Hello everyone,
I tried to improve the capacitance of my solid state supercapacitor (Reduce Graphene paper obtained by vacuum filtration was used as electrode materials) by generating pores in graphene paper by using freeze drier, unfortunately the capacitance is still very low. also I tried to change the concentration of the electrolyte (electrolyte was prepared by 1 g of PVA , 1g of H3PO4 , and 10ml deionized water), however the capacitance is low. The attached picture represent the CV voltammogram of my solid state supercapacitor. I would like to know how can I increase the capacitance for this type .
Thanks in advance
Dear Zuhair,
Your CV shows a comparatively better current response. Generally, carbon materials exhibit electric double layer capacitance which is lower than pseudocapacitance.You can increase the capacitance by increasing the specific surface area, improving the contact between electrode material and current collector. Doping graphene sheets with Nitrogen can also increase the specific capacitance.
Dear Naveen
Thank you for your response.
But I think the capacitance is very low compared with literature.
In my case I didn’t use current collector with graphene electrode.
again thank you for your cooperation.
Dear Vahid Moradi
thank you for your help.
I just conected the electrodes (free stand graphene paper) with copper wire using Silver conductive epoxy as seen in the attached picture
Dear Zuhair Elseddig,
Sorry I didn't catch it quite right, You have deposited graphene on a paper (cellulose paper for example) and used Silver paste on the other side?
this is free standing graphene paper!!
I mean that this is tow Graphene paper seprated by the electrolyte.
i just used selver to connect the copper wire with graphene paper.
(we used PVA +H3PO4 as seprater and and electrolyte)
For further understanding, you should give us the mass of the graphene you used to make sure the how big the specific capacitance you obtained and the reference value you are expected. The expected cause of the smaller specific capacitance than that of the literature is due to the high electronic resistance of the PVA based on my experiences. You should try to synthesize the PVA with using the accurate amount ratio of the PVA and H3PO4. In our laboratory, we mix PVA:H3PO4=2:1. To make sure this, you may also perform the EIS analysis in order to figure out where the major resistance is. And then, we could discuss further at least.
Dear Zuhair,
Can you provide the Capacitance you got in both methods... I mean before and after generating pores.. And did you use rGO alone or along with some metal oxides???
I would like to know more about how did you create the pores... Can you show the SEM image, If possible???
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