The word potentiostat comes from potential. In electronics and electrochemistry a potential is stored energy or the “potential to do work”.

Applying a potential with a potentiostat, for instance a PalmSens4, to a conducting surface in a conducting solution can induce a particular electrode current which is measured by the potentiostat while keeping the applied potential constant.

The advantage of a potentiostat is that it has complete control over the applied potential, unlike a normal power source.

An electrochemist typically spends many months together with a potentiostat to get research done. The potentiostat’s performance should not limit the results and the software should be user friendly and easy to use. Here are six factors to consider before buying a potentiostat. Read more

A potentiostat applies potential to a certain surface, an electrode. The amount of electrons on the surface is thereby reduced or increased. This causes the liquid to be triggered to deliver or consume electrodes to compensate for this. The exchange of electrons per time, the electrode’s current, can be measured by the potentiostat. This is usually done in a three-electrode setup (Figure 2).

An electrode made to deliver current of a certain substance is present is called a sensor. This sensor has a certain sensitivity to the substance that you want to measure. For this reason, there are many different sensors that react in different ways to certain chemical substances.

Sometimes a sensor can be used multiple times, but often they are disposable, so for a one-time use, and the sensor is permanently changed by the reactions happening at the electrodes.

Electrochemistry is a broad field with many different applications. This is reflected in the electrochemical instruments as well. Potentiostats, Galvanostats, and Impedance Analyzers are rather versatile but often have a focus on certain properties added with an application in mind.

Many researcher instruments are actually a combination of potentiostats, galavanostats, and impedance analyzers. Often people will call these combinations just potentiostats and not potentiostat/galvanostat.

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A potentiostat controls the potential and measures the resulting current. A galvanostat controls the current and measures the resulting potential. Most modern instruments are combinations of potentiostats and galvanostats.

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Devices that are as complex as a potentiostat have many different specifications and parameters listed in their documentation.

The first parameters to look at are the potential range and the current range. The currents and voltages, you want to apply and measure, must be within the capabilities of the instrument.

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A short introduction video to potentiostats is available in our knowledge base. A very simplified description is that a potentiostat keeps the potential between two electrodes, the working electrode and the reference electrode, at a set potential.

Current will flow between the working electrode and a third electrode, the counter electrode. This way the reference electrode has a constant electrochemical potential and can be used by the potentiostat as a fixed reference point.

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An impedance analyzer applies a sine wave-shaped potential profile to the cell and calculates from the sine wave current response the impedance and phase shift of the cell.

This makes potentiostats more versatile and their active control of a parameter more powerful than regular meters.

There are also specialized potentiostats on the market, that are labeled according to their application, e.g. battery cyclers. So, you might have used a potentiostat without knowing.

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Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV) are very popular electrochemical techniques and both of them have been covered in separate articles in our knowledge base:

• Electrochemical Impedance Spectroscopy
• Cyclic Voltammetry

1. We recommend first considering the technical specifications that are available in the documentation of an instruments, which are covered in this FAQ.
2. The next important point for most customers is the software. The software should support the technique you require.
3. Besides the specifications of the electrochemical measurements there are more technical features that could be interesting for your application.
4. Other factors concern the purchasing process. Important factors are transparent price information, support, how difficult it is to set up the device, and how long the guarantee is. 

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There are many different techniques and methods in electrochemistry. The differences between the techniques are the profile of the applied potential or current and when the signal is measured.

Techniques can be classified by what is controlled, for example, potentiostatic techniques, when the potential is controlled, and galvanostatic techniques, when the current is controlled.

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Batteries are systems that store electrical energy as chemical energy. A charged battery has two parts that have different potentials, which can be used to apply that potential to other devices. A current will flow, and the connected device is powered.

Electrochemical measurements can characterize batteries, for example how often they can be charged and discharged, how much charge is stored in the battery, or how the battery changes over time.

There are multiple methods for characterizing batteries, which one is applied usually depends on what parameter needs to be observed. The most common techniques are Electrochemical Impedance Spectroscopy (EIS) and Charge-Discharge curves.

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