Electrochemical test cell FlexCell-PTFE

Without applying an electrical current through the cell – that is, measuring open circuit potentials – tests can be done in any kind of cell.
However, when applying an electrical current to your cell, this will create an ohmic drop in the electrolyte. In order to handle this ohmic drop you, have to ensure the following:

• The counter electrode is the same size as the working electrode, and the activity of the counter electrode should always be high enough to support the reaction at the working electrode.
• The field line distribution within the cell must be parallel – otherwise, the current density of the working electrode is not homogeneous.
• You need a Haber-Luggin capillary to measure the exact potential without IR Drop correction.

FlexCell is optimized for these requests.

FlexCell can be used for all reactions without huge amounts of gas evolution at the working electrode. This includes corrosion tests on metal plates or gas-consuming reactions such as hydrogen oxidation, oxygen reduction, carbon dioxide reduction, etc. When producing gases, these reaction products can stick to the working electrode or in the electrolyte compartment and block further reactions.

The reference electrode Mini-HydroFlex is designed for our test cells FlexCell and ElyFlow. It also offers additional advantages such as adjustable length and a relatively small diameter.
However, please keep in mind that you will need an additional test lead.

Of course, you can also use our HydroFlex. You will then need an additional connector available for FlexCell-PP or FlexCell-PTFE as well as an additional test lead.

Yes. Because of the exact position of the reference electrode and the usage of a Haber-Luggin capillary, you always measure the correct potential. The large distance  between the working electrode and counter electrode ensures that the entire working electrode has the same potential, regardless of the position on the surface.

Due to the limited electrolyte volume of approximately 40 ml, the test duration is limited to 24h or several days, depending on the current density and the temperature (water evaporation losses).

Yes, you can purge the cell with Argon, for example. Make sure that the purge rate is low to avoid removing too much water vapour.

No. Due to the large distance of approxiametly 60 mm between the counter and working electrodes, a high voltage loss occurs due to the limited conductivity of the electrolyte.

Our FlexCell is a three-electrode setup – sometimes also called a half-cell setup. A counter electrode, a working electrode and a reference electrode are controlled by typical electrochemical potentiostats, for example from Biologic, Metrohm, etc. Unfortunately, these potentiostats usually cannot control the temperature of an electrochemical cell. - Gaskatel's control box can.

The temperature control box is made to operate the built-in heaters of FlexCell.

No. You can carry out measurements with FlexCell without a temperature control box.
Of course, you must not make use of the built-in heaters. You can only carry out your measurements at room temperature.

Yes. Electrochemical reactions are temperature-dependent. But not only the open-circuit potential is influenced by temperature. Electrolyte conductivity and ion mobility are also temperature-dependent. Last but not least, the pH value is temperature sensitive.

Yes, in principle, the electrochemical cell could be placed in a temperature-controlled chamber. However, our unique temperature controller is specifically tailored to the characteristics of the FlexCell. The good isolation of the PTFE ensures slow temperature cycling. A PID controller regulates the temperature with an accuracy of 0.1°C and a stability of 0.2°C.

A Pt100 temperature sensor is mounted to FlexCell and dipped in the electrolyte. The sensor is connected to the control box, where the temperature controller uses its signal to control the power supply of the heating elements of FlexCell.

The PID controller stores the optimal values for a fast heating and a stable temperature level. However, these PID values vary from temperature to temperature. If you always conduct experiments at the same temperature, you must first start the FlexCell's autotune mode. The temperature control box is storing the parameters once the flashlight stops blinking. If you want to measure at different temperatures, you can use the autotune mode or enter the PID values ​​manually (more conveniently with our software).

The temperature control box has an analog 0-10 V output referring to 0 to 200°C on the back. Most potentiostats have an auxiliary input for such norm signals. You can also read the temperature signal via the digital USB port using our software.

No. Our FEP isolated Pt100 sensor is stable in any electrolyte. No corrosion products can influence your measurement.