Question 56 from UPSC CSE 2025 - S&T

Question

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?

Accepted Answer

Correct Option: C. Only three

Strategy: When asked about elements in battery cathodes, focus on which are commonly associated with cathode chemistry in lithium-ion batteries. Cobalt, lithium, and nickel all feature prominently in cathode materials such as NMC (Nickel Manganese Cobalt), NCA (Nickel Cobalt Aluminum), and LCO (Lithium Cobalt Oxide). Graphite, however, is mostly found in the anode, not the cathode. Therefore, only cobalt, lithium, and nickel are typical cathode constituents; graphite is not.

Key Info: Lithium-ion batteries are rechargeable batteries widely used in electric vehicles, portable electronics, and energy storage. They consist of an anode (usually graphite), a cathode (various compounds), electrolyte, and separator.
- Cobalt (Co): Used in cathode materials such as Lithium Cobalt Oxide (LiCoO2), and mixed-metal oxides like NMC (LiNiMnCoO2) and NCA (LiNiCoAlO2). Cobalt improves energy density and battery cycle life but increases cost and raises ethical supply concerns.
- Lithium (Li): A defining component of the cathode compound, present in all major lithium-ion batteries (LCO, LFP, NMC, NCA). It acts as the charge carrier, moving between anode and cathode during operation.
- Nickel (Ni): Incorporated in modern cathodes (NMC, NCA) to enhance energy density and reduce dependence on cobalt.
- Graphite: Most commonly used as the anode (negative electrode), not typically as a cathode material. It enables lithium intercalation during charging and discharging.
Other cathode chemistries include Lithium Iron Phosphate (LFP, without cobalt/nickel) and Lithium Manganese Oxide (LMO), but graphite's primary use remains in anodes. Regulatory agencies and research bodies like the US Department of Energy and India's NITI Aayog refer to these materials in technological and supply chain contexts.

Answer

Option A: Only one

Answer

Option B: Only two

Answer

Option D: All four

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?

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?