KR20190113038A - Integrated Electrochemical Analysis Equipment including potentiostat, Electrochemical Impledance Spectroscopy and Electrochemical Quarts Crystal Microbalance - Google Patents

Abstract

The present invention relates to an integrated electrochemical measuring device. More particularly, the present invention relates to an integrated electrochemical measuring device that integrates potentiostat, EIS, and QCM, which are essential for measurement and characterization of energy devices such as OLED, display, printing system ink, fuel cell, battery, solar cell, hydrogen cell, thin film, organic, inorganic material and bio, precision measurement, chemical and physical change, or the like, enables experiments without replacing the equipment, and also obtains data from the potentiostate, EIS, and QCM simultaneously to process them collectively.

Description

Integrated Electrochemical Analysis Equipment including potentiostat, Electrochemical Impledance Spectroscopy and Electrochemical Quarts Crystal Microbalance}

The present invention relates to an integrated electrochemical measuring device, and more specifically, OLED, display, printing system ink, fuel cell, battery, solar cell, hydrogen device such as hydrogen cell, thin film, organic, inorganic Integrate potentiostat, EIS, and EQCM, essential equipment for measurement and characterization of materials and bio, precision measurement, chemical and physical changes, and perform experiments without replacing the equipment, and simultaneously acquire data from the potentiostat, EIS, and EQCM. The present invention relates to an integrated electrochemical measuring apparatus that can be obtained and processed and processed in a batch.

Chemical sensors, environmental sensors, bio-sensors, etc. are often used for a constant voltage polarizer (potentiostat) that applies a constant voltage and reads a steady state current.

Recently, due to the development of an array type sensor system or a complex sensor system, there is a demand for miniaturization and large-capacity integration of a constant voltage polarization device. The potentiostat can be tested and measured for the reversibility of chemical reactions through methods such as cyclic voltammetry, and has recently been tested on energy devices and materials, sensors, LED displays, etc. Necessity is increasing rapidly, and utilization is getting active.

The constant voltage polarization device using the potentiostat includes a sensor and an operational amplifier using three electrodes such as an auxiliary electrode (AE), a reference electrode (RE), and a working electrode (WE). Can be driven by a circuit device, and as the driving circuit of the specific device therefor, Martin, SM Gebara, F. H., T. D., R. B. "A low-voltage, chemical sensor interface for systems-on-chip: the fully-differential potentiostat", IEEE Proceedings of the International Symposium on Circuits and Systems, 2004. (ISCAS '04.), Vol. 4, pp. An example schematic of the potentiostat is presented in 892-895, Vancouver, Canada, 2004.

On the other hand, QCM (Quartz Crystal Microbalance) is a device that can measure a micro mass by using resonance generated by the piezoelectric properties of a crystal. An electrode and a quartz substrate disposed between the electrodes are provided, and the electrode may be formed by coating metal on both sides of the quartz substrate.

The crystal vibration scale may be obtained by coating the metal on both sides of the thin crystal to form an electrode by cutting the crystal in a specific direction with respect to the crystal axis (AT-cut), when the voltage is applied between the crystal Resonance occurs at a constant resonance frequency at the resonance point of the substrate and the structure consisting of the electrodes. At this time, when one of the pair of electrodes is exposed to air, and the micro mass M is in contact with the electrode, the value of the resonance frequency changes by the micro mass M. Therefore, the micro-mass (M) value can be measured by measuring the amount of change in the resonance frequency, and the crystal oscillation scale is a sensor capable of measuring the mass change in nanograms, so that the concentration change of the gas is measured and deposited. It can be applied in various fields such as amount measurement, protein detection and viscoelastic coefficient measurement.

In addition, as an application of the crystal oscillation balance, it is possible to measure the mass change of the crystal surface even in the solution phase, in which case one of the two electrodes of the QCM becomes a working electrode to work through the current-voltage relationship The mass change of the electrode can be measured, and in this case, the QCM can be separately classified as an electrochemical quartz crystal microbalance (EQCM).

The EQCM can be used in various fields involving mass changes of electrodes such as the formation of monolayer or multilayer thin films or the movement of materials due to redox in polymer thin films attached to electrodes, electroless plating, and adsorption and desorption of proteins. It may be applicable to.

In general, a QCM device includes a cell containing a crystal crystal, an oscillation circuit that selects and oscillates only a desired frequency, a frequency counter for measuring a frequency change occurring on an electrode of the crystal crystal, and outputs a voltage value. It can be composed of a DAQ board that converts into a recognizable digital signal, and a control board for controlling them.In addition, the EQCM can be modified by a working electrode by adding an electrochemical cell to the QCM. And a counter electrode and a reference electrode may be additionally included.

As a technology using the EQCM system, Korean Patent Publication No. 10-0859768 (2008.09.24) includes an electrochemical cell having a structure that minimizes the occurrence of interference during an electrochemical reaction and changes the surface of a working electrode during an electrochemical reaction. The EQCM device, which can measure the effect of the impedance on the impedance in real time and can measure the change in mass at the surface of the electrode with the precision of nanogram (ng), is described.

Figure 1 shows the EQCM device used in the prior art. In detail, the EQCM device includes an Ag / AgCl electrode and a working electrode 40 including a quartz crystal 41, a reference electrode 50, a reference electrode, and a counter electrode 60, respectively. An electrochemical cell 70 consisting of a conventional three-electrode system in which a platinum electrode is used, may contain materials that will induce chemical reactions or physical changes with a suitable solvent.

The electrochemical cell of the EQCM device should be equipped with a modification by exposing only one electrode of the QCM to the solution and sealing it against leakage.

In addition, the EQCM device is Potentiostat 45 for generating a DC voltage which is a reaction potential of the electrolytic solution and applying it to the electrolytic solution with a stable signal voltage may be connected to the working electrode.

In the EQCM, as in the QCM system, the oscillator circuit 10 selects and oscillates only a desired frequency, a frequency counter 20 measuring a frequency change occurring on an electrode of a crystal, and outputs a voltage value. It includes a DAQ board (30) for converting a digital signal that can be recognized, and a control board (not shown) for controlling them and a device such as a PC.

That is, both surfaces of the crystal crystal, which is a crystal oscillator that forms the electrochemical cell part, are coated with metal to form electrodes, and oscillate with the resonance frequency of the crystal according to the signal of the input voltage. By changing the frequency of the crystal oscillator, it is possible to detect the change of mass occurring in the electrode.

Here, the amount of material precipitated in the quartz crystal in the working electrode is calculated by measuring the resonance frequency f0 of the initial quartz crystal and the change Δf due to the precipitation of the crystal crystal frequency (ft) after material precipitation. Can be.

In this case, the oscillating circuit 10 functions to select and oscillate only a desired frequency, and the vibration of the crystal is converted into an electrical signal by the oscillating circuit, and the frequency measuring instrument uses the electrical signal to Measure the frequency.

On the other hand, electrochemical impedance spectroscopy (EIS) is widely used as a useful tool for characterizing electrode reactions or complexes mainly in the electrochemical field. System response analysis has become a very useful instrument in the field of applied chemistry, medical engineering and biotechnology by providing comprehensive information including the properties and structures of complexes and the resulting responses. Research has been conducted to model and simplify electrochemical power devices such as fuel cells, fuel cells and supercapacitors.

According to the prior art, the EQCM, potentiostat and EIS measuring equipments, which implement the main functions of each of them, are currently separately configured, and even if integrated, the final data is digitized separately and outputted to a PC. Controlled separately by the application or data is obtained.

FIG. 2 illustrates an EQCM, potentiostat, and EIS measuring apparatus according to the prior art. As shown in FIG. 2, a working electrode, a reference electrode, and a counter electrode including a crystal crystal are shown. On the basis of a three-electrode electrochemical cell including a counter electrode, QCM is described as a form in which the QCM is controlled and inputted with the oscillation circuit on the left side of FIG. 2, and a potentiostat and an EIS measuring instrument are shown on the right side of FIG. It is described as a controlled and input and output form, each of these data has a configuration that is output or controlled by an application program provided on a separate PC, and as shown in Figure 1, these QCM and potentiostat and EIS measurement Even if the equipment is output or controlled by one PC, the data input / output to QCM and the data input / output to potentiostat and / or EIS are separate. And input and output control are separately each eungeung program thereof as it is an independent separate program used, and has a separate hard to intuitively determine the correlation of the measured data to the respective equipment problems.

In particular, as described above, in the case of separately measured data according to the prior art, in the case of measuring in real time the changed data in the potentiostat and / or EIS according to the surface change of the working electrode in the course of the electrochemical reaction occurs Since the trend of each change must be observed in a separate application program in the PC, it is difficult to express the change of the surface or the visual visualization of the measurement data more intuitively.

Patent Publication No. 10-0859768 (2008.09.24.)

Martin, S.M. Gebara, F. H., T. D., R. B. "A low-voltage, chemical sensor interface for systems-on-chip: the fully-differential potentiostat", IEEE Proceedings of the International Symposium on Circuits and Systems, 2004. (ISCAS '04.), Vol. 4, pp. 892-895, Vancouver, Canada, 2004

Therefore, in order to solve the above problems, the present invention integrates EQCM, potentiostat and EIS measuring equipment into one, and outputs and outputs data to QCM, potentiostat and / or EIS to be output or controlled by one application program in one PC. It is an object of the present invention to provide an integrated electrochemical measuring apparatus including Potentiostat, EIS, and EQCM, which controls them integrally and enables input / output.

In order to solve the above problems, the present invention is an electrochemical reaction, electrochemical cell (cell) comprising a working electrode, a reference electrode and a counter electrode comprising a crystal crystal; An impedance measuring unit (EIS) electrically connected to the electrochemical cell and capable of measuring impedance in a solution in which an electrochemical reaction occurs; An electrochemical quartz oscillation device (EQCM) electrically connected to the electrochemical cell and configured to read a change in frequency according to a change in mass of the working electrode of the electrochemical cell; And a controller for processing data inputted to and outputted from the impedance measuring unit and the electrochemical quartz oscillation balance device, wherein the controller is configured to input and output data to and from the impedance measuring unit (EIS). A memory unit capable of simultaneously storing data input and output to the vibration balance device; And an operation unit configured to process data stored in the memory, such that data of an impedance measuring unit (EIS) and data of an electrochemical quartz oscillation device simultaneously stored in the memory unit can be simultaneously processed by the operation unit. Provide a chemical measuring device.

In this case, the integrated electrochemical measuring device, the impedance measuring unit (EIS) in the integrated electrochemical measuring device is electrically connected to the electrochemical cell, applies a constant voltage to a solution in which an electrochemical reaction occurs, and reads the current accordingly. The controller may include a constant voltage polarization device (potentiostat), and the controller may simultaneously store data input and output to the impedance measuring unit (EIS), data input and output to the constant voltage polarization device (potentiostat), and data input and output to the electrochemical quartz crystal balance device. A memory unit; And an operation unit configured to process data stored in the memory, such that data of an impedance measuring unit (EIS) simultaneously stored in the memory unit, data input / output to a constant voltage polarization device (potentiostat), and data of an electrochemical quartz crystal balance device are included. It can be processed simultaneously in the operation unit.

In addition, the present invention is an electrochemical reaction, electrochemical cell (cell) comprising a working electrode, a reference electrode and a counter electrode comprising a crystal crystal; A constant voltage polarization device electrically connected to the electrochemical cell and applying a constant voltage to a solution in which an electrochemical reaction occurs and reading a current according thereto; An electrochemical quartz oscillation device (EQCM) electrically connected to the electrochemical cell and configured to read a change in frequency according to a change in mass of the working electrode of the electrochemical cell; And a controller for processing data input and output to the constant voltage polarization device (potentiostat) and the electrochemical quartz oscillation balance device, wherein the control unit includes data input and output to the constant voltage polarization device (potentiostat); A memory unit capable of simultaneously storing data input and output to the electrochemical quartz oscillation device; And an operation unit configured to process data stored in the memory, such that the data of the constant voltage polarization device (potentiostat) and the data of the electrochemical quartz oscillation balance device simultaneously stored in the memory unit can be simultaneously processed by the operation unit. Provide a chemical measuring device.

In addition, the present invention by using an integrated electrochemical measuring device, at least one of the data input and output to the electrochemical crystal oscillation balance device, the data input and output to the impedance measuring unit (EIS) or the data input and output to the constant voltage polarization device (potentiostat) Is simultaneously stored in the memory unit of the control unit and processed simultaneously, thereby changing the mass in the working electrode of the electrochemical cell, and the potential potential value from the constant voltage polarity device or the impedance value from the impedance measuring unit EIS. It provides a method for simultaneously analyzing the mass change of the working electrode in the electrochemical cell and the impedance or current change in the cell, characterized in that it can be analyzed in one application in real time.

As described above, the integrated electrochemical measuring apparatus including the potentiostat, the EIS, and the EQCM provided by the present invention controls data input / output through the EQCM and data input / output through the potentiostat and / or the EIS through a single integrated controller. Since they can be input and output and controlled by a single integrated application, it is easy to intuitively determine the correlation between the data. In particular, the potentiostat and / or the surface change of the working electrode during the electrochemical reaction occur. Alternatively, when measuring the changed data in the EIS in real time, it is easy to observe the trends in the PC intuitively, and in addition, it is possible to more intuitively visualize the change of the surface or the measurement data. Has an advantage.

In addition, the integrated electrochemical measuring device according to the present invention can provide a one-step test solution in the electrochemical measuring device by integrating potentiostat, EIS, and EQCM, in particular, measuring only with expensive commercial equipment. It is possible to easily measure the internal impedance of such an electrochemical energy storage device.

FIG. 1 is a diagram illustrating an electrochemical measurement device to which an exemplary electrochemical quartz oscillation balance device (EQCM) and a constant voltage polarization device (potentiostat) are added, which are used in the prior art.
FIG. 2 is a diagram illustrating an electrochemical quartz oscillation device (EQCM) and an electrochemical measurement device to which a constant voltage polarization device (potentiostat) / impedance measurement unit (EIS) is added as another example used in the prior art.
3 illustrates an exemplary circuit configuration of an electrochemical quartz oscillation device (EQCM) and an integrated electrochemical measurement device to which a constant voltage polarization device (potentiostat) / impedance measurement unit (EIS) is added according to an embodiment of the present invention. One picture.
FIG. 4A illustrates an electrochemical input into a memory unit of an integrated electrochemical measuring apparatus to which an electrochemical quartz oscillation device (EQCM) and a constant voltage polarization device (potentiostat) / impedance measuring unit (EIS) are added according to an embodiment of the present invention. A graph of output data from a quartz vibration balancer (EQCM) is shown, and FIG. 4B is a graph of output data from a constant voltage polarizer (potentiostat) input to the memory unit, and FIG. 4C is an impedance input to the memory unit. The figure which shows the graph of the output value data from the measuring part EIS.
5 is a real-time analysis of the potential of the electrochemical cell in the electrochemical cell and the change of the current and impedance, the change in the mass of the working electrode through the data application from the integrated electrochemical measuring device according to an embodiment of the present invention One graph.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. In the drawings of the present invention, the size or dimensions of the structures are shown to be enlarged or reduced than actual for clarity of the present invention, and well-known configuration is omitted to show the characteristic configuration is not limited to the drawings. . In describing the principles of the preferred embodiment of the present invention in detail, if it is determined that the detailed description of the related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

The present invention includes at least one of an impedance measuring unit (EIS) or a constant voltage polarization device (potentiostat), an electrochemical cell, an electrochemical quartz oscillation device (EQCM), and the impedance measuring unit (EIS) or a constant voltage In the integrated electrochemical measuring device comprising a polarizer (potentiostat) and the controller for processing data input and output to the electrochemical quartz oscillation device, the controller is an impedance measuring unit (EIS) or a constant voltage polarizer (potentiostat) A memory unit capable of simultaneously storing input / output data and data input / output with an electrochemical quartz oscillation scale device; And an operation unit configured to process data stored in the memory, such that data of an impedance measuring unit (EIS) simultaneously stored in the memory unit, data of a constant voltage polarization device (potentiostat), and data of an electrochemical quartz crystal balance device are included. It provides an integrated electrochemical measuring device, characterized in that the processing unit can be processed simultaneously.

Here, the electrochemical cell includes a working electrode, a reference electrode, and a counter electrode, which are three-electrode systems commonly used in the electrochemical field, wherein the working electrode includes a crystal crystal. It may be linked with the electrochemical quartz oscillation device (EQCM).

In the electrochemical cell, at least one of an impedance measuring unit and a potentiostat described below and an electrochemical quartz oscillation device (EQCM) are joined to each other, and the electrochemical crystal oscillator is a crystal oscillator. Quartz crystals are provided, and at this time, both surfaces of the crystals used are coated with metal to make electrodes, and oscillate with the resonance frequency of the crystals according to the signal of the input voltage. By changing the frequency of the crystal oscillator, it is possible to detect the change of mass occurring in the electrode.

On the other hand, the constant voltage polarization device (potentiostat) is electrically connected to the electrochemical cell, a part of applying a constant voltage to the solution in which the electrochemical reaction occurs and reads the current according to, the step voltage and electrolysis according to a predetermined control signal It is possible to apply the signal voltage generated at the part that outputs the DC voltage by generating the DC voltage which is the reaction potential of the solution to the electrolytic solution at high speed and stable signal voltage, and to test the reversibility of the chemical reaction through a method such as Cyclic Voltammetry. Can be.

On the other hand, the impedance measuring unit (EIS) is a reference electrode for checking whether the constant voltage polarizer (potentiostat), the signal voltage applied from the constant voltage polarization device is correctly applied to the counter electrode and the electrolytic solution of the signal voltage, the counter electrode It may include a working electrode for measuring the current flowing through the electrolytic solution in accordance with the signal voltage applied in and a current / voltage converter for converting the current flowing from the working electrode into a voltage.

In order to measure the impedance, the generated sinusoidal sinusoidal signal is controlled to output a current of a specific frequency at a specific operating point. At this time, the current and the voltage are removed through a detection circuit and a filter to remove noise, and a digital conversion is performed through the DAQ Board. It can be implemented to have a system that is input through a PC, and it is a measurement part that analyzes the chemical reaction or the electrical structure of an electrochemical sample by measuring the impedance spectrum, and analyzes the characteristics of electrode reactions or complexes in the electrochemical field. It is widely available as a useful tool for doing so. In this case, when the sampling rate of the sample to be measured is low, a limit of the measurement range may appear, and thus, the impedance measuring unit corresponds to the sampling rate of an electrochemical quartz oscillation device (EQCM) and a constant voltage polarization device (potentiostat). In order to increase the accuracy when sampling and generating 1MHz sine wave higher than 20kHz, 50 points can be used in the range of 50MHz to collect accuracy, and 50MHz ~ 0.0005Hz when sine wave of 1MHz ~ 0.00001Hz is used. Free variable is possible.

 On the other hand, the electrochemical quartz oscillation device (EQCM) is electrically connected to the electrochemical cell, in order to read the change in frequency in accordance with the mass change of the working electrode of the electrochemical cell, in the working electrode of the electrochemical cell An oscillator circuit including a cell including a crystal crystal and an oscillator for selecting and oscillating only a desired frequency, and a frequency counter for measuring a frequency change occurring on an electrode of the crystal crystal. It may include.

On the other hand, the control unit in the present invention processes the data input and output to the impedance measuring unit (EIS) and the electrochemical quartz oscillation device, or input and output to the constant voltage polarization device (potentiostat) and the electrochemical quartz oscillation device Data may be processed, and the data input and output to the impedance measuring unit (EIS) and the constant voltage polarization device (potentiostat) included therein and the data input and output to the electrochemical quartz oscillation balance device may be simultaneously processed.

To this end, the control unit may include a memory unit capable of simultaneously storing data input / output to an impedance measuring unit (EIS) or a constant voltage polarizer (potentiostat) and data input / output to an electrochemical quartz oscillation scale device; And an operation unit configured to process data stored in the memory, wherein the data of the impedance measuring unit EIS and the data of the electrochemical quartz oscillation device are simultaneously stored in the memory unit.

 This will be described in detail with reference to FIG. 3. FIG. 3 illustrates an exemplary circuit configuration of an integrated electrochemical measuring device to which an electrochemical quartz oscillation device (EQCM) and a constant voltage polarization device (potentiostat) / impedance measurement unit (EIS) are added according to an embodiment of the present invention. As a figure, data is controlled and transferred from an external PC through Ethernet through a board designed with a bus structure using an appropriate FPGA and SRAM structure, in which the electrochemical modification is performed through the DSC chip and the FPGA chip. Data for controlling the vibration balance device (EQCM), constant voltage polarization device (potentiostat) / impedance measuring unit (EIS) and the electrochemical cell, and output data from them.

More specifically, the FPGA chip implements a sine wave through the DAC to the data of the EIS including the PotentioStat at a sampling rate of up to 50 MHz, and the signal passes through the electrochemical cell to convert the response characteristics of the signal that characterizes the electrochemical cell. It is designed to have the logic to store the data coming from the EQCM oscillation circuit in the SRAM at the same time as the real-time data of the EIS, and guarantee the real-time by accessing the data guaranteed in parallel by the parallel synchronization interface function with the DSP. do.

In addition, an sRAM is included as a memory unit therein, and the sRAM is input and output to each electrode in an electrochemical quartz oscillation device (EQCM), a constant voltage polarization device (potentiostat) / impedance measurement unit (EIS), and an electrochemical cell. To store data simultaneously.

That is, the potential potential value from the constant voltage polarization device (potentiostat) or the impedance value from the impedance measuring unit (EIS) and the thickness of the oscillation circuit in the electrochemical quartz oscillation balance device (EQCM) and the working electrode in the electrochemical cell An arithmetic unit configured to simultaneously store information regarding a change, and to include the simultaneously stored data in an FPGA; Or an arithmetic unit included in a DSP.

Meanwhile, the board may further include an ADC chip and a DAC chip for data communication with the electrochemical cell. Here, the ADC chip is a chip for converting analog data into digital, and the DAC chip corresponds to a chip for converting digital data into analog.

 Therefore, the data input and output from the external PC to the electrochemical cell through the board in more detail, first, the voltage control and oscillation of the oscillation circuit of the specific electrode in the electrochemical cell to be controlled by the user in the application program of the PC It transfers information such as frequency, amplitude and offset from the PC to the DSP and implements real-time logic in FPGA based on this. This ensures real-time performance by implementing 20KHz, the limit of DSP interface, by implementing parallel interface function of FPGA, DAC, ADC 50MHz output, and input as hardware logic. The signal output through the DAC by the real-time synchronization logic of the FPGA is input to the electrochemical cell, the signal output by the reaction from the electrochemical cell is stored in the SRAM by the synchronization logic of the FPGA via the ADC chip. At the same time, it is stored in SRAM together with the data of QCM, passed through DSP to FPGA by FPGA 2 Port SRAM Control Logic, and it is transmitted to comprehensive analysis software through Ethernet communication.

On the other hand, the operation unit in the control unit of the integrated electrochemical measurement device in the present invention can process the data stored in the memory unit and transfer the data to an external PC, the external PC received from the operation unit in one application program The data can be processed to analyze in real time the correlation between the mass change in the working electrode and the potential potential value from the constant voltage polarization device or the impedance value from the impedance measuring unit EIS.

 4 and 5, FIG. 4A is an integrated electrochemical quartz oscillation device (EQCM) and a constant voltage polarization device (potentiostat) / impedance measurement unit (EIS) according to an embodiment of the present invention. This is a graph showing the output data from the electrochemical quartz oscillation device (EQCM) input to the memory part of the electrochemical measuring device.The potential of the PotentioStat is sweeped and the current flow is observed to observe the flow of ions. Observe the EQCM value to observe the actual mass movement.In this case, the input value is applied a linear voltage of -0.4 ~ 0.7V so that the output value of the EQCM is blue and PotentioStat is the current change, and red is the mass change value of the EQCM. It is shown. At this time, the X axis of FIG. 4A represents the DAC output, the left side of the Y axis represents the electrochemical cell response current to the input of PotentioStat, and the right side of the Y axis represents the electrochemical cell response QCM Mass change to the input of PotentioStat.

On the other hand, Figure 4b is a graph of the output value data from the constant voltage polarizer (potentiostat) input to the memory unit, below to compare the potential Potential using only PotentioStat (polarizer) to compare the convenience and concurrency of the EQCM and analysis We observed the flow of current by sweeping and observed only the electron movement of ions. At this time, the PotentioStat input value applied a linear voltage of -0.4 ~ 0.7V, and the Potentiostat output value showed the DAC output (electrochemical cell input voltage, Y). The axis represents the electrochemical cell response current to the input of PotentioStat.

In addition, FIG. 4C is a diagram illustrating a graph of output value data from the impedance measuring unit (EIS) input to the memory unit. The EIS input value is obtained by dividing 40 sinusoids of 1 KHz to 0.1 Hz into a log scale. The output value is expressed as Nyquist Plot for the response of each frequency of 1KHz (bottom left) and 0.1Hz (top right) to represent the amplitude change and phase change of the sinusoidal output to the sinusoidal input. You can guess the circuit.

In FIG. 4C, the X axis represents the Nyquist Real value (effective resistance) of the electrochemical cell response current with respect to the sine wave input of PotentioStat, and the Y axis represents the Nyquist Image value of the electrochemical cell response current with respect to the sine wave input of PotentioStat (by capacitance). Imaginary current and phase difference), and one point in the Nyquist graph indicates that the response of the circuit to the response of one frequency is represented by the X and Y values, not in the form of Y values.

4A to 4C, the integrated electrochemical measuring device according to the present invention is output from each electrochemical quartz oscillation balance device (EQCM), and a constant voltage polarization device (potentiostat) / impedance measuring unit (EIS). The data values are input to the memory unit through the FPGA, and the input data values are output to the PC through the DSP, and the PC may process or control the respective data through one application program.

5 is a real-time analysis of the potential of the electrochemical cell in the electrochemical cell and the change of the current and impedance, the change in the mass of the working electrode through the data application from the integrated electrochemical measuring device according to an embodiment of the present invention As a graph, the data shown in FIGS. 4A to 4C are input to a memory unit through an FPGA, and the input data values are output to a PC through a DSP, and are output through a single application program written by a user in the PC. Variables related to the x and y axes represent real and image values on the electronic equivalent circuit inside the electrochemical cell, so that the circuit state of the corresponding electrochemical cell can be identified. The value can be displayed and it shows the change of impedance according to the progress of charging and discharging. In addition, by displaying the change of frequency according to the color of the sphere, it is easier to compare in the same frequency band when the phase change occurs compared to the conventional dotted line method, and can show the change of mass according to the size of the sphere. This is useful as an analysis tool that allows you to intuitively understand the overall flow of change.

In addition, the present invention uses at least one of the data input and output to the electrochemical quartz oscillation device, the data input and output to the impedance measuring unit (EIS) or the data input and output to the constant voltage polarization device (potentiostat) using the integrated electrochemical measuring device Mass storage in the working electrode of the electrochemical cell by storing one at the same time in the memory section of the controller and simultaneously processing the same; and the potential potential value from the constant voltage polarization device or the impedance value from the impedance measuring section EIS. It can provide a method for simultaneously analyzing the mass change of the working electrode in the electrochemical cell and the impedance or current change in the cell, characterized in that it can be analyzed in one application in real time, which is presented above Electrochemical Intracell Operation Using the Integral Electrochemical Measurement Apparatus of the Invention By analyzing the mass change of the coin pole and the impedance or current change in the cell at the same time, it is the method of obtaining the electrochemical information of the analysis target or the reaction information of the analysis target, through which the potentiostat and In real-time measurement of changed data in the EIS, it is easy to observe the trends in the PC intuitively, and more intuitively, visualize the change of the surface or the measurement data. It may have additional advantages.

 On the other hand, the integrated electrochemical measuring device according to the present invention may further include a temperature control unit which is directly in contact with and coupled to at least one of the electrochemical cell or the oscillation circuit, wherein the temperature control unit plate comprising a heater or Peltier element Is directly in contact with at least one of the electrochemical cell or the oscillation circuit, thereby allowing the temperature to be controlled.

The electrochemical quartz oscillation device (EQCM) in the integrated electrochemical measuring device according to the present invention minimizes the resonance frequency change according to the temperature change and also changes the temperature in a state where no substance is deposited on the electrodes formed at both ends of the crystal. It is possible to keep the temperature of the oscillation circuit and the cell, two major component parts of the temperature sensitive element in the electrochemical crystal vibrating balance device, in order to minimize the change of the resonance frequency of the crystal crystal according to have.

More specifically, the present invention may further include a temperature control unit which is directly contacted and coupled to at least one of the electrochemical cell or the oscillation circuit. Here, the temperature controller is in direct contact with ~ means that the temperature control unit is in close contact with any one or more of the top, bottom or side of the cell or oscillation circuit, thereby heating the cell or oscillation circuit or It means that it can be cooled.

In the present invention, the temperature control unit may be heated or cooled, or may be provided with both heating and cooling functions. For example, for the heating function, the hot plate is directly in contact with the cell or the oscillation circuit, or the hot plate or the plate including the heating wire is in direct contact with the cell or the oscillating circuit to raise the temperature or stop heating. To stop the temperature rise, and for the cooling function, the cooling plate directly contacts the cell or oscillation circuit, or the plate including the cooling tube through which the cooling plate or cooling solvent flows is directly contacted with the cell or oscillation circuit. As a result, the temperature drop can be stopped by stopping the temperature or stopping the cooling.

Here, the temperature control unit may include a temperature control unit capable of temperature control in the temperature control unit itself, or may be provided separately from the temperature control unit capable of temperature control outside the temperature control unit.

As an example, the temperature controller may adjust the temperature by directly contacting at least one of a cell or an oscillation circuit including a crystal or a plate including a heater or a Peltier device.

Here, the Peltier element is a Peltier effect, and the Peltier effect is a phenomenon in which two types of metal ends are connected to each other and current flows therein, whereby one terminal absorbs heat and the other terminal generates heat. to be. By using semiconductors such as bismuth and tellurium, which have different electric conduction methods, instead of two kinds of metals, a Peltier device capable of efficient endothermic or exothermic action can be obtained, which can switch endothermic and heat generation depending on the current direction. Since the endotherm or the calorific value is adjusted, it is possible to produce a precise temperature control unit in the vicinity of room temperature.

In order to minimize the resonance frequency change according to the temperature change in the present invention, preferably, the temperature control part may be directly contacted and coupled to the oscillation circuit, and more preferably, the lower part of the cell and the lower part of the oscillation circuit, respectively. The thermostat can be coupled in direct contact.

The oscillator circuit selects and oscillates only a desired frequency, thereby generating a constant resonance frequency. This part corresponds to the part of the electronic circuit provided away from the crystal, but the present invention can minimize the change in the resonance frequency by minimizing the temperature change of the oscillation circuit part.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not interpreted to be limited by these examples.

Example

As the electrochemical quartz oscillation device in the present invention, the oscillator (Resonant Frequency: 9 ㎒, Sensitivity: 4.2 ng / ㎐㎠ used to produce an EQCM device having a resolution up to 0.1 ng through this) . In addition, the frequency counter used is an AT slot type, and has a range of 1 / T: 1 ㎐ ~ 27 ㎒ and T: 1m㎐ ~ 27 ㎒.

The impedance measuring unit (EIS) used in the present invention includes a constant voltage polarizer (potentiostat) and the EIS is recognized by the constant voltage polarizer. This caused the sine wave of the EIS and the potential potential of the polarizer (PotentioStat) to contact the electrochemical cell electrolyte by the quartz electrode working electrode by the counter electrode and the reference electrode.

In addition, the basic composition of the electrochemical cell, working electrode, silver / silver chloride reference electrode, and platinum counter electrode, is used, and 10% KNO3 (Pottassium) is used as an experimental solution. nitrate) was mixed with distilled water) to perform a redox experiment.

 On the other hand, as a board for interfacing an electrochemical cell and an external PC, the PotentioStat + QCM condition considers the stability of noise and voltage supply and is produced through iterative simulation, and the EIS condition reduces the bandwidth and frequency noise to improve impedance measurement rate. RC time constant analysis is needed to improve the performance, and simulation is performed to study the optimal routing for the characteristics of impedance.

The measured voltage and current values in the electrochemical cell can be converted to digital data via a DAQ board and sent to a PC with analysis software to calculate the AC impedance.

To measure potentiostat, EQCM, and EIS functions, an OP_AMP controller design through DAQ is required. That is, various signals should be generated by controlling the current, voltage, etc., and the algorithm is coded to control OP_AMP inside the DSP to control the signal for each analysis method.

In the case of the EIS, the input signal sinewave is controlled to apply the digital lock-in amplifier structure.In the case of the impedance sinewave signal, the data is differentiated according to the frequency to 50 to 1000. And the number of data to make sinewave is coded to be changeable through software.

The GUI interface in the PC was coded using Labwindows software. As shown in FIG. 5, the X and Y axes display real and image values of the Nyquist Plot to easily determine the circuit form, and the Z axis is charged and discharged with potential change. It shows the change of impedance according to, the color of sphere shows frequency change, and the size of sphere shows EQCM data at mass change according to charging and discharging. In the real-time analysis using the change of sphere size and color as variables, the change of the data in potentiostat and / or EIS according to the change of the surface of the working electrode can be observed intuitively in real time in PC. In addition, the visual visualization of the measurement data was made more intuitive.

Although the above has been described with reference to the embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. It will be appreciated.

Claims (9)

An electrochemical reaction occurs, the electrochemical cell including a working electrode, a reference electrode, and a counter electrode including a crystal crystal;
An impedance measuring unit (EIS) electrically connected to the electrochemical cell and capable of measuring impedance in a solution in which an electrochemical reaction occurs;
An electrochemical quartz oscillation device (EQCM) electrically connected to the electrochemical cell and configured to read a change in frequency according to a change in mass of a working electrode of the electrochemical cell; And
An integrated electrochemical measuring apparatus comprising: a control unit for processing data input and output to the impedance measuring unit and the electrochemical quartz oscillation balance device,
The control unit may include a memory unit configured to simultaneously store data input / output to an impedance measuring unit (EIS) and data input / output to an electrochemical quartz oscillation scale device; And an operation unit configured to process data stored in the memory, such that data of an impedance measuring unit (EIS) and data of an electrochemical quartz oscillation device simultaneously stored in the memory unit can be simultaneously processed by the operation unit. Chemical measuring device.
An electrochemical reaction occurs, the electrochemical cell including a working electrode, a reference electrode, and a counter electrode including a crystal crystal;
A constant voltage polarization device electrically connected to the electrochemical cell and applying a constant voltage to a solution in which an electrochemical reaction occurs and reading a current according thereto;
An electrochemical quartz oscillation device (EQCM) electrically connected to the electrochemical cell and configured to read a change in frequency according to a change in mass of a working electrode of the electrochemical cell; And
An integrated electrochemical measuring apparatus comprising: a controller for processing data input and output to the constant voltage polarization device (potentiostat) and the electrochemical quartz oscillation balance device,
The control unit may include a memory unit capable of simultaneously storing data input / output to a constant voltage polarization device (potentiostat) and data input / output to an electrochemical crystal oscillation balance device; And an operation unit configured to process data stored in the memory, such that the data of the constant voltage polarization device (potentiostat) and the data of the electrochemical quartz oscillation balance device simultaneously stored in the memory unit can be simultaneously processed by the operation unit. Chemical measuring device. An integrated electrochemical measuring device, characterized in that.
The method of claim 1,
The impedance measuring unit (EIS) in the integrated electrochemical measuring device is electrically connected to the electrochemical cell, and includes a constant voltage polarization device (potentiostat) for applying a constant voltage to a solution in which an electrochemical reaction occurs and reading the current accordingly. ,
The controller may include a memory unit configured to simultaneously store data input / output to an impedance measuring unit (EIS), data input / output to a constant voltage polarization device (potentiostat), and data input / output to an electrochemical quartz oscillation scale device; And an operation unit configured to process data stored in the memory, such that data of an impedance measuring unit (EIS) simultaneously stored in the memory unit, data input / output to a constant voltage polarization device (potentiostat), and data of an electrochemical quartz crystal balance device are included. Integrated electrochemical measuring device, characterized in that the processing unit at the same time processing.
The method according to any one of claims 1 to 3,
The electrochemical quartz oscillation device (EQCM) has a cell containing a crystal crystal in the working electrode of the electrochemical cell, and also a frequency change occurring on the oscillation circuit and crystal crystal electrode which selects and oscillates only a desired frequency. Integrated electrochemical measurement device comprising a frequency counter for measuring the frequency (frequency counter).
The method of claim 4, wherein
The integrated electrochemical measuring apparatus of claim 1, wherein the memory unit in the control unit of the integrated electrochemical measuring apparatus includes an sRAM.
The method of claim 4, wherein
An operation unit within the control unit of the integrated electrochemical measuring apparatus may process data stored in a memory unit and transfer the data to an external PC, and the external PC may process data provided from the operation unit in one application program to operate within the working electrode. An integrated electrochemical measuring apparatus, characterized in that it is possible to analyze in real time a correlation between a mass change and a potential potential value from a constant voltage polarizer or an impedance value from an impedance measuring unit (EIS).
The method of claim 4, wherein
The integrated electrochemical measuring device further comprises a temperature control unit which is coupled in direct contact with at least one of the electrochemical cell or the oscillation circuit.
The method of claim 7, wherein
The temperature control unit integrated electrochemical measuring apparatus, characterized in that the temperature is controlled by the plate including the heater or Peltier element directly contact at least one of the electrochemical cell or the oscillation circuit.
Using the integrated electrochemical measuring device of any one of claims 1 to 3, the data input and output to the electrochemical quartz oscillation balance device, the data input and output to the impedance measuring unit (EIS) or a constant voltage polarization device (potentiostat) By simultaneously storing at least one of the input and output data to the memory unit in the control unit, and processing it simultaneously, the mass change in the working electrode of the electrochemical cell; and the potential potential value or impedance measurement unit (EIS) from the constant voltage polarization device (potentiostat) At least one of the impedance value from;) can be analyzed in real time in one application, the method of simultaneously analyzing the mass change of the working electrode in the electrochemical cell and the impedance or current change in the cell.

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