Electric field in batteries

In summary: The amount of energy stored as chemical potential energy is vastly greater than the amount of energy stored as separated charges in...a capacitor.
  • #1
tonyjk
227
3
Hello guys,

It is said, that the battery differs from a capacitor when it is not connected to a circuit, by not having a separation of charges. Its potential is due to a chemical process. My question is this chemical energy creates an electric field inside the battery? if no who creates it then?

Thank you
 
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  • #3
I mean a normal battery the one we study in chemistry. It is said that the electrochemical potential is responsible for the current in a circuit. But when the battery is not connected to a circuit, there is still a potential due to the chemical energy. But my question is there any electric field inside the battery? if yes who is responsible for it?
 
  • #4
tonyjk said:
I mean a normal battery the one we study in chemistry. It is said that the electrochemical potential is responsible for the current in a circuit. But when the battery is not connected to a circuit, there is still a potential due to the chemical energy. But my question is there any electric field inside the battery? if yes who is responsible for it?

Did you read the article I linked?
 
  • #6
tonyjk said:
Yes I read about the electrochemical cell. And it does not mention anything about electric field

So, what do you conclude?
 
  • #7
I think there is no electric field inside a battery just the electrochemical potential right?
 
  • #8
DEvens said:
So, what do you conclude?
A statement in the link says "When a battery is connected to an external circuit,Electrolytes are able to move as ions within, allowing the chemical reactions to be completed at the separate terminals and so deliver energy to the external circuit."
My question is that what happens in electrolyte when it is connected to the load? Why does the chemical reaction only take place when the load is connected?
 
  • #9
Hamza Abbasi said:
My question is that what happens in electrolyte when it is connected to the load? Why does the chemical reaction only take place when the load is connected?

From that link...

Redox reactions power the battery. Cations are reduced (electrons are added) at the cathode during charging, while anions are oxidized (electrons are removed) at the anode during charging.[12] During discharge, the process is reversed.

So during discharge electrons are needed at the anode. If the cell is open circuit (eg no load) there is no source of electrons so the chemical reaction stops.
If the circuit is made these electrons come from the cathode via the load.
 
  • #10
tonyjk said:
I think there is no electric field inside a battery just the electrochemical potential right?
 
  • #11
tonyjk said:
I think there is no electric field inside a battery just the electrochemical potential right?

If there is a potential difference between the electrodes, there is an electric field. You get the potential difference by intregrating the electric field along any path between the electrodes, inside or outside the battery. The only way to get rid of the field is to short out the battery.
The electric field is produced by the chemical reactions that produce electrons on one side of the battery and consume them on the other side, these reactions produce a surplus of electons on one side and a deficit on the other and that is what produces the electric field.
This electric field will eventually stop the chemical reactions. The movement of charges in the battery goes against the electric field. Connecting the electrodes and allowing a current to flow will lower the potential and the electric field and allow the reactions to proceed.
 
  • #12
willem2 said:
If there is a potential difference between the electrodes, there is an electric field. You get the potential difference by intregrating the electric field along any path between the electrodes, inside or outside the battery. The only way to get rid of the field is to short out the battery.
The electric field is produced by the chemical reactions that produce electrons on one side of the battery and consume them on the other side, these reactions produce a surplus of electons on one side and a deficit on the other and that is what produces the electric field.
This electric field will eventually stop the chemical reactions. The movement of charges in the battery goes against the electric field. Connecting the electrodes and allowing a current to flow will lower the potential and the electric field and allow the reactions to proceed.
Great, But why it is said that the battery when It is not connected to circuit, does not store charges like a capacitor?
 
  • #13
tonyjk said:
Great, But why it is said that the battery when It is not connected to circuit, does not store charges like a capacitor?

The amount of energy stored as chemical potential energy is vastly greater than the amount of energy stored as separated charges in a disconnected battery, so we say that a battery does not store charges like a capacitor does.
 
  • #14
tonyjk said:
Great, But why it is said that the battery when It is not connected to circuit, does not store charges like a capacitor?
The plates of a capacitor store a lot of charge with a very small separation with the energy being stored in the electric field and being highly dependent on the separation distance. The bulk dielectric polarises, but does not conduct and does not materially change during operation nor does it provide any net energy.

The electrode of a battery store a negligible amount of charge with a very large separation with energy being stored in the chemical potential and being largely independent of the separation distance. The bulk electrolyte does not polarize, but does conduct and does materially change during operation and does provide net energy.

There is, to my knowledge, no value in thinking of a battery like a capacitor.
 
  • #15
DaleSpam said:
The plates of a capacitor store a lot of charge with a very small separation with the energy being stored in the electric field and being highly dependent on the separation distance. The bulk dielectric polarises, but does not conduct and does not materially change during operation nor does it provide any net energy.

The electrode of a battery store a negligible amount of charge with a very large separation with energy being stored in the chemical potential and being largely independent of the separation distance. The bulk electrolyte does not polarize, but does conduct and does materially change during operation and does provide net energy.

There is, to my knowledge, no value in thinking of a battery like a capacitor.

This Chemical potential produces electric field inside the battery ?
 
  • #16
tonyjk said:
This Chemical potential produces electric field inside the battery ?
Yes. Usually it is called an EMF instead of an electric field.
 
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1. What is an electric field in a battery?

An electric field is a physical quantity that represents the force exerted on a charged particle at any given point in space. In a battery, the electric field is created by the separation of positive and negative charges across the battery terminals, which creates a potential difference or voltage.

2. How is the electric field created in a battery?

The electric field in a battery is created by the chemical reactions between the electrodes and the electrolyte. These reactions cause a buildup of charges, with positive charges at the anode and negative charges at the cathode, creating an electric field between them.

3. What role does the electric field play in the function of a battery?

The electric field is essential for the function of a battery as it creates the potential difference that drives the flow of electrons through the external circuit. Without an electric field, the battery would not be able to generate or maintain a current.

4. How does the electric field change as a battery discharges?

As a battery discharges, the electric field will decrease due to the reduction of the concentration gradient between the anode and cathode. This decrease in electric field is what causes the battery's voltage to decrease over time.

5. Can the electric field in a battery be measured?

Yes, the electric field in a battery can be measured using a voltmeter. The voltmeter measures the potential difference between the battery terminals, which is directly related to the strength of the electric field. A stronger electric field will result in a higher voltage reading on the voltmeter.

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