Batteries and electrons

[e44-72]

Hello

I have a question I can't find the answer to wondered if somone could help.

When a wire is connected between cathode and anode on battery, electrons flow from the cathode to the anode by chemical reactions taking place where atoms give up/receive electrons.
Therefor do batteries have a maximum/certain number of electrons they can emit from the cathode to anode until all ectrons are where they want to be.
Or do they have an infinit number of electrons that can be emitted until all energy is released?

Thank you for reading and any help offered.

 

[Sceadwian]

Of course there's a maximum number, when the chemicals change states electrons are released, once all the chemicals have gone to their lower energy state that's it they're done nothing else to cause more electrons to flow. Rechargeable cells can have energy pumped back into them which will reverse (mostly) the chemical process and store the energy back in the cell. Virtually all batteries can be recharged to some extent, the main difference between primary (not rechargeable) and secondary (rechargeable) cells is the type of chemistry used, for primary cells once all the chemical energy has been released the state of the passivated chemistry can't be reversed, or at least can't be reversed fully. Secondary cells are designed so that the chemistry is easily reversed back to it's charged state.

 

[e44-72]

Thank you for the answer, so does that mean batteries with higher voltage have a higher number of electrons that can be released in total?

 

[kubeek]

Batteries with larger Ah rating have more electrons. Voltage doesn´t affect the amount of electrons, just the energy they can deliver.

 

[KeepItSimpleStupid]

While we are on the subject of batteries and electrons... Conventional current flows from positive to negative. Electrons go the other way. Ben Franklin goofed. 99% of the time it doesn't matter.

 

[Sceadwian]

With free electrons yes KISS, this however is ion flow as well though meaning discrete physical chunks of matter changing form causing the electrons to become available, chemistry is a whole different world outside of electronics, and it's best left that way =)

E44, cells with higher voltages use different atoms for the cathode/anode materials that have higher potentials. The same number of electrons are involved however because they're going from higher to lower energy states more energy is involved.

Electrons should not really be looked at as what 'powers' an electronics device, because in fact the electrons are nothing more than what allows the energy to be carried. Something else, be it a photon striking a solar cell or a chemical cell oxidizing to release free electrons, electrons are just what allows energy to move around, nothing is actually consumed.

Just as the most readily apparent example consider radio energy, it's a self oscillating electric/magnetic field that travels through free space, no electrons are involved in their propagation in a vacuum but they transfer energy quiet well.

 

[e44-72]

Thank you for the replies and help, might have some more questions to ask at a later stage, I appriatiate your help

 

[Externet]

...Conventional current flows from positive to negative. Electrons go the other way.

Electrons go from negative to positive outside the battery.
Electrons go from positive to negative inside the battery.

 

[DerStrom8]

Electrons go from negative to positive outside the battery.
Electrons go from positive to negative inside the battery.

Yes, you're both right. The electrolyte strips electrons from the oxidizer (I think that's what it's called--the part that "gives" its electrons away in the chemical reaction) and they are pulled to the anode. They are then repelled by the anode through the circuit, and attracted back to the cathode.

 

[jpanhalt]

Yes, you're both right. The electrolyte strips electrons from the oxidizer (I think that's what it's called--the part that "gives" its electrons away in the chemical reaction) and they are pulled to the anode. They are then repelled by the anode through the circuit, and attracted back to the cathode.

It's the other way around. Loss of electrons is oxidation. Addition of electrons is reduction. To help remember that, think of a metal, such as sodium, or anything that you find easy to remember is oxidized.

[LATEX]Na^{0} --> Na^{+1} + e^{-}[/LATEX]

So, as sodium "gives" its electrons, it is oxidized, but it is considered the reducer in the reaction because it is providing electrons to reduce something else.

If you still remember learning valence bond theory in high school, "reduced" means the valence is reduced, i.e., made more negative by addition of electrons.

John

 

[DerStrom8]

It's the other way around. Loss of electrons is oxidation. Addition of electrons is reduction. To help remember that, think of a metal, such as sodium, or anything that you find easy to remember is oxidized.

[LATEX]Na^{0} --> Na^{+1} + e^{-}[/LATEX]

So, as sodium "gives" its electrons, it is oxidized, but it is considered the reducer in the reaction because it is providing electrons to reduce something else.

If you still remember learning valence bond theory in high school, "reduced" means the valence is reduced, i.e., made more negative by addition of electrons.

John

Thank you very much for that. You are right. I'm always getting the "oxidizer" and "reducer" mixed up and can never keep them straight.

 

[Sceadwian]

Thank you very much for that. You are right. I'm always getting the "oxidizer" and "reducer" mixed up and can never keep them straight.

You aren't the only one. Mixing chemistry/physics with electronics leads to this kind of confusion readily.

 

[DerStrom8]

Mixing chemistry/physics with electronics leads to this kind of confusion readily.

You can say that again!

 

[IntelGent]

Maybe this (with visual images) will help with explaining?
https://www.electronicsteacher.com/direct-current/batteries-and-power-systems/eElectron-activity-in-chemical-reactions.php

And I found this site a blessing of battery knowledge during my schooling days.
https://batteryuniversity.com/