1 research outputs found
“Wine-Dark Sea” in an Organic Flow Battery: Storing Negative Charge in 2,1,3-Benzothiadiazole Radicals Leads to Improved Cyclability
Redox-active
organic materials (ROMs) have shown great promise
for redox flow battery applications but generally encounter limited
cycling efficiency and stability at relevant redox material concentrations
in nonaqueous systems. Here we report a new heterocyclic organic anolyte
molecule, 2,1,3-benzothiadiazole, that has high solubility, a low
redox potential, and fast electrochemical kinetics. Coupling it with
a benchmark catholyte ROM, the nonaqueous organic flow battery demonstrated
significant improvement in cyclable redox material concentrations
and cell efficiencies compared to the state-of-the-art nonaqueous
systems. Especially, this system produced exceeding cyclability with
relatively stable efficiencies and capacities at high ROM concentrations
(>0.5 M), which is ascribed to the highly delocalized charge densities
in the radical anions of 2,1,3-benzothiadiazole, leading to good chemical
stability. This material development represents significant progress
toward promising next-generation energy storage