1. Concept: Ultracapacitors (or supercapacitors) bridge the gap between traditional dielectric capacitors and batteries by utilizing electrochemical phenomena to achieve massive capacitances.
2. Formula: $$ C = \frac{\epsilon A}{d} $$
3. Solution: - They achieve immense capacitance by utilizing the 'Electrochemical Double Layer' effect.
- Instead of a solid dielectric, they use a porous electrolyte where charged ions gather incredibly close to the electrodes (down to nanometer distances, drastically shrinking \( d \) in the formula).
4. Why other options are incorrect: Single, Triple, and Quadruple layers are scientifically fabricated distractors. The term of art in chemistry and physics for this specific boundary phenomenon is strictly 'Double Layer'.
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