The need for electrolytes between cathode and anode in battery

[Sleepycoaster]

My question is simple: Why do batteries need electrolytes? Wouldn't the battery need the charge to flow only through the circuit in the device being powered? The point of the anode and cathode's separation is to preserve the potential difference, so why allow charge to flow through an electrolyte?

 

[Matterwave]

A battery is different than a capacitor. A capacitor is what you're thinking of, it will simply discharge the charge it has accumulated. A battery, on the other hand, maintains a voltage through a chemical process. It produces an electro-motive force through the reaction of the anode and cathode with the electrolyte. When a batter drains, it's voltage stays roughly constant (because the chemical reactions are driving the voltage), while when a capacitor drains its voltage drops as it loses charge.

 

[Borek]

Typical alkaline AA battery has a capacity around 2Ah. Calculate how much charge it could push through the outside circuit in its lifetime. Assuming circuit is not closed, this charge has to build up somewhere. Let's assume charge builds up at the ends of the battery - they are separated by 50 mm. Try to calculate force that would attract both ends. This is a trivial application of Coulomb's law.

Now, compare that force with force required to lift Eiffel tower. Or better yet, to the gravitational attraction between Earth and the Moon.

 

[DrDu]

The point of the anode and cathode's separation is to preserve the potential difference, so why allow charge to flow through an electrolyte?

That's the meaning of "circuit", the current also flows inside the battery. A battery is not different in this respect from other sources of current, like, e.g., a dynamo. As Borek already pointed out, the reason is to avoid built up of (more than very small amount of) charge on the electrodes which would immediately stop the current.

 

[sardar]

Electrolytes play a crucial role in the function of batteries. They are responsible for allowing the flow of ions between the cathode and anode, which is essential for the battery to produce electricity.

Firstly, the anode and cathode are made of different materials, such as metals or metal oxides, and they have different chemical properties. When the battery is charged, chemical reactions occur at the anode and cathode, causing the release of electrons. These electrons flow through the external circuit, powering the device.

However, for the chemical reactions to continue, a balance of positively charged ions (cations) and negatively charged ions (anions) must be maintained within the battery. This is where the electrolyte comes in. It contains these ions and allows them to move between the anode and cathode, completing the circuit and enabling the battery to continue producing electricity.

Additionally, the electrolyte also helps to regulate the flow of ions, preventing the buildup of excess charge and ensuring the battery can operate safely and efficiently. Without electrolytes, the battery would quickly lose its ability to produce electricity, and its lifespan would be significantly reduced.

In summary, electrolytes are essential for the function of batteries as they facilitate the movement of ions, maintain the balance of charge, and regulate the flow of electricity.