In the context of electric vehicle batteries, consider the following elements:

1. Cobalt
2. Graphite
3. Lithium
4. Nickel

How many of the above usually make up battery cathodes?

1. Only one
2. Only two
3. Only three
4. All the four

Explanation

Cobalt is correct

• Cobalt is commonly used in EV battery cathodes, especially in Lithium Cobalt Oxide (LCO) and Nickel Manganese Cobalt (NMC) chemistries.

Graphite is incorrect

• Graphite is used in anodes, not cathodes. It’s the most common anode material in lithium-ion batteries.

Lithium is correct

• Lithium is a core component of the cathode materials. Though it is also present in the electrolyte and anode, it is central to the cathode structure.

Nickel is correct

• Nickel is commonly used in cathodes, especially in high-energy batteries like NMC and NCA (Nickel Cobalt Aluminium).

Answer: (c) Only three; Difficulty Level: Hard