Definition of KPI for RFB membranes

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Trying to study different alternatives regarding one of the most important but conflictive components of RFB, the Ion Exchange Membrane, INO-HUB Energy team contacted Swedish Cellfion company. Cellfion develops nanocellulose derived ion exchange membranes. These membranes could represent a green candidate that could significantly decrease the cost of the whole stack. During the meeting the main requirements for IEM to be implemented in INO-HUB Energy stack were depicted by R&D team. 

  1. Stability: The cellulose-based membrane needs to be stable in the vanadium electrolyte (acid and oxidizing agent). 
  1. Current density: The membrane should operate at high current densities (>200 mA/cm2) showing acceptable energy efficiency (75 %). 
  1. Area Specific Ressitance: The resistance should be around 1 Ohm cm2
  1. Crossover: Membrane should exhibit lower or comparable permeabilities values as the current state of the art (Nafion membrane).® 

Liam Hardey briefly described their first results and the possibility of sending some samples to INO-HUB Energy facilities to be studied was proposed.  

Cellfion membranes present 84% energy efficiency and 99% Coulombic efficiency at 100 mA/cm2 showing the half of capacity decay for VRFB at lab-scale (5 cm2). The main issue could be the water transport observed during this experiment.  

So, the preliminary collaboration between both companies was started. 


This work was supported by the project: IPCEI_IE_FLOW_BESS_012021