An electrode is a metal or conductor that touches nonmetals like salt water or a battery, helping electricity flow by moving electrons.
An electrode is a metal or conductor that touches something that is not metal, like salt water, a gas, or the inside of a battery. It helps move electrons; a spoon in lemonade is an example.
At the anode, electrons leave the material and travel into the wire (oxidation). At the cathode, electrons arrive from the wire and join with other atoms (reduction). Electrons go away from the anode toward the cathode.
A primary battery is made to be used once and then thrown away because its reactions can’t be easily reversed. A secondary battery can be recharged many times by pushing electrons back the other way.
Lithium-ion cathodes have layered materials that hold lithium between the layers. Cobalt can add more power but costs more, and manganese is cheaper but may wear down faster. Scientists also add carbon to help electricity move inside the cathode.
Lithium-ion anodes are where lithium moves in and out when charging. Many are made of graphite, which lasts a long time. Some types like silicon or metallic lithium can hold more charge, but they can swell or form tiny spikes, so researchers try special shapes to stay safe.
Electrodes are used in hospitals to read brain and heart signals, and in safety tools to restart a heart. They also help coat metal in electroplating, drive reactions in liquids, protect ships from rust, make electricity in fuel cells, and let scientists do tiny measurements with nanoelectrodes.