Introducing the Ossila Potentiostat
Posted on Tue, Jan 14, 2020 by Chris Bracher
Potentiostats are used extensively in electrochemistry to control and measure three electrode systems. Unfortunately, up until now this ubiquity has not resulted in potentiostats becoming cheaper or more accessible.
The new Ossila Potentiostat has been designed to help electrochemists perform cyclic voltammetry for less. The complete system is set to launch for just £1600 and includes cyclic voltammetry software, an electrochemical cell, and everything you need to start taking measurements.
The Three Electrode System
In electrochemistry, electrolyte solutions are typically studied using electrodes as interfaces.
These electrodes are named according to their use. The electrode where measurements are taken is known as the working electrode, the electrode which completes the circuit and allows current to flow is known as the counter electrode, and the electrode which provides a reference potential is appropriately called the reference electrode.
In a two electrode system, one electrode acts as both the reference and counter electrode. In this arrangement, it is difficult (or impossible) to control the potential while the measurement is being taken. While this is useful for certain applications, like measuring the efficiency of a battery, its applications in electrochemistry are limited.
Acknowledging electrode poential to be “the dominating factor governing many electrolytic processes” and identifying the difficulties with two electrode systems, the first three electrode system with a seperate reference and counter electrode was designed by Hickling in 1942 .
In his paper, Hickling described the advantages of an experimental setup where “the potential of a working electrode can be fixed at any desired arbitrary value”. This, Hickling said, “would seem [...] to have many valuable applications in the exploration of electrolytic processes”.
In order to achieve this, Hickling designed the first three electrode potentiostat.
What Does a Potentiostat Do?
Potentiostats are now the cornerstone of the electrochemistry field.
Like Source Measure Units (SMUs), potentiostats are control and measurement devices. The potential between the working and reference probes is controlled, and the current between the working and counter probes is measured.
In cyclic voltammetry, one of the most commonly performed electrochemical methods, the potential is increased linearly until a determined maximum is reached. It is then withdrawn and is cycled in this way as the current is being measured to form a characteristic ‘duck shaped’ plot.
From this plot, a number of electrochemical properties can be determined.
Introducing The Ossila Potentiostat
One of the major drawbacks of potentiostats is their price. This is particularly problematic for teaching labs where multiple units are required, but is a significant barrier to entry for any researcher looking to take electrochemical measurements. In addition to the considerable cost associated with the purchase of the unit itself, many potentiostats on the market either require computational knowledge or that dedicated software is purchased separately.
The Ossila Potentiostat has been developed as a powerful but low price device for performing cyclic voltammetry. The required software is included at no additional cost.
Working, counter, and reference electrodes and glassware are also provided (though the potentiostat can be purchased without these if they are not required) so that it is possible to very quickly set up a three electrode system and start taking electrochemical measurements.
- Studies in electrode polarisation. Part IV.-The automatic control of the potential of a working electrode, Hickling, A. (1942); doi:10.1039/TF9423800027.
Author: Chris Bracher
Chris joined Ossila in 2016 after completing a PhD in polymer and perovskite solar cells at the University of Sheffield. During his PhD, he gained expertise in photovoltaic device fabrication and characterisation, thin-film solution processing, and the construction of automated testing systems. Formerly part of the OFET and 2D materials teams at Ossila, he now focuses on the development of new test and measurement systems, with an emphasis on software.