Study of Tetraethylammonium bis(trifluoromethylsulfonyl)imide as a Supporting Electrolyte for an All-organic Redox Flow Battery Using Benzophenone and 1,4-di-tert-butyl-2,5-dimethoxybenzene as Active Species

摘要

An ionic liquid tetraethylammonium bis(trifluoromethylsulfonyl)imide (TEATFSI) is synthesized asthe supporting electrolyte in an all-organic redox flow battery system with acetonitrile as the solvent.Benzophenone (BP) and 1,4-di-tert-butyl-2,5-dimethoxybenzene (DBB) are used as the redox activespecies. The battery exhibits a high open voltage of 2.95 V. The electrode reactions are controlled bydiffusion, which is significantly influenced by the cations of the supporting electrolytes. WithTEATFSI as the supporting electrolyte, the diffusion coefficients are 1.21-1.43×10-5 cm2 s-1 and 0.89-1.16×10-5 cm2 s-1 at anode and cathode, respectively. The coulombic, voltage and energy efficienciesof the battery are 97%, 46% and 44%, respectively. The battery shows a stable performance during 50charge-discharge cycles.