In the context of electric vehicle batteries, consider the following elements : I. Cobalt II. Graphite III. Lithium IV. Nickel How many of the above usually make up battery cathodes?

Lithium, Cobalt, and Nickel are the primary active materials used in the cathodes of most high-performance EV batteries, such as Lithium Nickel Manganese Cobalt Oxide (NMC) and Lithium Cobalt Oxide (LCO). Graphite is the most tempting distractor because it is a critical battery element, but it functions as the anode (negative electrode) rather than the cathode. The core concept being tested is the chemical composition and internal architecture of Lithium-ion battery cells.