CN216013223U - Lithium ion concentration detection system - Google Patents
Lithium ion concentration detection system Download PDFInfo
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- CN216013223U CN216013223U CN202122571295.6U CN202122571295U CN216013223U CN 216013223 U CN216013223 U CN 216013223U CN 202122571295 U CN202122571295 U CN 202122571295U CN 216013223 U CN216013223 U CN 216013223U
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Abstract
The utility model discloses a lithium ion concentration detection system, include: the control module is used for sending a control instruction to the scanning signal generation module; the scanning signal generating module is used for generating a signal required by the constant potential generating module according to the control instruction; the constant potential generation module is connected with the polyanionic compound electrode module and is used for providing scanning voltage for the polyanionic compound electrode module; a working electrode, an auxiliary electrode and a reference electrode; the utility model discloses can gather working electrode's characteristic current in real time through control module, and then confirm the lithium ion concentration in the solution that awaits measuring. And online and offline detection of lithium ions is realized. The method can be used for simply, cheaply and quickly testing the concentration of the lithium ions. When the method is used for industrial production, the concentration of the lithium ions can be transmitted to a process system, and then the process can be adjusted in real time according to the concentration of the lithium ions, so that the method has the characteristics of real-time online, accuracy and high efficiency.
Description
Technical Field
The utility model relates to an ion concentration detection technical field especially relates to a lithium ion concentration detection system.
Background
In field surveying and industrial production processes, rapid detection of lithium ion concentration in aqueous solutions is important. At present, the commonly used detection methods of lithium ion concentration are atomic absorption spectrometry and inductively coupled plasma emission spectrometry, however, the two detection methods are difficult to move once the devices are installed, nitrogen or argon is required in the detection process, and the detection cost is high.
The lithium ion selective electrode is made of a material selective for lithium ions, and is classified into a voltage lithium ion selective electrode and a current lithium ion selective electrode. When the voltage lithium ion selective electrode works, the voltage lithium ion selective electrode and a reference electrode are immersed into a lithium-containing solution together to form a primary battery, and the potential of the primary battery and the logarithm of the lithium concentration of the solution form a linear relation, so that the lithium concentration of the solution can be detected. Materials such as crystal films, ion association complexes, neutral carriers and the like are used for manufacturing voltage lithium ion selective electrodes in sequence, however, the materials are expensive in manufacturing cost, difficult to use for a long time, or poor in anti-interference capability of impurity elements in the same family, and are difficult to meet the requirements. When the current lithium ion selective electrode works, the current lithium ion selective electrode is subjected to volt-ampere test, the obtained current and the concentration of solution lithium are in a linear relation, and therefore the concentration of the solution lithium can be detected, but the used material is an organic material and is poor in conductivity, and meanwhile, the material is complex in structure and large in synthesis difficulty, such as 6, 6-dibenzyl-14-crown-4.
Meanwhile, in the lithium production link, the lithium ion concentration of the solution in production needs to be obtained rapidly and in real time, so that the adjustment or feedback of the industrial production process is facilitated in time. The general method is to sample the solution, to obtain the lithium ion concentration by off-line inspection of the sample, and to adjust the production process according to the detected lithium ion concentration, which results in a complex detection process, and the inability to acquire signals in real time and make timely process adjustment.
SUMMERY OF THE UTILITY MODEL
In view of the above, it is necessary to provide a lithium ion concentration detection system in order to solve the above problems.
A lithium ion concentration detection system comprising:
the control module is connected with the scanning signal generation module and the constant potential generation module and used for sending a control instruction to the scanning signal generation module, collecting characteristic current flowing through the working electrode and carrying out data processing;
the scanning signal generating module is connected with the constant potential generating module and used for generating a signal required by the constant potential generating module according to the control instruction;
the constant potential generation module is connected with the polyanionic compound electrode module and is used for providing scanning voltage for the polyanionic compound electrode module;
the polyanion compound electrode module is connected with the control module and is used for reacting with lithium ions in the solution to be detected; the polyanionic compound electrode module includes: a working electrode, an auxiliary electrode and a reference electrode.
In one embodiment, the control module acquires a characteristic current of the working electrode after the working electrode is placed in a solution to be tested, and the control module determines the lithium ion concentration of the solution to be tested according to the characteristic current and a standard curve (hereinafter referred to as a standard curve) of a relation between the characteristic current and the lithium ion concentration in the solution, which is obtained by testing a standard solution.
In one embodiment, the potentiostatic generation module comprises: a first operational amplifier, a second operational amplifier, and a third operational amplifier;
the non-inverting input end of the first operational amplifier is grounded, the inverting input end of the first operational amplifier is connected to the signal sent by the scanning signal generating module, and the output end of the first operational amplifier is connected with the auxiliary electrode;
the non-inverting input end of the second operational amplifier is connected with the reference electrode, the inverting input end of the second operational amplifier is connected with the output end of the second operational amplifier, and the inverting input end of the second operational amplifier is connected with the signal;
the non-inverting input end of the third operational amplifier is grounded, the inverting input end of the third operational amplifier is connected with the working electrode, and the output end of the third operational amplifier is connected with the inverting input end of the third operational amplifier.
In one embodiment, the potentiostatic generation module further comprises: the circuit comprises a first resistor, a second resistor, a third resistor and a fourth resistor;
the first resistor and the second resistor are connected between the scanning signal generation module and the inverting input end of the first operational amplifier;
the third resistor is connected between the inverting input end of the first operational amplifier and the output end of the second operational amplifier; the fourth resistor is connected between the output end of the third operational amplifier and the inverting input end of the third operational amplifier, converts a current signal flowing through the working electrode into a voltage signal and sends the voltage signal to the control module for processing.
In one embodiment, the number of the working electrodes is multiple, and the working electrodes are respectively connected with the control module through switches; and the control module sends a control signal to the switch so as to realize the reaction between the corresponding working electrode and the lithium ions in the solution to be detected.
In one embodiment, the working electrode is a de-lithiated current collector electrode;
the auxiliary electrode is a graphite plate;
the reference electrode is a saturated calomel electrode.
In one embodiment, the auxiliary electrode may also be a platinum electrode.
In one embodiment, the working electrode is a current collector electrode composed of a conductive substrate and a polyanionic compound material layer disposed thereon.
In one embodiment, the working electrode is FePO4A current collector electrode;
coated with LiFePO4The FePO is obtained by removing lithium from the current collector electrode by an electrochemical method4And a current collector electrode.
The utility model discloses a lithium ion concentration detection system can send the instruction to scanning signal generation module through control module to make scanning signal generation module send scanning signal to the potentiostatic potential generation module, the potentiostatic potential generation module provides voltage for working electrode, auxiliary electrode and reference electrode according to test method's difference like this. During testing, firstly, a standard sample is tested by using a lithium ion concentration detection system, and the polyanionic compound electrode module is added into the standard solution, so that the working electrode reacts with lithium ions in the standard solution to generate characteristic current and establish a standard curve. Adding the polyanionic compound electrode module into the solution to be detected by the method, collecting the current flowing through the working electrode to obtain the characteristic current, and determining the lithium ion concentration in the solution to be detected by using the obtained standard curve.
The selective detection of lithium ions is realized: online and offline inspection. Can be used for testing the concentration of the lithium ions simply, cheaply and quickly. When the lithium ion concentration adjusting device is used for industrial production, the lithium ion concentration can be transmitted to a process system, and then the process can be adjusted in real time according to the lithium ion concentration, and the lithium ion concentration adjusting device has the characteristics of real-time online, accuracy and high efficiency.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Wherein:
FIG. 1 is a system block diagram of a lithium ion concentration detection system in one embodiment;
FIG. 2 is a circuit diagram of a potentiostat generation module in one embodiment;
FIG. 3 is a graph of the relationship between the peak delithiation current and the lithium concentration in the solution.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
The utility model provides a lithium ion concentration detection system, refer to fig. 1, do the utility model discloses the system diagram of embodiment, include:
the control module 100 is connected with the scanning signal generating module 200 and is used for sending a control instruction to the scanning signal generating module 200;
the scanning signal generating module 200 is connected with the constant potential generating module 300 and is used for generating signals required by the constant potential generating module 300 according to the control instruction;
a constant potential generating module 300 connected to the polyanionic compound electrode module for providing a scan voltage to the polyanionic compound electrode module; when a signal scanning generator is connected, the potential of the working electrode (relative to a certain reference electrode) can be controlled to change along with time according to a certain program, and the potential is not influenced by impedance change of an electrode system and is used for measuring the response of current to the potential. Instead of controlling the electrode potential to be constant below a certain potential, the electrode potential is controlled to vary according to a certain predetermined law. According to the scanning method of controlling the potential of the working electrode, it is possible to select: linear potential sweeps, differential pulsed voltammetric sweeps, square wave sweeps, and the like.
A polyanionic compound electrode module (hereinafter referred to as electrode module) is connected with the control module 100 and is used for reacting with lithium ions in the solution to be detected;
the electrode module includes: working electrode 400, auxiliary electrode 500, and reference electrode 600; the control module 100 collects the characteristic current of the working electrode 400 after being placed in the solution to be detected, and the characteristic current is used for determining the lithium ion concentration of the solution to be detected.
Particularly, the utility model discloses lithium ion concentration detection system is according to test method's difference, generate module send instruction to scanning signal through control module, so that scanning signal generation module generates the module send signal to the constant potential, constant potential produces the module like this according to received signal alright for working electrode, auxiliary electrode and reference electrode provide control scanning voltage, under auxiliary electrode and reference electrode's combined action, make the lithium ion in the solution that awaits measuring deviate from or the embedding reaction from working electrode, the generation electric current, control module can gather working electrode's electric current in real time this moment, obtain characteristic current, with this the characteristic current substitutes the standard curve of the characteristic current that forms when testing standard solution in the control module and lithium ion concentration relation in the solution, confirm the lithium ion concentration in the solution that awaits measuring. And the concentration of lithium ions in the solution is detected.
During testing, a standard solution is tested by using a lithium ion concentration detection system, a polyanionic compound electrode module is added to the standard solution to enable a working electrode to react with lithium ions in the standard solution, and the system collects and obtains characteristic current to establish a standard curve. And then adding the polyanionic compound electrode module to the solution to be detected by using the method, collecting the current flowing through the working electrode to obtain the corresponding characteristic current, and further determining the lithium ion concentration in the solution to be detected by using the standard curve. The detection of lithium ions is realized.
The characteristic current is the peak current value of the voltammetry curve of the lithium ions inserted or extracted from the working electrode reacting with the lithium ions in the solution under the scanning voltage, or the current value of the current plateau region in the current time curve during the process of inserting the lithium ions in the working electrode. The magnitude of the characteristic current flowing through the working electrode varies with the magnitude of the lithium ion concentration in the solution, and generally, the higher the lithium ion concentration in the solution, the larger the corresponding characteristic current value.
In one embodiment, the control module 100 includes:
a control module, configured to send a control instruction to the scanning signal generation module 200; and
collecting and acquiring the characteristic current of the working electrode 400 after being placed in the solution to be detected, and sending the characteristic current to the control module, wherein the control module determines the lithium ion concentration of the solution to be detected according to the characteristic current.
In one embodiment, as shown in fig. 2, the potentiostatic potential generation module 300 comprises: a first operational amplifier a1, a second operational amplifier a2, a third operational amplifier A3, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4;
the non-inverting input end of the first operational amplifier a1 is grounded, the inverting input end of the first operational amplifier a1 is connected to the signal sent by the scanning signal generating module 200, and the output end of the first operational amplifier a1 is connected to the auxiliary electrode 500;
the non-inverting input end of the second operational amplifier A2 is connected with the reference electrode 600, the inverting input end of the second operational amplifier A2 is connected with the output end of the second operational amplifier A2, and the inverting input end of the second operational amplifier A2 is connected with the signal;
the non-inverting input of the third operational amplifier A3 is grounded, the inverting input of the third operational amplifier A3 is connected to the working electrode 400, and the output of the third operational amplifier A3 is connected to the inverting input of the third operational amplifier A3;
the first resistor R1 and the second resistor R2 are both connected between the scan signal generation module 200 and the inverting input terminal of the first operational amplifier A1;
the third resistor R3 is connected between the inverting input terminal of the first operational amplifier A1 and the output terminal of the second operational amplifier A2; the fourth resistor R4 is connected between the output terminal of the third operational amplifier A3 and the inverting input terminal of the third operational amplifier A3, and converts the current flowing through the working electrode into a voltage signal to be processed by the control module. The signals sent by the scanning signal generating module 200 can be amplified by the first operational amplifier a1, the second operational amplifier a2 and the third operational amplifier A3, so that the constant potential generating module can provide accurate scanning voltages for the working electrode, the auxiliary electrode and the reference electrode.
In one embodiment, the working electrodes 400 are multiple and are respectively connected to the control module 100 through switches; the control module 100 sends a control switching signal to the switch to realize the corresponding intercalation or deintercalation reaction between the working electrode 400 and the lithium ions in the solution to be detected.
Specifically, in this embodiment, in order to ensure stable operation of the system and avoid performance degradation of only one working electrode during operation for a long time, in this embodiment, the working electrodes 400 are multiple, each working electrode 400 is connected to one switch, each switch is connected to the potentiostatic potential generation module, each switch is controlled by the control module 100, the service time of each working electrode is fixed, after the current working electrode reaches the fixed service time, the control module 100 controls the next switch to be turned on, and then the potentiostatic potential generation module provides a scanning voltage for the working electrode corresponding to the switch, so that the working electrode continues to normally operate, thereby avoiding manual replacement of the working electrode and improving the working efficiency of the system.
In one embodiment, the working electrode 400 is a delithiated current collector electrode;
the auxiliary electrode 500 is a graphite plate or a platinum electrode; the reference electrode 600 is a saturated calomel electrode; the scanning signal generating module 200 generates a waveform of a scanning signal, and a constant potential generating module control signal is output to the electrode module.
In one embodiment, the working electrode 400 is FePO4A current collector electrode;
coated with LiFePO4The current collector electrode of (a) is subjected to chemical delithiation, preferably electrochemical delithiation, so that the coating is made of LiFePO4The current collector electrode is subjected to lithium removal to obtain the FePO4And a current collector electrode.
The conductive substrate of the current collector electrode is one of metals such as titanium, zirconium, hafnium, tantalum, niobium, gold, platinum, etc., or an alloy thereof, and graphite, carbon paper, carbon fiber cloth, etc. may also be used.
Verification test example:
mixing LiFePO4Uniformly mixing Ketjen black and PVDF according to the mass ratio of 7:2:1, adding NMP, uniformly stirring, coating on titanium, drying, and preparing the electrode. Controlling the potential at 0.5V (vs SCE) at 15 deg.C, removing 100% of lithium by electrifying, and then removing lithium at 1-100ppm, sodium ion at 1g/L, magnesium ion at 2g/L, and potassium ion at 1.5g/LThe intercalation-deintercalation voltammetry test is carried out in the chloride solution, the potential is controlled to be-0.15V (vs SCE), the lithium is intercalated for 40s, then the delithiation scanning test is carried out, linear scanning is adopted, the scanning is carried out from-0.15V (vs SCE) to 0.5V (vs SCE), the scanning speed is 2mv/s, and the linear relation between the obtained delithiation peak current and the solution lithium concentration is shown in figure 3.
Chloride solutions with different lithium concentrations, sodium ion concentration of 1g/L, magnesium ion concentration of 2g/L and potassium ion concentration of 1.5g/L are prepared and tested according to the method, the obtained current is compared with a linear relation line in a figure 3, the lithium ion concentration of the solution can be measured, and the detection result and the recovery rate are shown in a table 1.
TABLE 1 test and comparison table for lithium ion in solution
| Numbering | True concentration/ppm | Detection concentration/ppm | Percent recovery% |
| 1 | 1.500 | 1.533 | 102.20 |
| 2 | 6.200 | 6.131 | 98.89 |
| 3 | 35.00 | 34.86 | 99.60 |
| 4 | 88.00 | 88.35 | 100.40 |
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (9)
1. A lithium ion concentration detection system, comprising:
the control module is connected with the scanning signal generation module and the constant potential generation module and used for sending a control instruction to the scanning signal generation module, collecting characteristic current flowing through the working electrode and carrying out data processing;
the scanning signal generating module is connected with the constant potential generating module and used for generating a signal required by the constant potential generating module according to the control instruction;
the constant potential generation module is connected with the polyanionic compound electrode module and is used for providing scanning voltage for the polyanionic compound electrode module;
the polyanion compound electrode module is connected with the control module and is used for reacting with lithium ions in the solution to be detected; the polyanionic compound electrode module includes: a working electrode, an auxiliary electrode and a reference electrode.
2. The lithium ion concentration detection system of claim 1, wherein the control module collects a characteristic current of the working electrode after being placed in a solution to be detected, and the control module determines the lithium ion concentration of the solution to be detected according to the characteristic current and a standard curve obtained according to a standard solution.
3. The lithium ion concentration detection system according to claim 1, wherein the constant potential generation module comprises: a first operational amplifier, a second operational amplifier, and a third operational amplifier;
the non-inverting input end of the first operational amplifier is grounded, the inverting input end of the first operational amplifier is connected to the signal sent by the scanning signal generating module, and the output end of the first operational amplifier is connected with the auxiliary electrode;
the non-inverting input end of the second operational amplifier is connected with the reference electrode, the inverting input end of the second operational amplifier is connected with the output end of the second operational amplifier, and the inverting input end of the second operational amplifier is connected with the signal;
the non-inverting input end of the third operational amplifier is grounded, the inverting input end of the third operational amplifier is connected with the working electrode, and the output end of the third operational amplifier is connected with the inverting input end of the third operational amplifier.
4. The lithium ion concentration detection system according to claim 3, wherein the constant potential generation module further comprises: the circuit comprises a first resistor, a second resistor, a third resistor and a fourth resistor;
the first resistor and the second resistor are connected between the scanning signal generation module and the inverting input end of the first operational amplifier;
the third resistor is connected between the inverting input end of the first operational amplifier and the output end of the second operational amplifier; the fourth resistor is connected between the output end of the third operational amplifier and the inverting input end of the third operational amplifier.
5. The lithium ion concentration detection system according to claim 1, wherein the number of the working electrodes is plural, and the working electrodes are respectively connected with the control module through switches; and the control module sends a control signal to the switch so as to realize the reaction between the corresponding working electrode and the lithium ions in the solution to be detected.
6. The lithium ion concentration detection system according to claim 1,
the working electrode is a current collector electrode after lithium removal treatment;
the auxiliary electrode is a graphite plate;
the reference electrode is a saturated calomel electrode.
7. The lithium ion concentration detection system according to claim 6, wherein the auxiliary electrode is a platinum electrode.
8. The lithium ion concentration detection system according to claim 1,
the working electrode is a current collector electrode consisting of a conductive matrix and a polyanionic compound material layer arranged on the conductive matrix.
9. The lithium ion concentration detection system of claim 8, wherein the working electrode is FePO4A current collector electrode;
coated with LiFePO4The FePO is obtained by removing lithium from the current collector electrode by an electrochemical method4And a current collector electrode.
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