A High Voltage Organic Redox Flow Battery with Redox Couples O₂/Tetrabutylammonium Complex and Tris(4-bromophenyl)amine as Redox Active Species

Abstract

Redox flow batteries (RFBs) are considered a vital part of the energy storage system for storing the energy generated from the renewable energy sources such as wind and solar. Limited by the water electrolysis potential window, the aqueous RFBs exhibit low energy density (<25 Wh L −1 ). In this context a non-aqueous organic solvent based RFB system is very attractive as it offers avenue to expand the operating potential window beyond 1.23 V, which has a direct impact on the RFB's energy and power densities. In this study, new redox systems based on tris(4-bromophenyl)amine (4-Br-TPA) and oxygen saturated N,N-dimethylformamide (DMF) containing tetra-n-butylammonium hexafluorophosphate (TBAPF 6 ) are utilized as catholyte and anolyte respectively. Here, TBAPF 6 performs dual role, both as supporting electrolyte and a stabilizer of superoxide anion radical.

Gaseous Nitrogen Oxides Catholyte for Rechargeable Redox Flow Batteries

“…[27] To date, there are limited examples of gaseous electrode materials in the literature. Oxygen [35][36][37][38] and CO 2 [39,40] are two of the most well-studied cathode materials in metal-gas batteries. One of the key challenges in O 2 and CO 2 -based cells is the sluggish charging processes, where insoluble and insolating metal peroxides, superoxides, and carbonates are oxidized back to O 2 or CO 2 .…”