Final answer:
In electrotherapy treatment, the negatively charged electrode is known as the cathode, which is different from the cathode in electrochemical cells, where it is the positive electrode due to reduction reactions.
Step-by-step explanation:
The electrode that is negatively charged during electrotherapy treatment is known as the cathode. This is in contrast to electrochemical cells, like those found in batteries, where the cathode is the positive electrode due to the reduction reaction that occurs there. It's important to note the difference because in the context of electrotherapy, the polarity is defined by the direction of the current flow from the device.
In electrochemical cells such as batteries, lithium-ion batteries being one example, the negative electrode is known as the anode. Here, oxidation occurs and electrons flow away from the anode towards the cathode, where reduction occurs. The charge flow in these cells involves the movement of ions between the anode and the cathode through an electrolyte, while the external circuit allows the flow of electrons.
An electrolyte is a substance that contains free ions and can conduct electricity. Understanding the distinction between these terms is crucial as they can vary depending on the system described - either operating under electrical device standards or standard electrochemical cell terminology.