Ultrastable aqueous phenazine flow batteries with high capacity operated at elevated temperatures

Aqueous organic redox flow batteries (AORFBs) permit us to utilize renewable energy through organic redox-active materials. While long cell-cycling lifetime has been aspired in AORFBs at room temperature, the exploration of robust organic molecules with thermal stability for energy storage, especially in sunlight- rich areas with elevated temperature, is of vital importance. In the present work, we demonstrate an extremely stable AORFB with high capacity based on propionic-acid-functionalized phenazine (PFP) at both room and elevated temperatures. The full redox-flow battery based on 1,8-PFP with 2.0 M electron concentration in 1.0 M KOH against ferrocyanide presents an OCV of 1.15 V, and no capacity fade is observed when cycled at 45 degrees C for 53 days, which is among the best capacity retention reported so far. These results demonstrate great promise of PFPs for future energy-storage technology in tough conditions with high temperature and strong alkaline solutions.

Automated summary

This study demonstrates the high capacity and extreme stability of propionic-acid-functionalized phenazine (PFP) in Aqueous Organic Redox Flow Batteries (AORFBs) at both room and elevated temperatures, showing promising potential for future energy storage technology in tough conditions with high temperature and strong alkaline solutions.