Grid Think

In my previous posts I have written a lot about the trident of problems with Iron-Chromium Redox Flow Battery, which are -  Hydrogen Evolution Reaction Slow Chromium Kinetics High operating temperature for the battery Now if you ask an AI (Gemini in my case), one of the first answers it will give would be Bismuth as master solution to all 3. It stops Hydrogen evolution and makes chromium react faster, hence solving all the problems of the battery. It does that by  acting as a catalyst. It forces the Cr3+ to accept electron quickly and react faster, and it has a more positive electrode potential (+0.32 V), as compared to chromium (-0.41 V), this stops water from splitting into hydrogen. Source But first you need to understand how Bismuth is incorporated in the battery - The Mechanisms- In order to use bismuth or any other catalyst in a flow battery, you have 2 choices - Electrodeposition-   Dissolve bismuth chloride in the liquid electrolyte and when you apply voltage...

Iron and Vanadium based electrolytes can both be used Redox flow batteries, both use tanks, pumps and cell stack, but they don't operate the same way. While Vanadium Redox Flow Batteries stay completely liquid in their operation, All Iron Hybrid Batteries don't. And the name itself tells you why-  Hybrid. When you charge an All Iron battery, its positive side converts Fe2+ to Fe3+, and stays liquid, but the negative side converts Fe2+ to Fe0, or solid iron.  So why is solid iron a problem ? Well because - 1.The electrode that we have used i.e. graphitic carbon felt, is a conductive sponge, it is designed to absorb liquid and transfer electrical energy to it, it instantly clogs when solid iron is deposited on it. 2. Solid iron is not soft, nor does it grow evenly, it grows in the shape of needles or dendrites (if you have ever seen iron filings, that's solid iron). Iron dendrites 3. Deposition of solid iron is also called electroplating, and current density in electroplating...