Herein, we report the synthesis and investigation of a novel phenazine derivative M1 with oligomeric ethylene glycol ether substituents as a promising anolyte material for non-aqueous organic redox flow batteries (RFBs). The designed material undergoes a reversible and stable reduction at −1.72 V VS. Ag/AgNO₃ and demonstrates excellent (>2.5 M) solubility in MeCN. A non-aqueous organic redox flow battery assembled using the novel phenazine derivative as an anolyte and a substituted triarylamine derivative as a catholyte exhibited high specific capacity (∼93% from the theoretical value), >95% Coulombic efficiency, 65% utilization of active materials and good charge–discharge cycling stability.

A series of arylamines bearing oligoethylene glycol ether solubilizing moieties were designed and comprehensively evaluated as promising catholyte materials for non-aqueous redox flow batteries (RFBs). The triphenylamine core maintains the chemical stability of the radical cation, the ethylene glycol chains enhance the solubility up to complete miscibility with organic solvents, and the electron-withdrawing bromine substituents increase the redox potential of the compounds up to 0.61 V vs. Ag/AgNO₃. The best material showed 99% coulombic efficiency in combination with good stability in over 50 charge–discharge cycles in laboratory RFB cells. The designed triarylamine-based catholyte materials appear promising for the development of next-generation high-voltage and high-capacity RFBs.

Evaporated pyrene-based hole transport materials deliver 17.9% efficiency in dopant free perovskite solar cells.

Aqueous organic redox flow batteries (AORFBs) are emerging energy storage technologies due to their high availability, low cost of organic compounds, and the use of eco-friendly water-based supporting electrolytes. In the present work, we demonstrate a unique phenazine-based material that shows redox reversibility in neutral, basic, and acidic conditions with the redox potentials of −0.85 V (1.0 M KOH), −0.67 V (1.0 M NaCl), −0.26 V, and 0.05 V (1.0 M H₂SO₄) vs. the Ag/AgCl reference electrode and two-electron transfer process at all pH values. High solubility of the phenazine compound in water-based electrolytes up to 1.3 M is achieved by introducing quaternary amonium-based substituents, leading to the outstanding theoretical volumetric capacity of 70 Ah L⁻¹. Laboratory redox flow batteries in neutral and acidic electrolytes presented >100 cycles of stable operation with a capacity loss of 0.25 mAh L⁻¹ and 1.29 mAh L⁻¹ per cycle, respectively. The obtained results demonstrate a material with the potential for not only fundamental understanding but also the practical application of AORFBs in the development of new-generation energy storage technologies.