Development of High Energy Density Diaminocyclopropenium?Phenothiazine Hybrid Catholytes for Non?Aqueous Redox Flow Batteries

This report describes the design of diaminocyclopropenium-phenothiazine hybrid catholytes for non-aqueous redox flow batteries. The molecules are synthesized in a rapid and modular fashion by appending diaminocyclopropenium (DAC) substituent to nitrogen phenothiazine. Combining versatile C-N coupling protocol (which provides access diverse derivatives) with computation structure-property analysis enabled identification catholyte that displays stable two-electron cycling at potentials 0.64 1.00 V vs. Fc/Fc+ as well high solubility all oxidation states (?0.45 M TBAPF6/MeCN). was deployed energy density RFB, exhibiting >90 % capacity retention over 266 hours cell >0.5 electron concentration.