Conductivity of activated (porous) carbon

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Discussion Overview

The discussion revolves around the conductivity of activated carbon, its ability to store electrical charge, and the relationship between its surface area and electrical capacity. Participants explore theoretical and experimental aspects of these properties, focusing on the implications of molecular structure and valence electrons.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant inquires about the level of conductivity of activated carbon and whether its internal surface area is affected by its conductivity.
  • Another participant seeks to determine how many coulombs of electricity can be stored per square meter on activated carbon, relating this to the surface area of capacitors and batteries.
  • A participant suggests that the effective surface area, rather than the molecular structure, is crucial for calculating charge storage in capacitors.
  • Another participant proposes a method for calculating the number of coulombs stored by averaging the number of available valence electrons per unit surface area, while acknowledging the complexity introduced by varying molecular structures.
  • One participant notes that storing energy as static electricity has lower energy density compared to chemical reactions, which may limit the performance of supercapacitors compared to batteries.

Areas of Agreement / Disagreement

Participants express differing views on the relevance of molecular structure versus effective surface area in determining the conductivity and charge storage capacity of activated carbon. The discussion remains unresolved regarding the exact calculations and implications of these factors.

Contextual Notes

Participants mention challenges in calculating charge storage due to the complexity of molecular bonding and the potential for experimental error at high voltages. There is an acknowledgment of limitations in current understanding and data availability.

taylaron
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Hi, I am doing an experiment involving activated carbon and I need to know if activated carbon has a high level of conductivity. I've searched the internet but without results. in addition, if the Active carbon can be made to be or is conductive, does the immense internal surface area still remain?

Thanks everyone. I appreciate your input

-Tay
 
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Ok, perhaps a different question.

I'm trying to find out how many coulombs of electricity I can store per m^2 on activated carbon. This is your classical question of "how much surface area in a capacitor does it take to equal the capacity of a battery?"

I'm having difficulty because calculating the number of available valence electrons is difficult since all of the carbon atoms are bonded with each other, filling many of those valence electrons. I don't understand how one can mathematically calculate how many coulombs can be stored per square meter without knowing the exact molecular structure.
Has there been an experiment done to provide this data?

Regards,

-Tay
 
taylaron said:
I don't understand how one can mathematically calculate how many coulombs can be stored per square meter without knowing the exact molecular structure.

If I'm not mistaken, the molecular structure doesn't matter so much as the effective surface area of the material. In the case of a simple flat plate capacitor, the effective surface area is equivalent to the cross sectional area of material being used for the capacitor.

And to answer your first question, yes carbon, activated or not, is very electrically conductive.
 
To my understanding, static electricity is the accumulation of electrons in the valence orbitals of an atom. I suppose if you took the mathematical average of the number of available valence shells per nanometer, one could calculate the exact number of coulombs that can be stored on a given amount of surface area. I was stuck with the concept that the varying molecular structure results in non-uniform bonds from atom to atom. The irregularity of these bonds would need to be known to calculate the number of valence shells to calculate the possible static electricity. The answer to my own question is to take the average number of valence electrons per unit surface area. If I am correct. One could take the measurement experimentally, but such high voltages have a tendency to leek through insulators, contributing to experimental error.

In addition, I found that the answer to my question in that storing energy in the form of static electricity has significantly less energy density compared to possible chemical reactions. There are only so many valence electrons in an atom, but even more electrons can be transferred during a chemical reaction. This is the primary reason why super capacitors can (I want to say never) provide as much power in the long term than a battery.

-Tay
 
Thoughts anybody?
 

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