Metrohm Autolab Potentiostats

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FRA2 module for impedance measurements

Electrochemical impedance spectroscopy (EIS) is a powerful technique for the characterization of electrochemical systems and has widespread application in the field of material and cell design. Routinely used in the characterization of coatings, batteries, fuel cells and corrosion phenomena, EIS has also been used extensively as a tool for investigating mechanisms in electrodeposition, electrodissolution, passivity and corrosion studies, diffusion of ions across membranes and study of semiconductor interfaces and biosensors.

You can perform EIS measurements with the FRA2 module installed into any basic PGSTAT systems. This allows you to perform both potentiostatic and galvanostatic impedance measurements over a wide frequency range from 10 µHz to 1 MHz.

In addition to the classical EIS, the FRA software also allows you to modulate other outside signals, such as the rotation speed of a rotating disk electrode or the frequency of a light source to perform electro-hydrodynamic or photo-modulated impedance spectroscopy. The FRA2 module also contains a powerful fit and simulation analysis software to help with the interpretation of impedance data.

Key features of the FRA2 module include:

• Frequency range: 10 µHz–1 MHz
• Frequency resolution: 0.003%
• Input range: ± 5 V
• Signal types: 1 sine, 5 sine, 15 sine
• Input channels: E and I from the potentiostat/galvanostat or X and Y external signals
• AC amplitude: 0.2 mV to 0.35 V rms in potentiostatic mode; 0.0002–0.35 times current range in galvanostatic mode
• Data presentation: Nyquist, Bode, admittance, dielectric, Mott- Schottky

Options for analyzing impedance data include:

• Find circle, to analyze semicircles in the Nyquist plot
• Equivalent circuit fitting, based on the circuit description code by Dr. B.A. Boukamp
  • With this powerful software, you can build complex equivalent circuits very easily and fit them to experimental data. The following equivalent circuit elements are available:
    • Resistance
    • Capacitance
    • Constant phase element
    • Inductance
    • Warburg
    • Gerischer impedance
    • Hyperbolic tangent
    • Hyperbolic co-tangent
• Subtraction of elements
• Kramers-Kronig test to determine the validity of the measured data