Further to Marie Berthuel 's answer,

My preference is to use CV first to determine the behaviour of the system: potential window, symmetry/asymmetry, Faradaic and non-Faradaic contributions, effect of scan rate, etc.

Then, I would use GCD cycling to determine the performance of the device over time: with different current densities, retention of capacity, etc.

You can calculate the capacitance using either method. Generally GCD is a more robust method, but it is always best to characterise using a variety of techniques.

I attach some literature relating to best practices and pros/cons of different techniques.

Jules

Hello Neil Madrigal

CV is varying the potential against time and measuring the current;

whereas GCD is applying a positive or negative current against time and measuring the voltage.

Best regards,

Marie B.

Further to Marie Berthuel 's answer,

My preference is to use CV first to determine the behaviour of the system: potential window, symmetry/asymmetry, Faradaic and non-Faradaic contributions, effect of scan rate, etc.

Then, I would use GCD cycling to determine the performance of the device over time: with different current densities, retention of capacity, etc.

You can calculate the capacitance using either method. Generally GCD is a more robust method, but it is always best to characterise using a variety of techniques.

I attach some literature relating to best practices and pros/cons of different techniques.

Jules

Thanks for references Jules Lloyd Hammond

Why is GCD used in cyclic stability and not CV?

In my opinion most applications for supercapacitors will have a controlled current charge-discharge profiles. In this way, GCD cycling naturally lends itself towards replicating these profiles.

However, you can indeed use CV to determine cyclic stability, but take care in considering what you are actually reporting; 500 cycles at 1 V.s-1 with a potential window of -1 to 1 V is just 33 min of operation.

I would also recommend charging the device and allowing it to rest, determining the charge retention.

Jules

A comparison of both techniques and how to extract kinetic information from them has recently been published by our group. see link below

Article Comparison between cyclic voltammetry and differential charg...

Hi Neil,

In the CV technique, you can see the variation of current by applying a fixed potential window. This is done in order to know the stable potential window. For any kind, of EDLC materials CV will come as a rectangle type, and for faradaic type materials, it will come as redox type. Also, some times while performing a CV, oxygen may evolve from the counter electrode in order to avoid that we have to choose a stable potential window by performing the CV tests.

The GCD is the technique where you fixed a potential (same as that of CV) and current to measure the time (charging time and discharging time). Both CV and GCD are useful for the calculation of specific capacitance values. Energy density, power density values also you can calculate from the GCD data.

Is it possible to calculate energy and power density with the help of cyclic voltammetry? If is it so then what would be the formula for both?

Thanks in anticipation..