Vanadium redox flow batteries store energy in liquid electrolytes containing ________ ions that undergo reversible redox reactions.
- Lithium
- Sodium
- Vanadium
- Zinc
Answer: Vanadium
VRFBs use V²⁺/V³⁺ (negative) and VO²⁺/VO₂⁺ (positive) couples in separate tanks. Power (stack size) and energy (tank volume) decoupled; ideal for grid-scale storage with long cycle life. [[MNRE Reports, NCERT Chemistry Class 12]]