Firstly, thank you for openning my question.
These days, I'm measuring capacitive behavior of Fe3O4 and Fe3O4-modified electrolytes.
As people say, metal oxides are senstive to bulk expansion during its redox reaction.
Without any modification like dispersing them on graphene, I guess its stability will be very bad due to its agglomeration.
As a result of my experiment about stabiity, the result is consistent with bad stability.
Here is my question.
In my data, Fe3O4 particles lost its stability within 500 CV cycles at 100 mV/s.
However, they maintained the stability even after 1000 galvano cycles at 10 A/g (of course, the capacitance has decreased, but less decreased than in CV)
I wonder why this phenomenon happened by the both principles.
Please, I'd appreciate it, if you'd help me. Thank you for reading it.
Hi Jason Ju,
If u could provide the CV profile and CD curves it will be more helpful to answer ur question precisely. Nevertheless, in my opinion the condition u scan ur electrode in CV and galvano (100 mV/s and 10 A/g) is not the same. Based on the current density the stability of the material may vary. The stability of an electrode also depends on the potential limits u set for measurements. If u ve changed the potential window, there will be an obvious difference.
Good day Ju,
Can you provide the potential limits used in the experiments?Mostly likely the current densities are not the same as you think like Naveen said.
Even if they re the same...from the information above, you are definitely not in thermodynamic condition as the scan rate of the CV and the C-rate of the Galvanostatic cycling(GC) seems high.
A material may have the same charge or exhibit similar performance in GC and CV in thermodynamic conditions (very slow scan rate and low C-rate) but as the scan rate and C-rate increases..Kinetics becomes relevant and in kinetic region, GC and CV becomes different for example, the Over-potentials (Ohmic, mass, and charge) are fairly constant in GC as applied current is constant but this is not the case in the CV, this may affect the performance of the sample.
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