Correct Option (C)
Three of the four listed elements-Cobalt, Lithium, and Nickel-are commonly found in the cathode compositions of lithium-ion batteries used in electric vehicles.
- Cobalt: It is a key component in several cathode chemistries, such as Lithium Cobalt Oxide (LCO), Lithium Nickel Manganese Cobalt (NMC), and Lithium Nickel Cobalt Aluminium (NCA). Cobalt enhances energy density, cycle life, and overall stability of the battery.
- Lithium: As the active ion, lithium is fundamental to the operation of these batteries. It is an integral part of cathode compounds (e.g., LiCoO₂, LiFePO₄, LiNiMnCoO₂) and facilitates the movement of charge between electrodes during charging and discharging.
- Nickel: Used in high-energy density cathodes like NMC and NCA, nickel contributes significantly to increasing the battery's energy storage capacity and extending the vehicle's driving range.
Incorrect Options
Graphite, while crucial for lithium-ion batteries, is primarily utilized as the anode material, not the cathode. Its layered structure allows for efficient intercalation and de-intercalation of lithium ions during the charge and discharge cycles. Therefore, graphite does not form part of the cathode composition. Given that only Cobalt, Lithium, and Nickel are cathode components among the listed elements, options stating "Only one," "Only two," or "All the four" are incorrect.