Redox flow battery

Redox Flow Batteries

Redox Flow Battery (RFB) is an electrochemical battery where different types of active materials are dissolved in liquids that are separated by membrance and circulated through the device.

RFB has been evaluated as a good Energy Storage System (ESS) for connection with renewable energy because of independent disign and long cycle life. Especially, with independent design, energy capacity can be increased by expanding the electrolyte tanks, and power can be improved by enlarging the electrode area.

Properties

  • Long cycle life (20 years, >10,000 cycles)

  • Independent design of capacity and power

  • Safety (aqueous electrolyte)

  • Fast response time

  • High efficiency ( > 75 % possible)

  • Excellent thermal management

Components

  • Electrode – Redox reaction site

  • Electrolyte – Storing electron

  • Bipolar plate – Conducting electron

– Cell stacking

  • Membrane – Crossover prevention layer

– Ion channel pathway


Machanism

Discharging ↔ Charging

Positive side : VO2++ H2O↔VO2++2H++e-

1 V vs. SHE


  • Negative side : V3+ + e- ↔ V2+

-0.26 V vs. SHE


→ Average voltage : 1.26 V

Electrochemical Catalyst

  • Lowering the activation energy

  • Providing the active sites

  • Redistribution of electron

  • Improving the charge/mass transfer

  • Enlarging the specific area