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📌 The 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?

(a) Only one
(b) Only two
(c) Only three
(d) All the four

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✅ Correct Answer: (c) Only three

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🧠 Classroom Explanation (Concept → Application):

First, anchor the structure of a Lithium-ion battery:

🔋 Three core components
• Cathode (positive electrode)
• Anode (negative electrode)
• Electrolyte

Now test each element strictly for cathode use 👇

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🔹 I. Cobalt ✅

• Used in cathode chemistries like:

• LCO (Lithium Cobalt Oxide)
• NMC (Nickel–Manganese–Cobalt)
• NCA (Nickel–Cobalt–Aluminium)
  • Improves energy density, thermal stability, and battery life

👉 Correct

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🔹 II. Graphite ❌

• Graphite is the standard anode material, not cathode
• Stores lithium ions during charging

👉 Incorrect

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🔹 III. Lithium ✅

• Core constituent of cathode compounds such as:

• LiCoO₂
• LiFePO₄
• LiNiMnCoO₂
  • Also participates via the electrolyte, but chemically integral to cathode

👉 Correct

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🔹 IV. Nickel ✅

• Widely used in high-energy cathodes (NMC, NCA)
• Enhances energy density and range of EVs

👉 Correct

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📌 Final Count:
Cathode elements = Cobalt + Lithium + Nickel = 3

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🔍 Curiosity Raiser:
⚡ Tesla and other EV makers are actively reducing cobalt content due to ethical mining issues, pushing nickel-rich cathodes instead.

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📚 Enrich Notes (UPSC Value-Add):

• Cathode metals decide EV range & cost
• Graphite = anode king, not cathode
• India’s strategic minerals focus: Lithium, Nickel, Cobalt
• LFP batteries (LiFePO₄) → no cobalt, safer but lower energy density

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🪶 IAS Monk Whisper:
When UPSC asks “usually”, think dominant industrial chemistry — not exceptions.