A bipolar verdazyl radical for a symmetric all-organic redox flow-type battery

摘要: Abstract A symmetric all-organic non-aqueous redox flow-type battery was investigated employing the neutral small molecule radical 3-phenyl-1,5-di-p-tolylverdazyl, which can be reversibly oxidized and reduced in one-electron processes, as sole charge storage material. Cyclic voltammetry of verdazyl 0.5 M tetrabutylammonium hexafluorophosphate (TBAPF6) acetonitrile revealed couples at − 0.17 V and − 1.15 V vs. Ag+/Ag, leading to a theoretical cell voltage 0.98 V. From dependence peak currents on square root scan rate, diffusion coefficients order 4 × 10−6 cm2 s−1 were demonstrated. Cycling performance assessed static Tokoyuma AHA anion exchange membrane, with 0.04 M catholyte anolyte TBAPF6 at current density 0.12 mA cm−2. Although coulombic efficiencies good (94%–97%) throughout experiment, capacity faded gradually from high initial values 93% discharge 35% by 50th cycle. Voltage energy 68% 65%, respectively. Post-cycling analysis cyclic that decomposition active material cycling is cause degradation.