Hello,
I'm working on supercapacitors based on silicon nanowires, i have prolem win IR drop and I do not arrive to fix this problem. photo attached
i use this steps :
1- electrode MoS2/SiNWs
2- i use 3 electrod system
3 - placing reference electrode tip withing close to the working electrode
4- decreasing the surface area of working electrode.
5- using deferent electrolyte.
Help me please.
Good (no press). For Silicon[1] . Also, maybe you can try to add (to your mat: SiNWs + TiO2 + MoS2) some C(
The image looks to be a common chronopotentiogram, not a charging/discharging cycle that I expected to see. Why you have negative values on the voltage axis?
Why you think iR drop is the problem? Maybe the process is faradaic. Attach here a CV for 0...0.5 V range.
as Cornel Radu : attach here a CV.
Also, which is the MoS2 morphology (electrode MoS2) ?
1. Check the working electrode preparation step.
2. At high -ve potential (-1 V), the proton would be reduced by MoS2 as it is known to be a good proton reductant. Hence, according to the above suggestion from Prof. Samaras and Radu, you should get a proper CV at that potential range. Moreover, the capacity of the material could be extracted from the CV also.
+1 more for CV
There is a feature there that looks a bit like an IR effect, but it can't be because it isn't proportional to current...it seems to be roughly the same magnitude on the 4 traces where it can be clearly identified, and probably similar on the 5th. That implies it is actually a capacitive effect, with the slower response being pseudocapacitive. No matter what, CV would be very helpful to try and figure out what is going on.
dear dr Cornel, dr Samars and ALL
CV curves attached,
i use SiNWs + TiO2 + MoS2 as work electrode.
Best regards.
my electrode morpholgy : 3D hierarchical molybdenum disulfide (MoS2) nano-sheets
It doesn't look like an Ru effect, though there may be some other resistive effects in there...maybe due to the nature of your electrode. Also, depending on your potentiostat, make sure you are either using an analog ramp or a surface mode data acquisition to capture accurate capacitance information.
The drop in potential can also be due to the leakage current along with IR drop. To resolve this, I will suggest you to stop at peak potential and measure the OCV for few minutes and if there is a huge drop in potential, you have parasitic reaction going in the cell at the potential, could be from electrolyte decomposition or other reaction
If you press the slurry (too much, at an electrode forming step), then the initial (nominal) beneficial 3D-MoS2 morphology might result to a (disadvantageous) effective 2D-MoS2 (composite electrode morphology).
Do you press the slurry ?
Dear Dr.Samaras,
I never press the slurry.
I try this methode also : sctratching Silicon where i take contact, then i make somme
In-Ga and the problem persists.
Good (no press). For Silicon[1] . Also, maybe you can try to add (to your mat: SiNWs + TiO2 + MoS2) some C(
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