Cathode
Cathode is the electrode where reduction occurs. In a lithium-ion battery delivering power, it is the positive electrode: lithium ions and electrons arrive from the negative side and are accepted by the cathode active material.
In a rechargeable battery
Charging reverses the cell reactions. Strictly, the electrode acting as the cathode therefore changes with the direction of the reaction. Battery engineering commonly keeps cathode as the name for the positive-electrode material and assembly defined during discharge, avoiding a name change whenever the current reverses. Positive electrode is the less ambiguous term.
Many familiar EV battery labels, including LFP, NMC, and NCA, describe the positive-electrode active material rather than the complete cell. The term cathode may refer narrowly to that active material or more broadly to the practical positive-electrode assembly.
Why it matters
Cathode chemistry and construction influence cell voltage, stored charge, energy density, thermal stability, material cost, and ageing. These outcomes depend on the complete cell design and operating conditions, not the cathode alone.
For electrode materials, interfaces, and complete-cell trade-offs, see Cell Chemistry & Components.