Electrodes are fundamental to batteries. In other words, we could not have electrochemical cells that store energy, without them. Michael Faraday derived the term from ‘ēlektron’ related to amber, and ‘hodós’ meaning path. We distinguish between anode and cathode electrodes, depending on the direction of the current passing through them.
Electrodes Are Unavoidable With Batteries
To simplify matters, this discussion focuses on common, single use batteries, with negative anodes and positive cathodes. When we charge a rechargeable battery, these roles basically reverse.
- Let’s start by imagining that electrodes work like chemical sponges. Each one is a different material. The anode electrode releases electrons to the cathode electrode, which accepts them.
- When we connect a battery to an external circuit or a device, a chemical reaction occurs at the negative anode. This releases electrons with negative polarity, that travel through the circuit or device.
- Meanwhile, the positive cathode electrode is ready to receive the negative electrons. Another chemical reaction takes place there, so it is able to complete the loop through the battery contacts.
- None of this would have been possible without the anode and the cathode electrodes. That’s why we say, electrodes are fundamental to batteries, but that’s not all.
- These processes disturb the negative / positive balance in the battery. Positive ions travel in the opposite direction through the electrolyte, restoring the electrochemical balance.
Electrodes In Most Rechargeable Batteries
Electrodes in rechargeable batteries are able to accept replacement electrons, and use these to power circuits and devices. Recharging is largely the reverse of charging, and it is logical that these are almost mirror images:
- When we discharge a battery, we release electrons from the negative anode to an external device.
- When we need to top up the supply, we add a new stock of electrons to the anode from a battery charger.
- Positive ions travel in the opposite direction inside most batteries, again to restore the electrochemical balance.
Once again, electrodes are fundamental to batteries when we recharge them too. It’s quite remarkable how simple batteries are, but yet so amazing too.
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