In general if we want to increase the specific capacitance or charge storage capacity in electrochemical energy storage devices we should have the pore size of the electrode material is slightly higher then the solvated ion size of the electrolyte for easily charging and discharging. If we have the pore size less then the solvated ions of the electrolytes. Can we enhance the parameter if yes How?
Would you please explain what is EESD to tell you the proper answer
Khaled Faisal Qasim Sir this represents the Electrochemical Energy Storage Devices most probably supercapacitors.
OK, I get it now. Changing morphology and surface properties (pore size, pore volume, surface area, etc.....) lead to change the specific capacitance. However, the nature of used material as an energy storage tells you what you suppose to do in this issue. For example, if you prepare metal oxide or mixed metal oxide (either pure or doped), the mesoporous material is better than microporous material (in specific capacitance parameter), due to the relative than electrons (or ions) adsorbed on the pores, or the surface in general (that depends if you have ionic, or electronic diffusion). Hope that makes suffice.
Regards
@Khaled Faisal Qasim yes sir you right, but my question is related to the pore size that is the less in size as compared to the electrolyte ion size (solvated ion size). How we can adsorbed these ions in to the pores or are their any other fundamental concepts if any? we have this type of problem so how we can increase the specific capacitance?
Supercapacitance depends on electronic conductivity and surface area in your host material. You can increase the surface area of your material by nanosizing it. You can also try to disperse your material in a conductive (noncapacitive) matrix. Agglomeration of particles will limit the exposed surface area facing your electrolyte. Mortar and Pestle and ultrasonication can help with this. If the material is nonporous then you are limited to surface reactions. You can try an experiment to screen various electrolytes from supercapacitor literature to compare the specific capacitance values.
The electric double layer formation of supercapacitors is governed by ion electrosorption at the electrode surface. The double layer is formed, when a charged electrode is placed in an electrolyte, which causes the electrolyte ions to migrate towards the charged surface in order to balance the applied potential.
It is a matter of debate whether pores provide the same contribution to the capacitance regardless of the size, or if subnanometer pores lead to an anomalous increase of capacitance[1].
1. Insights into the influence of the pore size and surface area...capacitor model https://pubs.rsc.org/en/content/articlelanding/2019/cp/c8cp06443a#!divAbstract
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