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I What material can act as electron sponge?

  1. Jul 3, 2016 #1
    We know earth grounding is huge electron sink. But the Earth is not portable, what material can absorb lots of electron inside or on surface? Maybe the supercapacitors already use it as its cathode?
    and what material dislike electron and push electron away?
    thanks
     
  2. jcsd
  3. Jul 3, 2016 #2

    davenn

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    do you understand how capacitors work ?
     
  4. Jul 3, 2016 #3
    not sure. abstractly like electron sponge to absorb electron as many as possible?
     
  5. Jul 3, 2016 #4
    In dry day, some stuff with high voltage electrostatic, and often shock me. Is the shocking voltage positive or negative to ground? or it accumulate surplus electrons or lost too many electrons and become positive charged?
     
  6. Jul 3, 2016 #5
    negative oxygen ion regularly only 2 electrons surplus, can some atom or molecule negative ion very high e.g.10000 electrons surplus?
    I guess silicon or silicon oxide can be that, because the earth is a huge electron sponge, many equipment have grounding wires.
     
  7. Jul 3, 2016 #6

    Dale

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    I have no idea what you mean by "electron sponge" in terms of voltages and currents. However, the Earth's capacitance is less than 1 farad, and it is pretty easy to buy 1 farad capacitors.
     
  8. Jul 3, 2016 #7
    the more the 'sponge' absorb electron, the more the voltage differential.
    Earth only 1F? unbelievable! Our earth total negative charge far more than positive charge, this attributes to the great electron reservoir of earth!
     
  9. Jul 3, 2016 #8

    Dale

    Staff: Mentor

    See the section on self capacitance.
    https://en.m.wikipedia.org/wiki/Capacitance

    It has a charge around 500 kC and a voltage around 300 kV between the surface and the atmosphere. So about 1 F, rounded off.
     
  10. Jul 4, 2016 #9

    davenn

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    there is no such thing as a an electron sponge

    no, a capacitor doesn't work like that ...... for every electron that goes onto one plate of the capacitor, one must come off the other plate
    The net charge on a capacitor therefore remains at zero. That is, for every negative charge on one plate, there is an equal number of
    of positive charges on the other plate

    it depends on the material used to generate the charge separation
     
  11. Jul 4, 2016 #10
    That means that one plate of capacitor "sponges" or draws electrons from the opposite plate, it complies with my concept.
    If both plates made of copper, do you mean all atoms in one plate can have Cu-29 negative ions, and another plate Cu+29 positive ions?
    Cu atom has 29 electrons.
     
  12. Jul 4, 2016 #11
    Can metal material such as copper collect electrons to form negative electrostatic?
     
  13. Jul 4, 2016 #12
    No, it doesn't. The electrons go to negative plate because the field of the battery or power supply forces them there. It has nothing to do with some special "sponge" quality of the plate.

    Copper has one free electron per atom. The ionic cores have a +1 charge in both plates. One of them just have more free electrons than the other one.
    You may be interested to read a little about conductivity in metals, free electrons and Drude's model. It will help to get a more realistic picture of the behavior of conductors.
     
  14. Jul 4, 2016 #13
    If an flying electron impinge material, it seems the energetic electron will reflect, even cause X-ray if too much kinetic energy.
    My imagined application is low energy (<1eV or < 593km/s) electron beam impinging material. I wish the electrons not scattering too far away after impingement.
    I need find a material that can attain electrons in a very close zone as much as possible, just like cotton cloud.
     
  15. Jul 6, 2016 #14

    ZapperZ

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    I find your whole thread to be very confusing, especially based on what you want to do (it is still very vague), and based on what I think you know (or don't know).

    If all you want is a material that can continually absorbs incoming electrons, then why not connect a metal plate to ground and be done with it? What is the issue here that prevents you from doing that? If the electrons have very low energy and very close to the plate, then the image charge alone is sufficient to pull the electrons into the grounded, metal plate!

    Zz.
     
  16. Jul 6, 2016 #15
    grounding good, but not portable. is it possible to collect 1kg pure "electron gas", and soak inside or on surface of special very small size "sponge"?
    I know Dr. Kenth Shoulders can produce 1 mol electrons cluster in 1 micron size.
     
  17. Jul 6, 2016 #16

    ZapperZ

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    You bring that metal plate to another location, ground it, and voila! It's portable!

    Do you see why your requirements here are still rather vague? You appear to suddenly realize what you want, or you don't know what you want, or you're just revealing bits and pieces at a time on purpose, or you're just making things up as you go along. You certainly didn't state anything about it being "portable", or how portable it has to be, in your very first post.

    Zz.
     
  18. Jul 6, 2016 #17
    Maybe if you estimate the repulsion energy of these 1 kg of electrons confined in a "very small" volume you will figure out the answer yourself. :smile:
    See here some discussion about the effect of unbalanced charges. He is talking about 1% extra electrons.
    http://www.feynmanlectures.caltech.edu/II_01.html
    You are asking about 1 kg of electrons which is about 1030 electrons extra on a piece of matter which naturally may contain 1025-1026 units of charge (both positive and negative).
     
  19. Jul 6, 2016 #18
    1 mol electrons = 1/1836 gram mass, how Ken Shoulders boast that electron cluster? that means the distance between electrons is circa 12fm (femtometers).
     
  20. Jul 6, 2016 #19
    I did mention portable in my initial post.
    You know, if apple jelly falls to stove ash, then it will sponge lots of ash after pick up. My intuitive thought is just like that, a material to attract as much as possible electron "ash".
     
  21. Jul 6, 2016 #20
    Now, I know basic idea: lookup the table of atom and molecule electron affinity. The bigger, the better.
    Carnauba wax have very high electron affinity, so it is a good choice.
    Some other electrets may also work.
     
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