is thin to electrode Piece is pressed on the two sides of solid electrolyte film respectively to constitute detecting electrode；

S3, the metal afflux thin slice side that the sealing frame with the electrode sample to be measured after being wrapped encapsulation is pressed on to detecting electrode And it is tightly fastened to constitute solid electrolyte electrochemical in-situ pond；

S4, solid electrolyte electrochemical in-situ pond is encapsulated in the solid state nmr sample cell.

8. according to the method described in claim 7, it is characterized by:

The S1 it includes the following steps:

S11, it the solid sample to be tested of certain mass is added to a certain amount of ethanol solution carries out ultrasonic disperse until substantially uniformity, Covering material solution is then added and dries several hours under room temperature in vacuum conditions in instilling fixing mould after mixing；Its In, the quality of the covering material solution is the quality of 0.5 to 10 times of sample to be tested, and the covering material solution is according to selected by The material taken carries out respectively corresponding solution production process；According to gel rubber material, then it is dissolved into aqueous solution, so that Its concentration is 1 to 10%, is then heated to 60 to 90 DEG C after mixing with sample dispersion liquid, then instill stent again after cooling down Dried for standby in tool；It according to plastic crystal material, is then dissolved in acetone, so that concentration is 1 to 10%, at room temperature After mixing, then dried for standby in fixing mould is instilled；Using polymer material, then directly concentration is polymerize for 1 to 10% Object material and testing sample solution dried for standby after mixing；

S12, humidification processing is carried out to the fixing mould with solid sample to be tested.

9. according to the method described in claim 7, it is characterized by:

Pressing condition in the S2 is that temperature is 100 to 150 DEG C, and pressure is 200 to 2000kg cm^-2, and and respectively will be electric Polar conductor is welded in metal afflux thin slice with the marginal position to electrode to constitute electrode side.