Hi. I have a question regarding electrochemical exfoliation of graphene. In every paper, whether anodic or cathodic exfoliation, voltage is mentioned (either 10V, 12V or 15V). I haven't read about the current required (in mA or A). Is it so that current does not have a significant role in electrochemical exfoliation?
If current is necessary., then what is the magnitude required for carrying electrochemical exfoliation?
Voltage drives the ions in the electrolyte to an electrode with opposite charge where redox reactions can take place. All the electrolytes have a corresponding electrochemical window which is one of the most important characteristics to be identified for solvents and electrolytes used in electrochemical applications. Moreover, voltage controls the thermodynamic condition - oxidation potential and the reaction that occurs at the electrode. On the other hand, current depends on the many parameters including conductivity of the electrolyte itself that may vary with time. Most works on electrochemical exfoliation of graphene by applying 10 V or higher, this voltage is high enough to drive the ions into the graphite electrode. You can also exfoliate using a constant current but if the voltage is low for that amount of current, intercalation of ions into the graphite and subsequent exfoliation will not be efficient.
A major factor will be the size of the substrate. If you are working on a very small sample, the current will be very small. If you have a large graphite substrate, the current required will be large. You need to be over a particular voltage (the force the electrons have) to drive the exfoliation, but the number of electrons needed will depend on the parameters: size of sample, electrolyte, etc.
Dear Rushiraj Kadge
Exfoliation is a favourable bulk method for produce graphene like materials from graphite in this method an applied voltage drives ionic species to intercalate into graphite where they form gaseous species that expand and exfoliate individual graphene sheets
https://www.nature.com/articles/s41598-018-32741-3
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