Potentiostats | Galvanostats

A potentiostat is a device used to control the potential of an electrode within a cell containing multiple electrodes. Often paired with a galvanostat, these instruments play a crucial role in ensuring the proper functioning of battery circuits. Avalon Test Equipment offers potentiostats and galvanostats for rent from leading manufacturers like Gamry and PalmSens.

How Do Potentiostats Work?

Potentiostats conduct 2-wire or 4-wire tests to measure a cell’s currents based on the applied voltage potential. By applying Ohm’s Law, they calculate impedance values at various current levels. This data can then be used to plot an I-V (current-voltage) curve and determine the cell’s resistance.

In addition to basic measurements, potentiostats also enable electrochemical impedance spectroscopy (EIS), which analyzes how a material behaves in response to an applied frequency. The data from EIS testing is typically displayed in a Bode or Nyquist plot, revealing characteristics such as electrochemical corrosion. This method is especially useful for battery testing, as it provides a non-destructive way to assess key attributes like battery lifespan and state of charge (SoC).

Potentiostats vs. Galvanostats

While potentiostats are commonly paired with galvanostats, each device serves a different function. Potentiostats apply a controlled voltage potential and are often used to detect corrosion in high-impedance systems. Galvanostats, on the other hand, apply variable currents while measuring voltage potential. When combined, they allow for precise measurements in battery testing, especially for systems with low internal resistance. Galvanostats also support EIS testing, providing results similar to those of an impedance analyzer.