We often compare the roles of electrons versus ions in batteries, in the context of discharging and recharging them. We drill down deeper into this topic in this particular article, in case you are curious to know more about how electrons and ions do their work…
A Structured Comparison of Electrons And Ions
Electrons and ions combine to complete circuits that allow batteries to do their work, although their roles are different:
- Electrons travel through EXTERNAL circuits which are usually our devices. This means they never pass through the battery electrolyte as they power their circuits.
- Ions remain INSIDE a battery in a solid, liquid, or gel electrolyte. They travel through a separator between cathode and anode electrodes, as they charge and discharge.
Electrons and ions both require trigger events to complete their journeys. Electrons move when a battery’s voltage pushes them through external circuits.
Whereas ions flow inside the battery because they naturally drift from regions with extra ions, to regions with fewer. Both electron and ion movements must occur at the same time though, for the battery to do its work.
Getting Closer to These Substances
We are getting closer to understanding electrons versus ions in batteries. Both have roles in pushing battery energy through connected devices. However, they do also both require a physical presence within which this potential power resides:
- Electrons are extremely tiny, microscopically small particles. We cannot break them down any further. They have nearly no mass, yet they are not tied to any other atoms.
- Ions are atoms or molecules that have gained or lost electrons. These can be either positive cations, or negative anions. Ions have a (relatively) large mass, thousands of times greater than electrons.
When we discharge a battery to power a device or a circuit, the electrons travel OUTSIDE the battery via the contacts, and give some of their energy away. This creates an imbalance between the battery electrodes.
Meanwhile, the ions travel in the opposite direction between the electrodes, but INSIDE the battery this time. This action restores the balance, although the battery is weaker, because it gave some of its energy away.
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