Modified electrolyte enhances vanadium battery performance

But now, researchers at the US Department of Energy’s Pacific Northwest National Laboratory have shown that modifying the battery’s electrolyte solution can significantly improve its performance.

They found that by adding hydrochloric acid to the sulphuric acid typically used in the batteries increased the batteries’ energy storage capacity by 70 per cent and expanded the temperature range in which they operate.

A vanadium battery generates power by pumping liquid from external tanks to the battery’s central stack, or a chamber where the liquids are mixed. The tanks contain electrolytes, which are liquids that conduct electricity. One tank has the positively charged vanadium ion V5+ floating in its electrolyte, while the other tank holds an electrolyte full of a different vanadium ion, V2+. When energy is needed, pumps move the ion-saturated electrolyte from both tanks into the stack, where a chemical reaction causes the ions to change their charge, creating electricity.

To charge the battery, electricity is sent to the vanadium battery’s stack. This causes another reaction that restores the original charge of vanadium ions. The electrolytes with their respective ions are pumped back into their tanks, where they wait until electricity is needed and the cycle is started again.