Features of our Electrochemical Test Cells FlexCell
Manufactured from Plastic
Test cell FlexCell is made of propylene (PP) or polytetrafluorethylene (PTFE). Both plastics are characterized by high chemical resistance. You can even measure in fluoride and highly alkaline media with the PTFE test cell.
These electrochemical cells (test cells) are break-resistant and quasi indestructible. Due to the CNC-technology, a precise manufacturing of all relevant drillings and deepenings for seals is possible.
Three-electrode Set-up
The three-electrode set-up is used during measurements in electrochemical cells with current flow.
The working electrode is formed by the material which is to be studied. The current is measured via the counter electrode. The working and counter electrode should be adjusted parallel to each other.
By means of the reference electrode, the potential of the working electrode is measured. The reference electrode has to be located close to the working electrode. This is achieved using the so-called Haber-Luggin capillary.
Homogenous Electrical Field
The potentials to be measured are only identical on the so-called equipotential surfaces. If the field lines are not parallel, the equipotential surfaces are not parallel either. In addition, a second measuring error arises due to the voltage drop between the working and the reference electrode (IR-drop) which is caused by the electrolyte resistance and the distance between the working and counter electrode. So, the measurements are not comparable if the reference electrode is positioned differently from measurement to measurement. The IR-drop is a permanently changing value during the measurement, especially when you work with electrolytes of bad conductivity.
To minimize the error and to run the potential measurement as replicable as possible, a homogeneous streamline field is needed as well as an immovable Haber-Luggin capillary. Only a tubular set-up with a working electrode as big as the counter electrode ensures a parallel field line course.
Gas Bubbles at the Working and Counter Electrode
Where current flows through a liquid, gas bubbles form, either intentionally at the working electrode or as a result of side reactions at the counter electrode.
Gas bubbles at the counter electrode can easily rise up to the top. At the working electrode, there is the risk that many small gas bubbles will accumulate into bigger bubbles and stick to the electrode. There can be no electrolyte where the gas bubbles stick to the electrode. Gas bubbles can block the reaction surface and local elements can form.
Gas Supply of Gas Diffusion Electrodes
The measuring cell FlexCell can be used to measure gas diffusion electrodes. These electrodes have to be supplied with the appropriate operating gas.
To study gas diffusion electrodes, the test cell FlexCell has a gas compartment that supplies the working electrode with gas without itself being flooded with the electrolyte.
Same Surface of the Electrodes
In the electrochemical test cell FlexCell, the parallel set-up of the working and counter electrode, their same size, and the tubular orientation of the electrolyte chamber ensure a homogeneous electrical field between the working and counter electrode. Therefore, pay attention that the active surface of the working electrode is as big as the counter electrode. If the working electrode is smaller than the counter electrode, there is a compaction of the field lines at the working electrode, which in turn causes a serious measuring error.
Parallel Orientation of Working and Counter Electrode
It is important that the electrodes are parallel to each other and mounted vertically. A sloping counter electrode (as shown in the example) also leads to an inhomogeneous field and thus to measuring errors.
Connection to the Potentiostat
It should be ensured that the electrodes are connected to the potentiostat via the correct inputs. These are usually labeled as WE for working electrode, CE for counter electrode, and RE for reference electrode. Before connecting, please check if the test cables are corroded or damaged. Use the hydrogen electrode HydroFlex as the reference electrode to avoid contaminations. Furthermore, it is a reference electrode of low resistance.
Would you like to learn more about the test cell FlexCell?
FlexCell - Electrochemical Test Cells
FlexCell is the optimized voltammetry test cell for electrochemistry with a three-electrode set-up. Here you can find some general information and take a look at the cross section of FlexCell.
What are Electrochemical Cells?
Electrochemical cells are systems that convert energy of chemical reactions into electrical energy. Conversely, electrical energy can also be used for electrochemical reactions.
How to Work with the Test Cell FlexCell
Here you will find information on commissioning, maintenance and troubleshooting of the electrochemical test cell FlexCell.
Would you like to learn more about the principles of electrochemical cells?
The Importance of Field Lines
The potentials which are to be measured are only identical on the so-called equipotential surfaces.
Homogeneous electric field lines are required for correct measurements. Here you can learn more about parallel field lines, equipotential surfaces and IR-drop.
The Importance of Haber-Luggin Capillaries
The electrolytical contact between the working and the reference electrode is made by the Haber-Luggin capillary. Haber-Luggin capillaries are reducing the IR-Drop between reference electrode and working electrode.
Electrolyte Key – Salt Bridge
An electrolyte bridge, also known as a salt bridge, is used for the contacting of various electrolytes. Commercial reference electrodes rely on salt bridges.
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Electrochemical test cell FlexCell-PTFE
FlexCell is the optimized electrochemical cell for electrochemistry with a three-electrode setup. Our Flexcell-PTFE is particularly suitable for measurements at high temperatures.
Electrochemical test cell FlexCell-PP
FlexCell is the optimized electrochemical cell for electrochemistry with a three-electrode setup.