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Application
Notes
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Many
variables affect the outcome of your electrochemical experiments.
We have prepared a series of Application and Technical Notes to assist you in getting
the most accurate results and the best performance possible from your
Gamry instrument.
These Application Notes have been created to share our knowledge of
electrochemical instruments, principles, and methods. It is not our
intention to promote our products in this section of our Website. We do,
however, reference our own products for the convenience of our users, to whom we
are forever grateful.
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Accuracy Contour Plots
If you want to know how a potentiostat works, then read our Potentiostat
Primer. But how do you know your potentiostat is working in YOUR
experiment with YOUR sample? Understanding
the implications of the Accuracy Contour Plot allows you to make an
informed judgment of the validity of your electrochemical experiment.
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Create Customized EIS Circuit Elements
For the first time in any commercial EIS Fitting Software, a component
can be added by the user. You just need to be able to calculate
the impedance as a function of its own parameters and frequency.
Check it out.
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Trouble-Shooting
Your Gamry Potentiostat with the Universal Dummy Cell 4
When
doing serious electrochemistry, you want to be sure your potentiostat is
functioning properly. Fortunately, that's
easy to do, especially with the Universal Dummy Cell 4 that is
included with every Gamry Potentiostat.
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EIS
Measurement of a Very Low Impedance Lithium Ion Battery
Low impedance samples, such as batteries and fuel cells, give rise to
that evil actor...inductance. Simple things, like the orientation
of your cell cables, begin to matter.
Read
more...
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Verification
of Low Impedance EIS Using a 1 mOhm Resistor
Making an EIS measurement on a low impedance sample is treacherous
territory.
Find out why...
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Potentiostat
Primer
The
Potentiostat is the fundamental electronic instrument in
electrochemistry. Gamry Potentiostats are built for high performance
and flexibility -- the software tailors the Potentiostat for the
application. Here's
how a Potentiostat works.
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Faraday Cage
You've heard of a Faraday Cage, but here's the detail you always wanted
but couldn't find. Neither could we! If your electrochemical
experiments deal with low currents (< 1 µA),
you need a Faraday Cage!
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Getting Started with Electrochemical Corrosion
Measurement
An
electrochemical corrosion measurement system is a virtual necessity in the
modern corrosion laboratory. Electrochemical techniques are fast,
sensitive, and accurate. And (ta-da!) they're even easy to use
because they primarily consist of standardized procedures. The hard
part is getting started, so take a look at this Application
Note on DC Corrosion Techniques. It's a brief-but-thorough
introduction to the subject with several very good references for further
reading.
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Basics of Electrochemical Impedance Spectroscopy
Not familiar with the basic concepts of
Electrochemical Impedance Spectroscopy? The Basics
of EIS Application Note will answer all your questions in an easy-to-understand format and even
provides a list of references for additional information. We revisited
this Application Note in early 2008 and brought it up-to-date.
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Determination of Double-Layer
Capacitance from a Constant Phase Element
The Constant Phase Element is used by many
researchers to fit an equivalent circuit to their EIS data. The CPE
is described by some as an "imperfect capacitor" and there are
many cases where a CPE fits much better than a capacitor, suggesting that
an electrochemical interface may be, in fact, imperfect.
Nevertheless, the interpretation of the CPE is not well understood by many
in the research community. Several researchers have suggested approaches to the
employment of the CPE in the real world. Dr. Vladimir Jovic of the
University of Belgrade has surveyed this literature and summarizes
it here. Our thanks to Dr. Jovic for sharing his
insight.
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Reference Electrodes
Experiencing problems with your
reference electrode? Be sure to see this Application Note on
Reference Electrodes and how
they can influence the operation of your potentiostat and experimental results.
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Equivalent Circuit Modeling in EIS
The
first step in the analysis of your EIS data is to choose an equivalent
circuit that represents your chemistry system. Then you use the
software of your choice to fit that model to your EIS data. But to
get the best fit to your data, you need to help the algorithm by providing
fairly accurate initial guesses for the values of the various elements in
your equivalent circuit. The Application
Note on Equivalent Circuit Modeling walks you through the process of
fitting your data for both a coated sample and a battery. Written in
a conversational tone and even showing what happens when you pick bad
values for your elements, this Note is the best example we've seen on a
very important but rarely discussed topic.
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EIS on
Coated Specimens
Not sure how your potentiostat may
affect the results of your EIS experiment when applied to coated specimens? Be sure
to see the EIS on Coatings
Application Note to answer these questions and more.
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Multiplexed EIS on
Coated Specimens
An Electrochemical Multiplexer, such as the Gamry Instruments’ ECM8, can lower the labor
requirements and instrumentation costs of an EIS test program. The ECM8 allows 8 samples
to be connected to a single EIS instrument. An EIS spectrum can be measured on each sample
in a sequential manner.
The Applicaton
Note on Multiplexed EIS on Coated Specimens will help you understand the limitations associated with performing these experiments
through an ECM8 Electrochemical Multiplexer. In addition, we will cover some basic
EIS techniques and show you how to set up your EIS300
Software and ECM8 Electrochemical
Multiplexer to perform your own testing. We have included A/B plots
depicting the differences between running these experiments using a solo potentiostat and
a Potentiostat/Multiplexer combination. This Application Note will help you
determine if using a Multiplexer is right for your application.
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Measurement of Small
Electrochemical Signals
As the current in your
electrochemical experiment becomes smaller and smaller, you may approach
the limit of your potentiostat. Our Application
Note on Small Electrochemical Signals describes the various
factors that come into play as you push the sensitivity of your
instrument.
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Understanding iR
Compensation
What is iR Compensation? When should I
worry about using it? What are the common techniques for measuring it? Be sure
to see Understanding iR Compensation
for answers to these questions.
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Checking the Impedance of Your Reference Electrode
The Reference Electrode is, by far, the most common source of problems
in the typical electrochemical cell. And the most common problem
with your Reference Electrode is that the impedance is too high.
To evaluate cell problems,
you need to
measure the impedance of your Reference Electrode.
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Rapid Electrochemical Assessment of Paint (REAP)
Improve testing accuracy for coatings while decreasing
your test time with the REAP Test.
The REAP Application Note details procedures for measuring Time To
Failure (TTF) of coated metals. REAP involves data acquisition
over a 24 hour period on several samples. The data is then
analyzed to extract three parameters that can be used to estimate the
relative time to failure of coatings.
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